This article was downloaded by: [Sílvia P. M. Germer]
On: 12 June 2014, At: 08:00
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Drying Technology: An International Journal
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/ldrt20
Influence of Processing Additives on the Quality
and Stability of Dried Papaya Obtained by Osmotic
Dehydration and Conventional Air Drying
a
a
c
a
Sílvia P. M. Germer , Cristhiane C. Ferrari , Julia P. Lancha , Shirley A. G. Berbari ,
d
Sandra M. Carmello-Guerreiro & Cristiane R. G. Ruffi
b
a
Fruit and Vegetable Technology Center, Institute of Food Technology, ITAL , Campinas , SP ,
Brazil
b
Cereal and Chocolate Technology Center, Institute of Food Technology, ITAL , Brazil
c
Food Engineering College, State University of Campinas, Unicamp , Campinas , Brazil
d
Department of Botany , Institute of Biology, State University of Campinas, Unicamp ,
Campinas , Brazil
Accepted author version posted online: 11 Jun 2014.Published online: 11 Jun 2014.
To cite this article: Sílvia P. M. Germer , Cristhiane C. Ferrari , Julia P. Lancha , Shirley A. G. Berbari , Sandra M.
Carmello-Guerreiro & Cristiane R. G. Ruffi (2014): Influence of Processing Additives on the Quality and Stability of Dried
Papaya Obtained by Osmotic Dehydration and Conventional Air Drying, Drying Technology: An International Journal, DOI:
10.1080/07373937.2014.924963
To link to this article: http://dx.doi.org/10.1080/07373937.2014.924963
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service
to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting,
typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of
the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the
content, and all legal disclaimers that apply to the journal relate to this version also.
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions
ACCEPTED MANUSCRIPT
Influence of Processing Additives on The Quality and Stability of Dried Papaya
Obtained by Osmotic Dehydration and Conventional Air Drying
Sílvia P. M. Germer1, Cristhiane C. Ferrari1, Julia P. Lancha3, Shirley A. G. Berbari1,
Sandra M. Carmello-Guerreiro4, Cristiane R. G. Ruffi2
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
1
Fruit and Vegetable Technology Center, Institute of Food Technology, ITAL, Campinas,
SP, Brazil 2Cereal and Chocolate Technology Center, Institute of Food Technology,
ITAL, Brazil 3Food Engineering College, State University of Campinas, Unicamp,
Campinas, Brazil 4Department of Botany, Institute of Biology, State University of
Campinas, Unicamp, Campinas, Brazil
Corresponding author: S. P. M. Germer Fruit and Vegetable Technology Center, Institute
of Food Technology, ITAL, Av. Brasil, 2880, 13070-178 Campinas, SP, Brazil E-mail:
sgermer@ital.sp.gov.br
The combination of osmotic dehydration and hot air drying (OD/HA) is an industrial
alternative to Papaya production, but tissue softening and color loss are technological
problems. The objective of this work was to study, during OD/HA processing of papaya
(Formosa cultivar), the influence of organic acids (citric and lactic), calcium salts (lactate
and chloride), and the enzyme pectinmethylesterase (PME) on the texture, color and
sensory characteristics of the product. The stability of the products treated with lactic
acid/calcium chloride, PME/calcium chloride and the standard sample (without additives)
was evaluated at 25ºC and 35ºC for up to 100 days, analyzing vitamin C and color
degradation. Light microscopy analysis performed at the beginning of stability study
showed that the additives better preserved the cell structure. The use of lactic
acid/calcium chloride maintained the color of the dried papaya, but the additives did not
have an effect on vitamin C degradation. The variations in the chromaticity parameters
(b* and a*) were adjusted to zero and first order kinetic models, respectively, with Q10
ACCEPTED MANUSCRIPT
1
ACCEPTED MANUSCRIPT
values ranging between 0.88 and 2.30 and R2~0.90. The combination of lactic
acid/calcium chloride resulted in higher sensory acceptance and color stability of dried
papaya during storage.
KEYWORDS: calcium, pectinmethylesterase, color, vitamin C, kinetics
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
INTRODUCTION
Brazil is the greatest world producer of Papaya (Carica papaya L.) with 1.8 million tons
per year, and the second largest exporter of the fresh fruit. [1,2] Three different cultivars
are grown: Comum, Solo and Formosa. The production of Formosa cultivar is directed to
the internal market, resulting in larger fruits with greater transportation resistance and
containing higher sugar contents. [3] The fruit has a high nutritive value, being rich in
vitamin C (30-130 mg/100 g), vitamin B1 (40-45 mg/100 g), B2 (40-50 mg/100 g) and A
(1200-1650 units/100 g), as well as minerals such as potassium (222 mg/100 g) and
magnesium (17 mg/100 g). [3,4] Papaya, principally the red pulp ones such as Formosa
cultivar, is also an important source of lycopene (21 to 29.6 µg/g), a bioactive compound
with preventative action against heart diseases and some types of cancer. [5,6]
The production of dried fruits could be an alternative to exploit any excess fruit
production, offering the opportunity to add value to the product and generate jobs and
income. On the other hand, dried fruit products present some aspects, such as healthiness
and convenience, attending new tendencies for food consumption. [7]
ACCEPTED MANUSCRIPT
2
ACCEPTED MANUSCRIPT
The production of dried fruit using the combined method of osmotic dehydration (OD)
and complementary hot air drying (HA) is a technological alternative with some
advantages when compared with conventional processes, improving nutritional and
sensory properties of air-dried products. [8] OD has been studied as a preliminary step in
the drying of fruits, and consists of immersing them in a hypertonic solution of one or
more solutes, such that the partial removal of water occurs mainly due to the chemical
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
potential established. [9,10] The combination of both techniques has been employed in
several fruits, such as cherry tomato [11], mulberry [12], seabuckthorn fruits [13], strawberry
[14]
and chayote [15], resulting in products with good quality.
Some studies have reported the potential for the application of osmotic dehydration (OD)
in papaya processing. [3,9,16–19] However, the technique presents some technological
problems which complicate the industrial scale process, notably softening of the
vegetable tissue during OD and loss of color. [17] The cell tissues of papaya are highly
fragile, tending to collapse during the process as a function of the ripening stage and
time-temperature conditions, making them difficult to handle, which results in losses. In
addition, due to carotenoid oxidation, the color of the fruit undergoes changes during
shelf life, compromising product quality. [9,16]
The application of organic acids and calcium salts during OD of papaya has been
reported in the literature with the aim of minimizing these problems. Weak acids such as
lactic and citric acids prevent the color change due to the inhibition of enzymatic
browning, while the calcium salts (calcium lactate and chloride) are applied as texture
ACCEPTED MANUSCRIPT
3
ACCEPTED MANUSCRIPT
agents [16–18,20–22]. According to Suttirak & Manurakchinakorn[23] weak acids retard
browning by lowering the pH of the product, minimizing the activity of poliphenol
oxydase (PPO). Some acids like citric acid also delay discoloration by chelating the
copper at PPO active site. According to Chiumarelli et al.[20], the use of weak acids, such
as citric acid, can avoid enzymatic browning of plant tissue, thereby reducing the product
appearance loss. The calcium ion is supposed to form a complex with pectin in the cell
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
wall and middle lamella of vegetable tissue, resulting in a firmer structure. [17]
The use of the enzyme pectinmethylesterase (PME) associated with calcium salts has also
been evaluated as a texture agent in fruit processing. PME is produced by fungi and
catalyzes the hydrolysis of methyl esters on the pectin molecule, resulting in pectin free
of carboxyl groups, whose negative charges bind to Ca2+ ions forming a tridimensional
matrix and promoting greater resistance of the cell wall middle lamella. The use of PME
associated to calcium chloride was reported in the combined OD/freezing and heat
processing/high pressure processes of strawberries. [24,25] However, the application of
PME/calcium chloride in the combined osmotic dehydration/hot air drying process has
not been reported yet.
In this context, the objective of the present study was to analyze the effect of some
organic acids (citric and lactic) associated with calcium salts (lactate and chloride) on the
combined OD/HA processing of papaya. The use of PME with calcium chloride was also
evaluated as an alternative, since its application is completely unknown. Technological
ACCEPTED MANUSCRIPT
4
ACCEPTED MANUSCRIPT
aspects such as texture, color and stability of the final products during storage were
determined.
MATERIAL AND METHODS
Raw Material
Papayas of Formosa cultivar (~2.5 kg) were obtained from the local market in Campinas,
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
Brazil, and stored at room temperature for maturation. The fruits were used in the
maturity state denominated as ¾, when 50 to 75% of the skin is yellow.[26] Table 1 shows
the physicochemical characteristics of the raw material.
Refined sugar of the brand União (Coopersucar, Piracicaba, Brazil) was used to prepare
the osmotic solution. The acids and organic salts were obtained from Labsynth (Brazil).
The enzyme E.C 3.1.1.11 (10 Pectin Esterase Units/ml) (NovoShapeTM , Novozyme,
Denmark), obtained from a fermentation process with Aspergillus aculeatus, was used.
Methodology
The study was carried out in two steps: (1) Study of the effect of the additives on the
combined OD/HA process; (2) Study of the stability during storage.
Study Of The Effect Of The Additives On The Combined OD/HA Process
Experimental OD/HA Trials
The fruits were selected, washed with tap water, peeled and cut into slices of
approximately 6x2x0.5 cm.
ACCEPTED MANUSCRIPT
5
ACCEPTED MANUSCRIPT
According to some preliminary tests, the trials were carried out with the following
combinations of additives: 0.1M citric acid with calcium lactate (0.5 g/100 g syrup)
(CA/CL); 0.1M lactic acid with calcium lactate (0.5 g/100 g syrup) (LA/CL); 0.1M citric
acid with calcium chloride (0.5 g/100 g syrup) (CA/CC); 0.1M lactic acid with calcium
chloride (0.5 g/100 g syrup) (LA/CC); and PME (1 ml/kg fruit) with calcium chloride (1
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
g/kg fruit) (PME/CC). The last trial, considered as the standard, was carried out without
additives (P).
The OD was carried out in an 8 liter heat controlled bath with circulation (10 L/min)
(Model 1266-02, Cole-Parmer, Vernon Hills, USA). The concentration of the sucrose
syrup was 65ºBrix and the mass ratio of syrup to fruit was 4:1 (mass syrup: mass fruit).
The additives were added to the syrup at the beginning of each trial. The manufacturer’s
instructions were followed in the trial with PME, using 1 ml of enzyme (10 Pectin
Esterase Units/ml) per kg of fruit, corresponding to 0.03 g/100 g of syrup, plus 1g
calcium chloride per kg of fruit, corresponding to 0.03 g/100 g of syrup. The process was
performed for 2 hours at 50ºC, according to some preliminary tests. At the end of the OD,
the slices were removed from the bath, drained, rinsed with water and carefully drained
with absorbent paper. The mass of the fruit was weighed at the beginning and at the end
of OD using a mechanical balance (BPS-15, Filizola, São Paulo, Brazil), separating
samples for the analyses.
ACCEPTED MANUSCRIPT
6
ACCEPTED MANUSCRIPT
The osmo-dehydrated fruits were dried in a tray drier (K13964, Proctor & Schwartz,
Lexington, USA) with air circulation (velocity of 1.5m/s) at 60ºC, for a time sufficient to
obtain a final moisture content around 16%.
Mass Transfer Parameters
During the osmotic dehydration process, water loss (WL) and solids incorporation (SI)
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
were calculated using the following equations:
WL = (UiMi − UfMf ) Mi × 100
(g of water/100 g of initial mass)
(1)
SI = ( STfMf − STiMi) Mi × 100
(g of solute/100 g of initial mass)
(2)
Analyses
The raw material used in the trials was subjected to the following analyses: moisture
content, vitamin C content and instrumental color. After OD, the osmo-dehydrated fruits
were analyzed with respect to moisture content and vitamin C content. The final product
after HA (dried fruits) was analyzed in terms of moisture content, water activity, color
and texture. These samples were also subjected to a sensory analysis.
The moisture content was determined in a vacuum oven at 70ºC to constant weight,
according to AOAC[27], and the water activity using a hygrometer (Aqualab-3TE,
Decagon Devices Inc., Pullman, USA) at 25 °C. A colorimeter (CR400, Minolta, Osaka,
Japan) was used for the color analyses making a direct reading of the sample with the d/0
configuration and D65 illuminant and employing the CIELAB system: chromaticity
parameters a* (green [-] to red [+]) and b* (blue [-] to yellow [+]). Lightness L* (L* = 0
ACCEPTED MANUSCRIPT
7
ACCEPTED MANUSCRIPT
for black and L* = 100 for white) was also measured. The texture (cutting force) was
evaluated using a Universal Testing Machine (TA.XT2i Texture Analyzer, Stable Micro
Systems, Godalming, England), with a blade set probe (HDP/BSK) and the HDP/90
platform. The parameters used in the test were: (i) pre-test velocity = 2.0 mm/s; (ii) test
velocity = 1.0 mm/s; (iii) post-test velocity = 10.0 mm/s; (iv) distance 99% of the sample,
with a compression force of 100 gram-force (gf), time of 5 s, trigger of 5 g and load cell
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
of 50 Kg. The vitamin C content was determined according to the titration method of
Oliveira et al.[28], and the percent retention of vitamin C in relation to the raw material
calculated according to Murphy et al. [29]
The physicochemical analyses were carried out in triplicate. Fifteen samples were used
per treatment for the texture determination (cutting force). Color analysis was performed
with ten measurements taken from five samples per treatment. The results for these
analyses are presented as the mean value plus the standard deviation. The means were
statistically evaluated by the analysis of variance (ANOVA) using the Statistica 7.0
program (StatSoft, Inc., Tulsa, USA), and the separation of the means was determined
employing Tukey’s test at p≤0.05.
Sensory Analysis
A sensory evaluation of the final products obtained from the trials with additives was
carried out with a panel of 16 trained judges using horizontal structured scales with 4
adjectives for each attribute and 12 corresponding numerical points: appearance [bad (13)/ regular (4-6)/ good (7-9)/ optimum (10-12)]; orange color [weak (1-3)/ regular (4-6)/
ACCEPTED MANUSCRIPT
8
ACCEPTED MANUSCRIPT
moderate (7-9)/ intense (10-12)]; texture/elasticity [low (1-3)/ regular (4-6)/ medium (79)/ much (10-12)]; flavor [bad (1-3)/ regular (4-6)/ good (7-9)/ optimum (10-12)] and
overall quality (bad (1-3)/ regular (4-6)/ good (7-9)/ optimum (10-12)]. [30] Standard
treatments (without additives) were not subjected to sensory analysis, since the main goal
of this work was to compare the treatments with the additives. Therefore, the use of
standard samples in sensory tests could have interfered with the results, confusing the
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
judges. The results were analyzed by the analysis of variance, F test and Tukey’s test,
employing the SAS program (Statistical Analysis System, SAS Institute Inc, USA).
Stability Study Of The Dried Papaya Slices During Storage
This study was carried out with the products obtained from two treatments chosen in the
first step and also with the product treated without additives (standard). To obtain the
samples, three new experimental OD/HA trials were carried out, under the same
conditions described before. The products were packed into double film packages of low
density polyethylene (LDPE) (1.5 mm thickness) and aluminum foil, and stored in a
BOD incubator (LS370, Logen Scientific, Diadema, Brazil) at 25 or 35ºC and relative
humidity of 65% for 70 to 100 days.
At the beginning of the study, the dried fruits were subjected to light microscopy analysis
and also to instrumental color, vitamin C content and moisture content analyses. The
vitamin C and instrumental color were periodically evaluated during storage according to
the methods previously described. Due to the low water activity values of the final
products and some previous results, microbiological stability and pH analysis were not
ACCEPTED MANUSCRIPT
9
ACCEPTED MANUSCRIPT
performed. Water activity and moisture content were also not evaluated, due to the very
good vapor barrier properties of the package employed. However, for a complete shelf
life study these analyses should be considered.
Light Microscopy
Samples of fresh papaya and dried fruit were submitted to a cell structure analysis by
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
light microscopy at zero time of the stability study. The samples were prepared according
to the methodology described by Ferrari et al.[31] and the light microscope used was an
Olympus BX51 (Olympus Optical CO., Tokyo, Japan).
Analysis Of The Reaction Order And Determination Of Kinetic Parameters
Changes in the vitamin C content and color parameters were evaluated using the zero and
first order kinetic models, equations (3) and (4), respectively, according to Teixeira Neto
et al. [32]
Ct = C0 − kt
(3)
ct
= − kt
c0
(4)
ln
The reaction order was determined with the model that best fitted the experimental data
(best determination coefficient – R2). The kinetic parameter k (reaction velocity) was
obtained from the best fitted models, and Q10 calculated using this parameter according to
equation (5). The half life, t 1/2 life, was calculated using equations (6) and (7) for the zero
and first order models, respectively, according to Teixeira Neto et al. [32]:
Q10 =
kT
kT−10
(5)
ACCEPTED MANUSCRIPT
10
ACCEPTED MANUSCRIPT
t1
2
life
=
c0
2k
(7)
RESULTS AND DISCUSSION
Study Of The Effect Of Processing Additives On The Combined OD/HA Process
Osmotic Dehydration Parameters
The values obtained for water loss (WL) and solids incorporation (SI) in the standard trial
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
(Table 2) were similar to those reported by Jain et al.[19] for the OD of papaya carried out
under similar conditions (50°C/60°Brix/4h): WL of 40 g/100 g; SI of 7.0 g/100 g. On the
other hand, the results obtained for WL in the trials with additives (Table 2) were higher
than the values obtained in the standard trial (P). The use of citric acid/calcium lactate
(CA/CL) resulted in an increase in WL of approximately 50%. Calcium lactate had a
slight greater effect on this parameter than calcium chloride for the same acids.
According to Ferrari et al.[31] , who studied the use of calcium lactate in the OD of melon,
the increase in WL is due to a more open cell structure with the formation of calcium
pectates and bridges in the cell wall. However, Table 2 shows that the values for solids
incorporation (SI) were slightly lower in the trials with additives as compared to the
standard trial, with the exception of the treatment with PME/calcium chloride (PME/CC).
Heng et al.[16] observed the same behavior in the OD of papaya with calcium chloride.
The authors stated that the association of calcium with the low methoxy pectin in the cell
wall causes an increase in the “tortuosity” of the intercellular spaces and also in the local
viscosity, decreasing the diffusion of sugar. In agreement with this result, Silva et al.[33],
studying the OD of pineapple, reported that the presence of calcium in the solution
decreased the diffusivity of sucrose within the samples. Nevertheless, in the trial with
ACCEPTED MANUSCRIPT
11
ACCEPTED MANUSCRIPT
PME/calcium chloride (PME/CC), there was an increase in the value for SI as compared
with the standard treatment (P). The same fact was observed by Van Buggenhout et al.[24]
in the OD of strawberry with sucrose and the addition of the same additives, who
reported a higher increase in dry matter content (44%) in the treatment with additives.
The moisture contents of the final products ranged from 14.2 to 18.5%. These differences
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
may be due to small operational variations and to natural variations in the biological
tissue. The values for water activity of the resulting products showed significant
differences (p≤0.05) and were in the range from 0.60 to 0.65. However, it was not
possible to verify the influence of the different additives on this property.
Texture
With respect to the texture (cutting force) of the final product, Table 2 shows that, with
the exception of PME/CC, all the treatments resulted in higher values, significantly
different from that of the standard treatment (p≤0.05). The highest mean was obtained for
the treatment with citric acid/calcium lactate (CA/CL), although this result could also be
related to the lower moisture content of the final product for this trial. Ferrari et al. [31]
also reported an important increase in the stress of failure of melons pre-treated with
calcium lactate, and Rodrigues et al.[17] showed a significant increase in the stress of
fracture with the use of calcium chloride in the OD of papaya. On the other hand, the
texture of the treatment with PME/calcium chloride (PME/CC) showed no significant
difference from the value obtained for the standard treatment (p>0.05).
ACCEPTED MANUSCRIPT
12
ACCEPTED MANUSCRIPT
Independent of the results obtained for instrumental texture, all the treatments with
additives, including PME/CC, resulted in more integral slices at the end of the OD, which
were also easier to handle when compared to the standard treatment. The osmo-dried fruit
treated with PME/calcium chloride showed an excellent appearance in terms of volume
and form, similar to that reported by Van Buggenhout et al.[24] in the freezing/thawing of
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
strawberries pre-treated with an aqueous solution of PME/calcium chloride.
Instrumental Color
According to the Table 3, it can be seen that the color parameters of fresh papaya were
located in the first quadrant of CIELAB color diagram (a* and b* >0), corresponding to
the region of red and yellow. Besides, a slight predominance of chromaticity parameter
b* was observed. According to Sentanin & Rodriguez-Amaya[6], the main pigments of
papaya of Formosa cultivar are lycopene, β-carotene and β-cryptoxanthine. For the
authors, lycopene, responsible for the red coloration, is the majority pigment,
representing 65% of the total pigments, whereas β-cryptoxanthine and β-carotene,
responsible for the yellow color, are present as 30% and 4%, respectively. Due to the
variability in the raw material, a dimensionless analysis of the color parameters was
carried out (Table 3). A comparison of color of dried products is shown in Figure 1. The
processes with additives, with the exception of the treatment with PME/calcium chloride
(PME/CC), resulted in lighter product when compared to fresh sample, as indicated by
the values for L*dim above 1 (Table 3). On the other hand, it is possible to observe that all
the processed fruits with additives are lighter than the standard product (Figure 1a). This
behavior could be partially explained by the action of the employed organic acids in
ACCEPTED MANUSCRIPT
13
ACCEPTED MANUSCRIPT
avoiding enzymatic browning. Germer et al.[34] reported similar results in a study with
peaches, and related the ‘lightening’ to a slight crystallization of sugars on the surface.
Rodrigues et al.[17] also observed an increase in lightness in their study on the OD of
papaya with calcium salts and organic acids, and associated the result to the incorporation
of calcium in the vegetable tissue.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
With respect to the other color components, Table 3 shows a slight increase in the values
for the parameter b* in the process (b* dim>1), indicating an intensification of the yellow
color, with the exception of the treatments PME/CC and P. However, Figure 1b shows
that, with the exception of the treatment with PME/calcium chloride (PME/CC), the
products obtained with additives are more yellow than that from standard process. This
behavior could be explained by the action of the employed organic acids in avoiding
enzymatic browning. For parameter a*, it was also observed a slight increase during the
process (a* dim >1), indicating an intensification of the red color for CA/CL, LA/CL and
CA/CC treatments (Table 3). The redder product obtained by P treatment could be
attributed to the differences from the raw material, since the fresh sample showed the
highest a* parameter values. In general, in a drying process, the removal of water
provides an increase in the color parameters values as a function of the concentration of
the pigments from the raw material. However, pigments losses to the syrup during OD
may occur, as well as their degradation, resulting in a decrease in the color parameters.[34]
Rodrigues et al.[17] reported higher a* and b* values during OD of papaya with additives,
and Germer et al.[34] found an increase of yellowness (higher b* values) in the osmotic
solution employed during OD of peaches, relating this fact to a leaching of pigments
ACCEPTED MANUSCRIPT
14
ACCEPTED MANUSCRIPT
from the fruit to the syrup. Similar behavior was pointed out by García-Martínez et al.[35]
For the authors, the variations in b* with the reuse of syrup in the OD of kiwi due to
leaching of pigments such as β-carotenes, chlorophylls and xanthophylls from fruit to
syrup. Furthermore, according to Heng et al. [16], at the beginning of processing,
hydrophobic carotenoids may concentrate in intra cellular spaces during parallel
dehydration of papaya (OD process). This leads to a relative increase of their content in
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
the dehydrated fruit. When dehydration time is long enough, the syrup becomes tinted,
meaning that a part of the pigments is lost by diffusion.
Based on the results observed, the use of processing additives, in general, helped to
preserve the instrumental color of the product, but the combination of PME and calcium
chloride was less effective in the maintenance of this quality characteristic.
Vitamin C Content
The mean vitamin C content of the raw material used in the trials was 60.12 mg/100 g
(Table 4). This value was between those reported by Garcia[36] and by El-Aouar[37] for
papaya of Formosa cultivar (44.30 mg/100 g and 71.31 mg/100 g, respectively). The
differences are due to variability in the raw material, principally in the state of maturity.
The mean loss of vitamin C during OD for the different treatments was approximately
55%, and the trial performed with PME and calcium chloride (PME/CC) resulted in the
greatest retention (Table 4). This result is almost within the range of 30 to 60% for
vitamin C retention reported by Heng et al.[16] in the OD of papaya under similar process
conditions. According to Santos & Silva[38], vitamin C losses occurring during OD are
ACCEPTED MANUSCRIPT
15
ACCEPTED MANUSCRIPT
related to both chemical deterioration and diffusion of ascorbic acid from the fruit to the
solution. Vitamin C content of the dried products was not presented in Table 4, since its
determination was compromised, due to the monitoring of the products’ weight during
hot air drying for the adjustment of the final moisture content, necessary for the other
analyses (mainly texture and sensory tests).
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
In a similar work, An et al. [11] studied the influence of osmotic dehydration (OD) and
pulsed vacuum osmotic dehydration (PVOD) with sucrose solutions (50 and 70ºBrix) in
combination with air drying on the vitamin C retention of cherry tomatoes. Air drying led
to a great loss of vitamin C, showing a retention rate of only 24.79%. Dried samples pretreated in sucrose solution had higher vitamin C retention rates (about 41–49%),
indicating that osmotic dehydration can greatly help to keep the retention of vitamin C,
due to the protective effect of the sugar. The PVOD process had a more favorable effect
in keeping vitamin C retention, due to a greater infusion of sugar solute and shorter hotair drying time. Dried samples pre-treated with 50ºBrix solution under PVOD had the
maximum vitamin C retention of about 55%.
Sensory Analysis
Concerning the attributes appearance and orange color, the best scores were obtained for
the fruits treated with CA/CC and LA/CC, according to Table 5, with no significant
difference between them (p>0.05). This fact can be partially related with the instrumental
color results, since these treatments showed similar behavior for the dimensionless
variations of L* and b* (Table 3). On the other hand, from Figure 1b, it is also possible to
ACCEPTED MANUSCRIPT
16
ACCEPTED MANUSCRIPT
see that these treatments resulted in products slightly more yellow. As previously
discussed, PME/CC treatment presented lower L* and b* values, but the mean scores for
color attribute did not differ from CA/CC and LA/CC treatments at p≤0.05, as seen in
Table 5. For the flavor, no significant differences (p>0.05) were observed between
LA/CL, LA/CC, CA/CC and PME/CC treatments, but samples produced with PME/CC
showed the best mean scores, followed by LA/CL and LA/CC treatments. As mentioned
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
before, the highest solids gain (SI) in OD was observed in PME/CC trial (Table 2), which
can explain the flavor results in the sensory analysis, as the product of this trial was
sweeter. Concerning the texture/elasticity, there was no significant difference (p>0.05)
between the means (Table 5), implying that the panelists did not notice the differences
pointed out in the previous analysis of instrumental texture (Table 2). With respect to
overall quality, PME/CC treatment was the most accepted sample with mean scores
around 8.50, showing significant differences (p≤0.05) from CA/CL, LA/CL and CA/CC
treatments (Table 5). LA/CC sample also presented high scores for this attribute, not
differing significantly from PME/CC treatment (p>0.05).
The treatments with lactic acid/calcium chloride (LA/CC) and PME/calcium chloride
(PME/CC) were selected for the next step of this work (stability study), based mainly on
the results of the sensory evaluation. For this choice, it was taken into account the
observation that all the treatments resulted in osmo-dehydrated products with better
aspect and greater handling facility as compared to the standard treatment, independent of
the instrumental texture results. Despite the lower efficiency in preserving the
instrumental color, the treatment PME/CC was chosen for the stability study, mostly due
ACCEPTED MANUSCRIPT
17
ACCEPTED MANUSCRIPT
to the sensory acceptance scores for flavor and overall quality attributes (Table 5), and
also to its innovative character. The choice of the treatment with lactic acid/calcium
chloride (LA/CC) was also based in the sensory analyses results (flavor and overall
quality attributes), though it showed a greater loss of vitamin C in comparison to the trial
with citric acid (CA/CC), as seen in Table 4.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
Stability Study
Microscopy
The images obtained in the light microscopy analysis for fresh papaya and dried papaya
(OD/HA) at zero time of the stability study are presented in Figure 2.
Figure 2a shows that the fresh papaya presented turgid, round-shaped cells with a welldefined, consistent cell wall. The presence of pectic substances was evidenced by the
toluidine blue (purple color), and they were concentrated in the cell wall and intercellular
spaces. Garcia-Noguera et al. [14], working with osmotic dehydration and ultrasound
processes prior to convective drying, reported that the cells of fresh strawberry were
evenly distributed, showing consistent semicircular shape with few distortion of the cells.
Pectin-laced walls were intact and the tissue presented several interlamelar spaces. In the
present work, the combined OD/HA process without additives resulted in important
alterations in cell format and turgor (Figure 2b). The cell wall was de-structured as
evidenced by the loss in adhesion between adjacent walls, intense plasmolysis being
observed in the cytoplasm (see arrows).
ACCEPTED MANUSCRIPT
18
ACCEPTED MANUSCRIPT
According to Figures 2c and 2d, OD process carried out with the addition of additives
resulted in better maintenance of the cell structure. In the trial with lactic acid/calcium
chloride, the cell walls of the samples were thicker due to the formation of calcium
pectate (see arrows), which could explain the higher cutting force values observed in the
previous part of the work (Table 2). Similar results were reported by Ferrari et al.[31] in
melon pre-dried with a sucrose solution containing calcium lactate. However, Pereira et
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
al.[39] found no differences in cell structure between guava pre-dried with calcium lactate
and the fresh fruit in a microscopic analysis, even though differences in texture had been
found. Figure 2d, which refers to the treatment with PME/calcium chloride, shows less
thickening of the cell wall, with an apparent spreading out of the pectic substances
throughout the tissue. This fact could explain the lower cutting force obtained for the
papaya subjected to treatment with PME/calcium chloride in the previous part of the
work (Table 2). Van Buggenhout et al.[19] reported an intense coloration of the cell wall
and of the intercellular spaces in the microscopic analysis of osmo-dehydrated strawberry
obtained with the addition of PME/calcium chloride during OD with sucrose. However,
the authors used larger amounts of enzyme (0.12% v/v) and calcium chloride (0.5% w/w)
than employed in the present study. Fraeye et al.[25], studying the infusion of strawberries
in a PME/calcium chloride solution, observed that the cell walls were more brightly
colored, and related this fact to the formation of a pectin-calcium network. However, OD
pre-treatment was followed by high pressure heat treatment, and the results showed that
prolonging the heat treatment (70ºC for more than 10 min) caused a loss of the firmness
obtained in the osmotic pre-treatment. Considering this observation, it is possible to say
that in the present study the hot air drying performed at 60ºC could have damaged the
ACCEPTED MANUSCRIPT
19
ACCEPTED MANUSCRIPT
pectin-calcium network established during the OD step, causing a decrease in texture
values (cutting force).
Color Degradation Kinetics
According to Figure 3, there was a decrease in the parameter b* of the dried papaya with
time under the different storage conditions, indicating a loss of yellow color. The zero
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
order kinetic model fitted the experimental data better (R2 between 0.83 and 0.92), as
seen in Table 6. Koca et al.[40] also reported a decrease in the parameter b* during storage
of dehydrated carrot, obtaining zero order kinetic models. In this study, the authors
correlated the decay in the chromaticity parameters with degradation of β-carotene.
Table 7 shows that b* values for samples treated with LA/CC and stored at 25ºC were not
fitted to kinetic models. No significant difference (p>0.05) was observed throughout
storage, meaning that the yellow color of the product was maintained during the time.
Considering this observation and the values obtained for t1/2 life at 35ºC in Table 6, it can
be said that the treatment with LA/CC resulted in greater stability of the yellow color,
followed by PME/CC and P treatments. On the other hand, the results for Q10 (Table 6)
indicated that the degradation reaction of b* for the samples subjected to PME/CC
treatment was less dependent on temperature than that observed for P treatment.
As shown in Figure 4, there was also a decrease in the parameter a* for the different
treatments throughout the study, indicating degradation of the red color of dried papaya.
The variations in a* followed first order models (R2 between 0.80 and 1.0) for P and
LA/CC treatments, with identical equations, as can be seen in Table 6, resulting in equal
ACCEPTED MANUSCRIPT
20
ACCEPTED MANUSCRIPT
values for t1/2 life at the respective temperatures. The degradation of parameter a* in light
guava jam was reported by Moura et al.[41], who also obtained a first order model and Q10
value of 2 for the total color difference (∆E). Similar values for Q10 were also reported by
Moura et al.[42] for the total color difference (∆E) of traditional blackberry jam. The
treatment with PME/CC also resulted in first order kinetics for parameter a*, with k
values (reaction velocity) much higher than the corresponding values in the other
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
treatments, and lower t1/2 life values, indicating less stability of the red color (Table 6).
However, the lower value for Q10 obtained for the treatment with PME/CC, indicated less
dependence of the degradation reaction on temperature.
Parameter L* (lightness) remained practically unchanged along storage for samples
subjected to treatment with LA/CC and stored at 25ºC, indicating that the fruits did not
get darker (Table 7). On the other hand, for the other treatments performed at this
temperature a slight increase in L* can be seen after 90 days, which means that the
papaya pieces became lighter. This could have occurred due to crystallization of sugar on
the surface. An increase in L* was also reported by Torreggiani et al.[43] during storage
of osmo-dehydrated cherries for 6 months at 25ºC. At 35ºC, no significant variation in
the parameter L* (p>0.05) was observed for the samples treated with PME/CC (Table 7).
However, lightness values significantly decreased (p≤0.05) at the end of storage time for
LA/CC (around 8%) and P (around 21%) treatments, which is related to a possible
browning.
ACCEPTED MANUSCRIPT
21
ACCEPTED MANUSCRIPT
Based on the above, the addition of lactic acid with calcium chloride to the sucrose syrup
used in the OD of papaya presented an effective contribution to color stability of the
product during a storage period of 75 to 100 days. This fact may be related to the action
of weak acids previously mentioned in avoiding enzymatic browning during process,
whose effect is prolonged during storage. The same behavior was not verified for the use
of PME with calcium chloride, since the red color component of the dried papaya
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
obtained in this treatment showed an important degradation along the time.
Vitamin C Degradation Kinetics
The samples (dried fruit) produced for the stability study presented initial vitamin C
contents of 152.28 ± 1.43 mg/100 g (P treatment), 115.59 ± 0.77 mg/100 g (LA/CC
treatment) and 144.54 ± 0.42 mg/100 g (PME/CC treatment), corresponding to retentions
of 63%, 37% and 62%, respectively, with respect to the raw material. These contents are
relatively high, independently of the observed losses. Thus, the dried papaya obtained by
these different processes can be considered an important source of the nutrient.
The first order kinetic model showed good fit (R2 from 0.91 to 0.99) for the experimental
values of vitamin C content throughout the stability study at 25 or 35ºC, as can be seen in
Table 8 and Figure 5. Similarly, Dermesonlouoglou et al. [44] reported first order kinetic
models for the degradation of vitamin C in osmo-dehydrated tomatoes. In another work,
Chottamon et al. [12] studied the osmotic treatment (using sucrose, sorbitol and maltose
solutions) in combination with air drying of mulberries and also evaluated the influence
of different osmotic solutions on drying kinetics, reaction kinetics, and anthocyanins and
ACCEPTED MANUSCRIPT
22
ACCEPTED MANUSCRIPT
phenolics content. Air drying caused degradation of anthoyanins and phenolics, which
followed a zero-order reaction with R2 values ranging from 0.866 to 0.996. Osmotic
treatment with maltose was found to be a good treatment for mulberry drying and
preserved the phenolic and anthocyanin contents and provide high antioxidant capacity.
Table 8 shows that the parameters obtained were very close, indicating that the velocity
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
of vitamin C degradation throughout the time was practically the same for the three
treatments. This means that the use of lactic acid, calcium chloride or PME/calcium
chloride did not contribute to the retention of vitamin C during storage in comparison to
the standard treatment. The half life of the different products at 25ºC was approximately
60 days (Table 8). Uddin et al.[45] reported a t1/2 life value of just 5 days for freeze dried
guava stored at 30ºC. In a similar work, Roopa et al.[46] showed that the vitamin C content
in dried star fruit, obtained by a combined OD/HA process, did not reduce to half the
original value in 10 months of storage at 25ºC. In the present work, the relatively high
Q10 values indicated great sensitivity of the vitamin C degradation reaction in relation to
the storage temperature, especially in the treatment with PME/calcium chloride (Table 8).
The values for Q10 were within the range reported by Labuza[47] for the degradation of
vitamin C in dehydrated vegetables (from 1.5 to 4).
CONCLUSIONS
The addition of the investigated additives in the osmotic dehydration of papaya resulted
in easier handling samples as compared to the standard trial. The instrumental color of
the papaya was better preserved during OD/HA process with the additives, despite the
ACCEPTED MANUSCRIPT
23
ACCEPTED MANUSCRIPT
higher color losses verified in the treatments performed with PME/calcium chloride.
Samples treated with PME/calcium chloride and lactic acid/calcium chloride showed
higher acceptance scores for overall quality and flavor attributes. With respect to the
morphology, the use of the additives resulted in better maintenance of the fruit cellular
structure. The combination of lactic acid/ calcium chloride practically kept the yellow
color (b*) of the dried papaya during storage at 25ºC for 100 days, but the additives did
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
not help to preserve the vitamin C content along storage. The variations in the color
parameters throughout storage were fitted to 1st order kinetic models with Q10 values in
the range from 1 to 2. First order kinetic models were obtained for the degradation of
vitamin C, with Q10 values ranging from 3 to 4. In general, papaya pieces treated with
lactic acid/calcium chloride presented the best results, especially regarding sensory
attributes and color stability throughout storage. The application of PME/calcium
chloride was less effective for color stability during storage, but this enzyme contributed
to the maintenance of the fruit texture, avoiding an excessive tissue hardening, and also
resulted in good sensory acceptance for dried papaya. Therefore, the use of PME
deserves to be investigated with others raw materials, calcium salts and processing
conditions.
ACKNOWLEDGEMENTS
The authors are grateful to the National Council for Scientific and Technological
Development, CNPq, for the financial support.
NOMENCLATURE
ACCEPTED MANUSCRIPT
24
ACCEPTED MANUSCRIPT
OD
osmotic dehydration
HA
hot air drying
OD/HA
combined process of osmotic dehydration and hot air drying
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
PME pectinmethylesterase
R2
coefficient of determination
Q10
temperature coefficient/ quotient
P
standard treatment, without aids
CA/CL citric acid with calcium lactate
LA/CL lactic acid with calcium lactate
CA/CC citric acid with calcium chloride
LA/CC lactic acid with calcium chloride
PME/CC pectinmethylesterase with calcium chloride
WL
water loss
SI
solids incorporation
Ui
initial moisture content
Mi
initial mass
Uf
moisture content at the end of the process
Mf
mass at the end of the process
STf
total solids content at the end of the process
STi
initial solids content
Ct
concentration of the quality component or parameter at time t
Co
concentration of the quality component or parameter at zero time
T
temperature
ACCEPTED MANUSCRIPT
25
ACCEPTED MANUSCRIPT
kT
reaction rate constant at temperature T
k T-10 reaction rate constant at a temperature 10ºC lower
t
time (day)
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
t 1/2 life half life time (day)
L*
lightness (L* = 0 for black and L* = 100 for white)
a*
chromaticity parameters (green [-] to red [+])
b*
chromaticity parameters (blue [-] to yellow [+])
L*dim dimensionless parameter L* (L*of dried papaya/L* of fresh papaya)
a*dim dimensionless parameter a* (a* of dried papaya/a* of fresh papaya)
b*dim dimensionless parameter b* (b* of dried papaya/b* of fresh papaya)
REFERENCES
1.
Evans, E.; Ballen, F.H. An overview of global papaya production, trade, and
consumption. Available in: <http://edis.ifas.ufl.edu/pdffiles/FE/FE91300.pdf>. Access in:
April 27th, 2013.
2.
Faostat. Food and Agriculture Organization of the United Nations. Available in:
<http://faostat.fao.org/site/342/default.aspx>. Access in: April 27th, 2013.
3.
El-Aouar, A.A. Study of drying process of Formosa papaya (Carica papaya l.)
fresh and osmotically pretreated. PhD Thesis. College of Food Engineering, State
University of Campinas, Campinas, Brazil. (in Portuguese), 2005.
4.
NEPA- Center for studies and research on food - Brazilian food composition
table. University of Campinas, Campinas, Brazil (in Portuguese), 2011.
ACCEPTED MANUSCRIPT
26
ACCEPTED MANUSCRIPT
5.
Rodriguez-Amaya, D.B.; Kimura, M.; Amaya-Farfan, J. Brazilian sources of
carotenoids: Brazilian table carotenoid composition of foods. In: Coradin, L.; Pombo,
V.B. (ed.). Ministry of the Environment, Brasília, Brazil. (in Portuguese), 2008.
6.
Sentanin, M.A.; Rodriguez-Amaya, D.B. Carotenoid levels in papaya and peach
determined by high performance liquid chromatography. Food Science and Technology
2007, 27(1), 13–19.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
7.
Fiesp/Ital – São Paulo State Federation of Industry/Institute of Food Technology.
Brazil Food Trends 2020. Fiesp, São Paulo, Brazil, 2010.
8.
Raoult-Wack, A.L. Recent advances in the osmotic dehydration of foods. Trends
in Food Science & Technology 1994, 5(8), 255-260.
9.
Fernandes, F.; Rodrigues, S.; Gaspareto, O.C.P.; Oliveira, E. Optimization of
osmotic dehydration of papaya followed by air-drying. Food Research International
2006, 39(4), 492-498.
10.
Chiralt, A.; Talens, P. Physical and chemical changes induced by osmotic
dehydration in plant tissues. Journal of Food Engineering 2005, 67(1), 167-177.
11.
An, K.; Li, H.; Zhao, D.; Ding, S.; Tao, H.; Wang, Z. Effect of osmotic
dehydration with pulsed vacuum on hot-air drying kinetics and quality attributes of
cherry tomatoes. Drying Technology 2013, 31(6), 698-706.
12.
Chottamom, P; Kongmanee, R.; Manklang, C; Soponronnarit, S. Effect of
osmotic treatment on drying kinetics and antioxidant properties of dried mulberry. Drying
Technology 2012, 30(1), 80-87.
ACCEPTED MANUSCRIPT
27
ACCEPTED MANUSCRIPT
13.
Araya-Farias, M.; Macaigne, O.; Ratti, C. On the development of osmotically
dehydrated seabuckthorn fruits: pretreatments, osmotic dehydration, postdrying
techniques, and nutritional quality. Drying Technology 2014, 32(7), 813-819.
14.
Garcia-Noguera, J.; Oliveira, F.I.P.; Gallão, M.I.; Weller, C.L.; Rodrigues, S.;
Fernandes, F.A.N. Ultrasound-assisted osmotic dehydration of strawberries: Effect of
pretreatment time and ultrasonic frequency. Drying Technology 2010, 28(2), 294-303.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
15.
Ruiz-López, I.I.; Huerta-Mora, I.R.; Vivar-Vera, M.A.; Martínez-Sánchez, C.E.;
Herman-Lara, E. Effect of osmotic dehydration on air-drying characteristics of chayote.
Drying Technology 2010, 28(10), 1201-1212.
16.
Heng, K.; Guilbert, S.; Cuq, J.L. Osmotic dehydration of papaya: influence of
process variable on the product quality. Sciences des Aliments 1994, 10(4), 831-848.
17.
Rodrigues, A.; Cunha, R.; Hubinger, M.D. Rheological properties and colour
evaluation of papaya during osmotic dehydration processing. Journal of Food
Engineering 2003, 59(2-3), 129-135.
18.
Pereira, L.M.; Ferrari, C.C.; Mastrantonio, S.D.S.; Rodrigues, A.C.C.; Hubinger,
M.D. Kinetic aspects, texture, and color evaluation of some tropical fruits during
osmotic dehydration. Drying Technology 2006, 24(4), 475-484.
19.
Jain, S.K.; Verma, R.C.; Murdia, L.K.; Jain, H.K.; Sharma, G.P. Optimization of
process parameters for osmotic dehydration of papaya cubes. Journal of Food Science
and Technology 2011, 48(2), 211–217.
20.
Chiumarelli, M.; Ferrari, C.C.; Sarantópoulos, C.I.G.L.; Hubinger, M.D. Fresh cut
‘Tommy Atkins’ mango pre-treated with citric acid and coated with cassava (Manihot
ACCEPTED MANUSCRIPT
28
ACCEPTED MANUSCRIPT
esculenta Crantz) starch or sodium alginate. Innovative Food Science and Emerging
Technologies 2011, 12(3), 381–387.
21.
Rodrigues, A.C.C.; Pereira, L.M.; Sarantópoulos, C.I.G.L.; Bolini, H.M.A.;
Cunha, R.L.; Junqueira, V.C.A.; Hubinger, M.D. Impact of modified atmosphere
packaging on the osmodehydrated papata stability. Journal of Food Processing and
Preservation 2006, 30(5), 563–581.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
22.
Torres, J.D.; Castello, M.L.; Escriche, I.; Chiralt, A. Quality characteristics,
respiration rates, and microbial stability of osmotically treated mango tissue (Mangifera
indica L.) with or without calcium lactate. Food Science and Technology International
2008, 14(4), 355–365.
23.
Suttirak, W.; Manurakchinakorn, S. Potential application of ascorbic acid, citric
acid and oxalic acid for browning inhibition in fresh-cut fruits and vegetables. Walailak
Journal of Science and Technology 2010, 7(1), 5-14.
24.
Van Buggenhout, Grauwet, T.; Van Loey, A.; Hendrickx, M. Use of
pectinmethylesterase and calcium in osmotic dehydration and osmodehydrofreezing of
strawberries. European Food Research and Technology 2008, 22(5), 1145-1154.
25.
Fraye, I.; Knockaert, G.; Van Buggenhout, S.; Duvetter, T.; Hendrickx, M.; Van
Loey, A.V. Enzyme infusion prior to thermal/high pressure processing of strawberries:
mechanistic insight into firmness evolution. Innovative Food Science and Emerging
Technologies 2010, 11(1), 23-31.
26.
PBMH and PIF Brazilian Program for the Modernization of Integrated Fruit
Production and Horticulture. Classification standards of papaya. Available in:
<http://www.ceagesp.gov.br/produtor/classific>, Access in: May 23th, 2013.
ACCEPTED MANUSCRIPT
29
ACCEPTED MANUSCRIPT
27.
Association of Official Analytical Chemists. Official Methods of Analysis of the
Association of Official Analytical Chemists, 18th Ed.; AOAC Press: Gaithersburg, MD,
2006.
28.
Oliveira, R.G.; Godoy, H.T.; Prado, M.A. Optimization of a colorimetric method
to determine ascorbic acids in fruit jelly. Ciência e Tecnologia de Alimentos 2010, 30(1),
244-249. (In Portuguese).
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
29.
Murphy, E.W.; Criner, P.E.; Gray, B.C. Comparisons of methods for calculating
retentions of nutrients in cooked foods. Journal of Agricultural and Food Chemistry
1975, 23(6), 1153-1157.
30.
Faria, E.V.; Yotsuyanagi, K. Sensory analysis techniques. Institute of Food
Technology, Campinas, Brazil. (In Portuguese), 2008.
31.
Ferrari, C.C.; Carmello-Guerreiro, S.M.; Bolini, H.M.A., Hubinger, M.D.
Structural changes, mechanical properties and sensory preference of osmodehydrated
melon pieces with sucrose and calcium lactate solutions. International Journal of Food
Properties 2010, 13(1), 112–130.
32.
Teixeira Neto, R.O.; Vitali, A.A.; Moura, S.C.S.R. Introduction to kinetics of
reactions in food. In: Moura, S.C.S.R.; Germer S.P.M. (ed). Transformation reactions and
shelf-life of processed foods. pp. 24-46. Institute of Food Technology, Campinas, Brazil.
(in Portuguese), 2010.
33.
Silva, K.S.; Fernandes, M.A.; Mauro, M.A. Osmotic dehydration of pineapple
with impregnation of sucrose, calcium, and ascorbic acid. Food Bioprocess Technology
2013. Available online. DOI: 10.1007/s11947-013-1049-0.
ACCEPTED MANUSCRIPT
30
ACCEPTED MANUSCRIPT
34.
Germer, S.P.M. Cultivars, process variables, reuse of sucrose syrup and economic
viability of osmotic pre-drying of peaches. PhD Thesis. College of Agricultural
Engineering, State University of Campinas, Campinas, Brazil. (in Portuguese), 2010.
35.
García-Martinez, E.; Martinez-Monzo, J.; Camacho, M.M.; Martínez-Navarrete,
N. Characterization of reused osmotic solution as ingredient in new product formulation.
Food Research International 2002, 35(2-3), 307-313.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
36.
Garcia, C.C. Evaluation of dehydration of papaya using combined methods. PhD
Thesis. Institute of Biosciences, Language and Physical Sciences (IBILCE), UNESP –
São Paulo State University, São José do Rio Preto, Brazil. (in Portuguese), 2012.
37.
El-Aouar, A.A. Evaluation of the combined process of osmotic dehydration and
drying on quality of Taiwan papaya cubes (Carica papaya L.). MS Thesis. College of
Food Engineering, State University of Campinas, Campinas, Brazil. (in Portuguese),
2001.
38.
Santos, P.H.S.; Silva, M.A. Retention of vitamin C in drying processes of fruits
and vegetables - A review. Drying Technology 2008, 26(12), 1421–1437.
39.
Pereira, L.M.; Carmello-Guerreiro, S.M.; Hubinger, M.D. Microscopic features,
mechanical and thermal properties of osmotically dehydrated guavas. LWT - Food
Science and Technology 2009, 42(1), 378–384.
40.
Koca, N.; Burdurlu, H.S.; Karadeniz, F. Kinetics of colour changes in dehydrated
carrots. Journal of Food Engineering 2007, 78(2), 449-455.
41.
Moura, S.C.S.R.; Prati, P.; Vissotto, F.Z.; Ormenese, R.C.S.C.; Rafacho, M.S.
Color degradation kinetics in low-calorie strawberry and guava jellies. Ciência e
Tecnologia de Alimentos 2011, 31(3), 758-764.
ACCEPTED MANUSCRIPT
31
ACCEPTED MANUSCRIPT
42.
Moura, S.C.S.R.; Rocha Tavares, P.E.; Germer, S.P.M.; Nisida, A.L.A.C.; Alves,
A.B.; Kanaan, A.S. Degradation kinetics of anthocyanin of traditional and low-sugar
blackberry jam. Food and Bioprocess Technology 2011, 5(6), 2488–2496.
43.
Torreggiani, D.; Forni, E.; Rizzola, A. Osmotic dehydration of fruit – part 2:
influence of the osmosis time on the stability of processed cherries. Journal of Food
Processing & Preservation 1987, 12(1), 27-44.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
44.
Dermesonlouoglou, E.K.; Giannakourou, M.C.; Taoukis, P.S. Kinetic modelling
of the degradation of quality of osmo-dehydrofrozen tomatoes during storage. Food
Chemistry 2007, 103(3), 985–993.
45.
Uddin, M.; Hawlader, M.N.; Ding, L.; Mujumdar, A. Degradation of ascorbic acid
in dried guava during storage. Journal of Food Engineering 2002, 51(1), 21–26.
46.
Roopa, N.; Chauhan, O.P.; Raju, P.S.; Das Gupta, D.K.; Singh, R.K.R.; Bawa,
A.S. Process optimization for osmo-dehydrated carambola (Averrhoa carambola L)
slices and its storage studies. Journal of Food Science and Technology 2012. Available
online. DOI: 10.1007/s13197-012-0756-2.
47.
Labuza, T.P. Shelf-life dating of foods. Food & Nutrition Press, Inc., WestPort,
USA, 1982.
ACCEPTED MANUSCRIPT
32
ACCEPTED MANUSCRIPT
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
Table 1. Physicochemical properties of fresh papaya.
Analysis
Mean Value
Methods
Moisture content
87.58 ± 1.43
AOAC[27]
Titratable acidity (g citric acid/100 g)
0.076 ± 0.001 AOAC[27]
pH
5.49 ± 0.08
Phmeter
Total sugar content (g/100 g)
10.15 ± 2.04
AOAC[27]
Reducing sugar content (g/100 g)
8.94 ± 1.66
AOAC[27]
Soluble solids content (ºBrix)
12.00 ± 0.17
Refractometer
Vitamin C content (mg ascorbic acid/100 g) 53.65 ± 2.63
Oliveira et al.[28]
* All data are the mean of triplicate measure ± standard deviation
ACCEPTED MANUSCRIPT
33
ACCEPTED MANUSCRIPT
Table 2. Processing additives used, OD/HA parameters and physical properties of the
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
dried papaya subjected to different treatments.
ACCEPTED MANUSCRIPT
34
ACCEPTED MANUSCRIPT
Table 3. Color parameters of the fresh papaya and the dried papaya subjected to different
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
treatments.
ACCEPTED MANUSCRIPT
35
ACCEPTED MANUSCRIPT
Table 4. Vitamin C content of the fresh and osmo-dehydrated fruits and the retention
values (%) observed in the different treatments.
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
Trial
Vitamin C content (mg/100g)
Vitamin C retention in OD (%)
fresh
osmodehydrated
CA/CL
76.56±0.26f
52.84±2.81b
33.10±3.78a
LA/CL
45.47±0.95a 41.18±0.01a
33.51±2.09a
CA/CC
64.61±0.19d 57.25±0.44c
46.62±0.72b
LA/CC
69.01±0.15e 53.36±0.23b
34.05±0.37a
PME/CC 55.18±0.65c 59.17±0.90c
62.81±2.06d
49.90±0.57b 43.23±0.33a
56.78±1.17c
P
* Means in the same column with different letters indicate significant differences at
p≤0.05
ACCEPTED MANUSCRIPT
36
ACCEPTED MANUSCRIPT
Table 5. Mean sensory acceptance scores of the dried papaya subjected to different
treatments.
Trials
Attributes
CA/CL
LA/CL
CA/CC
LA/CC
PME/CC
appearance
7.31 ± 1.82b
2.62 ± 1.20a
9.18 ± 1.97c
8.62 ±
7.75 ± 2.21b
1.71bc
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
orange color
Flavor
texture/elasticit
7.43 ± 1.90b
5.68 ± 2.55a
2.68 ± 1.49a
9.25 ± 2.02c
8.81 ±
8.37 ±
2.46bc
1.86bc
7.87 ± 2.63b
6.75 ±
6.43 ±
6.62 ±
2.38ab
2.19ab
2.00ab
7.00 ± 2.18a
6.31 ± 2.73a
6.18 ± 2.56a
6.87 ± 1.89a
5.56 ± 2.99a
5.93 ±
5.43 ± 2.06a
7.00 ±
7.81 ±
8.50 ± 2.13d
1.97bc
1.64cd
y
overall quality
1.57ab
* Means in the same line with different letters indicate significant differences at p≤0.05
ACCEPTED MANUSCRIPT
37
ACCEPTED MANUSCRIPT
Table 6. Kinetic parameters for the variations in a* and b* of the dried papaya subjected
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
to different treatments throughout storage.
ACCEPTED MANUSCRIPT
38
ACCEPTED MANUSCRIPT
Table 7. Color parameters values (not fitted to kinetic models) of the dried papaya
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
subjected to different treatments throughout storage.
ACCEPTED MANUSCRIPT
39
ACCEPTED MANUSCRIPT
Table 8. Kinetic parameters for vitamin C degradation of the dried papaya subjected to
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
different treatments throughout storage.
ACCEPTED MANUSCRIPT
40
ACCEPTED MANUSCRIPT
Figure 1. Comparison of color of dried papaya subjected to different treatments: (a) L*
(lightness) and chromaticity parameter a* (redness); (b) chromaticity parameter a*
(redness) and b* (yellowness): (♦) citric acid/calcium lactate CA/CL; (■) lactic
acid/calcium lactate LA/CL; (▲) citric acid/calcium chloride CA/CC; (x) lactic
acid/calcium chloride LA/CC; (∗) pectinmethylesterase/calcium chloride PME/CC; (•)
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
standard (P).
ACCEPTED MANUSCRIPT
41
ACCEPTED MANUSCRIPT
Figure 2. Light microscopy images of fresh papaya and dried papaya (OD/HA) at zero
time of the stability study: (a) fresh papaya, (b) OD with no processing additives (P); (c)
OD with lactic acid and calcium chloride (LA/CC); (d) OD with PME and calcium
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
chloride (PME/CC). Scale Bar = 200 µm.
ACCEPTED MANUSCRIPT
42
ACCEPTED MANUSCRIPT
Figure 3. Kinetics of the variation in parameter b* (blue-yellow) of the dried papaya
subjected to different treatments throughout storage: (a) standard (P); (b) lactic
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
acid/calcium chloride (LA/CC); (c) pectinmethylesterase/calcium chloride (PME/CC).
ACCEPTED MANUSCRIPT
43
ACCEPTED MANUSCRIPT
Figure 4. Kinetics of the variation in parameter a* (green-red) of the dried papaya
subjected to different treatments throughout storage: (a) standard (P); (b) lactic
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
acid/calcium chloride (LA/CC); (c) pectinmethylesterase/calcium chloride (PME/CC).
ACCEPTED MANUSCRIPT
44
ACCEPTED MANUSCRIPT
Figure 5. Kinetics of vitamin C degradation in dried papaya subjected to different
treatments throughout storage: (a) standard (P); (b) lactic acid/calcium chloride
Downloaded by [Sílvia P. M. Germer] at 08:00 12 June 2014
(LA/CC); (c) pectinmethylesterase/calcium chloride (PME/CC).
ACCEPTED MANUSCRIPT
45
View publication stats