Osmotic Dehydration Process Research Articles

SHAPING PROPERTIES OF HELIANTHUS TUBEROSUS L. JERUSALEM ARTICHOKE TOPINAMBU SNACK PRODUCED BY OSMOTIC DEHYDRATION AND DRYING METHODS

Background. Growing consumer awareness of food consumption and expectations related to its quality and health of food in a daily diet, including for people with various health problems, point to the need to look for new directions in food production, such as dried Jerusalem artichoke snacks. The aim of the work was to examine the effect of osmotic dehydration and drying methods on the selected properties of dried Jerusalem artichoke. The research material comprised Jerusalem artichoke tubers. Fresh Jerusalem artichoke, initially dehydrated in an osmotic dehydration process in 60 % sucrose solution at 50 °C for 1 h, was dried by means of convection, microwave-convection, microwave-vacuum and freeze-drying. Results and conclusion. Freeze-dried samples, both with and without pre-treatment, reached the lowest value of water activity. At the same time, they were characterized by the highest content of dry matter. Compared to the raw material, the dehydration and drying of Jerusalem artichoke reduced the total polyphenol content and antioxidant activity. High values of both indices (176 ÷ 183 mg GAE/100 g d.m./ EC50 = 4.4 ÷ 4.6 mg d.m./cm3 ), slightly lower than in the raw material, were found in convective and microwave-vacuum dried samples. Using osmotic dehydration and selecting a method of drying Jerusalem artichoke allows to shape the properties of the obtained dried snacks with health-promoting properties. Microwave-vacuum drying proved to be particularly useful, mainly due to the short time of the process and the preservation of polyphenolic compounds and high antioxidant activity compared to freeze-dried products, considered to be a standard.

Storage time effect on inoculated, osmodehydrated chicken meat-microbiological and chemical characteristics

In this research, chicken meat was inoculated with selected microorganisms and subjected to the osmotic dehydration process in two osmotic solutions, in an effort to investigate the effect of storage time duration on its microbiological and chemical characteristics. Total viable counts, numbers of Enterobacteriaceae, Salmonella spp., Listeria monocytogenes, Escherichia coli, proteolytic bacteria, psychotropic bacteria, of microbiological, and biogenic amine content, TBARS and DPPH, and chemical analyses were conducted on meat samples stored at 22?C, during 14 days. During storage, the number of all tested microorganisms on meat samples decreased. The highest reduction occurred in the first 4 days. The meat dehydrated in molasses achieved better results of microbiological profile during storage. Results of TBARS and DPPH analyses indicated lipid oxidation after 14 days of storage, while the results after 10 days were satisfactory. Developed mathematical models allows good prediction of microbiological and chemical responses of dehydrated chicken meat during the investigated storage duration.

Modeling antioxidative activity of osmo-dehydrated in molasses and successively lyophilized peach

Investigation and modeling of osmotic dehydration parameters on antioxidative activity of peach samples in combined dehydration methods of osmotic dehydration and lyophilization are done to produce the final product of preserved and enhanced antioxidative activity. Antioxidative activity of dehydrated peach samples was investigated by measuring DPPH radical scavenging capacity, and response surface methodology for developing mathematical models was applied. The results showed that combined osmodehydration and lyophilization processes have led to the increased antioxidative activity of dehydrated peaches samples. All three investigated osmodehydration process parameters affected the increase of DPPH values, where process time was found to be the most influential parameter. Maximal obtained DPPH value of 18.25% was achieved in osmotic dehydration process of 5 hours, in 80% concentration molasses, at a temperature of 50 °C and successive 5-hour lyophilization process. Developed mathematical model of DPPH response of dehydrated peach samples was statistically significant, while predicted and observed responses had good correlation, allowing good prediction of the peach samples’ antioxidative activity.

Osmo-air drying of banana slices: multivariate analysis, process optimization and product quality characterization.

In the present work, osmotic dehydration (OD) was applied as a pretreatment to hot air drying of banana slices and the effect of OD parameters on mass transfer characteristics, color profile was analysed. Principal component analysis (PCA) of OD process revealed that solid gain, weight reduction, water loss and total soluble solids were positively correlated with each other but were found to be negatively correlated with moisture content (MC) of sample. Response surface methodology was used for optimizing the OD of banana slices and and the optimum conditions were 61.26°Brix sucrose concentration at 50°C for 6h, resulting in moisture reduction from 75 to 49.78%. PCA-biplot of osmo-air drying (OAD) process showed the association among response parameters, which further revealed a positive correlation of MC with bioactive components. Additionally, OAD samples were also studied for microstructure and Fourier Transform Infra-red analysis. Addition of calcium lactate to sucrose solution resulted in preserving the firmness and bioactive components during osmosis, in addition to fortifying the sample with calcium. The present study provides new possibilities for food industries in preserving the ripe banana and developing calcium fortified functional food products.

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.

Optimization of maltodextrin (10DE)—Sucrose moderated microwave osmotic dehydration of mango cubes under continuous flow spray mode (MWODS) conditions

AbstractThe process of microwave osmotic dehydration of mango was optimized under continuous flow medium spray conditions (MWODS) with maltodextrin (10DE) moderated sucrose solutions. Optimization was carried out using a response surface methodology with a central composite rotatable (CCRD) design with three input variables at five levels (temperature, 33°C to 66.7°C; sucrose:maltodextrin ratio from 100:0 to 80:20; and solute concentration, 33 to 66.7%). The response parameters used for optimization were moisture loss (ML), solids gain (SG), weight reduction (WR), ML/SG ratio, color and texture values. For each response, RSM models (p < .05) were developed. As expected, all output variables were responsive to process variables and addition of maltodextrin to sucrose was found to have a significant effect on reducing the SG and increasing ML/SG, and total solute concentration had significant effects on ML, SG and quality parameters. The process was optimized by desirability approach and MWODS at 56°C with total osmotic solute 46% concentration and 84:16 sucrose:maltodextrin proportion had the highest desirability value. Selection of constraints was an influential factor as well.Practical ApplicationsOsmotic dehydration (OD) has many advantages, but is a slow process. Carrying out OD in MW environment accelerates the process, enhances moisture loss (ML) and limits the solids gain (SG). The quality of OD foods is related to ML/SG ratio and the MWOD process enhances ML/SG. This can be further enhanced by incorporating high molecular solutes like maltodextrins. This research optimizes the maltodextrin moderated MWOD process under continuous medium flow conditions. The process offers significant potential for reducing the treatment time (to 30 min) and improve the ML/SG ratio. The resulting product can be finish dried, used as intermediate moisture food or frozen (dehydrofreezing).

Design and Optimization of Edible Coating and Osmotic Dehydration Processes for the Development of High-value Fruits and Vegetables with Extended Shelf-life

Berries and mushrooms are some of the most important traditional Mediterranean products that are characterized by high nutritional value and beneficial properties for the human body. Mushrooms are popular for their texture and taste but also for their chemical and medicinal properties. Although they have beneficial properties for human health, the shelf-life of fresh produce is very limited. In addition, sea buckthorn (Hippophae rhamnoides) berry is valued for its high nutrient density, providing high amounts of vitamin C, vitamin E, carotenoids, oils rich in unsaturated fats, etc. However, these berries are fragile and delicate and have a short shelf-life. The aim of the present study was the design and development of new berry and mushroom products, which are characterized by prolonged shelf-life without the addition of chemical preservatives, high nutritional value with low salt and sugar levels, and increased seasonal availability. The design and development of these products was based on the optimization of osmotic dehydration process and the application of edible coatings, using alternative agents. Various osmotic agents, such as glycerol, natural pectins or fruit juices were examined as alternatives to the conventional ones, with the aim to reduce salt and sugar levels in final products. Osmotic dehydration process was further optimized in terms of several parameters (immersion time, temperature, osmotic agent concentration, product to solution ratio). Dehydrated products were then coated using alternative agents, such as chitosan and aloe vera. The dehydrated and coated products were evaluated for their quality and sensory properties, during storage in controlled conditions. The examined alternative osmotic agents had significant effect to the water loss and water activity of the selected products and led to products with advanced characteristics. The use of alternative agents during edible coating application also led to the increase of products’ shelf-life and the enhancement of their nutritional value.

The effect of osmotic dehydration before drying on the physicochemical and sensorial characteristics of dried onion slices

The effect of osmotic dehydration before drying on the physicochemical and sensorial characteristics of dried onion slices

Osmotic dehydration of pineapple slices pre-treated by electroplasmolysis: Determination of color change kinetics

The pineapple (Ananas comosus (L.) Merrill) is a commercial tropical fruit belonging to the Bromeliaceae family. It is rich in organic acids (citric acid, malic acid), minerals (Fe, Mg, Ca, P, K, and Zn), and vitamins (A, B1, B2, B3, and B6). Osmotic dehydration is a water removal technique by immersing the fruit in a hypertonic solution to obtain minimally processed food with a longer shelf life and high nutritional value. It can also be considered as a pretreatment that reduces the required energy inputs for convective drying and freeze-drying. Electroplasmolysis is an electrical method that is based on the growth of pores in cell membranes. It has an important effect on the dehydration and extraction processes as it increases the cell permeability and mass transfer coefficients of plant tissues. In this study, it was aimed to determine the effect of electroplasmolysis pretreatment on color change kinetics in the osmotic dehydration of pineapple slices. Electroplasmolysis was applied by a drum‐type electroplasmolyzator with 80 V/cm voltage gradient for 60 s. The osmotic dehydration process was carried out with sucrose solutions of 40, 50 and 60 ◦Bx at 20 ◦C. The processing time was 6 h in all osmotic treatments. This time was determined in preliminary experiments. Osmotically dehydrated samples with elelctroplasmolysis pretreatment and the samples without electroplasmolysis application were compared via L, a, and b values during 8 hours. The results of the study showed that fresh pineapple samples had higher L, a, and b values than both electroplasmolysis treated and untreated samples. The color values of all the samples, with and without electroplasmolysis pretreatment, decreased parallel to time increase after the osmotic dehydration process. L, a, and b values of the samples which osmotically dehydrated at 60 ◦Bx solution were higher than the color values of the samples which were dehydrated at 40 and 50 ◦Bx solutions. Lightness and yellowness were found higher in the electroplasmolysis group than the other groups. The zero-order and first-order kinetic models were used to explain the color change kinetics and it was observed that L, a, and b were fitted to a first-order kinetic model.

Osmotic dehydration of carrot strips and modelling

Osmotic dehydration kinetics using parameters moisture loss and solid gain during osmotic dehydration of carrot strips were studied. Carrot strips of 30×10×2 mm size were osmotically dehydrated in sugar syrup of 40°B, 50°B and 60°B. During osmotic dehydration process syrup solution to carrot sample ratio was kept 6:1. The process was carried out at various temperatures 27°C,40°C and 50°C for time period of 15, 30, 60, 90, 120 and 180 minutes. Mass transfer kinetics of the two main parameters of process, moisture loss and solid gain data were studied using five different mathematical models. The models used include Azuara, Peleg, Magee, Power and Penetration Model. Amongst the applied model Azuara’s and Peleg model were found to be best fitted for moisture loss while for solid gain Power law and Magee’s model were found to be best fit.

Osmotic dehydration under low agitation laminar flow condition: Effect on dielectric properties of broccoli stalk slices at 2.45 GHz

AbstractThe variation in dielectric constant, ε′ and the loss factor, ε″ of broccoli stalk slices after osmotic dehydration process conducted under continuous solution circulation with low agitation laminar flow condition was studied using open‐ended coaxial probe technique at 2.45 GHz. The results showed that both ε′ and ε″ were significantly influenced by all the osmotic dehydration operating variables. The relationship of osmotic dehydration operating variables on the dielectric properties of the broccoli stalk slices could be established by second‐order polynomial model, with the coefficient of determination higher than .9. Compared to fresh sample, the ε′ decreases and ε″ increases when broccoli stalk is subjected to the osmotic dehydration pretreatment under its optimum conditions of mass transfer exchange process. Higher dissipation factor with shorter penetration depth was obtained after osmotic pretreatment, which could facilitate absorption of energy during microwave drying of broccoli stalk slices.Practical ApplicationsDielectric properties are key factors to understand the interaction of microwaves with food materials. In recent years, there has been an increasing interest in osmotic dehydration used as pretreatment prior to microwave drying to achieve faster drying time and improves the final product quality. As osmotic dehydration process will cause a change in the dielectric properties of the food material and its ability to absorb microwaves energy, this work investigated the effects of osmotic dehydration on the dielectric properties of broccoli stalk slices at 2.45 GHz. The osmo‐pretreated sample improved the dielectric properties which result in rapid heating and therefore lead to fast drying process. The information provided in this study is helpful in the development of dried broccoli stalk slices using microwave drying.

Exploring the potential acceleration of the osmotic dehydration process via pretreatment with CO2-LASER microperforations

Osmotic dehydration (OD) typically requires a long processing time, so the incorporation of CO2-laser microperforations could reduce it. The aims of this study were 1) to explore the potential acceleration of the OD process coupled with CO2-laser microperforations and 2) to mathematically evaluate the diffusion process through a complementary error function (erfc). Apple slices pretreated with two micropore sizes and two configurations were immersed in a solution of 45° Brix at 40 °C for 10 h. The total solid content in the apple slices was measured. A model based on erfc was used to determine the effective diffusion coefficient (Deff). The results showed a significant increase in Deff for microperforated samples, especially for those with the largest pores compared with control (R2 > 0.92). Additionally, pores were able to reduce the processing time by up to 63% for big pores (600 μm) and between 22% and 45% for small pores (23 μm).

On the Study of Osmotic Dehydration and Convective Drying of Cassava Cubes

This paper aims to study the hybrid process of osmotic dehydration and convective air drying of foods. Emphasis has been put on cassava cubes (Manihot esculenta Crantz.). Convective drying kinetics of fresh and osmotically dehydrated cassava cubes was evaluated at the following hot air-drying conditions: temperature 50°C, velocity 1.35 m/s, and absolute humidity 0.060 dry water/g. Experimental results of the moisture loss, solids gain, and incorporation of sodium chloride are shown and analyzed. For estimation of the effective mass diffusion coefficient, experiment data of average moisture content of cassava cubes (fresh and osmotically dehydrated) was fitted to the simplified Fick model and a good agreement was obtained. The effective mass diffusivity of the osmotically dehydrated cassava cube was 2.75 x10-10 m2/s and to fresh cassava cubes 5.45x10-10 m2/s.

Current Applications of Ultrasound in Fruit and Vegetables Osmotic Dehydration Processes

Ultrasound (US) is a promising technology, which can be used to improve the efficacy of the processes in food technology and the quality of final product. US technique is used, e.g., to support mass and heat transfer processes, such as osmotic dehydration, drying and freezing, as well as extraction, crystallization, emulsification, filtration, etc. Osmotic dehydration (OD) is a well-known process applied in food processing; however, improvements are required due to the long duration of the process. Therefore, many recent studies focus on the development of OD combined with sonication as a pretreatment method and support during the OD process. The article describes the mechanism of the OD process as well as those of US and changes in microstructure caused by sonication. Furthermore, it focuses on current applications of US in fruits and vegetables OD processes, comparison of ultrasound-assisted osmotic dehydration to sonication treatment and synergic effect of US and other innovative technics/treatments in OD (such as innovative osmotic solutions, blanching, pulsed electric field, reduced pressure and edible coatings). Additionally, the physical and functional properties of tissue subjected to ultrasound pretreatment before OD as well as ultrasound-assisted osmotic dehydration are described.

Analiza efikasnosti procesa osmotske dehidratacije breskve u melasi

Energy consumption reduction per unit of product' removed moisture is necessary to lower production costs and increase the overall efficiency of the dehydration process. The goal of this research was to analyse efficiency and economics of the peach in molasses osmotic dehydration process, by investigating mass transfer parameters. Time, concentration and temperature of the osmotic dehydration of peach in molasses were varied and responses of water loss and solid gain were measured. The results showed that with the technological parameters of time, concentration and temperature increase, individual mass transfer parameters also increased, where maximal values of 0.7524 g/gi.s. and 0.1069 g/gi.s., were obtained for water loss and solid gain, respectively. On the basis of experimental data, mathematical models of peach osmotic dehydration in molasses responses dependence from applied technological parameters were developed, which showed good correlations between experimental and calculated results. Combined technological efficiency parameter analysis showed a total efficiency increase in the range of 40.67 to 51.71%, by using process temperature of 20°C. The highest process economics was obtained by application of energy undemanding process temperature of 20°C, where energy costs were avoided while at the same time achieved highest value of technology efficiency.

Physicochemical properties and sensory acceptability of beetroot chips pre-treated by osmotic dehydration and ultrasound

Abstract Red beet (or beetroot) is highly nutritious and can be preserved by drying, in order to avoid wastage, to take advantage of crop surpluses, and to add value during the off-season. The objective of this study was to evaluate the effects of osmotic dehydration (OD) and ultrasound (US) pre-treatments on the nutritional quality and sensory characteristics of dried beetroot chips. The kinetics of moisture loss during OD and US were predicted by fitting the experimental data with thin-layer models. The physicochemical parameters (moisture, protein, lipid, carbohydrate, energy, ash, sodium and nitrate) and sensory properties (affective preference-ordering and acceptance test) were determined. Correlations between the treatments and the sensory acceptability evaluated by consumer’s perceptions were performed by applying unsupervised chemometric techniques (Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA)). The two-term exponential model provided the best fit for the experimental drying data. The US treatment promoted a higher drying rate and lower lipid, ash and energy values, while the OD process resulted in higher ash and sodium values. Multivariate analysis revealed that the US and OD treatments improved the sensory properties of the beetroot chips. The US was more efficient pre-treatment for producing beet chips due to its leads a significant reduction on drying time and intermediate level of sensory preference.

MODELING AND OPTIMIZATION OF THE PULSED VACUUM OSMOTIC DEHYDRATION (PVOD) PROCESS OF CARROTS IN A TERNARY SOLUTION BY RESPONSE SURFACE METHODOLOGY

Optimization of the pulsed vacuum osmotic dehydration (PVOD) process of carrot slices in a ternary solution was carried out using the response surface methodology. During PVOD, the vacuum pulse was applied at the beginning of the process for 10 min at a reduced pressure of 500 mm of Hg throughout all the experiments. After that, the osmotic dehydration process was continued at atmospheric pressure according to the central composite rotatable design (CCRD). The effects of temperature (35-55oC), sugar concentration (40-50oBrix), salt concentration (5-15%) and osmosis time restored at atmospheric pressure (10-240 min) on the responses viz. water loss (WL), solute gain (SG) and colour difference (∆E) of the dehydrated samples were assessed and statistically optimized through the desirability function approach. The models obtained for water loss, solute gain and colour difference were found suitable to describe the experimental data. It was found that the time restored at atmospheric pressure has the most significant effect on the responses at the 95% confidence level. The optimum condition was found at a temperature of 50oC, sugar concentration of 45.47oBrix, salt concentration of 7.50%, and restoration time of 67.50 min. At these optimum conditions, the water loss, solute gain and colour difference were 42.61%, 10.42% and 4.38, respectively. The predicted optimum values for independent linear variables were validated by performing triplicate experiments and the simulated data were come across similar with the experimental ones.

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.

EVALUATION OF MASS TRANSFER DURING OSMO-CONVECTIVE DRYING OF BENINCASA HISPIDA CUBES IN SALT SOLUTION USING REGRESSIONAL-DESIRABILITY METHOD

Regressional-desirability approach in Box-Behnken response surface design was employed in this study to examine and optimize the osmotic dehydration process of Benincasa hispida cubes by impregnating in salt solution as an osmotic agent. The effect of independent parameters such as, concentration of solution (1-5%), sample to solution ratio (1:5-1:15 g/ml), temperature of osmotic solution (30-50℃) and time of immersion (30-180 min) on the weight reduction (WR), solid gain (SG), water loss (WL), rehydration ratio (RR) and shrinkage (SH) were studied. Second order polynomial mathematical models were developed for the responses and all the independent process variables have considerable consequence on the responses. The optimal dehydration process condition was found by regressional-desirability method and were: osmotic solution concentration of 2.73%, sample to solution ratio of 1:14 g/ml, osmotic solution temperature of 50℃ and osmotic dehydration time of 179 minutes with the mass transfer and quality properties such as weight reduction of 24.59%, solid gain of 7.69%, water loss of 32.28%, rehydration ratio 11.43%, shrinkage 8.58% and overall acceptability 8.19. The optimized samples were subjected to convective drying in cabinet tray dryer at different drying air temperatures (40, 50 and 60℃). The results indicated that the osmotic pre-treatment of the samples using salt solution was better in terms of water removal and reduction in the processing time when combined with convective drying process. Also, the quality of the final product was found to be good for the osmo-convective dried product using salt solution.