Sugar Gain Research Articles

Optimization of vacuum impregnated nutmeg rind candy using RSM modeling: effect on functional and nutritional properties.

Vacuum impregnation (VI) stands as an innovative technique, used to create novel food formulations by impregnating vital nutritive compounds into natural food matrices. Process variables were syrup temperature ranging from (50 to 70°C), syrup concentration (60° to 80° Brix), and VI duration (10 to 20min). The optimal conditions emerged at 66.81°C for syrup temperature, 71.58° Brix for syrup concentration, and a precise 11.59min for the VI duration. At these paramount conditions, the candy exhibited striking attributes such as 50.0% water loss, 12.23% sugar gain, chewiness of 9N, and lightness value of 22.17. The predicted values using the developed model were validated with experimental data and indicated the adequacy of the generated model. The functional characterization of the optimized nutmeg rind candy showcased a marked reduction in myristicin content, signifying an augmented level of safety for consumption. Furthermore in-vitro anti-bacterial assay, total phenolics, flavonoids and tannin content, anti-oxidant potential, proximate composition and microstructure of the optimized candy were analysed.

The influence of ultrasound-assisted osmotic dehydration as a pre-treatment method on the quality of vacuum dried pineapple

This study investigated the effect of ultrasound-assisted osmotic dehydration (UAOD) as a pre-treatment before vacuum drying on the drying time, quality, and microstructure of pineapple. At first, the best conditions for water desorption during osmotic dehydration (OD) were optimized. Pineapple cubes were subjected to OD at different osmotic solution concentrations (30, 40, and 60°Brix), pre-treatment time (0.5 and 1 hr), and temperature (35ºC) using two types of osmotic agents (sucrose and fructose). According to the results, sucrose was the best osmotic agent because it reduced the sample's moisture content and water activity. Secondly, the influence of UAOD on sugar gain, water loss, and drying time was evaluated using sucrose as an osmotic agent. Pineapple cubes were subjected to UAOD at different osmotic solution concentrations (30 and 60°Brix), pre-treatment time (10, 20, and 30 mint), and temperature (40 ºC) in an ultrasonic bath (ultrasound frequency of 40 kHz and ultrasound power of 300 W). Results exhibited that the application of UAOD increased the sugar gain and water loss, consequently decreasing the drying time. Overall, a 15.31 % reduction in vacuum drying time on a self-designed vacuum dryer and a 9 % reduction in total processing time were observed when UAOD (30 ºBrix) was applied for 20 min. Moreover, the influence of UAOD on the quality of dried pineapple in terms of rehydration ratio, firmness, and color change was also determined. Results showed that the pre-treatment with UAOD (30 ºBrix) of 20 min provided a better rehydration ability, with minimum change in color and textural properties. However, an increase in the pre-treatment time beyond 20 min diminished the rehydration ability of the dried product. Scanning electron microscope (SEM) images of pretreated and dried pineapples were also analyzed to determine the effect of pre-treatments applied for different lengths of time on the microstructure of the pineapple. The study's results suggested that applying UAOD as a pre-treatment considerably reduced the processing time and better retention of the pineapple properties.

Pulsed Electric Field and Freeze-Thawing Pretreatments for Sugar Uptake Modulation during Osmotic Dehydration of Mango

Osmotic dehydration kinetics depends on food tissue microstructure; thus, modulation of mango porosity could help selectively enhance water removal over sugar gain. In this present study, pretreatments of freeze-thawing (freezing at −36 °C for 2 weeks and thawing at 4 °C for 24 h) and pulsed electric field (1 kV/cm, 10 and 30 pulse numbers), were applied to mango 1 cm-thickness slices prior to osmotic dehydration conducted at 40 °C for 4 h. Three different 60 °Brix agave syrup solutions with or without added polysaccharides (inulin or xanthan gum) were used in the osmotic dehydration operation. Water loss (WL), sugar gain (SG) and microstructure images were used to compare the effects of pretreatments on mango osmotic dehydration efficiency. Results indicated that pulsed electric field (PEF) pretreatment increased slightly WL during osmotic dehydration, contrary to freeze-thawing (F-T), which for most cases led to a decrease. As for solids uptake, due to higher damage induced by F-T to mango tissue, SG was higher than for fresh and PEF pretreated mangoes. Using xanthan gum as additive to agave syrup solution, helped to decrease sugar uptake in frozen-thawed mango due to an increase in solution viscosity. A similar WL/SG ratio was obtained with frozen-thawed mango in solution with xanthan gum. Therefore, in the case of frozen-thawed mango, it is recommended to use an osmotic solution with high viscosity to obtain low sugar uptake in the final product. The novelty of this contribution is twofold: (i) using pretreatments (F-T or PEF) to minimize sugar uptake during osmotic dehydration, and (ii) using agave syrup with added polysaccharides to enrich final product with inulin.

Vacuum-Assisted Osmotic Dehydration of Autumn Olive Berries: Modeling of Mass Transfer Kinetics and Quality Assessment.

Autumn olive fruits were osmo-dehydrated in sucrose solution at 70 °C under vacuum and atmospheric pressure. The mass transfer kinetics data were applied to the models of Azuara, Crank, Page, and Peleg. The Peleg model was the best-fitted model to predict the water loss and solid gain of both treatments. The vacuum application decreased the effective diffusivities from 2.19 × 10−10 to 1.55 × 10−10 m2·s−1 for water loss and from 0.72 × 10−10 to 0.62 × 10−10 m2·s−1 for sugar gain. During the osmotic dehydration processes, the water activity decreased and stabilized after 5 h, while the bulk densities increased from 1.04 × 103 to 1.26 × 103 kg/m3. Titratable acidity gradually reduced from 1.14 to 0.31% in the atmospheric pressure system and from 1.14 to 0.51% in the vacuum system. pH increased significantly in both systems. Good retention of lycopene was observed even after 10 h of treatments. For the color parameters, the lightness decreased and stabilized after 30 min. In comparison, the redness and yellowness increased in the first 30 min and gradually decreased towards the initial levels in the fresh fruit.

Mass Transfer kinetics during osmotic dehydration of Beetroot Tutti -Frutti

Beetroot and beet juice have been known for their antioxidant, anticancer and anti-diabetic effects as well as being a source of dietary nutrients that reduce blood pressure and may improve athletic performance. Now-a-days, there is an increased interest in fruits and vegetables processing by products due to their nutritive value. The experiment consisted of various combination of sugar syrup temperature (40, 50 and 60°C), concentration (50, 60 and 70°Brix) and duration of osmosis (60,120 and 180 min) for preparation of beetroot tutti-frutti. The results indicated that the quality observations affected by various treatments. As the temperature and concentration of the solution were increased the water loss and sugar gain was also increased with increase in time. The optimized process parameters for osmotic oodehydration of beetroot cubes were found to be at 62Brix syrup concentration, 50C syrup temperature and 105 min duration of osmosis. The predicted water loss (maximum) and sugar gain (targeted) was 36.12 and 9.80 per cent, respectively at optimized input parameters on the basis of sensory evaluation, texture and overall acceptability.

Study of Efficacy and Safety of Injection Depot Medroxy Progesterone Acetate In Lactating and Non-lactating Women

Subject: This was a prospective study of efficacy and safety of injection depot medroxy progesterone acetate (DMPA) in lactating and non-lactating women. Abstract: The population of India is growing rapidly. The socio-economic problem of overpopulation is too well known. The use of safe and effective contraception is the need of the hour in India. Contraceptive advice is a vital component of good community health. Aims and Objective: The present study aims to study the establish safety and effectiveness of injection DMPA as a contraceptive method, acceptance, and continuation rate of injection DMPA in lactating mothers who had received first dose at postpartum period and non-lactating women and study the side effect of injection DMPA. Methods: A prospective study was conducted, at J K Lone mother and Child Hospital, Government Medical College Kota, Rajasthan, between April 2019 and April 2020. One hundred women were given injection DMPA 150 mg intramuscularly taken as study group and 100 women not using hormonal contraception were taken as controls group. They were followed at every 3 months. The comparison between the two groups was done using student t-test Chi-square test for calculation of p value. Results: The study was conducted to evaluate that women who were used DMPA mean age were 25.35 years. Overall accepted rate is 20%. No effect of literacy on acceptance rate. Significant menstrual irregularity found which was most common reason for attrition. Failure rate was zero among DMPA user. No significant effect on BP, blood sugar, and weight gain. No adverse effect on lactation. Conclusion: The study concludes that DMPA is a very effective contraceptive. Women accept it very easily without much degree of motivation. However, side effect decreases compliance.

Optimization of Osmotic Dehydration of Autumn Olive Berries Using Response Surface Methodology.

Autumn olive fruits are a rich source of nutrients and functional compounds, making them functional foods against many diseases and cancers. To increase the consumption, its processing, and its transformation into new products would help spread them to the consumer’s table. In this study, after giving an overview of the physicochemical characteristics and the antioxidant activity, the objective was to optimize the osmotic dehydration (OD) of the berries. Response surface methodology was used to investigate the effect of dehydration factors: syrup concentration (30–70%), temperature (20–70 °C), and fruit-to-syrup ratio (1:10–2:10) on the water loss (WL), sugar gain (SG), weight reduction (WR), density (ρ), water activity (aw), and total color change (ΔE) of fruits after 10 h of OD. Results obtained by employing Box–Behnken design (three variables, three levels), and significant terms of regression equations indicated that the syrup concentration and temperature variation are the most affecting factors on the previously mentioned independent variables (WL SG, WR, ρ, aw, and ΔE). Fruits to syrup ratio appeared to have a significant effect only on WL. Under the optimum conditions found (70%, 70 °C, 1.8:10), the predicted values were 59.21%. 19.21%, 32.34%, 1.22 g/cm3, 0.850, and 3.65 for WL, SG, WR, ρ, aw, and ΔE, respectively.

Effect of viscosity and rheological behavior on selective mass transfer during osmotic dehydration of mango slices in natural syrups

AbstractOsmotic dehydration of mangoes was investigated for the reduction of solids gain (SG) and potential use of natural syrups as osmotic solutions. Different osmotic solutions at 60 °Brix were used (made with sucrose, glucose, fructose, corn syrup solids (CSS), and agave syrup (AS) with or without added xanthan gum [XG] or inulin) during osmotic dehydration at 40°C of mango slices (0.4 and 1.5 cm thickness). Rheological behavior and viscosity of the different osmotic solutions were determined at 22 and 40°C. According to the results, increasing the viscosity and the sample thickness helped to reduce the sugar gain while maintaining an adequate water loss. The highest sugar gain was found for sucrose, glucose, fructose, AS solutions, and the lowest, for CSS solutions and XG added to AS. The impact of increasing apparent viscosity on SG was more pronounced for thin samples, indicating the importance of the Biot number on selective mass transfer during osmotic dehydration.Practical ApplicationsThis research aims to obtain osmotically dehydrated mangoes with low sugar content by using a natural multicomponent solution such as an AS with added ingredients. In this study, the role of solution viscosity combined to sample thickness in lowering SG during osmotic dehydration was elucidated. As well, AS used in this research as a model, is particularly interesting due to its rich content in vitamins and prebiotic (inulin) which levels up the mango nutritious values. This study would help industrials to offer healthier snacks, in particular for consumers who wish to reduce their sugar intake.

Blanching of papaya: effect on osmotic dehydration and characterization of the fruit invertase

ABSTRACT: This research evaluated the influence of blanching on osmotic dehydration in sucrose solutions of papaya of Formosa cultivar. The characterization of invertase present in the fruits was also done. Blanching possibly caused damages to the cellular structure resulting in higher water loss, sugar gain and, thus, effective diffusion coefficients than fresh papayas during osmotic dehydration. The invertase extracted from papaya pulp presented optimum temperature of 45 °C and optimum pH of 4.8. Considering the low production cost of papaya and the invertase characteristics, the fruit shows to be a potential source for the referred enzyme extraction.

Flavonoid enrichment of fresh-cut apple through osmotic dehydration-assisted impregnation

PurposeInclusion of bioactive compounds in food products is promising for developing novel functional food products. The feasibility of incorporating flavonoids and low-calorie sugar substitutes in fresh-cut apple through osmotic dehydration (OD) was investigated.Design/methodology/approachThe impregnation of quercetin and fisetin in apple cubes was tested. The effects of different osmotic agents, sucrose and sorbitol:mannose, on the water loss (WL) and sugar gain of the samples were studied at 25 and 40 °C for eight hours.FindingsTemperature was a significant factor in the mass transfer kinetics, that is to say, higher temperatures resulting in higher rates. The molecular weight of the solutes in the osmotic solution also affected the OD kinetics and flavonoids uptake, as well as the physico-chemical quality.Originality/valueOverall, the results indicate that OD using alternative low-calorie and health-promoting solutes can be an effective treatment to simultaneously enrich fresh-cut apples with senolytic flavonoids, therefore presenting a great potential for a novel functional food product.

Mass transfer modelling in ultrasound assisted osmotic dehydration of kiwi fruit

In this study, the effect of ultrasonic pre-treatment on osmotic dehydration of kiwi slices was investigated. Kiwi fruit slices were subjected to ultrasonic pre-treatment in a sonication water bath at a frequency of 25 kHz for 20 min. Osmotic dehydration of ultrasonic pre-treated samples were conducted for a period of 300 min in 60 Brix sucrose solution. The kinetics of moisture loss and solute gain during osmotic dehydration were predicted by fitting the experimental data with Azuara's model and Weibull's model. The effects of ultrasound application on water loss, sugar gain, effective moisture diffusivity and solute diffusivity of the samples were analysed. The osmotic dehydration process showed a rapid initial water loss followed by a progressive decrease in the rates in the later stages. From the Azuara's model, the predicted equilibrium water loss value for ultrasound pre-treated sample was 58.4% (wb) at 60°C that was nearly 16% higher than the samples treated under atmospheric conditions. Fitting of Weibull model showed that the ultrasound pre-treated and untreated samples had shape parameter (βw) ranging between 0.570–0.616 and 0.677–0.723 respectively. The lower values of shape parameter indicated that sonication caused accelerated water loss resulting faster dehydration rate. Results indicated that the effective moisture diffusivity and solute diffusivity was enhanced in ultrasonic pre-treated samples. The effective moisture diffusivity during osmotic dehydration of ultrasonic pre-treated samples was ranged between 5.460×10−10–7.300×10−10 m2/s and solute diffusivity was varied between 2.925×10−10–3.511×10−10 m2/s within the temperature range 25–60 °C. The enhanced moisture and solute diffusivity in ultrasound pre-treated kiwi slices was due to cell disruption and formation of microscopic channels.

Effect of air drying on quality characteristics and mass transfer kinetics of osmotically dehydrated sea buckthorn by stevia

Sea buckthorn is ranked among the most significant super foods worldwide. Its fruits and leaves are used as fresh or dried in food, pharmaceutical and cosmetic industry. As super food any pre-treatment should sustain this property and hence this research was focused on osmotic dehydration of sea buckthorn by stevia also a super food. Therefore, water loss, sugar gain, acidity, ascorbic acid and water diffusivity were evaluated during osmotic dehydration of sea buckthorn by two stevia solutions, 15ο and 30οBrix and following were air-dried at 50οC by comparing the effect of steam blanching per case. Steam blanched samples exhibited increased water loss at the end of the process, 55% at 30οBrix and 48% at 15οBrix, compared to untreated samples where losses were 43% (30οBrix) and 28% (15οBrix) respectively. Ascorbic acid was significantly reduced, exceeding 50% in steam blanched samples and 23% in untreated samples. Steam blanched samples dehydrated at 15oBrix exhibited 82% dry matter increase and only 39% the untreated samples. Similarly, samples dehydrated at 30oBrix exhibited 84% dry matter increase and 53% when no steam blanching was applied. Solid gain was seven times less compared to water loss which is attributed to high molecular weight of steviol glycoside. The osmotic dehydration and airdrying curves were described effectively by Peleg and Fick models, and Logarithmic and Fick models respectively, having in all cases R2 adj>99% and SEE<0.2. The water diffusivity of steam blanched samples was 3.2-5.57×10-11 m 2 /s for water loss and 1.27- 2.03×10-11 m 2 /s for solid gain at 30oBrix and 2.12-4.27×10-11 m 2 /s and 0.91-1.98×10-11 m 2 /s at 15oBrix. Finally, the water diffusivity of steam blanched samples during air-drying was 2.11-2.29×10-11 m 2 /s and 1.56-1.66×10-11 m 2 /s in the case of untreated samples.

Coupling osmotic dehydration with heat treatment for green papaya impregnated with blackberry juice solution

SummarySlices (1.5 mm thick) of green papaya were impregnated through osmotic dehydration with a blackberry juice–sucrose solution to produce an intermediate moisture product. The effect of processing temperature (T) and sucrose‐added molality (msucrose) on mass transfer during the operation was assessed, using a response surface methodology (RSM). The RSM was used to model water loss, sugar and anthocyanin gain during the process. Increasing sucrose molality resulted in increasing water loss and sugar gain, but decreasing anthocyanin gain. Water transfer therefore limits anthocyanin impregnation, but not sucrose incorporation. Afterwards, the impact of heat treatment at high temperatures was analysed, using numerical simulation. The conditions of the combined process, designed to achieve an anthocyanin‐rich final product, are low sucrose‐added molalities (sucrose molality < 1 mol kg–1) and high processing temperatures (T > 50 ºC) for osmotic dehydration, coupled with high‐temperature, short‐time (HTST) heat treatments for product stabilisation.

Hot air drying kinetics of novel functional carrot snack: Impregnated using polyphenolic rich osmotic solution with ultrasound pretreatment

AbstractIn this study, osmotic impregnation technique combined with ultrasonic pretreatment was applied to carrot slices followed by hot air drying in order to production of functional and healthy snack enriched with polyphenolic compounds derived from roselle extract (at least 400 ppm). The purposes of osmotic impregnation‐dehydration process were the maximum amount of dehydration and phenolic compounds diffusion along with the minimum sugar gain. Results revealed that increasing osmotic solution concentration and process time over optimal points, resulted in reduction of phenolic compounds saturation inside the samples. Also, it was found that prolonged ultrasound pretreatment had a damaging effect on fruit tissue microchannels and led to a decrease in the mass transfer rate. The optimal conditions of this stage were osmotic solution concentration of 60% and the process time of 60 min without ultrasonic pretreatment. In the second stage, the results of hot air drying showed that the highest amount in the total phenolic content was achieved at 70°C. Furthermore, among the several models evaluated, Jena & Das model with a determination coefficient of 0.99 and minimum error indexes, was the best fitted to drying experimental data and activation energy for effective diffusivity coefficient was calculated as 35.987 kJ/mol.Practical applicationsDue to elevation in consumer's awareness in recent decades about the importance of food composition for healthier life and diseases prevention, demand for functional foods has been increasing. Food enrichment with bioactive compounds like polyphenol compounds from different plant sources is an applicable method for this purpose. In this study, carrot, which is a valuable vegetable itself, was further extended to a more functional food by enrichment with rosella plant extract and then hot air dried to produce a snack which has more nutritional quality than conventional ones. Also, osmotic dehydration results in lower moisture content of carrot slices which helps reduced hot air drying time and lower energy consumption. Overall, results from this research is usable to develop a functional snack based on carrot and rosella extract.

Effect of osmotic dehydration with whole cane sugar on the convective drying of mango (Tommy Atkins) and on some physicochemical properties

This research evaluates the effect of osmotic dehydration (OD) as a pretreatment of convective drying in mango pieces (Tommy Atkins) using whole cane sugar solutions in concentrations between 30 and 65 °Brix, and temperatures between 50 and 80 °C in a central composite rotatable design. The effect on effective diffusivity, water loss, sugar gain, color index (CIE-L*a*b*), water activity, sensory perception (color, texture and flavor), and consumption probability were measured. Effective diffusivity was influenced only by temperature of solution, presenting a maximum of 1.4E-4 cm2s-1. Water loss in OD registered a maximum of 40%. Color perception was affected by both variables. The consumption probability was influenced by the conditions evaluated with a maximum value of 80%. It was found the optimal conditions of OD in 65°Brix and 79 °C.

Use of ultrasound for dehydration of mangoes (Mangifera indica L.): kinetic modeling of ultrasound-assisted osmotic dehydration and convective air-drying.

This work evaluated the production of dehydrated mangoes (Mangifera indica L.) and the effectiveness of ultrasonic-assisted osmotic dehydration on the drying kinetics of mangoes. Cube shaped mango samples were pretreated using ultrasound-assisted osmotic dehydration (UAOD) and dried in a circulating drying oven. An experimental design was created to evaluate the effect of pretreatment time and osmotic solution concentration on the water loss and sugar gain in the osmotic dehydration and on the drying time. The ultrasonic pretreatment was carried out in a bath ultrasound operating at 25kHz and outputting 55W/m3 of power. Osmotic solution ranging from 0 to 500kg sucrose/m3 was applied in the treatments, and air drying was carried out at 60°C. A mathematical model was developed for the osmotic pretreatment, and Fick's law was used to model the air-drying process. The mass transfer coefficients were estimated for the ultrasonic-assisted osmotic dehydration, and the apparent water diffusivity was estimated for the air-drying process. The mass transfer coefficient ranged from 0.017 to 0.109m2/s and the resistance to mass transfer at the surface ranged from 0.26 × 10-6 to 1.22 × 10-6m2/s on the UAOD, while the apparent water diffusivity during air drying ranged from 5.94 × 10-9 to 8.41 × 10-9m2/s. Mangoes presented a different behavior when compared to other fruits. The ultrasonic pretreatment was effective only when associated with an osmotic solution at 500kg sucrose/m3.

Influence of ultrasound and osmotic dehydration pretreatments on drying and quality properties of persimmon fruit

In this study, the effect of the ultrasound and osmotic dehydration pretreatments before the convective drying of the persimmon fruit was assessed via their drying behavior and quality properties. Ultrasound-assisted osmotic dehydration (30 °C, 45 °Brix) was performed at 35 kHz for 10, 20, and 30 min. Afterward, samples were placed first in 45 then in 70 °Brix sucrose solutions; the solutions were next shaken at 100 rpm. The control group without ultrasound treatment dehydrated osmotically. The samples were dried in a tray drier at a temperature of 60 °C and an air velocity of 1.5 m/s. Ultrasound-assisted osmotic drying treatments increased water loss and sugar gain; moreover, the osmotic dehydration time was shorter than in the untreated group. The ultrasound-assisted osmotic dehydration demonstrated a significantly decreased drying time, increased drying rates, and a 21% increase in effective water diffusivity by 30 min. The ultrasound pretreated osmotic dehydration prior to hot air-drying decreased the total required drying time. The ultrasound-assisted osmotic dehydration affected the rehydration rate and total phenolic content significantly and there was no significant difference between the color change (ΔE, ΔC, and Hue°) of the ultrasound treatment (30 min) group and the untreated group.

English

Sugarcane chemical ripening is aimed at accelerating the sucrose accumulation in the stems for harvesting when the climate conditions of crop year are hardly optimal for natural ripening. The study aims at determining the best response of sugarcane varieties to glyphosate ripening effect and the harvest delay after its application in Ferke 2 Sugar Bowl, Northern Cote d’Ivoire, in order to improve the technological qualities of canes at the early harvest season. Twenty plantations (700 ha) hosting two commercial varieties NCo376 and SP711406 were treated with glyphosate (360 emulsion concentrated) at 0.8 L/ha. For each plantation, two sample plots of 1 ha control and treated were determined. Those samples were analyzed to determine the sucrose gradient all along the stalks and monitor their technological qualities after 10, 15 and 20 days. As results, glyphosate improved sucrose content and the recoverable sugar of treated varieties. SP71-1406 was more sensitive than NCo376 with uniform qualities all along stalks after 20 days. Gains of 1.6% sucrose content and 1.5% recoverable sugar were obtained, compared to the control. So, the uppermost parts preservation of harvested stalks is justified and a sugar gain of 0.13 t/ha except those generated by the ripener. Key words: Glyphosate, ripener, technological quality, gradient, sucrose, recoverable sugar.

Study the Mass Transfer Kinetics of Aloe vera Gel Cubes

The present study was carried out to investigate the mass transfer kinetics of Aloe Vera gel cubes during osmo-convective and convective drying and its quality evaluation. Aloe Vera leaves were washed and cut into 25 x 25 x 25 mm cubes and were osmotically dehydrated in different concentration (43.2, 50, 60, 70, 76.8° Brix) and process temperature (43.2, 50, 60, 70, 76.8°C) with syrup to gel ratio (4.3:1, 5:1, 6:1, 7:1, 7.7:1) for 4 hr duration of osmosis. Central Composite Rotatable Design was used to analyse osmotic dehydration process. The osmosed and untreated Aloe Vera gel cubes were dried in tray dryer at 50°C, 60°C and 70°C and hot air dryer at 60°C, 70°C and 80°C. The effect of osmosis, sugar concentration and process temperature of syrup on mass reduction, water loss and sugar gain were studied during osmotic dehydration. It was found that mass reduction, water loss increased with increase of sugar concentration and process temperature while solid gain decreased with increase in sugar concentration and process temperature.

Mathematical Modelling of Osmotic Dehydration Kinetics of Apple Cubes

Apple cubes were osmotically dehydrated at 25, 40 and 60C, using sucrose or sorbitol, and the mass ratio of sample to solution of 1:4 and 1:10, at atmospheric pressure or vacuum pressure of 150 mbar. Six mathematical models were tested to describe the mass transfer kinetics of water loss (WL) and sugar gain (SG). Crank's, Azuara's, Peleg's, Page's and Weibull's models could fit well the experimental data, but the Penetration model resulted in a poor fit. The mass ratio of sample to solution did not have an influence on the mass transfer kinetics at the atmospheric pressure. The increase of temperature and the use of sorbitol as the osmotic agent resulted in an increase of the osmotic process rate at both pressures used. Therefore, sorbitol is a good alternative to sucrose. The vacuum presented a tendency to increase the initial rate of WL. Practical Applications This work confirms the potential to use sorbitol as an alternative to sucrose as the osmotic agent in OD. Besides presenting low calories, and being less sweet and less cariogenic than sucrose, sorbitol is a prebiotic. It induced an increased process rate, in comparison with sucrose. This is advantageous for a faster OD process. However, the benefit in the process time reduction may not justify the material costs. The mass ratio of sample to solution of 1:4 was identified as an alternative to 1:10 in the OD at the atmospheric pressure, as lower quantities of osmotic solution and, therefore, solute are required to carry out the OD process to the same level of dehydration. This work shows also that simple models, such as Peleg's and Page's, can be used to predict the mass transfer kinetics of WL and SG during OD processes at different conditions.