Effect of Osmo Dehydration on Quality Attributes of Bilimbi (Averroha bilimbi) Fruits

Background: Bilimbi is a profusely bearing tree and majority of fruits produced are wasted due to lack of proper preservation methods. Osmo-dehydration studies on quality attributes of bilimbi (Averroha bilimbi) was conducted with the objective to standardize the process variables for osmodehydrated bilimbi and to assess the retention of bioactive compounds. Methods: Harvested mature bilimbi fruits of uniform size were washed, surface dried, pricked and blanched in hot water for one minute. Blanched fruits were subjected to osmotic treatment, with sucrose solution of 40, 60 and 80°B for 60, 120 and 180 minutes. The osmodehydrated bilimbi fruits were analyzed for mass transfer, biochemical and sensory qualities. Best treatments were stored for four months in the room temperature. Result: Mass transfer characters viz., solid gain, water loss, percentage weight reduction, yield and biochemical parameters such as reducing sugar and total sugar increased with increase in osmotic concentration and immersion time whereas free acids, ascorbic acid and antioxidant activity were decreased. The osmotic treatment of 80°B for 180 minutes recorded the highest value for solid gain (5.10%), water loss (16.72%), weight reduction (22.57%), ratio of water loss to solid gain (3.25%) and yield (21.13%) which exhibited superior sensory scores for taste (8.43), flavor (8.27), texture (8.46) and overall acceptability (8.43). The best three treatments selected based on sensory analysis were subjected to storage stability studies under room temperature. Osmodehydrated bilimbi obtained highest sensory score at the end of storage.

Osmosis dehydration of sweet corn (Zea mays saccharata.) kernel with trehalose solution

Osmosis dehydration is a process of reducing water content by immersing the material in a hypertonic solution. It usually uses a sugar solution likes mono-saccharide or disaccharide. Trehalose is one type of disaccharide that can be used as a solute. Trehalose is able to maintain the nutrition content of food material and the aroma of horticulture products because it maintains and stabilizes complex molecules. Immersing of sweet corn kernel in trehalose solution was expected to maintain kernel sweet corn quality in relation to the next process. The objective of the research is to investigate the effects of the different immersing temperatures and trehalose concentrations on the physical quality of sweet corn. This study used solution with concentrations of 4%, 8%, and 12% trehalose. The variations of immersing temperature were 30°C, 40°C, and 50°C. The experiment was done with a factorial completely randomized design. The first factor was immersing temperature and the second factor was the concentration of trehalose solution. The data was analyzed using Duncan Multiple Range Test (DMRT) method. The temperature treatment of 50°C and trehalose concentration of 12% showed the highest weight reduction (6.18%), solid gain (4.5%), and water loss (10.38%). The lowest water content of corn kernel was also obtained in this treatment i.e 78.7%.

Impact of Using Alternative Sweetener as Osmotic Agent on Mass Transfer, Colour and Texture Properties During Dip Dehydration of Apple Slice

Previous study has explored dip dehydration as a novel variant of osmotic dehydration to reduce solid gain, which is the main problem of osmotic dehydration. However, this dehydration process commonly uses sucrose solution as osmotic agent which might contribute to the increase in glycaemic index and can also be linked to different diseases such as diabetes and obesity. Therefore, this study aims to investigate the effect of using alternative sweeteners as an osmotic agent on mass transfer, colour, and texture profiles during dip dehydration of apple slices. Three alternative sweeteners, i.e., erythritol, sorbitol and xylitol with 30% (w/v) concentration were used in this study. Apple slices with 1.5 mm thickness and diameter of 55 mm were dipped multiple time in the same concentrated solution every 40 minutes until 200 minutes before samples were analysed. Findings showed that different type of sweetener affect water loss and solid gain. Xylitol and sorbitol gave highest water loss about 36% and 40%, respectively. Lowest total colour different with fresh apple has been observed in sample treated with xylitol. As for texture, there is no remarkable effect of using alternative sweetener as osmotic agent at all processing times. Overall, the best alternative sweetener for sucrose is xylitol considering the mass transfer and quality of apple slices.

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.

Efficiency of Osmotic Dehydration of Pomegranate Seeds in Polyols Solutions Using Response Surface Methodology

This study investigates the influence of polyol compounds (sorbitol and erythritol) on the osmotic dehydration process of pomegranate seeds. The efficacy of the osmotic dehydration process was estimated based on the determination of water loss, weight reduction, solid gain, and effective diffusivity and also through a comparison of the results obtained between sucrose and polyol osmotic solutions. Response surface methodology was used to optimize the osmotic process. Quality attributes of pomegranate seeds were determined through the assessment of physical (texture and color) characteristics. This innovative research applies alternative solutions in the osmotic process, which until now, have not been commonly used in the osmotic dehydration of pomegranate seeds processing by researchers worldwide. Results revealed the excellent correlation of experimental values with the model. Erythritol and sorbitol exhibit stronger efficiency than sucrose. However, erythritol was not satisfactory due to the high solid gain. Therefore, the sorbitol osmotic agent seems to be the most suitable for the osmotic dehydration of pomegranate seeds. The optimal condition for maximum water loss (38.61%), weight reduction (37.77%), and effective diffusivity (4.01 × 10−8 m2/s) and minimum solid gain (−0.37%) were 13.03 min, 27.77 °Brix, and 37.7 °C, using a sorbitol solution. Results of texture and color revealed the major impact of erythritol and sorbitol osmotic agents on seed characteristics during the osmotic dehydration process.

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.

Increase of mass transfer rates during osmotic dehydration of apples by application of moderate electric field

Osmotic dehydration (OD) is a drying process that consists in placing the food in contact with concentrated solutions of soluble solids to reduce its water activity. The use of moderate electric field (MEF) may promote increase of the mass transfer rates due to the non-thermal effects of electroporation and permeabilization of the cells. In this context, the objective of this study was to investigate the mass transfer process kinetics during apples OD assisted by MEF, evaluating the non-thermal effects of this emerging technology. The experiments were conducted with sucrose solutions (40, 50 and 60%, m/m) at 40 °C. Samples were submitted to electrical field strength (0, 5.5 and 11.0 Vcm−1), according to an experimental design. Results indicated that the application of MEF favoured water loss and solid gain. The effective mass diffusivities of water and solids increased as voltage applied increases. Moreover, MEF negatively influenced color and reducing capacity of the samples.

Optimization of Osmotic Dehydration of Tomatoes in Solutions of Non-Conventional Sweeteners by Response Surface Methodology and Desirability Approach

The osmotic dehydration (OD) of tomatoes in solutions of alternative sweeteners was investigated using Response Surface Methodology (RSM), while selected desirability functions were implemented in order to define the optimum process parameters (temperature/duration of osmotic treatment, osmotic solution composition and concentration). Mass exchange, color and texture were measured during the process. Changes in color occurred rapidly at the beginning of the process, while firmness was significantly increased, indicating that OD processing led to tomato texture improvement. Color and firmness changes were adequately modeled using a polynomial model. RSM coupled with desirability functions was applied to optimize OD procedure in terms of color retention and maximum solid gain, a requirement for candied products. A maximum desirability was obtained by incorporating oligofructose into the osmotic solution, at relatively short treatment times. Results were validated and sensory analysis was conducted at the optimized conditions to assess samples’ organoleptic acceptance.

Osmotic Dehydration for the Production of Novel Pumpkin Cut Products of Enhanced Nutritional Value and Sustainability

The quality and preservability of fresh-cut fruits can be improved by osmotic dehydration (OD). In this study, the impact of Strained Yoghurt Whey (SY Whey) (along with other osmotic solutes) on mass transfer kinetics (water loss, solid gain, water activity decrease), quality attributes (color, texture, sensory characteristics, vitamin C), and microbial stability during OD and subsequent refrigerated storage (5–15 °C) of OD-processed pumpkin cuts was studied. The effect of temperature (35–55 °C), time (10–240 min), and type of osmotic solvent was evaluated to select the optimal processing conditions (55 °C–120 min; WL: 9-99-10.86 g w./g i.d.m. SG: 1.47–1.79 g s./g i.d.m., aw: 0.89). The use of SY Whey vs. water as solvent enhanced the mass transfer phenomena increasing the solids uptake diffusion coefficient by 20%. Water and whey osmosed samples were of similar quality (32–38% increase of hardness, total sensory quality score: 7.9–8.2/9.0, vitamin C content: 77–81 mg/100 g). At all studied storage temperatures, ODSY Whey samples presented lower quality degradation rates compared to the respective ODWater samples (e.g., almost half for hardness change). The shelf life of both OD processed pumpkin cuts exceeded 90 days at 5–15 °C (no microbial growth) supporting the applicability of SY whey as novel osmotic solvent.