Osmotic Process Research Articles

Optimization of osmotic dehydration of chestnut (Castanea sativa Mill.) slices using Response Surface Methodology

Osmotic dehydration of chestnut slices in sucrose was optimized for the first time by Response Surface Methodology (RSM). Experiments were planned according to a three-factor central composite design (α=1.68), studying the influence of sucrose concentration, temperature and time, on the following parameters: volume ratio, water activity, color variation, weight reduction, solids gain, water loss and normalized moisture content, as well as total moisture, ash and fat contents. The experimental data was adequately fitted into second-order polynomial models with coefficients of determination (R 2 ) from 0.716 to 0.976, adjusted-R 2 values from 0.460 to 0.954, and non-significant lacks of fit. The optimal osmotic dehydration process conditions for maximum water loss and minimum solids gain and color variation were determined by the “Response Optimizer” option: 83% sucrose concentration, 20 °C and 9.2 hours. Thus, the best operational conditions corresponded to high sugar concentration and low temperature, improving energy saving and decreasing the process costs.

Propriedades físicas de uva Sugraone submetida a desidratação osmótica

A desidratação osmótica, semelhante à desidratação clássica, permite a concentração parcial do material celular dos alimentos. No entanto, ao invés do emprego do calor, a atividade de água do produto é reduzida colocando-se o mesmo em contato com uma solução hipertônica de solutos. Como resultado desse processo, frutos perecíveis são transformados em produtos com boas condições de armazenamento, com maior estabilidade, qualidade semelhante à matéria-prima e, muitas vezes, melhor em cor, sabor e aroma que os produtos de tecnologias mais sofisticadas. Dessa forma, objetivou-se avaliar a influência desse processo em uvas sem sementes da variedade Sugraone, comparando alguns parâmetros físicos. As frutas foram avaliadas in natura e após o processo de desidratação osmótica. Para o processo de desidratação as uvas foram imersas em xarope de sacarose com concentração de 60 °Brix e mantidas sob osmose à temperatura de 40 °C por 24 horas em câmara do tipo B.O.D. Os parâmetros físicos avaliados foram determinados em triplicata, sendo eles: massa individual e específica real, volume, diâmetros mutuamente perpendiculares, área de projeção da posição de repouso, excentricidade e área superficial, volume por deslocamento de massa e por semelhança geométrica, circularidade e esfericidade. Observou-se que as uvas apresentaram ótima resposta ao processo de desidratação, sendo o processo indicado para essa variedade.

Efficacy of Osmo-Convective Process Parameters for Kinnow Fruit Slices and Its Optimization Using Response Surface Methodology

The optimal condition for osmo-dehydrated kinnow product from kinnow fruit slices with peel by simultaneous osmo-convective dehydration was evaluated. The process parameters used for sugar osmosed samples were; osmotic process temperature (35–75 °C), solution concentration (55–75°Brix), immersion time (150–270 min) and convective drying temperature (45–65 °C). A Central Composite Rotatable Design was employed to assess the different Osmo-convective parameters. The optimized conditions for developed kinnow product were found to be osmotic process temperature 65 °C, convective drying temperature 50 °C, concentration 61°Brix and immersion time 187 min.

Osmotic dehydration assisted impregnation of Lactobacillus rhamnosus in banana and effect of water activity on the storage stability of probiotic in the freeze-dried product

In this study the impregnation of Lactobacillus rhamnosus in banana slices and the storage stability of the dehydrated product were analyzed. Banana slices were enriched with L. rhamnosus at levels of 109 CFU/g d.b. using a hypertonic solution of 50% (w/w) sucrose. The high level of probiotic impregnation occurred at high rates of mass transfer during the first 200 min of osmotic process. Since dehydration is widely used for the preservation of fruits this work analyzed the stability of probiotics impregnated in the freeze-dried banana and its relation with the thermodynamic properties of the adsorbed water. The survival kinetics showed that the viability of probiotics decrease more rapidly over water activity of 0.327, which was considered as critical for maintaining these alive. This water activity could be obtained using the minimum integral entropy of the adsorbed water at the freeze-dried banana surface. These results have shown that is possible to obtain dried fruits enriched with probiotics with good storage stability and that the thermodynamic approach is a useful tool to establish the optimal conditions of water activity to preserve the dehydrated product.

Plant Cation-Chloride Cotransporters (CCC): Evolutionary Origins and Functional Insights.

Genomes of unicellular and multicellular green algae, mosses, grasses and dicots harbor genes encoding cation-chloride cotransporters (CCC). CCC proteins from the plant kingdom have been comparatively less well investigated than their animal counterparts, but proteins from both plants and animals have been shown to mediate ion fluxes, and are involved in regulation of osmotic processes. In this review, we show that CCC proteins from plants form two distinct phylogenetic clades (CCC1 and CCC2). Some lycophytes and bryophytes possess members from each clade, most land plants only have members of the CCC1 clade, and green algae possess only the CCC2 clade. It is currently unknown whether CCC1 and CCC2 proteins have similar or distinct functions, however they are both more closely related to animal KCC proteins compared to NKCCs. Existing heterologous expression systems that have been used to functionally characterize plant CCC proteins, namely yeast and Xenopus laevis oocytes, have limitations that are discussed. Studies from plants exposed to chemical inhibitors of animal CCC protein function are reviewed for their potential to discern CCC function in planta. Thus far, mutations in plant CCC genes have been evaluated only in two species of angiosperms, and such mutations cause a diverse array of phenotypes—seemingly more than could simply be explained by localized disruption of ion transport alone. We evaluate the putative roles of plant CCC proteins and suggest areas for future investigation.

AHP-based procedure for optimization of microwave-assisted blackberry sugar osmotic process

ABSTRACTDue to the limitations of single index analysis, the merits and demerits of microwave-assisted permeation process cannot be comprehensively evaluated. However, the analytical hierarchy process (AHP) was applied to optimize the conditions of microwave-assisted diffusion of sugar in blackberry. In this paper, the results of a single-factor experiment were compared with blackberry preserved after the treatment of microwave. An orthogonal rotation test procedure was designed to calculate the composite score of preserved blackberry fruit using AHP, and to determine the optimum processing conditions based on sugar osmosis characteristics. The results showed that the sugar content, vitamin C (VC) content, and color difference of treated blackberry increased with the increase of microwave power, the residence time, and the resulting sugar concentration. The composite grade points are listed to show that the optimum results were as follows: power level, the residence time, and the sugar concentration were, respectively, 210 W, 12 min, and 35%.

Ultrasound-assisted osmotic process on quality of microwave vacuum drying sweet potato

ABSTRACTThe effects of pretreatment before microwave vacuum drying (MVD) on texture, color, expansion, rehydration, drying rate, microstructure, sensory evaluation, and other properties of sweet potato were investigated in this study. The pretreatment consisted in five processing conditions, using blanching; osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (US); ultrasound in distilled water before osmotic dehydration (US + OD), and ultrasound-assisted osmotic dehydration (USOD). Pretreatments of sweet potato before MVD have shown success in reducing drying time with US treatment relatively more effective regarding drying time than other treatments. Compared with other treatments, US showed the highest rehydration ratio values. The osmotic group pretreatment exhibited a pronounced effect on water loss and solid gain, improved the color, aroma, and taste of dried sweet potato, whereas sucrose impregnation resulted in a hard texture observed with OD sample. USOD samples had a higher expansion ratio, lower hardness and color difference values, appeared less cell damaged, and recorded better overall quality than the other samples. There was a slight difference between USOD and US + OD samples. Combining osmotic dehydration with ultrasound as a pretreatment can significantly accelerate the heat transfer rate, reducing the dried time accordingly and increasing energy efficiency.

Obtaining candied fruit of calabash (Lagenaria siceraria)

Calabash is considered a non-traditional herb, for not being normally consumed. Osmotic dehydration is an alternative to add value to this vegetable. The objective of this study was to develop candied fruit of calabash ( Lagenaria siceraria) and evaluate their physical, chemical and sensory characteristics. The calabash was sanitized, peeled, cut into cubes and bleached. For the osmotic process of calabash pieces, sucrose was dissolved in water and treatments were prepared namely: T1 - Sucrose concentration at 10%; T2 - Sucrose concentration at 20%; T3 - Sucrose concentration at 40% and T4 - Sucrose concentration at 60%. The calabash cubes remained in their respective concentrations for a period of 10 days until complete saturation. After the crystallization the cubes were washed in running water and dried in an oven at a temperature of 60 oC for 6 hours. The physical, chemical, microbiological and sensory analyzes were performed. There was no significant difference between the treatments for pH values. The treatment T4 showed higher value of ascorbic acid (2.06) at the end of the treatment days. Moisture was greater in treatment T1, while T4 presented the lowest moisture content. T4 showed higher soluble solids content. The values found for molds and yeasts were within the legislation. The treatments T3 and T4 showed the highest acceptance rate for all the evaluated attributes. The in natura calabash transformation for its candied form added value to this product.

Mass Transfer Kinetics for Osmotic Dehydration of Kinnow Fruit in Sugar Solution

Mass transfer kinetic study was carried out for sheet geometry of whole kinnow fruit in sugar solution. The experiments were conducted using completely randomized design with the sucrose concentration (55–75°B) at various process temperatures (35–65 °C) and solution to fruit ratio (3–7:1 v/w) at varying immersion time interval (30–270 min). The water loss, solute gain and mass loss was systematically examined and recorded throughout the process. The water loss and solute gain for osmotic dehydration of kinnow was found to be at osmotic process temperature of 65 °C, sugar solution concentration of 65–75°B, solution to fruit ratio of 5:1 and immersion time of 270 min. The effective moisture and solute diffusivities was calculated. The maximum diffusivity of water was found to be 53.08 × 10−9 m2/s and minimum diffusivity of solute observed was 0.49 × 10−9 m2/s.

بررسی اثرتعداد لایهها و غلظتهای مختف پوششهای خوراکی کربوکسیمتیلسلولز و کاراگینان بر کارایی فرایند خشک کردن اسمزی سیب زرد لبنانی

در طی فرایند آبگیری اسمز، مواد جامد محلول توسط بافت ماده غذایی جذب شده و اثرات نامطلوبی بر خروج آب، خصوصیات تغذیه‌ای و حسی می‌گذارد. لذا برای بهبود فرایند اسمز از پوشش‌های خوراکی استفاده می‌شود. بهترین شاخص برای ارزیابی یک پوشش، کارایی فرایند (نسبت خروج آب به جذب مواد جامد) است. در این پژوهش از دو پوشش کربوکسی‌متیل‌سلولز و کاراگینان در سه غلظت 5/0، 1 و 5/1 درصد، به‌صورت یک‌لایه و دو لایه، جهت پوشش‌دهی قطعات مکعبی سیب زرد لبنانی و محلول اسمزی ساکارز با غلظت 30، 45 و 60 % استفاده شد. نتایج نشان داد که نمونه یک بار پوشش داده شده با کاراگینان 1% و تیمار شده در ساکارز 60 % و نمونه‌های یک و دو لایه پوشش داده شده با کربوکسی‌متیل‌سلولز 5/0% بیشترین میزان کارایی فرایند را داشته‌اند و به‌عنوان تیمارهای برگزیده به‌دست آمدند. این نمونه‌ها میزان جذب مواد جامد را کاهش داده و تاثیر قابل توجهی بر روی خروج آب نگذاشته‌اند. همچنین نتایج بیان‌گر این موضوع است که با افزایش غلظت محلول اسمزی ساکارز از 30 به 60% میزان حذف آب و جذب مواد جامد افزایش می‌یابد.

Drying characteristics of osmo-convectively dried sapota slices

Sapota is a highly productive, nutritious and tropical fruits of India contributing 1424 MT, on 160 ha area with the productivity of 8.9 MT/ha. In India, sapota is generally consumed fresh. Ripened sapota cannot be stored more than a day or two. However, it is highly perishable in nature, ripens faster and becomes unfit for consumption very soon. The post-harvest losses in sapota fruits is in the ranged from 25-30%. These losses mainly occur due to high ethylene evaluation and metabolic activity. To avoid the huge wastage, the surplus could be processed and preserved properly. Wastage of large quantities of sapota fruits before it reaches the consumer is due to poor quality transportation as well as storage facilities. One effective method of reducing this huge loss would be by converting it into various commercial sapota products like slices, powder, juice, concentrate, etc. Therefore, it is necessary to produce the final product with wholesome, soft and of acceptable quality. The products may be dehydrated, canned and refrigerated. Dehydrated fruit products have inherent advantages, such as prolong shelf-life, higher degree of resistance to bacterial attack and lower transportation, handling and storage costs. The use of faulty dehydration process causes quality defects of dehydrated fruits as tough woody texture, slow or incomplete rehydration, loss of juiciness and shrinkage. Osmotic dehydration is less energy intensive technique than air or vacuum drying process, since it can be conducted at low or ambient temperature. It is the process of water removal from a product by immersion in concentrated aqueous solution. The osmotic process prior to convective drying can be used as a pre-treatment for the dehydration of food prior to further processing such as freezing, vacuum drying, etc. Therefore, a study was proposed to investigate osmotic behaviour and drying characteristic of sapota slices under osmo-convective drying process. The optimum conditions for osmotic treatment were determined with the values of 27.72% WR and 8.25% SG for process parameters, syrup temperature of 47.36 °C, and sugar concentration of 53.53 °B for 167.85 min duration. After optimization, osmotically treated samples were dried in convective dryer at temperature 40, 50 and 60 °C. The convective drying behavior and drying characteristics was investigated for osmo-dehydrated sapota samples, at air temperature of 40, 50 and 60 °C. It was observed that the moisture content of the product was reduced exponentially with drying time and no constant rate period was observed. To determine the most suitable drying equation the the moisture ratio data of osmosed sapota dried at various air temperatures were fitted into the six thin-layer drying models. Among those two term model as best fitted for drying data. This indicated that the total mass transfer resistance was primarily due to the internal moisture diffusion within the sample.

Optimization of osmotic dehydration of Terung Asam (Solanum lasiocarpum Dunal).

This study was designed to determine the effect of osmotic dehydration (OD) process temperature (35-55°C), sucrose concentration (40-60% w/w) and immersion time (90-210min) on the water loss (WL), solid gain (SG), DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP) and sensory quality of the dehydrated Terung Asam slices. Response Surface Methodology with Central Composite Design was applied to investigate the influence of these variables on the aforementioned responses. The increase in the levels of these processing parameters increased the WL and SG. The antioxidant activities also increased with sugar concentration, but reduced with immersion time and temperature elevation. About 36-80% of IC50 and 47-72% of FRAP were depleted after osmotic process. The loss of antioxidants was predominantly due to leaching during osmotic treatment rather than hot air drying. Despite the losses of these compounds, osmotic pretreatment was able to improve the sensory quality of the product. The optimum OD process condition was predicted as process temperature 38.1°C, sucrose concentration 55.6% and osmotic duration 126.3min.

Effect of Maltodextrin, Sodium Chloride, and Liquid Smoke on the Mass Transfer Kinetics and Storage Stability of Osmotically Dehydrated Beef Meat

Osmotic dehydration is a non-thermal process for water removal from foods. The aim of the present study was (i) to investigate the effect of binary (NaCl and water) and ternary (maltodextrin, NaCl, and water) osmotic solutions with or without 0.5% liquid smoke on moisture loss, solids gain, and salt content during osmotic dehydration of beef meat and (ii) to evaluate the microbiological and oxidative stability of the processed meat. Osmotic processing resulted in 8.01–13.15% water loss and 3.53–7.59% solids gain depending on the concentration of the osmotic medium. Liquid smoke did not affect mass transfer phenomena (P > 0.05), except for the treatment with 25% NaCl. The applied models for the estimation of the apparent coefficients demonstrated a good fit with experimental data. The simplified Fick’s equations produced the best results. Osmotic treatment with binary and ternary osmotic solutions reduced total aerobic viable microbial counts (P > 0.05) of meat during storage at 4 °C for 9 days. Liquid smoke did not affect microbial counts, but it was very effective in inhibiting lipid oxidation during storage. The results demonstrate that osmotic dehydration with the addition of liquid smoke could effectively increase the shelf life of beef meat by at least 2 days.

Teaching Osmosis to Biology Students

Osmosis is a fundamental concept of great importance to understanding natural biological, physical, and chemical processes. We provide an instructional guide to assist instructors of advanced high school biology and college biology students in defining questions that are central to deriving a highly developed understanding of osmosis. We present teaching activities that focus on advancing multiple hypotheses about the cause of osmosis, presenting a tentative explanation and model of osmosis, and drawing scientifically accepted conclusions about osmotic processes.

Osmotic dehydration of blueberries pretreated with pulsed electric fields: Effects on dehydration kinetics, and microbiological and nutritional qualities

ABSTRACTFresh blueberries were treated by pulsed electric fields (PEF) at 2 kV/cm before osmotic dehydration in 70% cane sugar syrup. The changes in water loss, solids gain, populations of native microorganisms, antioxidant activity, contents of anthocyanins, predominant phenolic acids and flavonols, and total phenolics in blueberries were investigated after PEF pretreatment and during osmotic dehydration at 40°C. Compared with non-PEF-pretreated blueberry samples, PEF pretreatment reduced the osmotic dehydration time of blueberry samples from 120 to 48 h at target moisture content (3.0 g/g initial dry matter). No significant differences (p > 0.05) in total phenolics, antioxidant activity, anthocyanins, and predominant phenolic acids and flavonols were observed between the PEF-pretreated and non-PEF-pretreated blueberry samples. The PEF-pretreated blueberry samples had lower microbial populations than those which were not subjected to PEF pretreatment. Regardless of pretreatment, decreases in anthocyanins, predominant phenolic acids and flavonols, total phenolics, and antioxidant activity in blueberries were observed during the osmotic dehydration process. The results demonstrate that PEF pretreatment significantly reduced the dehydration time and enhanced the microbiological quality of blueberries without affecting their nutritional quality.

Reuse of sorbitol solution in pulsed vacuum osmotic dehydration of yacon (Smallanthus sonchifolius)

The osmotic solution (OS) used in pulsed vacuum osmotic dehydration (PVOD) could represent an environmental problem. The reuse of the solution minimizes the cost, but has to consider the properties of the dehydrated product and the solution itself. The reuse of sorbitol solution, 38 kg/100 kg solution, in 15 successive PVOD of yacon slices (35°C, 300 min) was studied. The evaluation was based on alterations of soluble solids, water activity, pH, turbidity, electrical conductivity, viscosity, density, color, and microbiological stability. The weight loss, moisture content, and soluble solids of the food were also evaluated. Among the OS characteristics, only the color, electrical conductivity, and turbidity of the solution changed significantly, alterations that could be reduced with filtration. The food properties were not significantly affected. The microbiological content was retained in acceptable levels. The reuse of the sorbitol solution could be performed without relevant alterations in the food or the solution. Practical applications The osmotic solution is used in osmotic dehydration to promote a partial removal of the moisture content of the food. However, after the osmotic process, the solution is diluted and contains native solutes from the food. For obtaining a dehydrated product within a standard production, the solution should also present standard characteristics. This works presents the evolution of some analysis as soluble solids, water activity, pH, turbidity, electrical conductivity, viscosity, density, color, and microbiological stability in a solution of sorbitol. Sorbitol solution is an alternative to sucrose for obtaining semidehydrated products with glycemic index. It was shown that the solution could be used for at least 15 times in yacon dehydration.

Process modelling and optimization of osmotic dehydration assisted drying of red bell peppper

Osmotic dehydration (pretreatment) of red bell pepper in hypertonic salt (NaCl) solution and drying was studied. A 4X4X4 factorial experiment in a Randomized Complete Block Design (RCBD) was used for the pretreatment and pretreated samples were later dried in a fabricated laboratory dryer. Process variables considered were four levels each of osmotic process durations (30, 60, 90 and 120 min), osmotic solution concentrations (5, 10, 15 and 20 % w/w of sodium chloride) and osmotic solution temperatures (30, 40, 50 and 600C) with each trial conducted in triplicates while a drying temperature of 600C was used throughout the experiment. Drying rate was estimated for all test runs while vitamin C, vitamin A, ash content, water loss and solid gain were estimated as quality parameters. Model equations were developed with Essential Regression (ESSREG) software package which related output parameters to process variables and validated. Results gave optimum drying rate (maximized), vitamin C (maximized), vitamin A (maximized), water loss (maximized), solid gain (maximized) and ash content (minimized) of 4.26 g/h, 152.82 mg/100g, 1.42 mg/100g, 0.24 g/g, 0.91 g/g and 8.04 % respectively.Keywords: osmotic dehydration, drying, optimization

MODELING OF LOW SALINITY WATERFLOODING IN CLAY-CONTAINING OIL RESERVOIRS

Analysis of osmotic and ion exchange processes between injected agent and clay-containing rock has been carried out. The analysis allowed to obtain reservoir properties depending on ionic composition and salinity of the injected water and ratio of clay-content of reservoir. It’s been shown that change of hydrochemicalmode of formation development leads to transformation of structure of porous medium, and as a result to changes in reservoir porosity and permeability properties. Analytical dependencies of porosity and relative phase permeability on the salt concentration and ion composition of injected fluid have been obtained on the basis of micromechanical description of fluid flow process in porous medium. The modeling of two-phase Newtonian fluids flow in clay-containing porous medium has been carried out. Influence of parameters of porous medium and injected saline liquid on oil production has been researched. Efficiency of low salinity solutions and highactive metals solutions injection in clay containing reservoir has been shown.

Enrichment of Banana with Lactobacillus rhamnosus Using Double Emulsion and Osmotic Dehydration

The aim of this study was to use the process of osmotic dehydration to enrich banana slices with Lactobacillus rhamnosus encapsulated in a double emulsion. The effect of a pulsed vacuum and the concentration of the osmotic solution on the impregnation of the microorganism and on mass transfer during osmotic dehydration of the fruit were assessed. The kinetics of the water loss (WL), solid gain (SG) and water activity (aw) were obtained using an aqueous solution with 40, 50 and 60% sucrose with emulsion and a vacuum pulse of 50 mbar for 10 and 20 min at the beginning of the osmotic process. The high concentrations of sucrose in the osmotic solution, combined with the application of a pulsed vacuum, produced an increase in the rates of WL and SG of the osmodehydrated banana, as well as a reduction of its aw. L. rhamnosus survived at levels above 107 CFU/g in the hypertonic solution and in the osmodehydrated bananas. Scanning electron microscopy (SEM) showed that the encapsulated probiotic adheres to the banana’s surface, which demonstrates that double emulsions can be used to impregnate probiotics in vegetal tissues.

Influence of sodium replacement and vacuum pulse on the osmotic dehydration of eggplant slices

Abstract Partial replacement of sodium chloride by potassium and calcium chlorides has been proposed as a strategy for reducing the sodium content of osmodehydrated eggplant. The influence of sodium substitutes and vacuum application (VA) on mass transfer parameters and chemical, mechanical and optical properties were investigated. Kinetics of water loss, solid gain and water activity were performed and fitted by the model of Barbosa Junior et al. This model was satisfactorily adjusted, mainly for the osmotic dehydration at atmosphere pressure. VA and the calcium increased the ascorbic acid retention in 29.33 and 85.06%, respectively. VA increased water loss up to 53% and ions incorporation, especially that of potassium (648%). The VA caused a higher total color difference, maximum stress and elasticity as compared to the osmotic dehydration at atmospheric pressure. Industrial relevance The present paper evaluates the osmotic process with atmospheric and reduced pressures and the production of osmodehydrated eggplant slices with reduced sodium content by the partial replacement of sodium chloride by potassium chloride and calcium chloride. Vacuum can accelerate the osmotic process and enhance the diffusion of water and solutes within the products. The coupling of sodium substitution with reduced pressure could offer an interesting array of different processes and healthier products. This project is a feasibility study of the partial replacement of NaCl by KCl and CaCl2 and the application of vacuum with regard to effects on mass transfer parameters and the chemical, optical and mechanical properties of osmodehydrated eggplant slices.