Osmotic Dehydration Conditions Research Articles

Sustainable Utilization of Mushroom By-Products Processed with a Combined Osmotic Dehydration Pretreatment and a Hot-Air-Drying Step.

Mushroom production and consumption are gaining increased interest due to their unique flavor and nutritional value. However, in the mushroom industry, large amounts of by-products are generated, which have a high negative environmental and economic impact. In this study, an osmotic dehydration process followed by hot-air-drying was applied to mushroom stems to produce dried mushrooms as the end product. The osmotic dehydration conditions (concentration of hypertonic solution, specifically, 10-30% maltodextrin and 20-40% oligofructose; a treatment time of 40-80 min; and a temperature range of 30-50 °C) were optimized using response surface methodology (RSM). The results showed that a four-factor three-level Box-Behnken experimental design was effectively implemented to evaluate the effect of the process parameters and identify the optimal osmotic dehydration conditions for producing osmotically dehydrated mushrooms. The main factor affecting mass transfer was the osmosis temperature, and the optimal conditions were found to be 38 °C, 40% oligofructose and 19.3% maltodextrin as the osmotic agents, and 80 min of immersion time. Moreover, the results showed that osmotic pretreatment, in the optimal conditions, significantly reduced the required drying time of the by-products compared to traditional hot-air-drying, especially at milder drying temperatures. Consequently, the required energy was also reduced by at least 40% at 50 °C.

Shelf-Life Enhancement Applying Pulsed Electric Field and High-Pressure Treatments Prior to Osmotic Dehydration of Fresh-Cut Potatoes.

From a quality standpoint, it is desirable to preserve the characteristics of fresh-cut potatoes at their peak. However, due to the mechanical tissue damage during the cutting process, potatoes are susceptible to enzymatic browning. This study pertains to the selection of the appropriate osmotic dehydration (OD), high pressure (HP), and pulsed electric fields (PEF) processing conditions leading to effective quality retention of potato cuts. PEF (0.5 kV/cm, 200 pulses) or HP (400 MPa, 1 min) treatments prior to OD (35 °C, 120 min) were found to promote the retention of the overall quality (texture and color) of the samples. The incorporation of anti-browning agents (ascorbic acid and papain) into the osmotic solution improved the color retention, especially when combined with PEF or HP due to increased solid uptake (during OD) as indicated by DEI index (2.30, 1.93, and 2.10 for OD treated 120 min, non-pre-treated, HP pre-treated, and PEF pre-treated samples, respectively). PEF and HP combined with OD and anti-browning agent enrichment are sought to improve the quality and microbial stability of fresh-cut potatoes during refrigerator storage. Untreated fresh-cut potatoes were characterized by color degradation from the 2nd day of storage at 4 °C, and presented microbial growth (total viable counts: 6 log (CFU)/g) at day 6, whereas pre-treated potato samples retained their color and microbiologically stability after 6 days of cold storage (total viable counts, <4 log(CFU)/g).

Evaluation of ascorbic acid impregnation by ultrasound‐assisted osmotic dehydration in plantain

The objective of this study was to evaluate the impregnation of ascorbic acid (AA) by ultrasound (US)-assisted osmotic dehydration (OD). A 25 factorial design was used. The highest water loss (WL) of 42% was obtained with the combined use of OD+US+AA. The effective diffusivities of water (EDw) and solids (EDs) were increased when OD was employed with a temperature of 60°C, a sucrose concentration of 60%, and a simultaneous application of US+AA treatments in plantain thin slices. The use of OD+US favored AA impregnation; in the treatment with 45% sucrose at 40°C, AA increased from 18% to 42%. Tonality did not change significantly in the OD+US+AA treatments at 40°C. However, except for the gumminess, significant differences from the control were observed in the texture profile analysis (TPA). In microstructure analyses, it was observed that by applying OD+US+AA, the cellular structure was not altered. Applying the specified operational conditions for OD, the AA impregnation pretreatments, and US, a plantain dry food could be obtained without reducing the specified quality parameters in this study. Novelty impact statement Applying the ultrasound pretreatment before osmotic dehydration favors the impregnation of ascorbic acid in the plantain, preserving its original physical and sensory characteristics, such as texture, color, and flavor, and the treatment also promotes the maintenance of the nutritional properties of the food, increases the transfer of mass, and incorporates bioactive compounds.

Optimization of Low-cost Drying Technology for Preservation of Peach (Prunus Persica) Using RSM

ABSTRACT Peach is an important fruit; however, its perishability limits its availability to the consumers. The present study fosters a low-cost preservation method of peach involving osmotic dehydration at 35–45◦C using a sugar solution (50–70◦Brix) for 60–180 minutes. The conditions for osmotic dehydration (OD) of peach slices in terms of maximum water loss (WL), rehydration ratio (RR), minimum solute gain (SG) with optimum hardness, and maximum overall acceptability (OA) were optimized using Box-Behnken Design (BBD) of response surface methodology (RSM). The regression coefficient of the models indicated that the time of immersion was the most significant (p < .001) factor for WL and SG, followed by the temperature. Furthermore, immersion time had a positive effect on hardness, whereas it had a negative effect on the organoleptic properties of osmo-dried peach slices. Sucrose concentration of 63.20◦Brix for 133 minutes at 41◦C was most suitable for osmotic dehydration of peach slices to obtain maximum possible WL, minimum SG, maximum RR, optimum hardness, and maximum overall acceptability. Combined drying (OD+CAD) significantly reduced the drying time and had better retention of sensory attributes. The peach slices subjected to a combination of OD+CAD had good retention (45–50%) of bioactive components even at ambient temperature and had an overall acceptability score of above 6.0 with a 6-months shelf life of the product. The technology was demonstrated among the small-scale processors and entrepreneurs and based on the response received, more than 90% highly rated this technique as efficient, energy-conserving, and easy to adopt.

Review: Effect of the combined application of edible coatings and osmotic dehydration on the performance of the process and the quality of pear cubes

SummaryThe objective of the present work was to evaluate the combined effect of the application of edible coatings (sodium alginate and low methoxyl pectin) and different osmotic dehydration conditions (sucrose solution: 40 and 60 °Brix, temperatures: 20 and 40°C and times: 1, 2, 4, 8 and 16 h) on pear cubes (water loss, solid gain, performance ratio, the total colour differences, mechanical properties, phenolic content and sensory analysis). The results indicated that samples coated with low methoxyl pectin and treated under 60 °Brix for 16 h at both temperatures (20 and 40°C) presented the best process performance. Statistical analysis showed that the application of the coatings resulted in greater firmness and stiffness of the pear cubes at the end of osmotic dehydration. Besides, alginate coating best preserved the phenolic content (31.4%) than uncoated (26.04%) and pectin‐coated (20.77%) ones. However, total colour differences were not improved with the use of edible coatings (alginate or pectin). In terms of quality, the samples coated with both hydrogels had good overall acceptability by the evaluators and good mechanical properties. However, further studies are required to decrease the difference in colour and leaching of bioactive compounds in pear cubes due to the osmotic dehydration treatment.

Dried Figs Quality Improvement and Process Energy Savings by Combinatory Application of Osmotic Pretreatment and Conventional Air Drying.

This study concerns the implementation of osmotic dehydration (OD) as a pre-treatment of air-drying in fig halves, aiming at drying acceleration, energy savings and product quality improvement. The effect of solid/liquid mass ratio, process temperature (25–45 °C) and duration (up to 300 min) on water activity (aw) and transport phenomena during OD, was modelled. The effective diffusion coefficients, drying time and energy consumption, were also calculated during air-drying at 50–70 °C. At optimum OD conditions (90 min, 45 °C), the highest water loss and solid gain ratio were achieved, while the aw (equal to an initial value 0.986) was decreased to 0.929. Air-drying time of OD- and control samples was estimated at 12 and 21 h, at 60 °C, respectively, decreasing the required energy by up to 31.1%. Quality of dried figs was systematically monitored during storage. OD-assisted air-drying led to a product of improved quality and extended shelf-life.

The effect of osmotic dehydration conditions on the calcium content in plant matrice

Osmotic dehydration is used as a pre-treatment before drying. This process can also be used as a method of modulation of the sensory values of plant components and fortifying them with selected components. The aim of this study was to examine the effect of osmotic dehydration as a method of pumpkin flesh 'Melon Yellow' (Cucurbita maxima) fortification with calcium. The studies showed for the first time that by selecting the appropriate process conditions it is possible to significantly increase the level of calcium in plant matrice. The highest calcium content was found in the pumpkin pulp dehydrated in 50% xylitol and inulin solutions with a calcium carbonate (5%), where the process was conducted for 120 min at 30 °C (1,380.4 and 1,328.4 mg Ca/100 g). Therefore, study has shown an innovative application of the osmotic dehydration process for the design of food with health-promoting properties, including for those at risk of osteoporosis.

Combined Osmotic and Air Dehydration for the Production of Shelf-Stable White Cheese

The research targeted on the production of an innovative shelf-stable cheese of high quality, through the combinatory effect of osmotic dehydration (OD) as pretreatment and conventional air-drying. The optimum OD processing conditions (process time/temperature, concentration of osmotic solution, food to OD agent ratio) were determined through a kinetic study of the effect of OD parameters on the water activity (aw) and water/solid transport phenomena, organoleptic and quality characteristics of the white cheese in cubes. Through Fick’s second law for mass transfer, water and solid diffusion coefficients were determined. Taking into consideration the aw, the quality, and organoleptic characteristics of the final product, the optimum OD conditions were selected as 15 °C process temperature, food to osmotic agent ratio 1:4 (w/w), concentration of osmotic agent 65% to glycerol, and treatment time 30 min. The final moisture and aw of the OD-treated product were calculated as 40% and 0.88, respectively. The time of OD-pretreated product for air-drying at 40, 55, and 67 °C to 5% residual moisture was reduced by 35, 51, and 65% respectively. The selected air-drying conditions were 67 °C for 4 h. Quality parameters of the final white cheese product were studied during its storage at 15–40 °C, and the shelf life was estimated as 6 months at ambient temperature.

OPTIMIZATION OF OSMOTIC DEHYDRATION PARAMETERS OF BANANA UNDER PULSED MICROWAVE CONDITIONS BY RESPONSE SURFACE METHODOLOGY

Microwave assisted osmotic dehydration (MWOD) conditions of banana were optimized using response surface methodology. In this study, the microwave energy was applied in pulsing form to adjust the intermittent temperature distribution and overheating problem at respective microwave power level. The experiments were conducted using a face-centered central composite design (FCCD) with four factors, viz. slice thickness (5-10 mm), sugar concentration (40-60oBrix), microwave power (100-1000W), and time (10-50 min) at three levels. Multiple regression analysis showed that all process factors significantly affects linearly on the water loss, solid gain, drying efficiency, and color difference at p

Air drying kinetics and quality characteristics of osmodehydrated-candied pumpkins using alternative sweeteners

In order to obtain nutritious, low calorie candied pumpkins, of superior quality, air drying kinetics of pretreated pumpkin slices were investigated using three different drying temperatures (40, 60 & 80 °C). Before drying, pumpkins were osmotically treated using different osmotic agents, namely sucrose, oligofructose and their mixture (1:1) in a solution of a constant concentration (70°Brix), at three temperature (75, 85 & 95 °C) for 150 min. Changes in texture (hardness and compression work) were determined during drying and sensory characteristics of the final products were evaluated by trained panelists. A first-order reaction kinetic model was used to predict the drying rate and hardness, in which the rate constant was a function of the process temperature. The results showed that as the drying temperature is increased, the drying constant also increases whereas the equilibrium moisture content of the dehydrated products decreases. The hardness of candied pumpkins was mostly affected by the air drying temperature regardless the osmotic dehydration conditions. Sensory evaluation of the final candied pumpkins, showed a preference for the products osmotically treated by oligofructose.

The Influence of Osmotic Dehydration Conditions on Drying Kinetics and Total Carotenoid Content of Kiwiberry (Actinidia Arguta)

AbstractKiwiberries (Actinidia arguta var. Geneva) were osmotically dehydrated in sucrose, xylitol and maltitol 60 % water solutions at 30 and 50 °C. After pre-treatment, the samples were dried using convective method at 70 °C until fruits have reached a dimensionless moisture ratio (MR) of 0.02. Osmotic pre-treatment significantly improved drying kinetics during the first stage of the process. All the pre-treated samples reached water activity level (aw) less than 0.6 after 7 h of drying. When maltitol or xylitol was used as an osmotic agent at 30 °C, the time required for drying was reduced by 23 and 32 %, respectively. In turn, dehydration performed at 50 °C had no positive effect on the drying kinetics. The shortest drying time was obtained for the samples dehydrated in xylitol at 30 °C. In the case of these samples target MR was reached after 542 min whereas in the case of untreated samples drying lasted 810 min. The highest retention of carotenoid was observed for the samples osmotically pre-treated in maltitol solution at 30 °C and sucrose solution at 50 °C.

Quality of ‘Royal Gala’ cut apple during osmotic dehydration

Abstract The present work aimed to evaluate quality parameters of ‘Royal Gala’ apple cubes during osmotic dehydration (OD). We investigated the following OD conditions: osmotic agent, pressure, and temperature. The osmotic agent, being lower after OD with sorbitol than sucrose solutions, mainly influenced the water activity of the product. The color changes increased with increased temperature and were higher in vacuum experiments than at atmospheric pressure. In general, we recommend OD at 25 °C and atmospheric pressure for the preservation of the total phenolic content (TPC) and antioxidant activity (AA) of apple cubes during the process. Peleg’s model was found to provide the best fit of TPC and AA data.

Combined drying of Nopal pads ( Opuntia ficus‐indica ): Optimization of osmotic dehydration as a pretreatment before hot air drying

The aim of this work was to optimize the osmotic dehydration (OD) as a pretreatment before hot air drying (HAD) in Nopal pads. A Box–Behnken experimental design was used to optimize the OD conditions with respect to physicochemical and chromatic parameters, and mechanical properties of Nopal pads. Factors studied were: Three concentrations of sucrose (30, 40, and 50°Brix), calcium lactate (1, 2, and3%), and immersion time (1.5, 2.5, and 3.5 hr). Results showed that sucrose concentration and immersion time were the variables with higher influence. Quality properties mentioned before and the final mineral content of the dried samples (at 60°C for 48 hr) were analyzed. The combined drying (OD + HAD) reduced the moisture content in the range of 23% to 30% compared to HAD alone. It was found that the optimization of OD allowed preserving the quality properties, being a good alternative to give an added value for dried Nopal pads. Practical applications Nopal has important bioactive properties for both humans and animal diets, since it is a rich source of vitamins, minerals, and fibers. However, the main problem of its production is that post harvesting waste is greater than 50%. For this reason, there is a great interest to study inexpensive preservation methods that allow keeping the main attributes of processed fruits. The osmotic dehydration (OD) and the hot air drying (HAD) are two simple and inexpensive techniques which can be applied by both the food industry and small-scale food producers. In the present study, the optimization of OD as a pretreatment before HAD was a reliable tool to preserve the quality properties of Nopal pads.

Evaluation of the combined effect of osmotic and Refractance Window drying on the drying kinetics, physical, and phytochemical properties of beet

The effect of osmotic dehydration (OD) with different sucrose concentrations and temperatures was studied in combination with drying by Refractance WindowTM (RW) in beet slices with thicknesses of 1 and 5 mm. The color, texture, total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant capacity (AC) of the beet with OD, RW, and OD-RW combined drying were evaluated. The best results of water loss (WL) and solid gain (SG) with OD were obtained with 65% sucrose solution at 60 °C. OD partially reduced the water content of the slices, decreasing the drying time with RW at 85 °C. However, the retention of qualities such as color, texture, TPC, TFC, and AC in beet was obtained with combined drying by OD-RW at 60 °C under OD conditions of 65% sucrose at 45 °C. These conditions afforded a stable product retaining its physical and chemical properties.

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.

Osmotic dehydration kinetics of biofortified yellow-flesh cassava in contrast to white-flesh cassava (Manihot esculenta).

In recent times, the cultivation, processing and consumption of biofortified yellow-flesh cassava is of significant interest to breeders and food processors due to its relatively high pro-vitamin-A content, compared to the conventional white-flesh cassava. In light of this, osmotic dehydration (OD) kinetics of a recently released biofortified yellow-flesh cassava was compared to that of a white-flesh cassava, using salt, sugar, and salt-sugar solutions at different temperatures (30, 45, 60°C) and fixed cube/solution-ratio. Water loss (WL) and solids gain (SG) data were fitted by non-linear regression using four models (Page, Weibull, Azuara, and Peleg). Azuara model was most appropriate in describing OD kinetics for both cultivars. Azuara estimates for equilibrium WL and equilibrium SG, respectively, ranged between 0.101-0.120 and 0.049-0.094g/g for salt solution, 0.158-0.212g/g and 0.107-0.268g/g for sugar solution and 0.234-0.306g/g and 0.189-0.276g/g for salt-sugar solution. The best conditions for OD of both cultivars by salt solution and sugar solution was at 60°C and 45°C, respectively, while that for salt-sugar solution varied with cultivar. Increasing temperature increased water loss and solids gain. Salt-OD conformed to Arrhenius temperature dependence of diffusivity, but sugar-OD and salt-sugar-OD did not. Micrographs reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava. Extent of dehydration by OD agents ranked: salt-sugar > sugar > salt. Osmotic dehydration may be useful as a means of dehydration for cassava prior to drying, and is especially relevant for the carotenoids-rich biofortified yellow cassava.

Experimental investigation of effective factors of pulsed electric field in osmotic dehydration of apple

The effects of various factors of the pulsed electric field (PEF) as an apple osmotic dehydration (OD) preprocess by using response surface methodology (RSM) are investigated and optimized in this paper. Electric field strength, pulse numbers and pulse duration were considered as PEF pretreatment effective factors in constant osmotic dehydration conditions such as concentration and temperature. After 4 h of osmosis, the results indicate decrease in amounts of water loss (WL) and solid gain (SG) by increasing field strength from 1 to 2 kV/cm and decreasing pulse duration from 0.5 to 0.02 s, respectively. The effect of increasing the pulse numbers from 8 to 16 give rise to the increase in amounts of water loss and solid gain at first and then by increasing to 24 pulses, the decrease in these amount has been evident. The ratio of water loss to solid gain (WL/SG) and response surface methodology (RSM) were used for optimization effects of PEF factors on the OD process. In optimal values of electric field strength, pulse numbers and pulse duration, the WL/SG ratio provided highest reduction sample mass.

Optimization of processing conditions for osmotic dehydration of orange segments

The orange is 5th most important tropical fruit in the world production. The juice or pulp is extracted from the oranges and preserved for further use. Whereas for fruits and vegetables, osmotic dehydration is considered as one of best method for preservation. Hence in the present research focus on optimize process conditions for osmotic dehydration of orange segments. Fresh orange fruits were peeled and segments were separated. These segments were osmotically dehydrated at different sugar syrup concentrations 40 to 700B, time 60 - 300 min. and fruit solution ratio 1:3 to 1:5. The observation recorded with respect to water loss (WL), solid gain (SG) and weight reduction (WR). The results showed 500 B sugar syrup concentration, 300 min. time, and 1:4 fruit to solution ratio were optimum conditions to obtain water loss of 44.49 %, solid gain 6.91 % and weight reduction of 51.40%. Osmotic dehydration can be one of the alternative methods for the orange preservation than the traditional methods of food preservations. Also, it will be helpful to preserve orange segments for the longer time, which will be beneficial to small scale entrepreneur to improve their socio- economical status.

Optimization of processing conditions for osmotic dehydration of orange segments

The orange is 5th most important tropical fruit in the world production. The juice or pulp is extracted from the oranges and preserved for further use. Whereas for fruits and vegetables, osmotic dehydration is considered as one of best method for preservation. Hence in the present research focus on optimize process conditions for osmotic dehydration of orange segments. Fresh orange fruits were peeled and segments were separated. These segments were osmotically dehydrated at different sugar syrup concentrations 40 to 700B, time 60 - 300 min. and fruit solution ratio 1:3 to 1:5. The observation recorded with respect to water loss (WL), solid gain (SG) and weight reduction (WR). The results showed 500 B sugar syrup concentration, 300 min. time, and 1:4 fruit to solution ratio were optimum conditions to obtain water loss of 44.49 %, solid gain 6.91 % and weight reduction of 51.40%. Osmotic dehydration can be one of the alternative methods for the orange preservation than the traditional methods of food preservations. Also, it will be helpful to preserve orange segments for the longer time, which will be beneficial to small scale entrepreneur to improve their socio- economical status.

Application of osmotic dehydration to improve the quality of dried goji berry

Quality and preservation of dried goji berry can be improved with the application of osmotic dehydration (OD) as a pre-treatment step. The aim was to optimize OD conditions based on water loss, solid gain, water activity decrease and quality (color, antioxidant capacity, total phenolics, sensory properties) during processing and post-processing, to develop and produce a dried goji berry product of improved quality and with reduced energy requirements. Goji berries were treated in concentrated solution of glycerol, maltodextrin, ascorbic acid, sodium chloride for 60 min at 55 °C, and air-dried for 300 min at 60 °C (target aw 0.50–0.55). Combining OD and air-drying led to drying time decrease by 120 min, bright red color close to the fresh berry color, improved texture characteristics, higher antioxidant capacity and total phenolic content of the final dried product. Quality of OD-treated and non-treated air-dried samples was monitored during storage at 25-35-45 °C. Shelf life was significantly prolonged for OD-treated goji berries: 206 days at 25 °C compared to 99 days for the non-treated.