pre-treatment of cheese milk: principles and developments

HAL Id: hal-00895794https://hal.archives-ouvertes.fr/hal-00895794

Submitted on 1 Jan 2008

HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, estdestinée au dépôt et à la diffusion de documentsscientifiques de niveau recherche, publiés ou non,émanant des établissements d’enseignement et derecherche français ou étrangers, des laboratoirespublics ou privés.

Pre-treatment of cheese milk: principles anddevelopments

Alan L. Kelly, Thom Huppertz, Jeremiah J. Sheehan

To cite this version:Alan L. Kelly, Thom Huppertz, Jeremiah J. Sheehan. Pre-treatment of cheese milk: principles anddevelopments. Dairy Science & Technology, EDP sciences/Springer, 2008, 88 (4-5), pp.549-572. <hal-00895794>

https://hal.archives-ouvertes.fr/hal-00895794

https://hal.archives-ouvertes.fr

Dairy Sci. Technol. 88 (2008) 549–572 Available online at:c© INRA, EDP Sciences, 2008 www.dairy-journal.orgDOI: 10.1051/dst:2008017

Review

Pre-treatment of cheese milk:principles and developments

Alan L. Kelly1*, Thom Huppertz2, Jeremiah J. Sheehan3

1 Department of Food and Nutritional Sciences, University College Cork, Ireland2 NIZO Food Research, Ede, The Netherlands

3 Moorepark Food Research Centre, Fermoy, Co. Cork, Ireland

Abstract – Classically, very few pre-treatments are applied to milk for cheese-making, with somecheese varieties simply made from raw whole milk, but most made from pasteurised milk of whichthe composition (e.g., fat:protein ratio) may have been standardized. However, there has been con-sistent interest in more novel and sophisticated strategies for pre-treatment of cheese-milk. Ap-proaches explored include the use of alternative processing technologies (e.g., membrane filtration,high-pressure treatment, homogenisation, heat treatments more severe than pasteurisation) or addi-tion of sources of protein or milk solids (e.g., milk powders, whey protein products) or enzymes.The principal reasons for such pre-treatments of cheese-milk are: (1) to control the microbiologyof the raw milk and the resulting cheese better than is possible by pasteurisation (e.g., inactivationor removal of spores, control of non-starter lactic acid bacteria); (2) increasing the yield of cheese,e.g., through heat- or pressure-induced incorporation of whey proteins, or enhancing sensory prop-erties of reduced fat cheese by direct addition of microparticulated whey proteins; (3) manipulationof cheese ripening, e.g., reducing the likelihood of off-flavour development by inactivation of en-zymes or accelerating ripening through increasing enzyme-substrate interactions; or (4) improvingthe texture and other functional properties, e.g., melting. Finally, the considerations for manufactureand ripening of different cheese varieties, or sub-classes of specific varieties (e.g., low-fat cheese)will clearly differ and add to the complexity of the technological options available. This article willreview the key principles for pre-treatment of cheese-milk, as summarised briefly above.

milk / cheese / heat treatment / membrane separation / high pressure / homogenisation /standardisation

摘摘摘要要要 –干干干酪酪酪原原原料料料奶奶奶预预预处处处理理理的的的原原原理理理及及及其其其进进进展展展。。。本文综述了干酪生产原来奶预处理的原理及其进展。传统干酪生产很少使用原料乳预处理技术,许多品种的干酪直接用生鲜乳加工,即使大多数以巴氏杀菌乳生产的干酪也只是对其组成 (脂肪和蛋白质的比率)进行标准化。但是,干酪用原料乳预处理作为一种新兴的技术已经引起广泛关注,人们不断开发出来新的方法,如加工技术 (膜过滤、高压处理、均质、比巴氏杀菌有效的热处理) ;添加蛋白质、乳固形物 (如乳粉、乳清蛋白),或外源酶。对干酪用原料乳进行预处理的主要原因有 : (1)控制原料乳中的微生物,使干酪质量优于巴氏杀菌干酪 (如去除芽孢或使其失活、控制非发酵剂乳酸菌) : (2)增加干酪的产量,如通过热处理或加压促进乳清蛋白与酪蛋白的融合,或者通过直接添加微粒化的乳清蛋白来改善低脂干酪的感官性质 ; (3)控制干酪成熟,如减少由于酶失活而引起干酪产生异味的可能性,或者通过提高酶与底物相互作用程度来加速干酪的成熟 ;(4)改进质构及功能性,如融化性。由于不同种类干酪或某一种类干酪的亚类 (如低脂干酪)生产和成熟过程所要考虑的因素完全不同,也增加了所选技术的复杂性。

奶奶奶 /干干干酪酪酪 /热热热处处处理理理 /膜膜膜分分分离离离 /高高高压压压 /均均均质质质 /标标标准准准化化化

* Corresponding author (通讯作者): [email protected]

Article published by EDP Sciences

http://www.dairy-journal.org

http://dx.doi.org/10.1051/dst:2008017

http://www.edpsciences.org

550 A.L. Kelly et al.

Résumé – Pré-traitement du lait de fabrication de fromage : principes et avancées.Classiquement, très peu de pré-traitements sont appliqués au lait de fabrication de fromage :quelques variétés de fromage sont faites simplement à partir de lait entier cru, mais la plupartd’entre elles sont fabriquées à partir de lait pasteurisé dont la composition (par exemple rapportmatière grasse/protéine) a pu être standardisée. Cependant, un intérêt constant s’est manifesté pourdes stratégies nouvelles et plus sophistiquées pour le pré-traitement du lait de fromagerie. Les ap-proches explorées incluent l’utilisation de technologies de traitement alternatives (par exemple fil-tration membranaire, haute pression, homogénéisation, traitements thermiques plus sévères que lapasteurisation) ou addition de sources de protéines ou de matière sèche de lait (par exemple poudresde lait, protéines de lactosérum) ou d’enzymes. Les principales raisons de tels pré-traitements dulait de fabrication fromagère sont : (1) de contrôler la microbiologie du lait cru et du fromage résul-tant, mieux que ce qui est possible par pasteurisation (par exemple inactivation ou retrait des spores,contrôle des bactéries lactiques non levain) ; (2) d’accroître le rendement en fromage, par exempleen induisant l’incorporation de protéines de lactosérum par traitement thermique ou haute pression,ou d’améliorer les propriétés sensorielles du fromage allégé en matière grasse par l’addition directede protéines de lactosérum microparticulées ; (3) d’orienter l’affinage du fromage, par exemple enréduisant la probabilité de développement de défauts de flaveur par inactivation d’enzymes ou enaccélérant l’affinage en accroissant les interactions enzyme-substrat ; ou (4) d’améliorer la texture etles autres propriétés fonctionnelles, par exemple la fonte. Finallement, les facteurs à considérer pourla fabrication et l’affinage des différentes variétés de fromage, ou classes de variétés spécifiques (parexemple fromages allégés) vont différer clairement et augmenter la complexité des options techno-logiques disponibles. Cet article passe en revue les principes clés pour le pré-traitement du lait defabrication de fromage tels que résumés brièvement précédemment.

lait / fromage / traitement thermique / séparation par membrane / haute pression / homogé-néisation / standardisation

1. INTRODUCTION

For centuries, milk for cheese-makingwas subjected to no pre-treatment be-fore curdling, and many cheese varietiesworldwide are still made from raw milk,particularly, but not exclusively, artisanalcheeses. However, predominantly for rea-sons of safety, but also consistency of qual-ity, and manipulation of product character-istics, most cheese-making today involvesthe treatment of milk by one or more pro-cessing steps prior to addition of coagulantand starter culture.

Perhaps the simplest and earliest tech-nological intervention, driven by safetyconcerns, was the pasteurisation of milk,first carried out in vats or kettles at temper-atures around 63–65 ◦C (low-temperature,long-time, LTLT, pasteurisation) and morerecently in continuous-flow plate heat ex-changers at 72–74 ◦C for 15–30 s (high-temperature, short-time, HTST, pasteuri-sation). For a high proportion of cheesevarieties, pasteurisation is the sole treat-ment applied to the cheese-milk. Pasteuri-

sation also inactivates some enzymes, re-verses shifts in the mineral balance of milkinduced by cold storage, and influences themicroflora of non-starter lactic acid bac-teria (NSLAB) in the final cheese. It isprimarily for the latter reason that manycheese-makers prefer to continue to useraw milk, as the contribution of NSLABbacteria to cheese flavour is felt to be unac-ceptably impaired by pasteurisation. Therehas also been interest for some time inthe application of heat treatments moresevere than pasteurisation, which will re-sult in significant denaturation of wheyproteins and their resulting incorporationinto cheese curd, with significant effects oncheese yield and composition.

In several varieties, or industrial pro-duction settings, the consistency of com-position of cheese may also be controlledby standardisation of the incoming milk,generally in terms of manipulation of theratio of fat to total protein or casein,by centrifugal separation and proportionalmixing of cream whole milk and/or skim

Pre-treatment of cheese milk 551

milk, by membrane filtration, or by addi-tion of sources of milk protein.

In addition, in recent years, there havebeen studies of application of a number ofnew approaches to processing of cheese-milk, including the application of tech-nologies new either to cheese productionor to food processing in general, to achievecertain product or process benefits; theseinclude use of homogenisation, treatmentat high pressures, and addition of exoge-nous enzymes other than those requiredstrictly for coagulation of the milk.

This review will provide an overview ofthe broad approaches to pre-treatment ofcheese-milk mentioned briefly above (seesummary in Tab. I). A particular focus willbe given to recent studies of the applica-tions of novel and innovative processingstrategies.

2. PRINCIPLES OF CHEESE-MAKING

The fundamental physico-chemicalprinciple under-pinning the conversion ofmilk to a cheese curd is the destabilisationof the casein micelles to such an extent thata gel is formed which, when cut, syneresesin a manner which can be accelerated bymechanical stirring and/or mild heating(for general reviews on cheese manu-facture and ripening, see [38–41]). Thisyields curd particles which can readily berecovered from the bulk aqueous serumphase of the milk, i.e., whey. In parallel,cultures of lactic acid bacteria addedalmost concurrently with the coagulantbegin to grow and metabolise lactose tolactic acid, lowering the pH of the curdand ultimately playing a key role in thedevelopment of cheese flavour, throughthe release upon death and lysis of a rangeof catabolic enzymes which hydrolyseor otherwise convert milk constituentsentrapped in the curd to a range of flavourand aroma compounds. Within a short time

of the addition of coagulant and culture,the curd and whey are separated and thecurd is pressed to enable fusion into asolid visco-elastic mass; this is then storedunder conditions which allow the requisitebiochemical reactions to be catalysed bythe cheese micro-flora, which principallyconsists of the starter bacteria mentioned,but may also include other (non-starter)lactic acid bacteria and, in some varieties,yeasts and moulds deliberately added.During the storage, or ripening, period,enzymes within the coagulant and alsoarising from the milk itself break downthe coagulated casein matrix, resulting inchanges in cheese texture.

The broad principles outlined sum-marise the principle of manufacture ofwhat are called rennet-coagulated cheeses,which represent the vast majority of bothcheese varieties and actual tonnage ofcheese produced globally and are the onlycheese varieties dealt with in this review.The huge diversity of cheese varieties,from Pamesan (dry, crumbly and pungent)to Camembert (soft and mould-encrusted)results from surprisingly minor alterationsin these core principles, such as the startof culture (bacterial and mould, if used),the extent to which whey is removed bystirring, cooking or pressing (greater wheyremoval leads to lower-moisture, harder,cheese) and the conditions during ripening(particularly temperature and relative hu-midity).

To consider the impact of milk process-ing technologies on cheese, it is importantto consider what the milk contributes tocheese, as it is clear that much of cheese-making relies on external agents added tothe milk (coagulant and cultures) and op-erations applied to the resulting curd. Thekey constituents, properties and popula-tions of milk which are of interest to thecheese-maker are summarised in Table I.

Clearly, there are numerous potentialadvantages to applying more ambitioustechnological strategies for processing


Table I. Milk constituents, properties and populations of interest for cheese-making.

Parameter Significance for cheese-making Reasons and strategies for manipulation

Casein Forms rennet gel, synereses to yieldcheese curd

Increase level (addition of milk proteinsource) either of total protein, or relativeto fat content (standardisation), or changeproperties (enzyme addition)

Fat Contributes to cheese texture and yield Increase or decrease fat content relative tototal composition or protein level (stan-dardisation); incorporate more directly intocheese curd through interactions with pro-tein (homogenisation); accelerate release ofvolatile flavour compounds (enzyme addi-tion)

Wheyprotein

Normally largely lost in whey Incorporate into curd to increase yield (heattreatment, high-pressure treatment)

Water Major constituent of cheese; level may becharacteristic of particular varieties

Increase level to increase yield (heat treat-ment, high-pressure treatment) but mayimpair quality

Bacteria Raw milk microflora either intact (raw milk)or pathogens and many spoilage and non-starter bacteria eliminated, but not spore-forming species (pasteurised milk)

Increase efficiency of removal of spore-forming bacteria for some species (mem-brane filtration)

cheese-milk, in terms of manipulatingyield, composition, microbiological qual-ity, and even biochemistry of ripening.However, in many cases actual implemen-tation of new strategies has met with signif-icant hurdles or barriers to implementation,and this review will consider these chal-lenges alongside the possible advantagesof each approach discussed.

3. HEAT TREATMENTS OTHERTHAN PASTEURISATION

As outlined above, milk for cheese man-ufacture is heated to eliminate pathogenicbacteria, to minimise damage to caseinsby proteolytic bacteria on storage or to in-corporate heat-denatured whey proteins incurd, thereby improving cheese yield [7].Furthermore, more severe heat treatment ofmilk may be applied to inactivate sporesfrom Clostridium tyrobutyricum by 4 log

cycles and thus minimise the late blowinggas defect during cheese ripening [124].

Heat treatment of milk at conditionsmore severe than those used for conven-tional pasteurisation results in denatura-tion of whey proteins, interactions be-tween whey proteins and casein micelles,and transfer of soluble calcium, magne-sium and phosphate to the insoluble col-loidal state. Casein micelles are very sta-ble at high temperatures, although changesin zeta potential, size, hydration of mi-celles and some association-dissociationreactions do occur under severe heat treat-ments [37,126–129]. Denaturation of wheyproteins exposes side chain groups orig-inally buried in the native structure, par-ticularly reactive thiol groups, and theunfolded proteins may self-aggregate orinteract with casein micelles, throughinteractions with κ-casein. Ionic strength,pH and the concentrations of calcium and


protein influence the extent of denaturationof the whey proteins [24,100,129]. The ex-tent of association of denatured whey pro-tein with casein micelles is dependent onthe pH of the milk prior to heating, lev-els of soluble calcium and phosphate, milksolids concentration and mode of heating(direct or indirect).

For cheese-makers, the principal inter-est has been in increasing yield by exploit-ing this heat-induced association of caseinswith whey proteins, while attempting tominimise undesirable changes in cheesequality. The effects of heat treatment attemperatures between 72 and 140 ◦C forholding times between 15 s and 5 minon whey protein denaturation prior to in-corporation into cheese were reported byLaw et al. [80]. Heat treatment of milk at∼ 110 ◦C for 60 s increased protein recov-ery in curd by 10% [6]. Where facilities toheat to temperatures> 100 ◦C are not avail-able, increasing milk pH prior to heatingincreases levels of whey protein denatura-tion [9].

In the cheese vat, high heat treatmentof milk prolongs rennet coagulation timesand reduces the strength of rennet gels [5,26], leading to impaired syneresis [10, 92,115]. The adverse effects on coagulationare attributed to the inhibition of hydrol-ysis of κ-casein by chymosin due to theβ-lactoglobulin/κ-casein complex at themicelle surface impairing the accessibilityof κ-casein to the coagulant [55, 59, 139],to reduced reactivity of renneted micelleswith attached denatured whey proteins toaggregation, or to a reduction in the con-centration of micellar calcium [139, 142].Reduced shrinkage of the para-casein-whey protein network promotes increasedwater-binding [145], leading to poor coag-ulation and syneresis properties, increasedset-to-cut times, soggy curds with poormatting ability, ragged curd chips andpoor curd fusion during cheese manu-facture [48, 92]. Gel-forming propertiesof high-heat-treated milks may be partly

restored by ultrafiltration of milk to higherprotein levels prior to cheese manufacture,reducing pH and increasing milk temper-ature during coagulation, increasing thelevel of added rennet and/or by the ad-dition of CaCl2 to the cheese-milk [54,55] or by pH cycling [129]. Acidificationof heated milks reduces charge repulsionand increases solubilisation of colloidalcalcium [22]. Acidification to pH 5.8 orpH 6.2 prior to renneting of strongly heatedmilks increases cheese yield [5, 8, 10]and pH cycling (acidification to pH 5.5,overnight storage at 4 ◦C and adjustment topH 6.2) prior to renneting has been shownto increase moisture and protein contentsin Cheddar cheese [70] although that studydid not report on cheese texture and sen-sory properties.

High heat treatment increases cheeseyield and retention of whey protein andmoisture in cheese and reduces the levelof calcium and phosphorus due to re-duced dry matter and increased whey pro-tein content [7–9, 129]. Flavour intensityis reduced in cheeses made from stronglyheated milk [5, 8, 48] but bitterness waslargely eliminated by a reduction in rennetquantities used [6].

Guinee et al. [48] attributed decreasedcheese firmness with increased heatingseverity of milk to increased cheese mois-ture and decreased protein content. Adjust-ment of pH to 6.2 prior to renneting re-sulted in Cheddar cheese with a texturecomparable to control cheese [5, 8] andBanks et al. [9] reported that manipulationof pH prior to heating had a significant ef-fect on melt characteristics of a Cheddar-type cheese.

Calvo et al. [23] reported greater break-down of β-casein during ripening ofCheddar-type cheese manufactured frommilk heated to 110 ◦C for 30 s thanin cheese made from pasteurised milk,but Benfeldt et al. [12] attributed re-duced hydrolysis of β- and αs2-caseins inDanbo cheese made from milks heated


to 90 ◦C for 60 s to thermal inactiva-tion of the plasminogen activation sys-tem and heat-induced interactions betweenthe plasminogen activation system andβ-lactoglobulin. Guinee et al. [55] reportedhigher levels of primary proteolysis and re-duced levels of smaller peptides and aminoacids in cases of increased levels of wheyprotein denaturation in cheeses manufac-tured from UF retentate produced fromstrongly heated milk.

From studies of other varieties, severeheat treatment of milk resulted in a moreopen microstructure in Quarg [76], whileCamembert-type cheese produced fromseverely heated milk had a higher yield andflavour, body and texture attributes similarto that of control cheeses made from pas-teurised milk [43].

4. CARBON DIOXIDETREATMENT OFCHEESE-MILK

There has been interest for some time inthe use of carbon dioxide (CO2) as a treat-ment for milk for preservation and tech-nological reasons, due to its solubility inmilk and inhibitory effect against a broadspectrum of micro-organisms [61]. It hasbeen shown that addition of CO2 to rawmilk decreased proteolysis, due to effectson both microbial growth and concomitantprotease production and inhibited plasminactivity due to pH reduction; lipolysis wasalso retarded, probably due to reduced mi-crobial growth [90].

A small number of studies have con-sidered the possible use of such treat-ment prior to cheese-making. Nelsonet al. [103] injected CO2 into milk toa level of 1600 ppm after pasteurisation,which reduced pH to around 5.9, and madeCheddar cheese using normal levels of co-agulant and starter addition. Milk treatedwith CO2 had lower whey pH at drainage,shorter total make time, and altered yield

due to increased losses of calcium and fat,and increased salt retention. When cheesemade using CO2 addition was ripened,cheese retained CO2 and treated cheeseshowed accelerated proteolysis, perhapsdue to changes in substrate availabilityof increased retention or activity of chy-mosin [104].

5. HIGH-PRESSURETREATMENT OFCHEESE-MILK

High-pressure (HP) treatment of foodhas progressed in a relatively short spaceof time from a research subject of aca-demic curiosity limited by perceived hugeexpense of use at industrial scale to a com-mercially realistic processing option, al-beit for specific niche applications suchas oysters, meat, guacamole and fruitproducts, including juices and smooth-ies. While these applications have grownrapidly within the last ten years, applica-tions for dairy products have been notablyabsent; however, within the last year appli-cations for treatment of processed cheesespreads (Spain) and functional and fer-mented dairy products (New Zealand) havebeen launched. The relative slowness oftransfer of research in dairy products tomarket applications does not reflect a lackof potential interest; in contrast, whereas,for many of the products listed above, HPtreatment results in microbial or enzymaticinactivation without loss of nutrients orflavour attributes (the principal advantageof using HP for these products), the effectsof pressure on milk are far more complex,and often unique.

HP treatment principally exerts effectson macromolecules with complex struc-tures, changing their structure and proper-ties; as milk proteins are an enormouslycomplex protein system, it is perhapsnot surprising that dramatic changes oc-cur under pressure, with repercussions


for a whole range of milk and dairyproduct properties. The principal heat-induced change in milk proteins, denat-uration of whey proteins, as discussedearlier, also occurs under pressure, withβ-lactoglobulin being more susceptible todenaturation, at pressures above 100 MPa(the typical units of pressure, where 1 MPais 10 times atmospheric pressure), thanα-lactalbumin, which is significantly dena-tured only at or above 400 MPa [65].

However, arguably the most interestingeffects of pressure concern the casein mi-celles, which change little at normal milkprocessing temperatures, except for the in-teractions with whey proteins mentioned.Depending on the pressure applied, dura-tion and temperature of treatment and pHof milk, HP treatment of milk can resultin aggregation of casein micelles (around250 MPa) or significant dissociation (atpressures above 400 MPa). These phenom-ena have been shown to be due to the extentto which reassociation occurs after varyingextents of pressure-induced disruption ofthe cohesive forces maintaining the struc-tural integrity of casein micelles, e.g., theextent of solubilisation of colloidal cal-cium phosphate (CCP) [65].

Such fundamental changes in the char-acteristics of the basic building blocks ofmilk gels have predictably profound effectson the cheese-making properties of milk.Rennet coagulation time, for example, maybe reduced by treatment at 100–300 MPa,but increased following more severe treat-ments [113, 150]. Huppertz et al. [67]showed that HP treatment increased wetcurd yield, by up to 25% after treatmentat 600–800 MPa, due to both incorporationof denatured whey protein and increasedmoisture retention. The combined effectsof heat and pressure on rennet coagulationhave also been reported [87], and it hasbeen shown that HP treatment can modu-late the negative effects of excessive heattreatment on cheese-making properties ofmilk [68].

There have been contradictory reportson the effect of HP treatment on acidifi-cation of milk by lactic acid bacteria, withPandey et al. [113] reporting a reduced rateof pH change in HP-treated milk relativeto raw or pasteurised milk, but Huppertzet al. [66] reporting the reverse, which theysuggested may be due to increased avail-ability of substrates for bacterial growthdue to pressure-induced dissociation of ca-sein micelles.

While a number of authors have thusdescribed the changes in rennet coagu-lation properties following HP treatment,there have been relatively few studies inwhich actual cheese is produced from HP-treated milk [110, 123, 136]. Of these, anumber also concentrate mainly on cheesecomposition, yield and textural properties.One of the earliest studies on Cheddarcheese reported that, while HP treatmentincreased the yield of Cheddar cheese, tex-tural defects resulted from increased in-corporation of moisture into cheese [31].San Martín-González et al. [122] pro-duced Cheddar cheese from milk treatedat 483 or 676 MPa at a range of tempera-tures and found pressure- and temperature-dependent increases in cheese yield andmoisture content, and increased cheesehardness.

A number of studies of the biochemi-cal properties of cheese made from raw,pasteurised or HP-treated goats’ milk haveindicated that the latter had higher levelsof incorporated β-lactoglobulin (β-lg), andaltered rates of proteolysis of caseins andprofiles of free amino acids during ripen-ing [20, 137] and altered profiles of or-ganic acids [19], while levels of lipolysisin cheese made from HP-treated milk werecloser to those in raw milk cheese than inthat made from pasteurised milk [17]. Thesame authors have reported on the texturaland microstructural properties of the threetypes of cheese [21], and have reported thatthe microbiological quality of cheese madefrom HP-treated milk was similar to that


of that made from pasteurised milk [18].There have also been reports that HP treat-ment of milk can improve the acceptabilityof reduced-fat cheese [101].

A recent paper has indicated that treat-ment of raw milk at 500 MPa for 10 minreduced an innoculum of Listeria mono-cytogenes to undetectable levels in bothmilk and cheese, without significant effectson cheese composition [86]. Another po-tentially interesting application of HP incheese involves inactivation of bacterio-phage in milk or whey [102].

In terms of potential industrial ap-plication, HP treatment involves packag-ing product into sealed flexible containers(e.g., bags) and immersing them in apressure-transmitting medium (typicallyan emulsion or alcohol:oil mixture) in achamber within which the pressure canbe raised to the requisite level and main-tained for the desired time, with controlledrates of compression and decompression;the manipulation of pressure is typically at-tained by use of a piston or high-pressurepumps. This is clearly a batch systemand currently available commercial sys-tems treat up to around 300 kg of productper cycle; the limitations of scale for largecheese factories are thus a possible barrierto implementation. Some semi-continuousplants have been developed where liquidssuch as milk could be pressure-treated di-rectly by a piston within a chamber calledan isolator; connection of several suchchambers in sequence but operating outof phase allows semi-continuous opera-tion, but such systems do not seem tohave been adopted by the food industry.This, and the very substantial capital in-vestment for HP treatment systems, makesit critical that very attractive advantages forthe cheese-maker will need to be provenbefore commercial adoption is likely (seePatel et al. [114] for a discussion of the hur-dles involved in commercialisation of HPin the dairy industry).

6. HOMOGENIZATION OFCHEESE-MILK

Since its presentation by AugusteGaulin at the Paris World Fair in 1899,the homogenizer has become a standardtool in the dairy industry. The primaryaim of homogenization of milk is to re-duce the size of the fat globules, therebydelaying their creaming rate [69]. In rawmilk, fat globule size commonly rangesfrom ∼ 0.2–15 μm, and homogenizationgenerally aims to reduce the maximum to< 2 μm. For this purpose, two-stage valvehomogenizers are commonly used, whichoperate at pressure of ∼ 20 MPa. More re-cently, novel homogenization devices, e.g.,high-pressure homogenizers and microflu-idisers, which can operate at pressures ofseveral hundred MPa and achieve greaterreductions in fat globule size, have beendeveloped [69]. In cheese-making, homog-enization of cheese-milk can be of inter-est for the purpose of preventing creamingof fat globules, reducing fat losses in thewhey or controlling development of free fatin the cheese [71, 112, 119].

Due to the reduction in fat globulesize on homogenization, the total surfacearea of the fat globules increases and theamount of original fat globule membranematerial is by far insufficient to fully coverthe newly-formed surface [69]. As a re-sult, other surface-active components ofmilk, primarily caseins and, to a lesserextent, whey proteins, become adsorbedonto the surface of the newly formed glob-ules [69, 146]. Thus fat globules in ho-mogenized milk almost resemble casein-covered emulsion droplets. The adsorptionof caseins onto the fat globules has thefollowing implications for cheese-makingcharacteristics of milk:(1) casein surface area in milk is increased,

but the amount of micellar casein is re-duced;

(2) two types of particles with a casein mi-celle surface layer exist: native casein


micelles and casein-covered fat glob-ules;

(3) when adsorbed, casein micelles tendto spread over the surface of the fatglobule and hence increase in effectivesurface area but with reduced surface-density of κ-casein.

The rennet coagulation time (RCT) ofunhomogenised milk is generally lowerthan that of homogenized milk [57, 62,135, 149]. This is probably related tothe larger casein surface area in ho-mogenized milk, as well as the lowersurface density of κ-casein. The for-mer increases the probability of interac-tions between particles, whereas the lat-ter, for a subclass of particles, reducesthe amount of κ-casein that needs to behydrolyzed before micellar flocculationis induced. Conflicting reports exist onthe influence of homogenization on therate of rennet-induced gel formation; bothhomogenization-induced increases [57, 62,149] and decreases [135] therein have beenreported. Zamora et al. [149] reported that,on high-pressure homogenization (100–330 MPa), the rate of gel formation maybe either increased or decreased, with noclear trend as a function of homogenizationpressure, but large differences in the pH ofsamples hinder a clear and unequivocal in-terpretation of these data.

Negative aspects of homogenizationoccur in the subsequent stages of cheese-making, i.e., the syneresis of the para-casein matrix and the fusion of the para-casein micelles into a strong and cohesivenetwork. Cheese curd from homogenizedmilk shows poor syneresis [32,46,62] and,as a result, has high moisture content.Furthermore, cheese curd prepared fromhomogenized milk is also often character-ized by a coarse and brittle structure [46,135, 149].

The reason for the impaired syneresisof curd prepared from homogenized milkcan be traced back to the role of fat glob-ules in the para-casein matrix. In curd

from unhomogenised milk, milk fat glob-ules are, on average, of the volume ofseveral thousand para-casein micelles andare distributed throughout the matrix in-dividually or in clusters with areas of upto tens of micrometers [50]. Native fatglobules do not interact with the para-casein micelles in the curd matrix and donot participate in syneresis. Hence, theyact as plasticizers, with their spatial dis-tribution determining the length scale overwhich syneresis in the para-casein matrixoccurs, and prevent the excessive synere-sis of the para-casein matrix that is, forinstance, observed in cheese curd madefrom skim milk [50, 116]. In homoge-nized milk, the much smaller fat globulesare distributed at a considerably smallerlength scale, thereby reducing the scaleover which syneresis can occur. Further-more, unlike their unhomogenized coun-terparts, homogenized milk fat globules dointeract with the para-casein matrix, thusreducing the overall effectiveness of thesyneresis process because less of the para-casein micelle surface is available for in-teraction with other micelles [46, 50]. Thealready reduced amount of micellar ca-sein present in homogenized (see above) islikely to contribute to this phenomenon.

Cheese made from homogenized milkis generally characterized by an increasedmoisture content [47,71,72,84,143], whichcan lead to deviations in ripening profiles.In addition, if cheese from homogenizedmilk is not heat-treated sufficiently, exces-sive lipolysis may occur, due to the fact thatthe membrane of homogenized fat globulesis more permeable for lipase than the nativemilk fat globule membrane [72, 146].

7. MEMBRANE SEPARATION OFCHEESE-MILK

Membrane separation processes arecommonly applied to separate a liq-uid under a pressure gradient through asemi-permeable membrane into two liquid


streams of different composition, the per-meate (which flows through the mem-brane) and the retentate (which concen-trates those substances which do not passthrough the membrane in a reduced vol-ume of fluid). These processes are appliedin dairy processing for an ever-increasingrange of applications, e.g., concentration,demineralization, protein separation, or re-moval of bacteria. Four types of membranefiltration can be distinguished [77, 93, 94]:

(1) ultrafiltration (UF), which selec-tively separates macromoleculeshaving a molecular mass of 1000–200 000 g·mol−1;

(2) microfiltration (MF), which selec-tively separates particles and macro-molecules with a molecular massgreater than 200 000 g·mol−1;

(3) nanofiltration (NF), which selec-tively separates molecules witha molecular weight ranging from200–1000 g·mol−1;

(4) reverse osmosis (RO), which separatessolutes with a molecular mass smallerthan 150 g·mol−1.

Of these technologies, UF, and, to alesser extent, MF can be used as a pre-treatment for cheese-milk. For an extensiveand detailed overview of membrane pro-cessing in cheese technology, the reader isreferred to the reviews of [96–98].

7.1. Ultrafiltration

Essentially, UF enables concentrationof casein content and recovery of wheyproteins for cheese manufacture [51, 53].UF of milk at pH 6.6–6.8 concentratesmineral salts bound to casein micelles inthe same proportion as proteins and in-creases buffering capacity, which affectsacidification, pH, rennet coagulation andrheological characteristics of curd [98].Acidification before or during UF [53]and/or salt addition to retentate leads to

solubilisation of colloidal calcium in thepermeate.

In cheese-making, three types of UF re-tentate can be distinguished:

(1) Low-concentration UF retentate:Milk is concentrated a maximum of2-fold prior to cheese-making, mainlyfor standardization of protein level.Advantages of this application areincreased manufacturing efficiency,reduced rennet requirements andincreased cheese yield.

(2) Medium-concentration UF retentate:Milk is concentrated a minimum of2-fold and a maximum of 5-fold. Thisapplication is presently of little com-mercial interest.

(3) Liquid pre-cheese: Milk is concen-trated to a composition similar to thatof the cheese variety to be made, fol-lowed by addition of starter culture andsubsequent setting with rennet. Pro-cesses based on this technology havebeen developed successfully for themanufacture of some softer cheese va-rieties, e.g., Camembert, Feta and bluecheese.

During UF, milk runs pressure tangen-tially across a membrane with a molec-ular weight cut-off (MWCO) of 1000–200 000 g·mol−1; for cheese-milk, MWCOis generally < 20 000 g·mol−1. Compoundswith a molecular mass greater than theMWCO of the membrane, e.g., globularfat, caseins, whey proteins and micellarsalts, are selectively concentrated in theUF retentate, whereas those with a molec-ular smaller than the MWCO, e.g., lac-tose, serum salts and peptides, are foundlargely in the UF permeate at their origi-nal concentration. This has two major im-plications for cheese-making properties ofmilk:

(1) The inter-micellar mean free dis-tance is reduced considerably, from∼ 200 nm in unconcentrated skim


milk [146] to < 10 nm in skim milkconcentrated to a casein content of∼ 20% [75]. The reduced inter-micellarmean free distance forces the micellesto interact more frequently with eachother as a result of collisions inducedby Brownian motion [27, 144].

(2) The buffering capacity of the milk is in-creased considerably [96, 98]. This in-crease in buffering capacity is primar-ily due to the increased concentrationsof proteins and micellar minerals in theUF retentate, both of which are keycontributors to the buffering capacity ofmilk, particularly in the pH region 5.5–7.0 [121].

As a result of these changes, the cheese-making properties of UF retentates differfrom those of unconcentrated milk in sev-eral aspects. Rennet coagulation time isnot affected by concentration if the sameamount of rennet is added to unconcen-trated or UF concentrate [42, 93, 98], in-dicating that the proportion of κ-caseinhydrolyzed at the point of flocculation islower in UF retentate than in unconcen-trated milk, as is indeed observed exper-imentally [25, 75, 140]. Following 4-foldconcentration, hydrolysis of ∼ 50% ofκ-casein is required to induce gel forma-tion [25] whereas, at ∼ 7 fold concentra-tion, hydrolysis of only 20% of κ-casein isrequired [75]. The rate of gel firming canalso be enhanced by concentration [97,98],although recent studies by Karlsson et al.[75] showed that, following ∼ 7-fold con-centration (casein content ∼ 20%, w/w),the rate of gel formation of the UF retentatewas lower than that of the unconcentratedmilk. The reduced coagulation and floccu-lation rate was related to a high zero-shearviscosity of milk reducing the rate [75].

This emphasises the fact that the rateof gel formation is strongly influencedby both casein concentration and the de-gree of hydrolysis of the κ-casein and thatoptimization is required to maximize the

rate of gelation of UF retentates. Whencheese-milk was partially supplementedwith UF retentate, RCT decreased [113]and increasing protein level resulted in re-duced gelation time and increased firmingrates [53].

Microstructural analysis by confocallaser scanning microscopy of rennet-induced gels of ∼ 7-fold concentratedUF retentate revealed that larger rennet-induced casein aggregates are formed inunconcentrated milk than in UF reten-tate [75]. The degree of macroscopicsyneresis, i.e., separation of whey from thegel on a macroscopic level, is consider-ably less for curd prepared from UF re-tentate than for curd prepared from uncon-centrated milk [75, 117]. Microsyneresis,i.e., re-arrangement of the protein networkon a microstructural level, was observedin renneted unconcentrated milk as well as7-fold concentrated UF retentate, but oc-curred at a considerably later time-point inthe latter [75]. This delay in microsyneresisin a rennet gel from UF retentate is proba-bly due to the fact that micelles therein arestill partially covered by κ-casein at the on-set of gelation and thus have a low affin-ity for binding and subsequent rearrange-ment and fusion [28, 141]. Further studieson the microstructure of rennet gels pre-pared from retentate concentrated 2–5 foldby UF are recommended to further our un-derstanding of this area.

Although dependant on concentrationfactor, adjustment of manufacture proto-cols, etc., increasing milk protein levelsin Cheddar cheese manufacture by use oflow-concentration UF results in increasedmoisture-adjusted yield and actual cheeseyield, increased cheese protein, salt-in-moisture, calcium and phosphorous con-tents and decreased moisture levels [51,79]. An optimum degree of concentrationfor making hard cheese varieties of ∼ 1.7:1has been recommended [35, 36, 79].

Cheese made from UF retentate is of-ten characterized by a long time required


to reach the desired pH and an acidictaste [96–98] which is related to the higherbuffering capacity of a UF retentate. Fur-thermore, flavour development in hard andsemi-hard cheese made from UF retentateis generally slow, which has been related toa reduced rate of proteolysis of caseins dur-ing ripening of such cheese [11, 98], prob-ably resulting from retention of inhibitorsof chymosin and plasmin in the UF reten-tate [11].

UF of milk to 4–4.5% protein reducedmoisture-in-nonfat-substance (MNFS) lev-els in cheese made from late-lactation milkto levels similar to those for mid-lactationmilk with no significant difference in pro-teolysis or flavour and with enhanced tex-ture [16]. Increased starter inoculum andreduced cook and Cheddaring tempera-tures resulted in similar composition andmoisture-adjusted yields to control cheeseswith improved texture and increased pro-teolysis in Cheddar cheese manufacturedfrom UF milk [125].

Homogenisation of cream in milks sup-plemented with UF skim milk to 5.93%protein resulted in Cheddar cheeses of im-proved functionality and texture, yields,solids and fat recovery [112]. Proteinlosses in whey were reported to be similarto those for control cheeses [51] or lowerfrom retentate cheese when expressed askg component lost per kilogram cheese ob-tained [79].

7.2. Microfiltration

While applications of MF in cheese-making are by no means as widely stud-ied as those for UF, there have been somerecent developments that are worth noting.First of all, MF may be used for partialmicrobial decontamination of cheese-milk,as outlined in Figure 1. The “Bactocatch”process [97, 98] involves microfiltration ofthe skim milk using 1.4 μm pore sizeat 37 or 50 ◦C to concentrate the mi-

crobes in milk in the UF retentate, which,together with the cream, is subjected toa heat treatment, e.g., a UHT treatmentat 115–120 ◦C. The retentate containingbacteria and somatic cells (accounting for∼ 5% of the skim milk stream or ∼ 0.5%if a second MF process is incorporated)may be added to the cream prior to heattreatment; however, thermostable enzymespresent may have deleterious effects onsubsequent cheese quality [94].

Average decimal reduction of bacteriais > 3.5 (10 to 50 cfu·mL−1 milk) and is> 4.5 for sporeforming bacteria, due tobinding of bacterial spores to part of thecell wall resulting in larger apparent cellsize [94]. Decimal reduction of pathogenicbacteria is 3.5–4.0 and somatic cells aretotally removed [94]. However, milk pro-duced using this process has been de-scribed by cheese-makers as ‘too clean’and cheese prepared therefrom may lackflavour development as a result. MF resultsin reduced cheese NSLAB counts, withreduced intensity of cheese flavour andaroma, secondary proteolysis and levelsof short-chain volatile acids in Swiss-typecheeses [13] and lower populations of het-erofermentative lactobacilli, propionic acidbacteria and enterococci than from rawmilk or from pasteurised milk with addedMF retentate. However, Roy et al. [120]reported similar counts of Lactobacilluscasei and lactococci in both MF and ther-mised milks but with a lower mesophillicspore count in the latter. Beuvier et al. [13]reported that MF treatment of milk resultedin lower levels of hydrolysis of β-casein incheeses than from pasteurised milk; how-ever, Roy et al. [120] proposed that heatingof cream or skim milk during MF treat-ment increased hydrolysis of β-casein inCheddar cheese, possibly due to activa-tion of the plasminogen-plasmin activationsystem. Further optimization is required toachieve desirable ripening characteristicsof such cheeses.


Raw whole milk

Separation

Cream Skim milk

Microfiltration

MF retentate MF permeate

Heat

Blending

Cheese milk

Figure 1. Process for decontamination of milk by microfiltration (adapted from [98]).

A second application of MF in cheese-making is in standardization of the caseincontent of milk, rather than the total pro-tein content that is standardized by UF.MF uses larger pore sizes and lower pres-sures than UF. Whey proteins are smallermolecules (3 to 5 μm) compared to caseinmicelles (15 to 600 nm) and can be sep-arated by use of 0.1 to 0.2 μm pore sizemembranes [14]. This separation producescasein enriched retentate and permeatescontaining significant amounts of nativestate α-lactalbumin and β-lactoglobulin.MF also concentrates calcium phosphatein the micellar form [105]. Brandsma andRizvi [14] showed in-process pH adjust-ment and microfiltration of acidified skimmilk with 0.2 μm membrane to producehighly concentrated retentate with reduced

Ca and whey protein content suitable foruse in cheese manufacture.

Casein-enriched milk prepared by MFhas been reported to have improved ren-net coagulation properties [95, 133] andreduced loss of fat and fines in thewhey [98]. Increasing MF concentrationfactor resulted in Mozzarella and Ched-dar cheeses with increased moisture, pro-tein and calcium contents, total solids re-covery, actual and composition-adjustedcheese yields, proteolysis and flavour anddecreased hardness. Increasing chymosinlevel and adjusting MNFS levels for milkconcentrated 1.8 X resulted in Cheddarcheese similar to control cheese [14, 15,105, 106]. Furthermore, the MF perme-ate that is produced is an ideal sub-strate for production of high quality whey


protein isolate or further fractionation ofindividual whey proteins, due to its neutralpH, and lack of residual coagulant or otherproteases and lack of caseinomacropep-tide [95].

Processes for the extensive concentra-tion of milk by MF, to the point wherewhey removal subsequent to addition ofrennet and starter is minimal or absent,have also been described [2, 15, 90]. Thedevelopment of proteolytic and functionalcharacteristics of Mozzarella cheese madefrom MF retentates has been reported to beslower than in control cheeses due to theabsence of starter culture, lower levels ofrennet used and inhibition of cheese prote-olysis due to residual whey proteins in theMF retentates [2,15]. This problem may beameliorated through increased rennet lev-els, standardisation of curd cook times andaddition of starter culture [2, 15, 105].

8. STANDARDISATION OFCHEESE-MILK BY PROTEINADDITION

Standardisation of milk protein/caseinlevels, by concentration of milk solids orby producing a protein rich fraction whichmay be subsequently added to milk priorto cheese manufacture, may be used to re-duce some negative defects associated witha seasonal milk supply [5, 52], such asvariable protein/casein contents which re-sult in poor curd-forming properties andin variations in yield and in compositionand consistency of resultant cheeses [3,83, 109]. Increased yield results from re-duced losses of fat and casein particles inwhey and better retention of whey pro-teins in the aqueous phase of cheese. Fur-thermore, standardisation of milk proteinto higher than normal levels enables in-creased plant throughput without installa-tion of extra cheese vats [52].

Protein standardisation may be achievedby: use of low-concentrated reten-tate (LCR) produced by UF or RO of

cheesemilk; enrichment of casein by MF;or addition of phosphocasein powder (PC)or milk protein concentrate (MPC) [52],typically followed by cheese manufactureusing conventional equipment [98]. Addi-tion of denatured microparticulated wheyproteins to cheesemilk may also be used toameliorate defects associated with reducedfat cheese [34, 134].

MPC has the same casein:whey pro-tein ratio as milk [56]. MF of skimmilk allows water, lactose, α-lactalbumin,β-lactoglobulin, soluble minerals and NPNto pass through the membrane in the per-meate but retains casein in the retentate[105, 106]. MPC produced by spray dry-ing of retentate from ultrafiltration of skimmilk contains ∼ 65% protein, 3% fat,2% calcium and 20% lactose [138], whileMPC made by ultrafiltration of skim milkand diafiltration contains very little lactose.SMP and skim milk condensed by evapo-ration contain ∼ 51% and 14% lactose re-spectively [138]. High lactose content incheese may promote undesirable fermenta-tion, atypical flavour or white crystal defectduring cheese ripening [1].

Commercial calcium caseinate pro-duced by acid precipitation is rich in caseinbut low in minerals. Rennet coagulationtime for cheese-milk supplemented with6% calcium caseinate powder was signif-icantly higher than for a similar level ofsupplementation with diafiltered microfil-tered DMF or UF retentates [133]. Milkenriched with calcium caseinate beforeproduction of low-fat Cheddar producedcurd which did not retain fat, possiblydue to reduced calcium levels inhibit-ing coagulation and formation of adequatecurd structure, and yields were lower thancheese from DMF powder [133]. PC andMPC have rennet coagulation propertiessimilar to those of milk at similar pro-tein concentration and ionic strength [33,74, 78]. In a comparative study, increas-ing milk protein content through standard-isation with UFR, MPC or PC resulted


in enhanced rennet coaguability, reducedgelation time and increased curd firmnessbut there was no significant effect of pro-tein type [52].

Manufacture of reduced-fat Cheddarcheese from milk standardised with MPCdoubled cheese yields per unit weight ofmilk, significantly increased total solidrecoveries, reduced lactose contents andNSLAB counts, but had no significant ef-fect on starter bacteria count, and gavelower levels of FAA and brothy and bit-ter scores than control cheeses [138]. De-creased levels of primary proteolysis werepossibly due to reduced plasmin activity orto addition of chymosin on a volume ba-sis, rather than on a casein basis. Increasedmoisture-adjusted yield may be due to ahigh level of whey protein denaturation inthe MPC and thus a high level of proteinrecovery in the MPC-fortified cheese [52].Standardisation of milk protein content us-ing PC, UFR or MPC resulted in signif-icantly increased fat recovery and yieldof cheese per unit weight of milk, nor-malised to reference levels of casein andfat [52, 56]. However, as PC is a relativelynew ingredient, limited availability couldlimit its use [52].

Microparticulated whey proteins (pro-duced by microparticulation of whey pro-tein concentrate under conditions of heatand shear) act as a non-interacting fillerin the cheese matrix and can mimic thestructural properties of fat [91] and may beused in manufacture of low-fat cheese [29].Lucey and Gorry [89] reported that a com-mercial microparticulated milk protein hadlittle effect on rennet coagulation; how-ever, Fenelon and Guinee [34] and Guineeet al. [49] reported impaired rennet coag-ulation properties, with lower curd-firmingrates and curd firmness after a fixed ren-neting time, possibly due to the denaturedprotein content or dilution of the casein,i.e., the active gel forming component.Addition of microparticulated whey pro-tein resulted in reduced-fat Cheddar with

increased moisture and MNFS contents,higher yields, probably due to hydratedwhey proteins, lower firmness, but had lit-tle effect on or slightly reduced levels ofproteolysis and flavour grades [34, 89].

9. TREATMENT OF CHEESE-MILK WITH EXOGENOUSENZYMES

Apart from coagulant, the most com-mon reasons for incorporation of exoge-nous enzymes in cheese manufacture are:(i) acceleration of ripening, usually by ad-dition of commercial proteinase or lipasepreparations; (ii) enhancement of cheeseflavour, by addition of peptidases and li-pases; (iii) increasing cheese yield, e.g., byaddition of transglutaminase or phospholi-pases. Enzymes (as individual enzymes oras mixtures) may be added to cheesemilkprior to cheese manufacture or during man-ufacture, alongside the starter or rennet [4].However, addition of proteinases directlyto cheesemilk with rennet or starter culturemay prematurely hydrolyse casein, inter-fere with renneting, and reduce yield [148],and losses of ∼ 90% of added enzyme atwhey drainage are typical [81]. Encapsula-tion of free enzymes provides an alterna-tive approach to enzyme addition and alsoenables protection from the outside envi-ronment and may allow for controlled re-lease [44, 132]. One specific approach isthe use of liposomes, which are micro-scopic lipid vesicles comprising an outershell of phospholipid and an internal aque-ous core [82, 118, 130, 147]. The potentialadvantages of liposomes over other meth-ods of enzyme encapsulation for cheeseapplications are that they are made frommaterials naturally present in cheese, theyprotect casein from early hydrolysis dur-ing cheesemaking, and they partition wellin the curd [148].


9.1. Use of phospholipase

During cheese manufacture, 85–95%of milk fat is entrapped in the cheesecurd [107] with the remaining fat lost in thewhey and, to a lesser extent, in the brine,if used. In manufacture of pasta filata-typecheese, the fat retention rarely exceeds90% because of additional losses encoun-tered in the hot stretching step [85]. A newenzymatic method for increasing cheeseyield through treating milk with phospho-lipase prior to cheesemaking has been re-ported [60,85,107,108]. Phospholipase A1(EC 3.1.1.32) hydrolyses the sn-1 esterbond of phospholipids, resulting in forma-tion of the less hydrophobic and thus morewater-soluble lysophospholipids and fattyacids. It is proposed that lysophospholipidsreleased from the fat globule membranesact as surface-active agents in the cheesecurd, which emulsify water and fat duringprocessing and reduces syneresis. Further-more, αs1-casein and β-lactoglobulin inter-act with lysophopsholipids and also formsurface-active lipoprotein complexes [85].Phospholipases used are specific and havelittle activity towards di- or tri- glycerides;thus, flavour defects caused by the releaseof short chain fatty acids are avoided, be-cause phospholipids mainly contain non-volatile palmitic, oleic and stearic acids.

There have been a small number ofstudies of the use of phospholipases incheese applications; no effect of phospho-lipase treatment of cheese-milk on rennet-ing properties of the cheese-milk has beenreported as yet. Hydrolysis of milk phos-pholipids with a commercial preparationof fungal phospholipase A1 from Fusar-ium venenatum added to cheese-milk priorto renneting during manufacture of low-moisture part-skim Mozzarella cheese re-duced fat losses in whey and cooking waterand increased cheese yield, as a result ofimproved fat and moisture retention in thecheese curd [60, 85]. Despite enzymaticmodification of the fat globule mem-

brane, the fat globules retained their orig-inal size and appearance [85]. Lysophos-pholipids were retained in the curds inhigher amounts compared to native phos-pholipids, possibly because of interactionwith casein and subsequent incorporationinto the cheese matrix. It was proposed byLilbaek et al. [85] that the observed im-provement in yield results from improvedemulsification and water-holding capac-ity as a consequence of the presence oflysophospholipids in the curd. No signif-icant differences in cheese microstructureor functionality (melt, stretch, browning)were observed between control cheesesand those treated with phospholipase, andthere was no significant effect of phospho-lipase treatment of cheesemilk on sensoryattributes of the cheese or downstream pro-cessing of the whey [60].

The potential for further yield improve-ments by combining use of phospholipasewith enrichment of cheesemilk with butter-milk phospholipids to increase the amountof lysophospholipids in the curd was sug-gested by Lilbaek et al. [85]. Enrichmentof cheesemilk with phospholipids frombuttermilk or soy milk increased cheeseyield and improved the texture of low-fat cheese [30, 45, 97, 99]. Enhanced fatretention has also been reported in full-fat Colby cheese manufactured with addedsoy lecithin [58].

9.2. Applications oftransglutaminase incheese-making

The enzyme transglutaminase (TGase;EC 2.3.2.13) catalyzes the formation ofan intermolecular covalent isopeptide-bond between protein molecules viaan acyl-transfer reaction between theε-amino group of a lysine residue andthe γ-carboximide groups of a glutamineresidue [73]. The caseins are excellent sub-strates for TGase-induced cross-linking,because of their unfolded native structure.


For micellar casein, the order of suscep-tibility to TGase-induced cross-linking isκ-CN > β-CN > αs-CN, which is predom-inantly related to the easy of accessibilityof the caseins for the enzyme [131]. Light-scattering measurements have shown that,in unconcentrated milk, cross-linkingof micellar caseins is exclusively intra-micellar and not inter-micellar [64]. Thisintra-micellar cross-linking stabilizesthe micelle against disintegration underunfavourable conditions [64, 131] andalso has major implications for the hairybrush, consisting predominantly of κ-CN,which provides colloidal stability to themicelle [64].

Pre-treatment of milk with transglu-taminase increases RCT considerably [63,88,111], and small-deformation oscillatoryrheology shows similar trends. When mostκ-CN is cross-linked, no rennet-inducedflocculation of micelles is observed atall [63]. Cross-linking of caseins in the mi-cellar core is unlikely to be the cause ofTGase-induced increases in RCT, since in-ternally cross-linked para-casein micelles,prepared by TGase treatment of casein mi-celles following cold-renneting, do form afirm coagulum on warming to 30 ◦C [111].Lorenzen [88] and O’Sullivan et al. [111]observed that the amount of CMP releasedduring renneting decreases with increas-ing degree of cross-linking and concludedtherefrom that rennet-induced increases inRCT are due to a reduction in the rateof enzymatic hydrolysis of κ-CN. How-ever, decreases in the rate of release ofCMP do not necessarily indicate that κ-CNis not hydrolysed, since it can remain at-tached to the micelles following hydroly-sis by chymosin [63]. This point was fur-ther highlighted by in-situ diffusing wavespectroscopy measurements during rennet-ing by Huppertz and De Kruif [63] whichstrongly indicated that the time point atwhich inter-micellar repulsion is reducedsufficiently to induce micellar floccula-tion is only increased slightly by TGase-

treatment, and that it is the rate of aggre-gation of these renneted micelles that isreduced.

Studies on the properties of cheesecurd or ripening of cheese prepared frommilk pre-treated with TGase are, to ourknowledge, not available at the moment.However, based on the aforementionedimpaired coagulation properties of milkfollowing TGase treatment, it is unlikelythat many beneficial effects may be ex-pected in cheese-making.

10. CONCLUSIONS

Where centuries ago, cheese was es-sentially prepared from unprocessed milk,cheese-making nowadays can involve acomplex sequence of milk pre-treatments,e.g., membrane filtration, (partial) homog-enization and heat treatment. These treat-ment steps are performed to reach re-quired or desirable characteristics of themilk prior to cheese-making. As outlinedin this review, such treatment in general donot only induce the desired change, but aregenerally accompanied by other changes,which are often less desirable and requireadjustment of operations and parameters ofthe cheese-making process. The recent de-velopments in this area that are describedhighlight the importance of understandingthe manner in which the changes inducedby particular pre-treatments of milk willlead to a successful application thereof,and ultimately allow cheese-makers toachieve their goals, e.g., increased yield,consistency, throughput, controlled or ac-celerated ripening or simply optimal con-trol of food safety.

REFERENCES

[1] Anderson D.L., Mistry V.V., BrandsmaR.L., Baldwin K.A., Reduced-fatCheddar cheese from condensed milk.1. Manufacture, composition and yield, J.Dairy Sci. 76 (1993) 2832–2844.


[2] Ardisson-Korat A.V., Rivzi S.S.H., Vatlessmanufacture of low-moisture part-skimMozzarella cheese from highly concen-trated skim milk microfiltration retentates,J. Dairy Sci. 87 (2004) 3601–3613.

[3] Auldist M.J., Coats S., Sunderland B.J.,Mayes J.J., McDowell G.M., Rogers G.L.,Effects of somatic cell count and stage oflactation on raw milk composition and theyield and quality of Cheddar cheese, J.Dairy Res. 63 (1996) 269–280.

[4] Azarnia S., Robert N., Lee B.,Biotechnological methods to acceler-ate Cheddar cheese ripening, Crit. Rev.Biotechnol. 26 (2006) 121–143.

[5] Banks J., The quality of milk in relation tocheese manufacture, J. Soc. Dairy Technol.43 (1990) 35–39.

[6] Banks J.M., Elimination of the develop-ment of bitter flavour in Cheddar cheesemade from milk containing heat-denaturedwhey protein, J. Soc. Dairy Technol. 41(1988) 37–41.

[7] Banks J.M., Heat treatment of cheese milk,in: Practical guide for control of cheeseyield, Special Issue 0001, Int. Dairy Fed.,Brussels, Belgium, 2000, pp. 36–39.

[8] Banks J.M., Law A.J.R., Leaver J., HorneD.S., The inclusion of whey protein incheese – an overview in: Cheese yield andfactors affecting its control, Special Issue9402, Int. Dairy Fed., Brussels, Belgium,1993, pp. 387–401.

[9] Banks J.M., Law A.J.R., Leaver J., HorneD.S., Maturation profiles of Cheddar-typecheese produced from high heat treatmentmilk to incorporate whey proteins, in:Malin E.L., Tunick M.H. (Eds.), Chemistryof Structure-Function Relationships inCheese, Plenum Press, New York, 1995,pp. 221–236.

[10] Banks J.M., Stewart G., Muir D.D., WestI.G., Increasing the yield of Cheddar cheeseby acidification of milk containing heat-denatured whey protein, Milchwissenschaft43 (1987) 212–215.

[11] Benfeldt C., Ultrafiltration of cheese milk:effect on plasmin activity and proteolysisduring cheese ripening, Int. Dairy J. 16(2006) 600–608.

[12] Benfeldt C., Sorensen J., Ellegard K.H.,Petersen T.E., Heat treatment of cheesemilk: Effect on plasmin activity and prote-olysis during cheese ripening, Int. Dairy J.7 (1997) 723–731.

[13] Beuvier E., Berthaud K., Cegarra S., DasenA., Pochet S., Buchin S., Duboz G.,Ripening and quality of Swiss-type cheesemade from raw, pasteurized or microfilteredmilk, Int. Dairy J. 7 (1997) 311–323.

[14] Brandsma R.L., Rizvi S.S.H., Depletion ofwhey proteins and calcium by microfiltra-tion of acidified skim milk prior to cheesemaking, J. Dairy Sci. 82 (1999) 2063–2069.

[15] Brandsma R.L., Rizvi S.S.H., Manufactureof Mozzarella cheese from highly concen-trated skim milk microfiltration retentatedepleted of whey proteins, Int. J. Food Sci.Technol. 36 (2001) 611–624.

[16] Broome M.C., Tan S.E., Alexander M.A.,Manser B., Low-concentration-ratio ultra-filtration for cheddar cheese manufacture.Part 1: Effect on seasonal cheese composi-tion, Aust. J. Dairy Technol. 53 (1998) 5–10.

[17] Buffa M., Guamis B., Pavia M., TrujilloA.J., Lipolysis in cheese made from raw,pasteurized or high-pressure-treated goats’milk, Int. Dairy J. 11 (2001) 175–179.

[18] Buffa M., Guamis B., Royo C., TrujilloA.J., Microbiological changes throughoutripening of goat cheese made from raw,pasteurized and high-pressure-treated milk,Food Microbiol. 18 (2001) 45–51.

[19] Buffa M., Guamis B., Saldo J., Trujillo A.J.,Changes in organic acids during ripeningof cheeses made from raw, pasteurized orhigh-pressure-treated goats’ milk, Lebens.-Wiss. Technol. 37 (2004) 247–253.

[20] Buffa M., Guamis B., Trujillo A.J., Specificeffect of high-pressure treatment of milk oncheese proteolysis, J. Dairy Res. 72 (2005)385–392.

[21] Buffa M.N., Trujillo A.J., Pavia M., GuamisB., Changes in textural, microstructural,and colour characteristics during ripeningof cheeses made from raw, pasteurizedor high-pressure-treated goats’ milk, Int.Dairy J. 11 (2001) 927–934.

[22] Bulca S., Leder J., Kulozik U., Impact ofUHT or heat treatment on the rennet gel for-mation of skim milk with various whey pro-tein contents, Milchwissenschaft 59 (2004)590–593.

[23] Calvo M.M., Leaver J., Law A.J.R., BanksJ.M., Changes in casein levels during theripening of Cheddar type cheese madefrom overheated milk, Milchwissenschaft47 (1992) 516–518.

[24] Creamer L.K., Matheson A.R., Effectof heat treatment on the proteins of


pasteurised skim milk, N. Z. J. Dairy Sci.Technol. 15 (1980) 37–49.

[25] Dalgleish D.G., Effect of milk concentra-tion on the rennet coagulation time, J. DairyRes. 47 (1980) 231–235.

[26] Dalgleish D.G., The enzymatic coagula-tion of milk, in: Fox P.F. (Ed.), AdvancedDairy Chemistry, Vol. 1, Proteins, ElsevierScience Publications Ltd., London, 1992,pp. 579–620.

[27] De Kruif C.G., Skim milk acidification, J.Coll. Interf. Sci. 185 (1997) 19–25.

[28] Dejmek P., Walstra P., The syneresisof rennet-coagulated curd, in: Fox P.F.,McSweeney P.L.H, Cogan T.M., GuineeT.P. (Eds.), Cheese: Chemistry, Physics andMicrobiology, Volume 1: General Aspects,3rd edn., Academic Press, Amsterdam,The Netherlands, 2004, pp. 71–103.

[29] Desai N., Nolting J., Microstructure stud-ies of reduced-fat cheeses containing fatsubstitute, in: Malin E.L., Tunick M.H.(Eds.), Chemistry of Structure-FunctionRelationships in Cheese, Plenum Press,New York, 1995, pp. 295–302.

[30] Drake M.A., Chen X.Q., Gerard P.D.,Gurkin S.U., Composition and quality at-tributes of reduced fat cheese as affected bylecithin type, J. Food Sci. 63 (1998) 1018–1023.

[31] Drake M.A., Harrison S.L., Asplund M.,Barbosa-Canovas G., Swanson B.G., Highpressure treatment of milk and effectson microbiological and sensory quality ofCheddar cheese, J. Food Sci. 64 (1997)843–845, 860.

[32] Emmons D.B., Lister E.E., Beckett D.C.,Jenkins K.J., Quality of protein in milkreplacers for young calves. V. Effect ofmethod of dispersing fat on curd formationand whey syneresis, J. Dairy Sci. 63 (1980)417–425.

[33] Famelart M.H., Lepesant F., Gaucheron F.,Le Graet Y., Schuck P., pH induced physio-chemical modifications of native phospho-caseinate suspensions: Influence of aqueousphase, Lait 76 (1996) 445–460.

[34] Fenelon M.A., Guinee T.P., The composi-tional, textural, and maturation characteris-tics of reduced-fat Cheddar made from milkcontaining Dairy-LoTM, Milchwissenschaft52 (1997) 385–389.

[35] Fernandez A., Kosikowski F.V., Low mois-ture Mozzarella cheese from whole milk re-tentates of ultrafiltration, J. Dairy Sci. 69(1986) 2011–2017.

[36] Fernandez A., Kosikowski F.V., Physicalproperties of direct acidified Mozzarellacheese from ultrafiltered whole milk reten-tates, J. Dairy Sci. 69 (1986) 643–648.

[37] Fox P.F., Heat induced changes in milk pre-ceding coagulation, J. Dairy Sci. 64 (1981)2121–2137.

[38] Fox P.F., McSweeney P.L.H., Cheese: anoverview, in: Fox P.F., McSweeney P.L.H.,Cogan T.M., Guinee T.P. (Eds.), Cheese:Chemistry, Physics and Microbiology,Volume 1, General Aspects, 3rd edition,Elsevier Applied Science, Amsterdam,The Netherlands, 2004, pp. 1–18.

[39] Fox P.F., McSweeney P.L.H., Chemistryand biochemistry of cheese manufactureand ripening, Food Sci. Technol. 20 (2006)28–32.

[40] Fox P.F., McSweeney P.L.H., Cogan T.M.,Guinee T.P. (Eds.), Cheese: Chemistry,Physics and Microbiology, Volume 2,Major Cheese Groups, 3rd edition,Elsevier Applied Science, Amsterdam,The Netherlands, 2004.

[41] Fox P.F., McSweeney P.L.H., CoganT.M., Guinee T.P. (Eds.), Cheese:Chemistry, Physics and Microbiology,Volume 1, General Aspects, 3rd edition,Elsevier Applied Science, Amsterdam,The Netherlands, 2004.

[42] Garnot P., Influence of milk concentrationby UF on enzymatic coagulation, Int. DairyFed. Bull. 225 (1988) 11–15.

[43] Ghosh B.C., Steffl A., Hinrichs J., KesslerH.G., Effect of heat treatment and homoge-nization of milk on camembert-type cheese,Egyptian J. Dairy Sci. 27 (1999) 331–343.

[44] Gibbs B.F., Kermasha S., Alli I., MulliganC.N., Encapsulation in the food industry:a review, Int. J. Food Sci. Nutr. 50 (1999)213–224.

[45] Govindasamy-Lucey S., Lin T., Jaeggi J.J.,Johnson M.E., Lucey J.A., Influence ofcondensed sweet cream buttermilk on themanufacture, yield, and functionality ofPizza cheese, J. Dairy Sci. 89 (2006) 454–467.

[46] Green M.L., Marshall R.J., Glover F.A.,Influence of homogenization of concen-trated milks on the structure and proper-ties of rennet curds, J. Dairy Res. 50 (1983)341–348.

[47] Guinee T.P., Auty M.A.E., Mullins C.,Corcoran M.O., Mulholland E.O.,Preliminary observations on the effects offat content and degree of emulsification


on the structure-functional relationship ofCheddar-type cheese, J. Texture Stud. 31(2000) 645–663.

[48] Guinee T.P., Fenelon M.A., MulhollandE.O., O’Kennedy B.T., O’Brien N., RevilleW.J., The influence of milk pasteurisationtemperature and pH at curd milling onthe composition, texture and maturation ofreduced fat cheddar cheese, Int. J. DairyTechnol. 51 (1998) 1–10.

[49] Guinee T.P., Gorry C.B., O’Callaghan D.J.,O’Kennedy B.T., O’Brien N., FenelonM.A., The effects of composition and someprocessing treatments on the rennet coag-ulation properties of milk, Int. J. DairyTechnol. 50 (1997) 99–106.

[50] Guinee T.P., McSweeney P.L.H.,Significance of milk fat in cheese, in:Fox P.F., McSweeney P.L.H. (Eds.),Advanced Dairy Chemistry 2: Lipids,3rd edn., Springer Verlag, New York, 2006,pp. 377–440.

[51] Guinee T.P., O’Callaghan D.J., MulhollandE.O., Harrington D., Milk protein standard-isation by ultrafiltration for cheddar cheesemanufacture, J. Dairy Res. 63 (1996) 281–293.

[52] Guinee T.P., O’Kennedy B.T., Kelly P.M.,Effect of milk protein standardization usingdifferent methods on the composition andyields of Cheddar cheese, J. Dairy Sci. 89(2006) 468–482.

[53] Guinee T.P., Pudja P.D., Mulholland E.O.,Effect of milk protein standardisation, byultrafiltration, on the composition and mat-uration of cheddar cheese, J. Dairy Res. 61(1994) 117–131.

[54] Guinee T.P., Pudja P.D., Mulholland E.O.,Reville W.J., Ultrafiltration in cheesemak-ing, in: Cogan T.M. (Ed.), 3rd Cheesesymposium, Moorepark, National DairyProducts Research Centre, Moorepark,Fermoy, Co. Cork, Ireland, 1992, pp. 21–29.

[55] Guinee T.P., Pudja P.D., Reville W.J.,Harrington D., Mulholland E.O., Cotter M.,Cogan T.M., Composition, microstructureand maturation of semi-hard cheeses fromhigh protein ultrafiltered milk retentateswith different levels of denatured whey pro-tein, Int. Dairy J. 5 (1995) 543–568.

[56] Harvey J., Protein fortification of cheesemilk using milk protein concentrate – yieldimprovement and product quality, Aust. J.Dairy Technol. 61 (2006) 183–185.

[57] Hayes M.G., Kelly A.L., High pressure ho-mogenization of raw whole bovine milk (a)

effect on fat globule size and other proper-ties, J. Dairy Res. 70 (2003) 297–305.

[58] Hicks C.L., O’Leary J., Holbrook J., Effectof lecithin on cheese yield, J. Dairy Sci. 68(1985) 1603–1607.

[59] Hindle E.J., Wheelock J.V., The primaryphase of rennet action in heat-sterilizedmilk, J. Dairy Res. 37 (1970) 389–396.

[60] Høier E., Lilbæk H., Broe M.L., SørensenN.K., Enhancing cheese yield by phospho-lipase treatment of cheesemilk, Aust. J.Dairy Technol. 61 (2006) 179–182.

[61] Hotchkiss J.H., Werner B.G., Lee E.Y.C.,Addition of carbon dioxide to dairy prod-ucts to improve quality: a comprehensivereview, Comp. Rev. Food Sci. Food Safety5 (2006) 158–168.

[62] Humbert G., Driou A., Guerin J., Alais C.,Effets de l’homogénéisation à haute pres-sion sur les propriétés du lait et son apti-tude à la coagulation enzymatique, Lait 60(1980) 574–594.

[63] Huppertz T., De Kruif C.G., Rennet-induced coagulation of enzymaticallycross-linked casein micelles, Int. Dairy J.17 (2007) 442–447.

[64] Huppertz T., De Kruif C.G., Structure andstability of nanogel particles prepared bycross-linking casein micelles, Int. Dairy J.18 (2008) 556–565.

[65] Huppertz T., Fox P.F., De Kruif C.G., KellyA.L., High pressure-induced changes inbovine milk proteins: a review, BiochimBiophys Acta – Prot. Proteomics 1764(2006) 593–598.

[66] Huppertz T., Fox P.F., Kelly A.L., Influenceof high pressure treatment on acidifica-tion of bovine milk by lactic acid bacteria,Milchwissenschaft 59 (2004) 246–249.

[67] Huppertz T., Fox P.F., Kelly A.L., Effectsof high pressure treatment on the yield ofcheese curd from bovine milk, Innov. FoodSci. Emerg. Technol. 5 (2004) 1–8.

[68] Huppertz T., Hinz K., Zobrist M.R.,Uniacke T., Kelly A.L., Fox P.F., Effectsof high pressure treatment on the rennetcoagulation and cheese-making propertiesof heated milk, Innov. Food Sci. Emerg.Technol. 6 (2005) 279–285.

[69] Huppertz T., Kelly A.L., Physical chem-istry of milk fat globules, in: Fox P.F.,McSweeney P.L.H. (Eds.), Advanced DairyChemistry 2: Lipids, 3rd edn., SpringerVerlag, New York, USA, 2006, pp. 173–212.


[70] Imafidon G.L., Farkye N.Y., Compositionof cheddar cheese made from high-heattreated milk, in: Cheese Yield and Factorsaffecting its control, Special Issue 9402,Int. Dairy Fed., Brussels, Belgium, 1993,pp. 433–438.

[71] Jana A.H., Upadhyay K.G., The effect ofhomogenization conditions on the texturaland baking characteristics of buffalo milkMozzarella cheese, Aust. J. Dairy Technol.46 (1991) 27–30.

[72] Jana A.H., Upadhyay K.G.,Homogenization of milk for cheese-making – a review, Aust. J. Dairy Technol.47 (1992) 72–79.

[73] Jaros D., Partschefeld C., Henle T., RohmH., Transglutaminase in dairy products:chemistry, physics, applications, J. TextureStud. 37 (2006) 113–155.

[74] Kameswaran S., Smith D.E., Rennet clot-ting times of skim milk based rennet gelssupplemented with an ultrafiltered milkprotein concentrate, Milchwissenschaft 54(1999) 546–550.

[75] Karlsson A.O., Ipsen R., Ardo Y.,Rheological properties and microstructureduring rennet induced coagulation of UFconcentrated milk, Int. Dairy J. 17 (2007)674–682.

[76] Kelly A.L., O’Donnell H.J., Composition,gel properties and microstructure of Quargas affected by processing parameters andmilk quality, Int. Dairy J. 8 (1998) 295–301.

[77] Kelly P.M., Membrane separation,in: Roginski H., Fuquay J.W., FoxP.F. (Eds.), Encyclopaedia of DairySciences, Academic Press, Amsterdam,The Netherlands, 2003, pp. 1777–1786.

[78] Kelly P.M., Kelly J., Mehra R., OldfieldD.J., Raggett E., O’Kennedy B.T.,Implementation of integrated mem-brane processes for pilot scale developmentof fractionated milk components, Lait 80(2000) 139–153.

[79] Kosikowski F.V., Masters A.R., MistryV.V., Cheddar cheese from retentate-supplemented whole milk, J. Dairy Sci. 68(1985) 548–554.

[80] Law A.J.R., Banks J.M., Horne D.S.,Leaver J., West I.G., Denaturation ofthe whey proteins in heated milk andtheir incorporation into Cheddar cheese,Milchwissenschaft 49 (1994) 63–67.

[81] Law B., Kirby C., Microencapsulated en-zymes for cheese technology, North Eur.Food Dairy J. 6 (1987) 194–199.

[82] Law B.A., King J.S., Use of liposomes forproteinase addition to Cheddar cheese, J.Dairy Res. 52 (1985) 183–188.

[83] Lawrence R.C., Gilles J., Creamer L.K.,Crow V.L., Heap H.A., Honore C.G.,Johnston K.A., Samal P.K., Cheddarcheese and related dry-salted cheese va-rieties, in: Fox P.F., McSweeney P.L.H.,Cogan T.M., Guinee T.P. (Eds.), CheeseChemistry, Physics and Microbiology,Major Cheese Groups, Elsevier AcademicPress, Amsterdam, The Netherlands,3rd edn., Vol. 2, 2004, pp. 71–102.

[84] Lemay A., Paquin P., Lacroix C., Influenceof microfluidization on Cheddar cheesecomposition, quality and yields, in: Cheeseyield and Factors Affecting its Control,Special Issue 9402, Int. Dairy Fed.,Brussels, Belgium, 1994, pp. 288–292.

[85] Lilbaek H.M., Broe M.L., Hoier E., FatumT.M., Ipsen R., Sorensen N.K., Improvingthe yield of Mozzarella cheese by phospho-lipase treatment of milk, J. Dairy Sci. 89(2006) 4114–4125.

[86] Linton M., Mackie A.B., Upadhyay V.K.,Kelly A.L., Patterson M.F., The fate ofListeria monocytogenes during the manu-facture of Camembert-type cheese: a com-parison between raw milk and milk treatedwith high hydrostatic pressure, Innov. FoodSci. Emerg. Technol. 9 (2008) 423–428.

[87] López-Fandiño R., Olano A., Effects ofhigh pressures combined with moderatetemperatures on the rennet coagulationproperties of milk, Int. Dairy J. 8 (1998)623–627.

[88] Lorenzen P.C., Renneting proper-ties of transglutaminase-treated milk,Milchwissenschaft 55 (2000) 433–437.

[89] Lucey J.A., Gorry C., Effect of Simplesse100 on the manufacture of low fat Cheddarcheese, in: Cheese yield and factors af-fecting its control, Special Issue 9402,Int. Dairy Fed. Brussels, Belgium, 1994,pp. 439–447.

[90] Ma Y., Barbano D.M., Santos M., Effectof CO2 addition to raw milk on proteolysisand lipolysis at 4 ◦C, J. Dairy Sci. 86 (2003)1616–1631.

[91] Mackey K.L., Desai N., Rheology ofreduced-fat cheese containing a fat sub-stitute, in: Malin E.L., Tunick M.H.(Eds.), Chemistry of Structure-FunctionRelationships in Cheese, Plenum Press,New York, USA, 1995, pp. 21–26.


[92] Marshall R.J., Increasing cheese yields byhigh heat treatment of milk, J. Dairy Res.53 (1986) 313–322.

[93] Maubois J.-L., Applications of membranetechniques in the dairy industry, Int. DairyFed. Bull. 244 (1989) 26–29.

[94] Maubois J.-L., Membrane microfiltration: atool for a new approach in dairy technology,Aust. J. Dairy Technol. 57 (2002) 92–96.

[95] Maubois J.-L., Fauquant J., Famelart M.H.,Caussin F., Milk microfiltrate, a con-venient starting material for fractiona-tion of whey proteins and derivatives, in:Proceedings of the 3rd International WheyConference, Munich, Germany, Sept. 12–14: The Importance of Whey and WheyComponents in Food and Nutrition, B.Behr’s Verlag, Hamburg, Germany, 2001,pp. 57–72.

[96] Mistry V.V., Membrane processing incheese manufacture, in: Roginski H.,Fuquay J.W., Fox P.F. (Eds.), Encyclopediaof Dairy Sciences, Academic Press,Amsterdam, The Netherlands, 2003,pp. 300–306.

[97] Mistry V.V., Maubois J.-L., Application ofmembrane separation technology in cheeseproduction, in: Fox P.F. (Ed.), Cheese:Chemistry, Physics and Microbiology,Vol. 1., Chapman & Hall, New York, USA,1993, pp. 493–522.

[98] Mistry V.V., Maubois J.-L., Applicationof membrane separation technologyin cheese production, in: Fox P.F.,McSweeney P.L.H., Cogan T.M.,Guinee T.P. (Eds.), Cheese: Chemistry,Physics and Microbiology 1: GeneralAspects, Academic Press, Amsterdam,The Netherlands, 2004, pp. 261–285

[99] Mistry V.V., Metzger L.E., Maubois J.-L.,Use of ultrafiltered sweet buttermilk in themanufacture of reduced fat Cheddar cheese,J. Dairy Sci. 79 (1996) 1137–1145.

[100] Mohammad K.B., Fox P.F., Heat-inducedassociation-dissociation of casein micellespreceeding coagulation, J. Dairy Res.(1987) 377–387.

[101] Molina E., Alvarez M.D., Ramos M.,Olano A., López-Fandiño R., Use of high-pressure-treated milk for the production ofreduced-fat cheese, Int. Dairy J. 10 (2000)467–475.

[102] Mueller-Merbach M., Rauscher T.,Hinrichs J., Inactivation of bacteriophagesby thermal and high-pressure treatment,Int. Dairy J. 15 (2005) 777–784.

[103] Nelson B.K., Lynch J.M., Barbano D.M.,Impact of milk preacidification with CO2on Cheddar cheese composition and yield,J. Dairy Sci. 87 (2004) 3581–3589.

[104] Nelson B.K., Lynch J.M., Barbano D.M.,Impact of milk preacidification with CO2on the aging and proteolysis of Cheddarcheese, J. Dairy Sci. 87 (2004) 3590–3600.

[105] Neocleous M., Barbano D.M., Rudan M.A.,Impact of low concentration factor micro-filtration on the composition and aging ofCheddar cheese, J. Dairy Sci. 85 (2002)2425–2437.

[106] Neocleous N., Barbano D.M., Rudan M.A.,Impact of low concentration factor mi-crofiltration on milk component recoveryand cheddar cheese yield, J. Dairy Sci. 85(2002) 2415–2424.

[107] Nielsen E.W., Principles of cheese produc-tion, in: Hui Y.H., Goddik L.M., HansenA.S., Josephsen J. (Eds.), Handbookof Food and Beverage FermentationTechnology, Marcel Dekker, New York,USA, 2004, pp. 221–239.

[108] Nielsen P.M., Process for producing cheese,U.S. Patent No. 6 399 121 (2002).

[109] O’Brien B., Mehra R., Connolly J.F.,Harrington D., Season variation in the com-position of Irish manufacturing and retailmilks, 1. Chemical composition and rennet-ing properties, Irish J. Agric. Food Res. 38(1999) 53–64.

[110] O’Reilly C.E., Kelly A.L., Murphy P.M.,Beresford T.P., High pressure treatment: ap-plications to cheese manufacture and ripen-ing, Trends Food Sci. Technol. 12 (2001)51–59.

[111] O’Sullivan M.M., Kelly A.L., Fox P.F.,Influence of transglutaminase treatment onsome physico-chemical properties of milk,J. Dairy Res. 69 (2002) 433–442.

[112] Oommen B.S., Mistry V.V., Nair M.G.,Effect of homogenization of cream on com-position, yield and functionality of Cheddarcheese made from milk supplemented withultrafiltered milk, Lait 80 (2000) 77–91.

[113] Pandey P.K., Ramaswamy H.S., St-GelaisD., Evaluation of pH change kinetics dur-ing various stages of Cheddar cheese-making from raw, pasteurized, micro-filtered and high-pressure-treated milk,Lebensm.-Wiss. Technol. 36 (2003) 497–506.

[114] Patel H., Carroll T., Kelly A.L., Newdairy processing technologies, in: ChandanR.C., Kilara A., Shah N.P. (Eds.), Dairy


Processing Technology and QualityAssurance, Elsevier, London, 465–483.

[115] Pearse M.J., Linklater P.M., Hall R.J.,MacKinlay A.G., Effect of heat inducedinteraction between β-lactoglobulin and κ-casein on syneresis, J. Dairy Res. 52 (1985)159–165.

[116] Pearse M.J., MacKinlay A.G., Biochemicalaspects of syneresis: a review, J. Dairy Sci.72 (1989) 1401–1407.

[117] Peri C., Lucisano M., Donati B., Studieson the coagulation of milk ultrafiltrationretentates. 2. Kinetics of whey syneresis,Milchwissenschaft 40 (1985) 650–652.

[118] Reineccius G., Liposomes for controlledrelease in the food industry, in: RischS., Reineccius G. (Eds.), Encapsulationand controlled release of food ingredients,American Chemical Society, WashingtonD.C., 1995, pp. 113–131.

[119] Rowney M.K., Hickey M.W., Roupas P.,Everett D.W., The effect of homogenizationand milk fat fractions on the functionality ofmozzarella cheese, J. Dairy Sci. 86 (2003)712–718.

[120] Roy D., Pitre M., Blanchette L., SavoieL., Bélanger G., Ward P., Maubois J.-L.,Monitoring proteolysis and cheese juicecomposition during ripening of Cheddarcheese made from microfiltered milk, Lait77 (1997) 521–541.

[121] Salaun F., Mietton B., Gaucheron F.,Buffering capacity of dairy products, Int.Dairy J. 15 (2005) 95–109.

[122] San Martín-González M.F., Rodriguez J.J.,Gurram S., Clark S., Swanson B.G.,Barbosa-Cánovas G.V., Yield, compositionand rheological characteristics of Cheddarcheese made with high pressure processedmilk, LWT - Food Sci. Technol. 40 (2007)697–705.

[123] San Martín-González M.F.J., Welti-ChanesJ., Barbosa-Cánovas G.V., Cheese manu-facture assisted by high pressure, Food Rev.Int., 22 (2006) 275–289.

[124] Schreiber R., Hinrichs J., Rennet coagula-tion of heated milk concentrates, Lait 80(2000) 33–42.

[125] Sharma S.K., Ferrier L.K., Hill A.R., Effectof modified manufacturing parameters onthe quality of Cheddar cheese made fromultrafiltered (UF) milk, J. Food Sci. 54(1989) 573–577.

[126] Singh H., Review: Effects of high tempera-ture on casein micelles, N. Z. J. Dairy Sci.Technol. 23 (1988) 257–273.

[127] Singh H., Creamer L.K., Heat stabilityof milk, in: Fox P.F. (Ed.), AdvancedDairy Chemistry, Vol. 1, Proteins, ElsevierScience Publications Ltd., London, 1992,pp. 621–656.

[128] Singh H., Fox P.F., Heat stability of milk:pH dependent dissociation of micellar κ-casein on heating milk at ultra-high temper-atures, J. Dairy Res. 52 (1985) 529–538.

[129] Singh H., Waungana A., Influence of heattreatment of milk on cheese making prop-erties, Int. Dairy J. 11 (2001) 543–551.

[130] Skeie S., Developments in microencapsula-tion science applicable to cheese researchand development. A review, Int. Dairy J. 4(1994) 573–595.

[131] Smiddy M.A., Martin J.E.G.H., Kelly A.L.,De Kruif C.G., Huppertz T., Stability of ca-sein micelles cross-linked by transglutami-nase, J. Dairy Sci. 89 (2006) 1906–1914.

[132] Sparkes R.E., Jacobs I.C., Selection of coat-ing and microencapsulation processes, in:Scher H.B. (Ed.), Controlled release deliv-ery systems for pesticides, Marcel DekkerInc., New York, USA, 1999, pp. 3–28.

[133] St Gelais D., Roy D., Audet P., Manufactureof low fat Cheddar cheese from milk en-riched with different protein concentratepowders, Food Res. Int. 31 (1998) 137–145.

[134] Theophilou P., Wilbey A.R., Effects of faton the properties of halloumi cheese, Int. J.Dairy Technol. 60 (2007) 1–4.

[135] Tosh S.M., Dalgleish D.G., The physicalproperties and renneting characteristics ofthe synthetic membrane on the fat glob-ules of microfluidized milk, J. Dairy Sci. 81(1998) 1840–1847.

[136] Trujillo A.J., Capellas M., Buffa M., RoyoC., Gervilla R., Felipe X., Sendra E., SaldoJ., Ferragut V., Guamis B., Application ofhigh pressure treatment for cheese produc-tion, Food Res. Int. 33 (2000) 311–316.

[137] Trujillo A.J., Royo C., Ferragut V., GuamisB., Ripening profiles of goat cheese pro-duced from milk treated with high pressure,J. Food Sci. 64 (1999) 833–837.

[138] Ur-Rehman S., Farkye N.Y., Considine T.,Schaffner A., Drake M.A., Effects of stan-dardization of whole milk with dry milkprotein concentrate on the yield and ripen-ing of reduced-fat Cheddar cheese, J. DairySci. 86 (2003) 1608–161.

[139] Van Hooydonk A.C.M., de Koster P.G.,Boerrigter I.J., The renneting of heatedmilk, Neth. Milk Dairy J. 41 (1987) 3–18.


[140] Van Hooydonk A.C.M., Van de Berg G.,Control and determination of the curd-setting during cheesemaking, Int. DairyFed. Bull. 255 (1988) pp. 2–10.

[141] Van Vliet T., Van Dijk H.J.M., Zoon P.,Walstra P., Relation between syneresisand rheological properties of particle gels,Colloid Polym. Sci. 269 (1991) 620–627.

[142] Vasbinder A.J., Rollema H.S., de KruifC.G., Impaired rennatability of heated milk:study of enzymatic hydrolysis and gela-tion kinetics, J. Dairy Sci. 86 (2003) 1548–1555.

[143] Versteeg C., Ballintyne P.C., McAuleyC.M., Tan S.E., Alexander M., BroomeM.C., Control of reduced-fat cheese qual-ity, Aust. J. Dairy Technol. 53 (1998) 106.

[144] Walstra P., Physical Chemistry of Foods,Marcel Dekker Inc., New York, USA, 2003.

[145] Walstra P., van Dijk H.J.M., Geurts T.J.,The syneresis of curd. 1. General consid-erations and literature review, Neth. MilkDairy J. 39 (1985) 209–246.

[146] Walstra P., Wouters J.T.M., GeurtsT.J., Dairy Science and Technology,

2nd edition, CRC Press, Taylor and FrancisGroup, Boca Raton, USA, 2006.

[147] Weiner N., Phospholipid liposomes: prop-erties and potential use in flavor encap-sulation, in: Ho C.T., Tan C.T., TongC.H. (Eds.), Flavor technology, physi-cal chemistry, modification and process,American Chemical Society Symposiumseries, Washington, DC, 1995, pp. 210–218.

[148] Wilkinson M.G., Kilcawley K.N.,Mechanisms of incorporation and re-lease of enzymes into cheese duringripening, Int. Dairy J. 15 (2005) 817–830.

[149] Zamora A., Ferragut V., Jaramillo P.D.,Guamis B., Trujillo A.J., Effects of ultra-high pressure homogenization on thecheese-making properties of milk, J. DairySci. 90 (2007) 13–23.

[150] Zobrist M.R., Huppertz T., Uniake T., FoxP.F., Kelly A.L., High pressure-inducedchanges in the rennet coagulation proper-ties of bovine milk, Int. Dairy J. 15 (2005)655–662.

pre-treatment of cheese milk: principles and developments

Documents