storage studies in guava cheese-libre

8/12/2019 Storage Studies in Guava Cheese-Libre

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Annals of Agri-Bio Research l0 (l) : 97 -100, 2005Storage Studies in Guava CheeseSURABIII RAI, VIJAY SETHI ATID IC S. JAYACHANDRANDivision of P6t-Hott'6t Tlrchrulogt, Indian Agriailtural Raeorch Insfitutq New Delhi-110 012, IndiaABSTRACTGuava cheese was packed in three different packaging materials and subjected to four months storageat low and ambient temperature. The storage stability was evaluated by analyzing periodically forchanges in the nutritional and microbiological characteristics. There was increase in the TSS, total andreducing sugars, acidity and non-enrymatic browning with storage period, while ascorbic aciddecreased. Microbial counts increased.Key words : Guav4 fruit cheese, storage, ascorbic acidINTRODUCTIONGuava is an important ftrit of India. Low cost of production combined with high nutritive valuemakes it an ideal dessert of the common man. However, it is highly perishable and very fewprocessed products of guava arecommercially available. Thus, there is need to popularize moreprocessed products of guava with the view to exploit its nutritive goodness as well as ensuremore income for the farmers. Guava cheese, a confection similar to the popular Karachi Halw4has a good future and can be a healthy altemative to toffees and chocolates. The present studywas carried out to determine the nutritional and mircorbial changes in guava cheese duringstorgae at ambient and low temperature in three different packaging materials.MATERIALS AND METHODSThe guavas used in the experimen were not garden fresh but were purchased from the localmarket, the variety and history of the fruits being unknown. Fruit cheese was prepared accordingto the recipe given for guava cheese by Jain et al. (1954) with some modifications. The guavacheese was packed in three types of packaging material viz., butter paper bags, polyethylenepouches and aluminium co-extruded film pouches and stored at ambient (16.6"-32"C) and lowtemperature (7-10"C). TSS was measured by a hand refractrometer and expressed as Brix.Titratable acidity was determined by the method A. O. A. C. (1980) and expressed as per centcitric acid. pH was recorded with the help of a digital type pH meter (Control Dynamics). Reducingand total sugars were determined according to the method of Lane and Eynon ( 1923) and expressedin percentage. Ascorbic acid was determined by titration against standard 2,6 dichlorophenolindophenol and expressed as mgl100 g of sample (Ranganna, 1997). Non-enzymatic browningwas expressed is O. D. at420nm (Ranganna"tggl).The guavacheese was subjected to microbialstudy initially and at the end of storage period of four months. Samples were analysed for thepopulation of yeast and osmophiles in malt glucose yeast peptone agar (M. G. Y. P.) and maltextract yeast exfact 40olo glucose agar (MY40G) media (AP[{A, 1992).


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98 Rai, Sethi and Jayachandran

RESI'LTS AND DISCUSSIONThe cherirical composition of the fresh fruits and cheese is given in Table l. During storage,moisture content decreased alongwith an increse in TSS as given in Table 2. Moisture retentionwas maximum in the samples packed in aluminium coextuded film pouches and minimum insamples packed in butter paper bags. The maximum TSS was present in cheese packed inbutter paper bags (82.88' B) and the lowest (8l.ll" B) in samples packed in aluminium co-extruded film pouches. The TSS was higher in samples stored at ambient temperature. Thehigher retention of moisture in aluminium co-extruded fihn pouches was due to the lowerpermeability ofthese pouches to water vapour in comparison to other packages. Acidity increasedTable l. Chemical composition of guava fruits and cheeseParameter Fruit (pulp) CheeseMoisture (%)TSS("Brix)Titratable acidity (% cihic acid)pHTotal sugars (%)Reducing sugars (%)Ascorbic acid (mg/100 g)Non-enzymatic browning (O. D. at 420 nm)

81.508.000.603.66304.80

t63.4rN.E.

19.3680.00.753-447820

35.78572t0.625

Table?. Changcs in moisture (7e), TSS ("Brix), titratable acidity (% ciric acid) and pH during storage ofguavachccse [Initial valuc : Moisture (19.36YQ, TSS (80-"Brix), Titratable acidity (0.75o/t citric acid), pH3.Ml

Storagepriod(months)

Packagingmaterial(moisture)

PackagingmaterialGSS)

Packagingmaterial Packagingmatoial(titratable acidity) (pH)

PE BP ACF BP ACF BP ACF PE BP ACFAmbientI234InvI234

18.20 17.80 t8.3717.97 17.42 17.9817.79 t7.t9 17.7217.56 17.t0 17.69t8.37 I7.86 t8.30t7.92 17.44 18.37t7.79 17.24 18.1617.58 17.t3 I8.01

80.04 80.53 80.1380.86 8t.07 80.2281.19 8r.74 81.098t.22 82.01 8l.l l80.09 80.45 80.0180.55 81.03 80.0081.20 81.69 80.7981.08 82.88 81.02

0.780 0.796 0.7700.780 0.810 0.7700.785 0.876 0.7800.796 0.%0 0.7830.760 0.796 0.7800.770 0.800 0.7700.783 0.810 0.780o3go 0.840 0.780

3.46 3.46 3.463.46 3.46 3.463.M 3.46 3.M3.42 3.38 3.463.46 3.46 3.463.46 3.46 3.463.46 3.46 3.463.46 3.46 3.46

PE : Polyethylene pouch, BP : Butter paper bag, ACF : Aluminium co-extruded film pouch.


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Storage ofguava cheese

with storage in guava'cheese at both ambient and low temperature (Table 2). The highesttitratable acidity values were in the guava cheese paked in butter paper bags (0.940%o; ani ttrelowest in aluminium co'-extruded film pouches (O.7S}yo).Increasi in acidity can be correlatedto the moisture loss since there was greater increase in the acidity in the samples, whichunderwent higher moisture losses. During storage, there was increase in both reducing andnon-reducing sugars (Table 3). The increase in reducing sugars was highly significani andhigher in samples packed in polyethylene pouches in comfarison to other materials. Thepercentage reducing sugars increased by 7.2% at both ambient and low temperafures. Totalsugars increased slightly during storage. The increase in reducing sugars may be due to hydrolysisofpolysaccharides and their subsequent inversion to reducing.ug*r. The inversion p.o""r,Table 3. Changes in total sugars (7o), reducing sugars (7o), ascorbic acid (mgl100 g) and non-enzymatic browning

(O. D. at 420 nm) during storage of guava cheese [Initial value : Total sugars (78.2%), Reducing sugars(35.78%), Ascorbic acid (57.21mgll00 g), Non-enzymatic browning (0.625 o. D. at 420 nm)lPackagingmaterial Packagingmaterial packagingmaterial packagingmaterial(total sugars) (reducingsugars) (ascorbicacid) (NEB)PE BP ACF BP ACF BP ACF BP ACF

99

Storageperiod(months)

AmbientI2J4IlwI234

78.10 78.50 78.2078.40 78.50 78.3778.67 78.57 78.4078.54 78.60 78.5078.20 78.23 78.2078.35 78.40 78.3578.37 78.43 78.3778.47 78.50 78.47

36.67 36.83 36.0637.t3 37.18 36.7638.37 38.24 38.5540.94 39.42 40.6236.42 36.42 36.7837.r3 37.17 37.1337.00 37.76 37.ts38.27 38.08 37.19

32.84 35.32 37.1730.60 34.86 34.4229.87 32.37 33.1226.26 29.41 30.7436.45 38.42 38.1733.23 35.67 37.3731.47 33.91 36.0530.t4 32.67 36.44

0.797 0.704 0.6820.835 0.743 0.7000.971 0.796 0.7660.932 0.815 0.7920.683 0.691 0.6650.728 0.721 0.6s30.775 0.782 0.7740.816 0.798 0.786

PE : Polyethylene pouch, BP : Butter paper bag, ACF : Aluminium co-extruded film pouch.being more pronounced at higher temperatures. The slight increase in total sugars may besimply due to the loss of moisture from the samples leading to concentration of all constituentsincluding sugars' There was decline in ascorbic acid during the storage of apple cheese (Table3). Highest loss of ascorbic acid was in samples stored in polyethylene ioucnes e6.-44%).More ascorbic acid was retained at lower temperatures. The loss tf asc'orbic acid may betraced to its oxidation and involvement in non-enrymatic browning reaction. The maximumloss of ascorbic acid at ambient temperature may be attributed to theiigher rate of oxidation ofascorbic acid. Lower retention of ascorbic acid in polyethylene pouches may be due to greaterpermeability of these packages to light and oxygen. During storage, there was u "ortlnuou.ignificant increase in non-enzymatic browning (Table 3). Non-enzymatic browning was highestin polyethylene pouches (0.932). Browning intensity was lowei at low temperiture thfr: atambient temperature. This can be attributed to the higher rates of inversion of sugars and


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100 Rai, Sethi and Jayachandran

breakdown of ascorbic acid and consequently higher rates of browning reaction at ambientthan at low temperature. The microbial examination revealed absence of both yeasts andosmophiles in the freshly made cheese (Table 4). At the end of the storage period of fourmonths counts foryeast ranged from 0-30 cfir/g ofcheese with maximum counts in polyethylenepouches at arrbient (30 cfir/g). The osmophile species were identifi ed as Aspergillus spp. andPenicillium spp. The samples packed in polyethylene pouches registered comparatively highmicrobial counts and among them higher counts were obtained at low temperature storage.This can be explained on the basis of higher moisture retention at lower temperature than atambienttemperature andthe higherpermeabilityofpolyettrylene film in comparisonto aluminiumco-exfuded film pouches.Table 4. Microbial counts of guava cheese after four months storageStorage temperature Packaging material

Polyethylenepouch Butter paper bag Aluminiumco-extrudedfilm pouch

Yeast cfir/gOsmophiles cfu/gYeast cfu/gOsmophiles cfu/g

nl05n

30l5nn

Ambient (16.6 to 3l.7oc)l00Low(7to 10oC)00

REFERENCESA. O. A. C. (1980). fficial Methods of Analysis, I4th edz. Association of Official Analytical Chemists,Washington, D. C.APHA (1992). Compendium of Methods for Mitobiological Examination of Foods, 3rd edn.Jain, N. L., Das, D. P. and Lal, G. (1954). Preparation of guava cheese. Chem. Age of India Series 9 : 88.Lane, J. H. and Eyron, J. (1923). Determination of reducing sugars by Fehlings solution with methyleneblue as indicator. J. Sci. Chem. Ind. 42:327.Rangannq S. (1997). Handbook of Analysis of Quality Control for Fruit and Vegetable Products,

2nd edn. Tata McGraw Hill Publishing Company Limited, New Delhi.

storage studies in guava cheese-libre

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