innovative pre-treatments to enhance food drying: a
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Innovative pre-treatmentS to enhance food DRYING: a current review
B Llavata, JV Garcıa-Perez, S Simal, JA Carcel
PII: S2214-7993(19)30130-4
DOI: https://doi.org/10.1016/j.cofs.2019.12.001
Reference: COFS 531
To appear in: Current Opinion in Food Science
Please cite this article as: Llavata B, Garcıa-Perez J, Simal S, Carcel J, Innovativepre-treatmentS to enhance food DRYING: a current review, Current Opinion in Food Science(2019), doi: https://doi.org/10.1016/j.cofs.2019.12.001
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© 2019 Published by Elsevier.
INNOVATIVE PRE-TREATMENTS TO ENHANCE FOOD DRYING: A CURRENT REVIEW
1Llavata, B., 1García-Pérez, J.V., 2Simal, S., 1Cárcel, J.A.
1Analysis and Simulation of Agro-food Processes Group. Food Technology Department, Universitat Politècnica de València, Camino de Vera s/n, E46022, Valencia, Spain
2Department of Chemistry, University of the Balearic Islands, Ctra. Valldemossa, km 7.5, E07122, Palma de Mallorca, Spain
Corresponding author:
Juan A. Cárcel
E-mail:jcarcel@tal.upv.es
Tf: +34 96 387 93 65
Graphical abstract
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Highlights
The influence of pre-treatments on drying kinetic was updated
Ultrasound, pulsed electric field, high pressure and ethanol were reviewed
Pre-treatments significantly reduce energy consumption
Pre-treatments can affect bioactive compounds retention, colour or texture
This influence depends on pre-treatment, process variables and products
Abstract
The application of pre-treatments before drying represents an alternative to better
preserve fresh food properties and reduce the energy needs. The aim of this review
was to analyse the influence of different pre-treatments (ultrasound, pulsed electric
fields, high pressure processing or ethanol) on drying. For this purpose, the effect on
food matrices, drying kinetics and different quality parameters has been addressed
through the review of the most recent studies. The results can differ greatly depending
on the type of pre-treatment and the product considered but, in some cases, an
increase in the drying rate and a better retention of quality can be observed. Even so, it
is necessary to continue studying these pre-treatments to better understand the effect caused.
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Keywords: ultrasound, pulsed electric fields, high pressure, ethanol, kinetics, quality
1. Introduction
Drying is one of the oldest, widely-applied food preservation operations. It consists of
the reduction in the water content slowing down microbial or enzymatic degradation
reactions. The quality of the product obtained depends largely on the methodology
used. Generally, processes that involve low temperatures (such as freeze-drying)
require long drying times, so high temperature drying techniques are more extensive,
although this may compromise the quality. So, the food industry faces the challenge of
achieving shorter drying times under moderate conditions and maximizing product
quality.
Conventionally, the use of different pre-treatments has been one of the most
commonly-followed strategies. In this sense, the blanching of vegetable tissue, one of
the most widely-used pre-treatments, implies enzymatic inactivation, intracellular air
expulsion, a reduction in colour and taste loss, as well as an improvement in the drying
rate [1]. Another conventional pre-treatment is osmotic dehydration. It consists of the
introduction of the food matrix into a hypertonic solution which entails a partial loss of
water, shortening the subsequent drying time, and reducing the gain of solids, which
results in products with better organoleptic or functional properties [2].
In recent years, the introduction of emerging technologies as drying pre-treatments has
come under consideration. The application of ultrasound, pulsed electric fields, high
pressures or ethanol pre-treatments does not involve high temperatures but can
shorten the drying time, improve the final quality of products, and is more
environmentally-friendly because of the lower energy consumption.
The aim of this paper is to review the current findings in some of these alternative pre-
treatments addressing their effectiveness at drying enhancement as well as the
influence on quality parameters, such as the retention of bioactive compounds, the
colour or the texture of the final product.
1. Pre-treatments
1.1 Ultrasound
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Ultrasound (US) consists of mechanical waves with a frequency greater than 20 kHz.
When applied with enough energy, it produces effects, such as cavitation, the
successive compressions and expansions of the treated material or an intense
microstirring at interfaces, which facilitate mass transfer (Figure 1A). However, the
large impedance difference between the generator systems and gas media makes the
propagation of the waves quite difficult [3]. This is the reason why the offer of
commercial transducers for liquid systems, where it is easy to propagate the acoustic
waves, is greater than for gas systems. In this sense, many studies can be found that
deal with the application of ultrasound in hyper or hypotonic solutions as pre-treatments
before drying.
The pre-treatments in hypertonic media (osmotic dehydration, OD) result in water loss
(WL) and solid gain (SG) in the matrix treated. US application during the OD process
can contribute to enhance the mass flows. The stress produced by US generates
microchannels that make the water movement inside the solid matrix easier. Moreover,
the weakening of the cellular structure and the creation of microcracks facilitate the
penetration of soluble solids into the structure. In this sense, US has been observed to
be effective in mass transfer during OD in blueberries [4] and carrots [5]. Generally, the
longer the pre-treatment time [6–8], the higher the frequencies [9,10] and the more
ultrasonic power applied [11], the more significant the effects of US.
In the case of US pre-treatment in hypotonic media, the sample can also undergo a
series of microstructural changes such as the deformation of cell walls that results in
the appearance of microchannels and pores. Some authors have studied the
microstructure of pre-treated materials as a means of better understanding the US
effect [12,13]. Thus, Wang et al. [14], studying the case of carrots treated from 360 to
1080 W (30 min, 20 kHz), or Wu et al. [11] analysing Pakchoi stems treated from 300
to 900 W (30 min, 20 kHz), found that the higher the ultrasonic powers is, the greater
the effect on cell structures will be. The immersion time needed to achieve the desired
effect also depends on the food matrix to be treated. Thus, Wang et al. [15] observed
that the kiwifruit treated at 20 kHz and 400 W needed at least 20 minutes to achieve
pore formation, while Miano et al. [16] found that at least 60 minutes of immersion were
required in the pre-treatment of potato at 25 kHz and 364 W.
All these microstructural changes lead to a clear improvement in the mass transfer
during subsequent drying. In this way, it has been reported that US pre-treatment
significantly shortens the drying time in processes, such as freeze-drying [17], hot air
drying [18], microwave [19] or infrared [12]. Generally, the longer the pre-treatment
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time is, the greater the US effect will be, increasing the effective diffusivity of water
during drying [16,20]. Thus, a drying time reduction of 26% was reported in persimmon
fruit [8] when a 20 minute pre-treatment was applied, but this reduction was 39% when
a 30 minute pre-treatment was considered. The US power applied also has a
significant influence on the drying rate. Thus, in the case of Pakchoi stems [11], a
drying time reduction of 25% was obtained when applying 300 W, but this was of 32%
when applying 600 W or 42% when it was 900 W; or in bananas [21] with a 14%
shorter drying time when using 500 W and 22% shorter when applying 1000 W. The
drying time is correlated with energy consumption as has been observed during the
drying of different products, such as almond [20], walnut [19], or potato [18].
However, other authors did not find a significant influence on the drying rate of the US
pre-treatment. Thus, Corrêa et al. [22] attributed the non-effect of the US pre-treatment
to the non-porous product structure and the high fibre content. In addition, the use of a
highly concentrated sugar solution can make the US transmission difficult as a result of
the energy losses due to viscosity. Mierzwa et al. [5] also attributed the non-effect of
the US pre-treatment to the absorption of solids from the osmotic dehydration that
could block the pores of the food matrix and thereby worsen the water transfer.
On the other hand, the improvement of mass transfer in liquid pre-treatments brought
about by US can lead to an enhanced loss in bioactive compounds. Thus, vitamin C
can be diluted in the solution due to its soluble character and facilitated by the
microchannels formed in the food. This has been observed in strawberry [9], kiwifruit
[15] or Pakchoi stems [11]. Losses in phenolic compounds in the osmotic solution have
also been reported in persimmon fruit [8], strawberries [9] and pomegranate arils [10].
Nevertheless, the drying time reduction produced by US pre-treatment involves less
exposure to the high temperatures during drying. In this sense, a greater vitamin C final
content has been found in quince slices [23] and honeyberry fruits [24] and a greater
phenolic compound content in quince [23], banana [21] and sweet potatoes [25].
Colour plays a crucial role in the final consumer acceptance of products. In this sense,
the shorter time exposure to drying produced by the US pre-treatment can reduce the
colour changes with regards to the fresh product [15,21,26]. Moreover, when the US
propagation is carried out in hypertonic media there is an uptake of solids and a
release of gas from the food, which permit a better retention of pigments, as has been
observed in plums [27] or strawberry [28]. On the contrary, in other materials, such as
carrots [5] or tilapia fillets [29], the uptake of solids during OD affects the colour negatively.
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Texture is another important parameter in terms of product quality. Exposure to US and
the subsequent drying results in changes in the tissues. In this sense, the formation of
cracks and microchannels caused by sonication softens the structure, producing food
with a lower degree of hardness and elasticity, as observed by Wang et al. [14] working
on carrots or Zhao et al. [12] studying shiitake mushrooms. On the contrary, although
the US pre-treatment in hypertonic media can reduce hardness in the early stages of
pre-treatment, there is a subsequent increase due to the progressive uptake of solids,
as was observed in the cases of strawberry [9] and pomegranate [10].
1.2 Pulsed electric field
Pulsed electric field (PEF) technology consists of the application of very short, high
voltage, electric pulses to the food matrix. Its main effect is electroporation, which is the
formation of pores (permanent or reversible) in the cell membrane (Figure 1B),
facilitating the mass transport through it. This technology has been studied for different
applications, such as the intensification of compound extraction [30], non-thermal
pasteurization [31] or the improvement of drying. The cell disintegration index (Z-index)
has been widely used to quantify the level of electroporation induced by PEF and
depends on variables, such as matrix structure [32], treatment intensity [33,34] or
number of pulses [35].
PEF has been used as a pre-treatment in different drying processes, such as osmotic
dehydration, vacuum drying, convective drying or freeze-drying. Thus, Yu et al. [36]
observed that in the osmotic dehydration of blueberries, the PEF pre-treatment (3
kV/cm) can significantly accelerate the WL and SG rates. Some studies [37,38] point to
a more pronounced effect on water diffusivity than solute, probably due to membrane
selectivity as well as the greater molecular weight of solids. The PEF pre-treatment
also increases the kinetics of vacuum drying. The level of sample damage can depend
on both the product and the conditions. Thus, when working on blueberries, Yu et al.
[39] observed that the PEF can increase the proportion of damaged samples due to the
pressure gradient generated. However, when drying basil leaves, Telfser and Gómez-
Galindo [35] found no increase in the amount of damage done. As regards convective
air drying, the PEF pre-treatment of samples can increase the drying velocity
[34,40,41]; the greatest effects are found when drying is carried out at moderate
temperatures. For example, 45 °C for onion (1.07 kV/cm) [33] and blueberries (3
kV/cm) [39], 50 °C for potatoes (0.6 kV/cm) [42] or 60 °C for carrots (0.9 kV/cm) [32]. In
the case of other products, such as parsnips (0.9 kV/cm) [32], PEF effects can be more
marked when drying at higher temperatures (70 °C). These apparently contradictory
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effects can be explained by the different interaction of PEF with the initial structure
(porosity, cellular shape and size…) and composition of samples. The
electropermeabilization can also significantly enhance freeze-drying processes, as
reported by Lammerskitten et al. [43] when studying apple. However, the effectiveness
does not reach the levels achieved in other drying processes. Thus, when studying the
drying of basil, Telfser and Galindo reported drying time reductions of 57%, 33% and
25 % for convective, vacuum and freeze-drying respectively [35].
As concerns the effect of the PEF pre-treatment on the retention of the bioactive
compound, no clear trend has been found. In some cases, it has been reported that the
use of PEF has not brought about any significant losses in antioxidant capacity [36,39].
Moreover, PEF treatments combined with sulphites [40] or multicomponent solutions
[37] can allow the uptake of components which improve the antioxidant activity of
products. On the contrary, other studies reported that the electropermeabilization
produced a greater migration of water and other compounds, facilitating the
degradation activity of enzymes, which results in a decrease in antioxidant capacity
[36,39]. In this sense, Lammerskitten et al. [44] observed both an antioxidant
degradation effect and the formation of new phenolic compounds during the drying of
apple samples pre-treated with PEF. On the other hand, the pre-treatment can affect
the antioxidant compounds, such as carotenoids, in different ways. Thus, Huang et al.
[40] observed that the PEF pre-treatment led to an increase in the β-carotene in dried
apricots (45 °C) due to a better extraction as a consequence of electropermeabilization.
This was not observed by Fratianni et al. [45] when studying dried carrots (50 to 70 °C),
which can be attributed to the fact that PEF made these compounds more sensitive to
high temperatures.
Samples pre-treated with PEF generally preserve their colour better due to the release
of intercellular content that affects the activity of some enzymes [32,37]. However, this
depends on the food structure and process conditions. In the case of basil [35] or
apricot [40], for instance, convective drying after PEF pre-treatment can lead to a
decrease in luminosity compared to untreated samples. Nevertheless, when freeze-
dying is applied, the luminosity can increase, this is probably linked to an increase in
product porosity [44].
As for the texture, temperature can induce a greater effect on texture than PEF in the
case of convective drying. In this sense, when working on carrots and parsnips, Lyng et
al. [32] found a higher shear stress in samples dried at high temperatures (70 °C) than
at moderate (50/60 °C), while no differences were found between those samples that
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had been PEF pre-treated (0.9 kV/cm) and those non-pre-treated at the same
temperature. On the contrary, Tylewicz et al. reported that the PEF pre-treatment
produced a dramatic reduction in the hardness of osmotically dehydrated strawberries,
this decrease being proportional to the applied electric field (0.1 – 0.2 – 0.4 kV/cm).
This was attributed to cellular rupture and the creation of pores that led to a softening
of the samples, although in the later stages of the process, a slight increase in
hardness could be evidenced as a result of the uptake of solids. This softening has
also been reported when studying freeze-dried apples (1.07 kV/cm) [44]. In any case, it
must be mentioned the extremely difficult to compare results due not only to the
characteristics of the PEF applied, but also to the subsequent drying process and to
highly variable nature of the products.
Recently, some authors have studied the combination of PEF and US. Using both
technologies for the pre-treatment has obtained a significant shortening in the drying
time of foods, such as carrots [46] or cranberries [47]. The order of application of these
technologies could be an important factor. Thus, some authors have found that the
application of PEF followed by US significantly accelerated the drying process when
compared to the samples treated with US followed by PEF [48]. In addition, the
PEF+US pre-treated samples retained not only the original colour better, but also
polyphenols, anthocyanins or flavonoids. There are, however, still very few studies in
this field.
1.3 High Pressure Processing
High-Pressure Processing (HPP) consists of maintaining food under hydrostatic
pressures (100-800 MPa) during a certain period of time (Figure 1C). The liquids may
be treated directly, but solids have to be previously packaged. This technique has been
widely studied for enzymatic inactivation [49], non-thermal sterilization [50], high
pressure assisted thermal processes [51] or bioactive compound extraction [52]. Its
application as a pre-treatment in drying processes has also been reported.
It is known that HPP causes the modification of the cellular structure, reducing the
turgor pressure and then affecting the permeability and mass transfer. In this sense,
Belmiro et al. [53] found a higher drying rate in beans pre-treated with HPP, especially
at high pressures (600 MPa) and for longer times (10 min). A higher drying rate due to
better effective water diffusivity was also found by George et al. [54], who reported a
significant effect on ginger treated at 400 MPa for 10 min, similarly to Swami Hulle and
Rao [55] when working on Aloe vera samples. These authors found there was a
greater effect of the pressure at moderate temperatures (50/60 °C), than at higher ones
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(70 °C). This has been demonstrated by means of the microstructural analysis of HPP
samples, showing a more irregular structure in ginger [54], with the evident separation
of cells and thinner walls, and without the presence of organelles in Aloe vera samples
[55]. Some of these changes have already been reported by other authors when
studying carrots, sweet potatoes and cocoyams [56].
Changes in the cellular membrane produced by HPP, led to an improvement in the
phenolic compound content, due to their better extraction. Thus, George et al. [54]
found an increase in the 6-gingerol content of samples pre-treated with 400 MPa for 10
minutes. Previous studies of Aloe vera already obtained similar results, observing that
the antioxidant capacity remained stable or improved during the HPP pre-treatment
[55].
The influence of HPP pre-treatments on the colour of dried products is quite limited
[55], as has been observed in studies carried out, for example, on potato [57]. On the
other hand, some of these authors reported a significant decrease in hardness and
compressive strength, explained by changes produced in the cell wall [53,54].
However, other authors, such as Swami Hulle and Rao [55], found an increase in
hardness due to the possible inactivation of pectimethylesterase in treatments of Aloe
vera done at pressures above 500 MPa.
1.4 Ethanol
The application of ethanol as a pre-treatment is a simple but efficient technique that
has also been studied for the purposes of drying intensification. The effect of an
ethanol pre-treatment is based on its ability to dissolve components of the cell wall,
causing changes in the structure and increasing its permeability [58]. Moreover, the
Marangoni effect (Figure 1D), which is based on the formation of a surface tension
gradient between the ethanol and the food’s water content, can significantly enhance
the water transport [59].
Microstructural analyses have shown that the ethanol pre-treated samples have more
compact, thin-walled cells as well as an intracellular air loss [60,61]. As these structural
modifications in the food matrix permitted a greater extraction of water, significant
reductions in the drying time were reported for scallions (25%) [58], potatoes (10%)
[59] and pumpkins (49.5%) [61]. Similar results had already been obtained by means of
the injection of ethanol into balls of mixed rice and soybean protein [62], and in
modified atmospheres during the drying of bananas [63]. The increase in the drying
rate in samples pre-treated with ethanol can be explained by the interaction of ethanol
with water, resulting in a mixture with higher vapour pressure. Otherwise, it is worth
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noting that the combination of ethanol with other techniques, such as vacuum drying
[58], US [60,64] or perforation [59], leads to their intensification.
On the other hand, a greater retention of bioactive compounds in dried samples that
have been pre-treated with ethanol has been reported. Thus, the absorption of ethanol
could provide greater protection against the oxidation of different components, such as
vitamin C [58]. In addition, the shorter drying time means less exposure to high
temperatures and, therefore, greater bioactive retention [65]. A higher volatile
compound content for pineapples treated with ethanol has also been postulated, due to
the condensation of ethanol on the sample surface [66,67].
Minor changes in colour differences have been observed when this pre-treatment is
applied due to a possible inhibition of enzymatic activity, avoiding browning reactions.
This has been found in scallion samples [58] and garlic [64]. With regard to the
mechanical properties of the dehydrated samples, not too much information has been
reported, so it would be interesting to carry out further research in this field.
2. Conclusion
This paper reviews the effectiveness of the application of different drying pre-
treatments. The reduction in the drying time achieved by pre-treating the samples can
result in a better preservation of food quality, as well as significant energy savings.
However, the extent of the effects depends on the pre-treatment, the food matrix
considered and the objective followed. Thus, it has also been shown that each pre-
treatment has some limitations and can sometimes lead to a loss in the quality of
treated foods. In addition, further studies are needed to evaluate and quantify the effect
of pre-treatments, especially in the case of HPP and ethanol. Very interesting results
have been obtained through both the combination of these two pre-treatments or via
the combination of either of them with other techniques; further research into them,
therefore, could be of special interest.
Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal
relationships that could have appeared to influence the work reported in this paper.
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Acknowledgements
The authors would like to acknowledge the financial support of the National Institute of
Research and Agro-Food Technology (INIA), co-financed with ERDF funds (RTA2015-
00060-C04-02 and RTA2015-00060-C04-03).
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References
1. Deng LZ, Pan Z, Mujumdar AS, Zhao JH, Zheng ZA, Gao ZJ, Xiao HW: High-humidity hot air impingement blanching (HHAIB) enhances drying quality of apricots by inactivating the enzymes, reducing drying time and altering cellular structure. Food Control 2019, 96:104–111.
2. Prosapio V, Norton I: Influence of osmotic dehydration pre-treatment on oven drying and freeze drying performance. LWT - Food Sci Technol 2017,
80:401–408.
3. Cárcel JA, García-Pérez JV, Riera E, Rosselló C, Mulet A: Ultrasonically
Assisted Drying. In Ultrasound in food processing. Edited by Villamiel M, García-
Pérez JV, Montilla A, Cárcel JA, Benedito J. John Wiley & Sons; 2017:371-391.
4. Celejewska K, Mieszczakowska-Frąc M, Konopacka D, Krupa T: The influence of ultrasound and cultivar selection on the biocompounds and physicochemical characteristics of dried blueberry (Vaccinium corymbosum L.) snacks. J Food Sci 2018, 83:2305–2316.
5. Mierzwa D, Kowalski SJ, Kroehnke J: Hybrid drying of carrot preliminary processed with ultrasonically assisted osmotic dehydration. Food Technol
Biotechnol 2017, 55:197–205.
6. Fernandes FAN, Braga TR, Silva EO, Rodrigues S: Use of ultrasound for dehydration of mangoes (Mangifera indica L.): kinetic modeling of ultrasound-assisted osmotic dehydration and convective air-drying. J Food
Sci Technol 2019, 56:1793–1800.
7. Shekar F, Javadi A: The effect of ultrasound-assisted osmotic dehydration pretreatment on the convective drying of apple slices (var.Golab). J Food
Biosci Technol 2019, 9:83–94.
8. Bozkir H, Ergün AR, Serdar E, Metin G, Baysal T: Influence of ultrasound and osmotic dehydration pretreatments on drying and quality properties of persimmon fruit. Ultrason Sonochem 2019, 54:135-141.
doi:10.1016/j.ultsonch.2019.02.006.
9. Noshad M, Savari M, Roueita G: A hybrid AHP-TOPSIS method for prospectively modeling of ultrasound-assisted osmotic dehydration of strawberry. J Food Process Eng 2018, 41:1–8.
10. Allahdad Z, Nasiri M, Varidi M, Varidi MJ: Effect of sonication on osmotic
Jour
nal P
re-p
roof
dehydration and subsequent air-drying of pomegranate arils. J Food Eng
2019, 244:202–211.
11. Wu XF, Zhang M, Mujumdar AS, Yang CH: Effect of ultrasound-assisted osmotic dehydration pretreatment on the infrared drying of Pakchoi Stems.
Dry Technol 2019, 0:1–12.
12. Zhao YY, Yi JY, Bi JF, Chen QQ, Zhou M, Zhang B: Improving of texture and rehydration properties by ultrasound pretreatment for infrared-dried shiitake mushroom slices. Dry Technol 2019, 37:352–362.
13. Tüfekçi S, Özkal SG: Enhancement of drying and rehydration characteristics of okra by ultrasound pre-treatment application. Heat Mass
Transf 2017, 53:2279–2286.
14. Wang L, Xu B, Wei B, Zeng R: Low frequency ultrasound pretreatment of carrot slices: Effect on the moisture migration and quality attributes by intermediate-wave infrared radiation drying. Ultrason Sonochem 2018,
40:619–628.
15. Wang J, Xiao HW, Ye JH, Wang J, Raghavan V: Ultrasound pretreatment to enhance drying kinetics of kiwifruit (Actinidia deliciosa) slices: pros and cons. Food Bioprocess Technol 2019, 12:865-876. doi:10.1007/s11947-019-
02256-4.
** It is studied the effect of the ultrasonically assited OD in drying kinetics,
phenol content, vitamin C, microstructure and color of kiwifruit. The results show
the enhancement of drying by ultrasound application as well as the influence on
the retention of color and bioactive compounds.
16. Miano AC, Rojas ML, Augusto PED: Structural changes caused by ultrasound pretreatment: Direct and indirect demonstration in potato cylinders. Ultrason Sonochem 2019, 52:176–183.
17. Cao X, Zhang M, Mujumdar AS, Zhong Q, Wang Z: Effects of ultrasonic pretreatments on quality, energy consumption and sterilization of barley grass in freeze drying. Ultrason Sonochem 2018, 40:333–340.
18. Jarahizadeh H, Dinani ST: Influence of applied time and power of ultrasonic pretreatment on convective drying of potato slices. Food Sci Biotechnol
2019, 28:365–376.
19. Abbaspour‐Gilandeh Y, Kaveh M, Jahanbakhshi A: The effect of microwave
Jour
nal P
re-p
roof
and convective dryer with ultrasound pre‐treatment on drying and quality properties of walnut kernel. J Food Process Preserv 2019,
doi:10.1111/jfpp.14178.
20. Kaveh M, Jahanbakhshi A, Abbaspour-Gilandeh Y, Taghinezhad E, Moghimi
MBF: The effect of ultrasound pre-treatment on quality, drying, and thermodynamic attributes of almond kernel under convective dryer using ANNs and ANFIS network. J Food Process Eng 2018, 41:1–14.
21. Nadery Dehsheikh F, Taghian Dinani S: Coating pretreatment of banana slices using carboxymethyl cellulose in an ultrasonic system before convective drying. Ultrason Sonochem 2019, 52:401–413.
* US influence on drying time, color, phenols and energy requirements is
evaluated. The pre-treatment improves drying rate, energy consumption while
preserving final quality.
22. Corrêa JLG, Rasia MC, Mulet A, Cárcel JA: Influence of ultrasound application on both the osmotic pretreatment and subsequent convective drying of pineapple (Ananas comosus). Innov Food Sci Emerg Technol 2017,
41:284–291.
23. Yildiz G, Izli G: The effect of ultrasound pretreatment on quality attributes of freeze‐dried quince slices: Physical properties and bioactive compounds. J
Food Process Eng 2019, 42:1–8.
24. Šic Žlabur J, Colnar D, Voća S, Lorenzo JM, Munekata PES, Barba FJ,
Dobričević N, Galić A, Dujmić F, Pliestić S, et al.: Effect of ultrasound pre-treatment and drying method on specialized metabolites of honeyberry fruits (Lonicera caerulea var. kamtschatica). Ultrason Sonochem 2019,
56:372–377.
25. Rashid MT, Ma H, Jatoi MA, Wali A, El-Mesery HS, Ali Z, Sarpong F: Effect of infrared drying with multifrequency ultrasound pretreatments on the stability of phytochemical properties, antioxidant potential, and textural quality of dried sweet potatoes. J Food Biochem 2019, 43:1–14.
26. Osae R, Zhou C, Xu B, Tchabo W, Tahir HE, Mustapha AT, Ma H: Effects of ultrasound, osmotic dehydration, and osmosonication pretreatments on bioactive compounds, chemical characterization, enzyme inactivation, color, and antioxidant activity of dried ginger slices. J Food Biochem 2019,
Jour
nal P
re-p
roof
43:1–14.
27. Dehghannya J, Gorbani R, Ghanbarzadeh B: Influence of combined pretreatments on color parameters during convective drying of Mirabelle plum (Prunus domestica subsp. syriaca). Heat Mass Transf und
Stoffuebertragung 2017, 53:2425–2433.
28. Prosapio V, Norton I: Simultaneous application of ultrasounds and firming agents to improve the quality properties of osmotic + freeze-dried foods.
LWT 2018, 96:402–410.
29. Li M, Ye B, Guan Z, Ge Y, Li J, Ling CM: Impact of ultrasound-assisted osmotic dehydration as a pre-treatment on the quality of heat pump dried tilapia fillets. Energy Procedia 2017, 123:243–255.
30. Toepfl S, Mathys A, Heinz V, Knorr D: Review: Potential of high hydrostatic pressure and pulsed electric fields for energy efficient and environmentally friendly food processing. Food Rev Int 2006, 22:405–423.
31. Vega-Mercado H, Martín-Belloso O, Qin BL, Chang FJ, Góngora-Nieto MM,
Barbosa-Cánovas G V., Swanson BG: Non-thermal food preservation: Pulsed electric fields. Trends Food Sci Technol 1997, 8:151–157.
32. Lyng JG, Frontuto D, Marra F, Cinquanta L, Alam MR: Effect of pulsed electric field pretreatment on drying kinetics, color, and texture of parsnip and carrot. J Food Sci 2018, 83:2159–2166.
*It is investigated the impact of PEF pre-treatment in drying kinetics, color and
textural changes in parsnip and carrot. This study shows the clear influence of
the food matrix on the effect caused by PEF.
33. Siemer C, Jäger H, Giersemehl P, Ostermeier R, Töpfl S: Influence of pulsed electric field (PEF) pre-treatment on the convective drying kinetics of onions. J Food Eng 2018, 237:110–117.
34. Chauhan OP, Sayanfar S, Toepfl S: Effect of pulsed electric field on texture and drying time of apple slices. J Food Sci Technol 2018, 55:2251–2258.
35. Telfser A, Gómez Galindo F: Effect of reversible permeabilization in combination with different drying methods on the structure and sensorial quality of dried basil (Ocimum basilicum L.) leaves. LWT 2019, 99:148–155.
** This paper evaluates the influence of PEF pre-treatment in later drying by
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using hot air drying, vacuum or freeze-drying reporting significant differences
among the different methods. In addition, the authors also studyied the influence
of pre-treatment with PEF in cell viability and final product quality.
36. Yu Y, Jin TZ, Fan X, Wu J: Biochemical degradation and physical migration of polyphenolic compounds in osmotic dehydrated blueberries with pulsed electric field and thermal pretreatments. Food Chem 2018, 239:1219–1225.
37. Dermesonlouoglou E, Chalkia A, Dimopoulos G, Taoukis P: Combined effect of pulsed electric field and osmotic dehydration pre-treatments on mass transfer and quality of air dried goji berry. Innov Food Sci Emerg Technol
2018, 49:106–115.
38. Tylewicz U, Tappi S, Mannozzi C, Romani S, Dellarosa N, Laghi L, Ragni L,
Rocculi P, Dalla Rosa M: Effect of pulsed electric field (PEF) pre-treatment coupled with osmotic dehydration on physico-chemical characteristics of organic strawberries. J Food Eng 2017, 213:2–9.
39. Yu Y, Jin TZ, Xiao G: Effects of pulsed electric fields pretreatment and drying method on drying characteristics and nutritive quality of blueberries. J Food Process Preserv 2017, 41.
40. Huang W, Feng Z, Aila R, Hou Y, Carne A, Bekhit AEDA: Effect of pulsed electric fields (PEF) on physico-chemical properties, β-carotene and antioxidant activity of air-dried apricots. Food Chem 2019, 291:253–262.
41. Liu C, Grimi N, Lebovka N, Vorobiev E: Convective air, microwave, and combined drying of potato pre-treated by pulsed electric fields. Dry Technol
2018, 0:1–10.
42. Liu C, Grimi N, Lebovka N, Vorobiev E: Effects of preliminary treatment by pulsed electric fields and convective air-drying on characteristics of fried potato. Innov Food Sci Emerg Technol 2018, 47:454–460.
43. Lammerskitten A, Mykhailyk V, Wiktor A, Toepfl S, Nowacka M, Bialik M,
Czyżewski J, Witrowa-Rajchert D, Parniakov O: Impact of pulsed electric fields on physical properties of freeze-dried apple tissue. Innov Food Sci
Emerg Technol 2019, 57:102211.
44. Lammerskitten A, Wiktor A, Siemer C, Toepfl S, Mykhailyk V, Gondek E, Rybak
K, Witrowa-Rajchert D, Parniakov O: The effects of pulsed electric fields on the quality parameters of freeze-dried apples. J Food Eng 2019, 252:36–43.
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45. Fratianni A, Niro S, Cristina M, Gianfranco M, Francesco P, Cinquanta L:
Evaluation of carotenoids and furosine content in air dried carrots and parsnips pre ‑ treated with pulsed electric field ( PEF ). Eur Food Res
Technol 2019, doi:10.1007/s00217-019-03367-0.
46. Wiktor A, Witrowa-Rajchert D: Drying kinetics and quality of carrots subjected to microwave-assisted drying preceded by combined pulsed electric field and ultrasound treatment. Dry Technol 2019, 0:1–13.
47. Wiktor A, Nowacka M, Anuszewska A, Rybak K, Dadan M, Witrowa-Rajchert D:
Drying kinetics and quality of dehydrated cranberries pretreated by traditional and innovative techniques. J Food Sci 2019, doi:10.1111/1750-
3841.14651.
48. Wiktor A, Dadan M, Nowacka M, Rybak K, Witrowa-Rajchert D: The impact of combination of pulsed electric field and ultrasound treatment on air drying kinetics and quality of carrot tissue. Lwt 2019, 110:71–79.
* This study analyzes the combination of US and PEF as pretreatment to drying
and its influence on the retention of bioactive and color. The authors found very
promising results regarding the improvement of drying and retention of
compounds.
49. Giannoglou M, Alexandrakis Z, Stavros P, Katsaros G, Katapodis P, Nounesis
G, Taoukis P: Effect of high pressure on structural modifications and enzymatic activity of a purified X-prolyl dipeptidyl aminopeptidase from Streptococcus thermophilus. Food Chem 2018, 248:304–311.
50. Codina-Torrella I, Guamis B, Zamora A, Quevedo JM, Trujillo AJ:
Microbiological stabilization of tiger nuts’ milk beverage using ultra-high pressure homogenization. A preliminary study on microbial shelf-life extension. Food Microbiol 2018, 69:143–150.
51. Evelyn, Silva FVM: Heat assisted HPP for the inactivation of bacteria, moulds and yeasts spores in foods: Log reductions and mathematical models. Trends Food Sci Technol 2019, 88:143–156.
52. Irna C, Jaswir I, Othman R, Jimat DN: Comparison Between High-Pressure Processing and Chemical Extraction: Astaxanthin Yield From Six Species of Shrimp Carapace. J Diet Suppl 2018, 15:805–813.
53. Belmiro RH, Tribst AAL, Cristianini M: Impact of high pressure processing in
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hydration and drying curves of common beans (Phaseolus vulgaris L.). Innov Food Sci Emerg Technol 2018, 47:279–285.
54. George JM, Sowbhagya HB, Rastogi NK: Effect of high pressure pretreatment on drying kinetics and oleoresin extraction from ginger. Dry
Technol 2018, 36:1107–1116.
* The innfluence of HPP pretreatment in drying kinetics, microstructure as well
as in the retention of biaoactive compounds is studied in this paper. The images
obtained from the microstructure probe the influence of pre-treatment and help
to explain the improvement of drying kinetics and alteration of compounds.
55. Swami Hulle NR, Rao PS: Effect of high pressure pretreatments on structural and dehydration characteristics of aloe vera (Aloe barbadensis Miller) cubes. Dry Technol 2016, 34:105–118.
56. Oliveira MM De, Tribst AAL, Leite Júnior BRDC, Oliveira RA De, Cristianini M:
Effects of high pressure processing on cocoyam, peruvian carrot, and sweet potato: Changes in microstructure, physical characteristics, starch, and drying rate. Innov Food Sci Emerg Technol 2015, 31:45–53.
57. Al-Khuseibi MK, Sablani SS, Perera CO: Comparison of water blanching and high hydrostatic pressure effects on drying kinetics and quality of potato.
Dry Technol 2005, 23:2449–2461.
58. Wang X, Feng Y, Zhou C, Sun Y, Wu B, Yagoub AEGA, Aboagarib EAA: Effect of vacuum and ethanol pretreatment on infrared-hot air drying of scallion (Allium fistulosum). Food Chem 2019, 295:432–440.
59. Rojas ML, Silveira I, Augusto PED: Improving the infrared drying and rehydration of potato slices using simple approaches: Perforations and ethanol. J Food Process Eng 2019, doi:10.1111/jfpe.13089.
60. Rojas ML, Augusto PED: Ethanol and ultrasound pre-treatments to improve infrared drying of potato slices. Innov Food Sci Emerg Technol 2018, 49:65–
75.
61. Rojas ML, Augusto PED: Ethanol pre-treatment improves vegetable drying and rehydration: Kinetics, mechanisms and impact on viscoelastic properties. J Food Eng 2018, 233:17–27.
** This work evaluates the effect of ethanol pre-treatment on the microstructure,
drying kinetics and viscoelastic properties of food matrixes. The results obtained
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demonstrate the potential of ethanol as a pre-treatment for drying.
62. Tatemoto Y, Mizukoshi R, Ehara W, Ishikawa E: Drying characteristics of food materials injected with organic solvents in a fluidized bed of inert particles under reduced pressure. J Food Eng 2015, 158:80–85.
63. Taylor P, Luiz J, Corrêa G, Murteira A, Braga P, Hochheim M, Murteira A, Braga
P, Luiz J, Corre G: The influence of ethanol on the convective drying of unripe, ripe , and overripe bananas. Dry Technol 2012, 30:8:817–826.
64. Feng Y, Zhou C, ElGasim A. Yagoub A, Sun Y, Owusu-Ansah P, Yu X, Wang X,
Xu X, Zhang J, Ren Z: Improvement of the catalytic infrared drying process and quality characteristics of the dried garlic slices by ultrasound-assisted alcohol pretreatment. LWT 2019, 116:108577.
65. Santos PHS, Silva MA: Kinetics of L -ascorbic acid segradation in pineapple drying under ethanolic atmosphere. Drying Technol 2009, 27:947-954.
doi:10.1080/07373930902901950.
66. Braga AMP, Pedroso MP, Augusto F, Silva MA: Volatiles identification in pineapple submitted to drying in an ethanolic atmosphere. Dry Technol
2009, 27:248–257.
67. Braga AMP, Silva MA, Pedroso MP, Augusto F, Barata LE: Volatile composition changes of pineapple during drying in modified and controlled atmosphere. International Journal of Food Engineering 2010, 6:1
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