Osmotic Dehydration Process Research Articles

Optimization of Osmotic Dehydration Process for Aonla (Emblica officinalis Gaertn) Pieces with Salt Solution and Spices by Response Surface Methodology

The optimization of osmotic dehydration process of aonla (Emblica officinalis Gaertn) slices in brine solution containing spices (cumin powder, fenugreek powder, fresh ginger extract) was carried out using response surface methodology. The independent process variables for osmotic dehydration are salt concentration in water (4-12%), spices concentration in the brine solution (39%), solution to fruit ratio (3-5) and duration of 60-90 minutes at room temperature. The osmotic dehydration process was optimized for maximum water loss, solute gain, overall acceptability and minimum acidity and vitamin C loss based on the RSM. The optimum conditions were predicted as 12% salt concentration, 7.09 % spices concentration, 4.30 solutions to fruit ratio and 84.15 minutes process time. Among the process variable, salt concentration, process duration and spices concentration have the most significant effect on water loss, solute gain, acidity and overall acceptability; process time has the most effect on vitamin-C loss and acidity whereas solution-to-fruit ratio had significantly lower effect on all the responses. Osmotically dehydrated aonla samples were observed to be less in functional compounds compare to fresh aonla samples due to leaching out of minor compounds to hypertonic solution during osmotic dehydration process.

Aplicação de processos combinados osmótico e secagem em air fryer em berinjelas condimentadas com hibisco

O presente trabalho tem como objetivo avaliar a influência da incorporação da solução obtida com hibisco, sacarose e cloreto de sódio no processo de desidratação osmótica e estudo da cinética de secagem em Air fryer nas características físicas e físico-químicas. A berinjela foi cortada em cubos medindo 1,0 × 1,0 × 1,0 cm e foram submetidos ao processo de desidratação osmótica em solução hipertônica com infusão de hibisco, durante 30 minutos na temperatura de 25 ± 2 °C, após esta etapa foi determinado o percentual de perda de água (PA) e ganho de sólidos (GS). O estudo da cinética de secagem foi realizado em um equipamento doméstico Air fryer nas temperaturas de 70, 80 e 90 °C e velocidade de ar do próprio equipamento (não ajustável) e modelos matemáticos empíricos foram ajustados aos dados experimentais. Os cubos de berinjelas in natura e após o processo de secagem nas temperaturas indicadas anteriormente foram caracterizada quantos aos seguintes parâmetros: pH, acidez total titulável (ATT), teor de água, sólidos totais, sólidos solúveis totais (SST), ratio (SST/ATT) e cor (L*, a*, b*, C* e h°). O processo de desidratação osmótica ocasionou uma redução do teor de água inicial da fruta e um ganho de sólidos de 16,34%. Com relação a cinética de secagem o modelo de Page foi o que apresentou os maiores coeficientes de determinação (R2) e os menores valores da função qui-quadrado em todas as temperaturas analisadas; o aumento da temperatura de secagem proporcionou maior diferença de cor, indicando eficiência no processo de impregnação da infusão de hibisco na berinjela. Portanto, a temperatura de 90 °C é a mais indicada para a secagem dos cubos de berinjela, uma vez que apresentou o menor teor de água e boas características físicas e físico-químicas.

Osmotic Dehydration and Assessment of Quality Attributes of Seasonal Vegetable Crops: Carrot and Beetroot Cubes

Fulfilling the food demand of a growing population is the biggest challenge as lot of food globally got wasted due to improper storage and processing. Osmotic dehydration offers high-quality preservation and maintenance of the integrity of fruits & vegetables. Response surface methodology was performed to estimate the main effect of osmotic dehydration process on quality attributes of carrot and beetroot cubes. Higher values of the osmotic solution of salt and sucrose at sample to solution ratio of 1:5 had provoked higher flows of water and solutes through the carrot and beetroot cubes. The range of NaCl concentration varies from 4-12 % w/v in carrot and 12-16 % w/v in beetroot for 2, 4 and 6 hour. However, sucrose concentration varies from 40-60º Brix in both carrot and beetroot. Quality attribute of carrot and beetroot including ascorbic acid, carotenoid, total phenol etc. didn’t changed on recommended process variables 50º Brix of sucrose + 8 % w/v sodium chloride for carrot and 50º Brix of sucrose + 14 % w/v NaCl for beetroot under osmotic dehydration for 4 hours. It was considered to get maximum water loss, weight reduction, subsequent rehydration ratio, overall acceptability and minimum solute gain of rehydrated product. Keywords: Osmotic dehydration; Carrot; Beetroot; Preservation; Response Surface Methodology

PENGARUH KONSENTRASI DAN SUHU LARUTAN OSMOTIK TERHADAP PENYUSUTAN VOLUME, KEKERASAN DAN WARNA PADA BUAH NAGA

Osmotic dehydration is one of the methods in making of intermediate moisture food. Osmotic dehydration is done by immersing the material in a osmotic solution in the form of a sugar solution. The purpose of this research is to investigate the effect of concentration and temperature of osmotic solution on volume shrinkage, hardness and color change during the process of osmotic dehydration of dragon fruit.Dragon fruit has been immersed in osmotic solution with varying concentrations of 30 oBrix, 50 oBrix, and 70 oBrix and a solution temperature of 30 oC, 40 oC, and 50 oC. The average value of the largest to the smallest volume shrinkage in succession is in the treatment of 70 oBrix, 50 oBrix, and 30 oBrix. The lowest level of material hardness during osmotic dehydration is found in the treatment of 70 oBrix and 50 oC (B3T3). The CIELAB diagram values ​​show that the average color of the material for all treatments is in the purple-red color column. Based on anova test, the difference in concentration and temperature of the solution did not have a significant effect on the discoloration of dragon fruit after osmotic dehydration.

The effects of the osmotic dehydration parameters on reduction of selected microorganisms on chicken meat

Analysis of the influence of osmotic dehydration on reduction of selected microorganisms inoculated on dehydrating chicken meat, as a mean of assessing the microbiological safety of osmotic dehydration process, is conducted. Chicken meat cubes were inoculated with Esherichia coli, Listeria monocytogenes, and Salmonella spp. and subjected to the osmotic dehydration process with varied parameters of: process duration, osmotic solutions concentration, and type of solution. Samples of osmodehydrated chicken meat were analyzed by standard and modified ISO methods. The results pointed that the increase in time and concentration have led to the higher microbiological reduction, while the osmotic dehydration performed in sugar beet molasses exerted the higher reduction ratios compared to the process in aqueous osmotic solution. Calculated mathematical models of reduction ratios for selected microorganisms on chicken meat were statistically significant, indicating on satisfactory approximation of reduction ratios values within the applied parameters. Practical applications Mathematical models, calculated in this investigation, which describe the effects of osmotic dehydration on reduction of selected microorganisms on chicken meat, allow better understanding and managing of product safety during the process of osmodehydration.

The Application of Combined Pre-Treatment with Utilization of Sonication and Reduced Pressure to Accelerate the Osmotic Dehydration Process and Modify the Selected Properties of Cranberries

The aim of this study was to investigate the effect of a pretreatment, performed by a combined method based on blanching, ultrasound, and vacuum application, on the kinetics of osmotic dehydration and selected quality properties such as water activity, color, and bioactive compound (polyphenols, flavonoids, and anthocyanins) content. The pretreatment was carried out using blanching, reduced pressure, and ultrasound (20 min, 21 kHz) in various combinations: Blanching at reduced pressure treatment conducted three times for 10 min in osmotic solution; blanching with reduced pressure for 10 min and sonicated for 20 min in osmotic solution; and blanching with 20 min of sonication and 10 min of reduced pressure. The osmotic dehydration was performed in different solutions (61.5% sucrose and 30% sucrose with the addition of 0.1% of steviol glycosides) to ensure the acceptable taste of the final product. The changes caused by the pretreatment affected the osmotic dehydration process by improving the efficiency of the process. The use of combined pretreatment led to an increase of dry matter from 9.3% to 28.4%, and soluble solids content from 21.2% to 41.5%, lightness around 17.3% to 56.9%, as well as to the reduction of bioactive compounds concentration until even 39.2% in comparison to the blanched sample not subjected to combined treatment. The osmotic dehydration caused further changes in all investigated properties.

The effects of osmotic dehydration of white cabbage on polyphenols and mineral content

Within this work, the content of polyphenolic compounds, vitamin C and minerals in white cabbage (Brassica oleracea) was studied, as affected by the variety of cabbage (var. Futoški, hybrid Bravo) and osmotic dehydration in different osmotic solutions. Three osmotic solutions were used: 1) aqueous solution of NaCl and sucrose (S1); 2) mixture of S1 and sugar beet molasses in proportion 1:1 (S2); and 3) 100% beet molasses (S3). The osmotic dehydration of cabbage in molasses (S3) resulted in a substantial increase in the content of iron and potassium in the dehydrated cabbage by 80–100%. On the other hand, a loss of minerals (Fe, Mg and Ca) at 30–60% after cabbage dehydration in sucrose solution is presented. Also polyphenols content was significantly increased during osmotic dehydration in molasses particularly for kaempherol (6.63 mg/kg dm), p-cumaric acid (1.01 mg/kg dm), caffeic acid (20.35 mg/kg dm), catechin (153.81 mg/kg dm) and gallic acid (17.54 mg/kg dm). Additionally, osmotic dehydration process demonstrated a good retention of l-ascorbic acid in cabbage.

Contribution of Osmotically Dehydrated Wild Garlic on Biscuits' Quality Parameters

Wild garlic generally improves strengths and regenerates the body and also helps in the treatment of various diseases. In this study the contribution of wild garlic osmotic dehydration process in sugar beet molasses on biscuits' quality parameters is investigated. Presented results showed that addition of osmotically dehydrated wild garlic in molasses impoved textural characteristics of biscuits by lowering hardness and increasing fracturability and also changed colour characteristics of biscuits. Chemical composition of biscuits with added osmotically dehydrated wild garlic was improved in comparison to the biscuits with added fresh wild garlic, where proteins, total sugars, celulose and ash compositions were increased in amounts of 1.86, 3.2, 15.8 and 5.76 % respectively. Addition of osmodehydrated wild garlic had provided higher Zn, Cu and Fe biscuits' content in comparison to the addition of fresh wild garlic, in amounts of 2.75, 15.33 and 15.84 % respectively. Developed mathematical models of biscuits quality parameters were statistically significant, while predicted and observed responses corresponded very well. In effort of obtaining new types of products, new application of known ingredients was proposed, allowing incorporation of sugar beet molasses' rich nutrient content in wheat products formulation.

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.

Optimisation of Osmotic Dehydration of Plums

Abstract The paper presents kinetics of osmotic dehydration of plums in relation to the treatment time and concentration of sucrose solution. The main aim of the study was polyoptimisation of the preservation process, namely selection of optimal parameters of osmotic dehydration processes including changes in selected quality indicators. Defining of optimal conditions of the entire course of preservation may influence limitation of consumption of preserving substances (osmotic substances) and reduction of the energy demand. Based on the research which was carried out, it was found that parameters of osmotic dehydration had a significant impact on mass transfer coefficients and physico-chemical indicators of fruit - along with the increase of concentration of osmotic solution and extension of the time of the process, the increase of the investigated sizes was observed. In the second part of the paper, optimization of the fruit preservation process was performed. The idea of the objective function consisted in minimization of the difference between the expected values of criteria and the values obtained from the experimental results. For the defined scalar optimization criterion an explicit relation between quality and cost of the product was showed.

Modelling energy savings in chicken meat osmotic dehydration process

Osmotic dehydration is a low energy demanding process, and in order to investigate and estimate the energy efficiency of the osmotic dehydration process, convective drying is taken as a base treatment for comparison. Obtained energy savings data of the osmodehydration process are used to develop mathematical models of the energy savings of the process. Results showed that maximal quantity of heat saved, indicated on high levels of energy efficiency of chicken meat osmodehydration process, while both technological parameters statistically significantly influenced process energy efficiency. The developed mathematical the model, allows good prediction of the quantity of heat saved based on applied technological parameters.

Optimization of the osmotic dehydration of ginger

ABSTRACT: The present research aimed to optimize the process of osmotic dehydration (OD) of ginger with hypertonic sucrose solution employing response surface methodology. A 23 experimental planning was carried out and 17 experimental assays were performed based on three independent variables (temperature, concentration of the osmotic solution and immersion time) and three dependent variables (moisture loss (ML), solids gain (SG) and dehydration efficiency index (DEI)). The selected assay conditions exhibited the preferred DEI value (the highest ML and lower SG), which were considered in the optimization. Assay 16 demonstrated to be the most favorable conditions for the osmotic dehydration of ginger (DEI =1.61) at 40 40 °C, 50 °Brix and 90 minutes of immersion time. Assay 1 performed at 34 °C, 44 °Brix and 120 minutes of immersion time also displayed desirable response (DEI =1.45). Thus, these two assays were evaluated for the presence of thermal-tolerant coliforms: Bacillus cereus and Salmonella sp.. The analyses presented values below the acceptable limits, which assured high quality hygienic and sanitary conditions of the product.

Sensory evaluation of dehydrated tomatoes using the proportional odds mixed model

In order to identify products acceptance and commercialization, researchers performed sensory evaluation. The responses to these studies are ordinal categorical variables, thus, they are normally based on a hedonic scale. Generally, in sensory experiments, each judge evaluate several products and the answers given by the same judge can be classed as repeated measures. In this paper, we propose an alternative statistical analysis to consider the natural ordering and repeated measures simultaneously using proportional odds mixed models. Such models were proposed to compare the taste acceptance of two varieties of tomato, Italian and Sweet Grape, after the osmotic dehydration process. The experiment was designed in the way that each judge, randomly selected and evaluated each variety once. The results showed that the Sweet Grape presented better acceptance than Italian variety. This model allowed the predictions and estimations probabilities to be calculated for each of the response categories according to each variety. PRACTICAL APPLICATIONS: Tomate is a product highly perishable and new dehydration techniques are being developed and needs to have good accepted by consumers. In this paper, we proposed an alternative statistical model to compare the taste acceptance of two varieties of dehydrated tomato, Italian and Sweet Grape. The model presented can be used in different sensorial evaluations and can help researchers to analyze ordinal categorical data, focusing on how to identify and account for specific issues arising from experimental design (such as correlated observations). The results showed that the Italian tomato was 6.89 times more likely to be classified with lower scores at hedonic scale compared to Sweet Grape tomato regardless of sex. The Sweet Grape variety has a probability of 44% (32%; 57%) of receiving score 9 and for Italian variety this happens with a probability equal of 10% (5%; 19%). In addition, the results showed no significant correlation between responses from the same judge.

Study and optimization of high hydrostatic pressure (HHP) to improve mass transfer and quality characteristics of candied green plums (Prunus mume)

Osmotic dehydration (OD) is the most important procedure for producing candied green plums. This study investigated high hydrostatic pressure treatment (HHP) to improve OD process. Central composite design was applied to optimize HHP parameters with pressure ranging from 50 to 400 MPa and time from 1 to 30 min. Innovative HPP procedure was compared with traditional heating treatments on the acceleration efficiency by Peleg’s model. The physico-chemical and sensorial properties were compared. The results showed that HHP was effective to accelerate the OD process, but was not as efficient as heating methods. HHP promoted higher titratable acid content, firmness and greener color than heating on the obtained product. Sensory results revealed that HHP allowed to better preserve the typical odor and flavor of the final products. Generally, HHP treatments show high potentiality to improve the OD performances of candied green plums, together with the overall quality of the final product. Practical applications Candied green plum is a popular snack in Eastern Asian countries. The traditional process includes a heating assisted treatment in order to accelerate the candying progress, which may induce decrease to the quality of the final product. Non-thermal high hydrostatic pressure could improve the osmotic dehydration process performances, minimizing the thermal damages on the final products, promoting the improvement of its overall quality.

Effect of High Hydrostatic Pressure (HHP) on the Antioxidant and Volatile Properties of Candied Wumei Fruit (Prunus mume) During Osmotic Dehydration

Candied wumei fruit (Prunus mume) is a traditional product in Eastern Asian countries generally obtained by a long osmotic dehydration (OD) process. This study evaluated the effect of the application of high hydrostatic pressure (HHP) and heating pre-treatments to accelerate the OD process on some bioactive compound content, antioxidant activity, and volatile profile of wumei fruit. Whole fruits were subjected to HPP treatment (50 MPa for 1 min) and heating (100 °C for 1 min) and then to OD in a 40% sucrose solution for 5 days. Results showed that both heating and HPP pre-treatment increased mass transfer in a comparable way; however, HPP allowed a significant higher retention of antioxidant compounds and activity compared with the heating treatment, resulting in similar values to the untreated product. Moreover, HPP promoted the release of various volatile components resulting in a richer volatile profile compared with both control and heat-treated samples. Hence, HPP showed good potentiality as an alternative non-thermal pre-treatment for the production of candied wumei fruit characterized by high nutritional and sensorial properties.

Effect of different sugars on the freezing characteristics of Kyoho grape.

The aim of this work was to analyze the effect of different osmotic dehydration (OD) processes (sucrose, trehalose, glucose, and lactose) as a pretreatment for grape before exposure to freezing. The osmotic treatment had less effect on blueberry moisture content among different sugars. Impregnation with sugars decreases the freezing time of grapes, compared to untreated grapes. Trehalose and lactose had a remarkable effect on shortening the time for grapes to pass the zone of maximum crystallization of ice. It was concluded that drip loss and electrolyte permeability of cell membranes decreased and the soluble solids content increased after OD treatment. In addition, the firmness and L* values of trehalose-treated grapes were significantly higher than those of other treatments (p < .05). In summary, osmosis with a carbohydrate solution not only increased the freezing rate but improved quality characteristics of grapes after freezing and thawing. PRACTICAL APPLICATIONS: Grapes are subject to freezing damage during storage, including significant water loss, berry softening, off flavor occurrence, which reduce the commodity and consumption of grapes. OD can improve the freezing rate by reducing the moisture content in the raw material and reducing the impact of freezing on the quality of fruits and vegetables, which may be beneficial to the process of freezing grapes.

Metabolic and sensory evaluation of ultrasound-assisted osmo-dehydrated kiwifruit

Abstract The aim of this work was to investigate the effect of ultrasound (US) pre-treatment on endogenous metabolic activity of kiwifruits slices subjected to osmotic dehydration (OD), measured by metabolic heat production in isothermal calorimeter, respiration rate, structure changes and cell viability. Moreover, the overall changes on minimally processed kiwifruit were also studied by means of electronic tongue system. Kiwifruit slices (10 mm thick) were treated with US in the bath at a frequency of 35 kHz for 10, 20 and 30 min. The OD process was conducted in a 61.5% sucrose solution at 25 °C for pre-established contact period of 0, 10, 20, 30, 60 and 120 min. The results showed that the application of US pre-treatment and OD process promoted the reduction of metabolic heat as a consequence of a partial loss of vitality. Moreover, US and US + OD treatment specifically impacted the structure and the chemical picture of kiwifruit samples. Industrial relevance Ultrasound treatment coupled with osmotic dehydration could be applied at industrial level in order to save time and energy for a further dehydration process. Moreover, fruit tissue treated with ultrasound treatment promoted structural modifications and chemical changes in the kiwifruit tissue, as resulted from the present study, which could be useful for the industries to design novel products with intermediate moisture content.

Study of the Effect of High Hydrostatic Pressure (HHP) on the Osmotic Dehydration Mechanism and Kinetics of Wumei Fruit (Prunus mume)

Osmotic dehydration (OD) is the most important procedure for obtaining candied wumei (Prunus mume), which is a very popular snack in Eastern Asian countries. This study aims to evaluate the effects of high hydrostatic pressure (HHP) pre-treatment (50–400 MPa) on the mass transfer kinetics and on the water diffusivity of wumei fruit during OD and to investigate the effect on water distribution and cell viability aspects. The results showed that HHP increased initial rate and effective diffusivity of mass transfer values compared to non-treated samples. Time domain nuclear magnetic resonance revealed that, upon HHP treatment, the water redistributed in vacuole, cytoplasm/extracellular spaces, and cell wall/membrane. The application of 400 MPa probably caused some irreversible damages to the cell membranes. The cell viability study determined by fluorescein diacetate staining showed a loss of cell viability at pressures higher than 200 MPa. HHP exhibited an effective pre-treatment to increase mass transfer of wumei fruit during OD process.

Combined effect of pulsed electric field and osmotic dehydration pre-treatments on mass transfer and quality of air dried goji berry

Abstract Pulsed electric field (PEF) and osmotic dehydration (OD) pre-treatments can improve the slow and energy intensive process of goji berry drying. The effect of PEF and OD processing conditions on mass transfer, color, antioxidant capacity and total phenolic content was studied. Application of PEF (0.9–2.8 kV/cm, up to 7500 pulses) caused tissue permeabilization (electrical conductivity disintegration index, Zp, value up to 0.38, due to the structure of goji berry waxy peel) and significantly enhanced mass transfer during subsequent OD and air drying (increased effective diffusivity coefficients Dew and Des and drying rate kdrying respectively). Combining OD (55 °C, 60 min), PEF (2.8 kV/cm, 750 p) and air drying (60 °C) compared to conventional air drying led to total processing time decrease (by 180 min or 33%), better color retention, higher antioxidant capacity and total phenolic content.

Modelling of factors influencing the effect of osmotic solution on reduction of selected microorganisms.

The goal of this research is to model the effects of two osmotic solutions factors on the reduction of selected microorganisms, and to assess the application in osmotic dehydration process of animal raw materials from the aspect of microbiological safety. Sugar beet molasses and aquatic osmotic solution were prepared and inoculated with Escherichia coli, Listeria monocytogenes and Salmonella spp. Varied factors of osmotic solutions were: time, temperature and concentration of osmotic solutions. Samples of osmotic solutions were subjected to standard and modified microbiological ISO methods. The result showed that increase in factors had a positive effect on the reduction of microbiological load, while the time of the process was the most influential technological parameter. Number of L. monocytogenes was reduced to <10 CFU per g at the end of the process in the highest concentration of sugar beet molasses at all process temperatures. Developed mathematical models of reduction ratios for tested microorganisms were statistically significant, allowing good prediction of reduction ratio values based on applied factors. Obtained levels of reduction of all tested microorganisms present good base for the production of safe osmotically dehydrated products of animal origin.