Effect of stirring in the osmotic dehydration of chestnut using glycerol solutions

Combined Effect of Impregnation with an Origanum vulgare Infusion and Osmotic Treatment on the Shelf Life and Quality of Chilled Chicken Fillets

The scope of this work is the study of a combined process including a dipping step into an oregano (Origanum vulgare ssp. hirtum) infusion (OV) followed by osmotic treatment of chicken fillets at 15 °C. Chicken fillets were immersed in an osmotic solution consisting of 40% glycerol and 5% NaCl with (OV/OD) and without (OD) prior antioxidant enrichment in a hypotonic oregano solution. A comparative shelf life study of all the samples (untreated, OD and OV/OD treated) was then conducted at 4 °C in order to assess the impact of this process on the quality and shelf life of chilled chicken fillets. Microbial growth, lipid oxidation and color/texture changes were measured throughout the chilled storage period. Rates of microbial growth of pretreated fillets were significantly reduced, mainly as a result of water activity decrease (OD step). Rancidity development closely related to off odors and sensory rejection was greatly inhibited in treated fillets owing to both inhibitory factors (OD and OV), with water-soluble phenols (OV step) exhibiting the main antioxidant effect. Shelf life of treated chicken fillets exhibited a more than three-fold increase as compared to the untreated samples based on both chemical and microbial spoilage indices, maintaining a positive and pleasant sensory profile throughout the storage period examined.

Effect of ultrasonic vacuum pretreatment on mass transfer kinetics during osmotic dehydration of black jamun fruit

The study investigates the effects of novel combination of ultrasound and vacuum pre-treatment on osmotic dehydration of black jamun fruit. The osmotic dehydration was conducted under three different conditions namely atmospheric osmotic dehydration (AOD), vacuum pre-treated osmotic dehydration (VOD), ultrasonic vacuum pre-treated osmotic dehydration (USVOD). The changes in water and solute content during osmotic dehydration were fitted to Peleg model to predict the equilibrium moisture and solute content values. The adequacy of Weibull distribution model for predicting the moisture and solute contents during osmotic dehydration at different temperatures were assessed. The effective diffusivity of samples in AOD, VOD and USVOD were estimated by application of Fick's second law. The high regression coefficient (R² > 0.9) and low χ² value represented the suitability of Peleg model for predicting equilibrium moisture and solute content and Weibull model for predicting both moisture and solute fraction in jamum fruit during AOD, VOD and USVOD processes. Both vacuum and ultrasound vacuum pretreatment enhanced the moisture loss and solute uptake during osmotic dehydration. The results showed the osmotic drying rate was significantly influenced by different pre-treatment techniques and both vacuum and ultrasonic vacuum pretreatment process enhanced moisture loss and solute uptake during osmotic dehydration. The effective moisture and solute diffusivity were highest in ultrasonic vacuum pretreated samples and the values at 30-50 °C temperature were ranged from 8.53 × 10^-10 to 9.27 × 10^-10 m²/s and 3.81 × 10^-10 to 4.39 × 10^-10 m²/s respectively. The results were interrelated to changes in tissue structure caused by application of vacuum and ultrasonic vacuum pretreatment.

Evaluation and modelling of osmotic pre-treatment of peach using alternative agents in a multiple-component solution

BACKGROUND

Peach is a perishable fruit of great importance for the Greek food export market which is prone to rapid deterioration after harvesting. Its short shelf life can be substantially prolonged by applying an appropriate osmotic dehydration (OD) pre-treatment, which is a mild, non-thermal procedure. The aim of this study was to describe mass transfer and quality retention induced by the OD process.

RESULTS

Peach pieces were immersed in tertiary solutions of glycerol, erythritol, steviol glucosides and mineral salts at pre-selected OD conditions (25-45 °C for 3-240 min, w_fruit /w_solution = 1:5). Water loss (WL), solid gain (SG), water activity (a_w ) as well as representative quality indices (colour, texture) were measured during OD, showing that osmotically dehydrated peach presented significant a_w reduction (from 0.97 to 0.88) combined with quality retention.

CONCLUSION

This research showed that OD can be an effective pre-processing step in the production of intermediate moisture novel products. A second-degree polynomial model was developed describing adequately the effect of OD time and temperature and glycerol concentration on WL, SG, a_w , colour and texture of osmotically dehydrated peach, and analysis of variance was applied to identify those factors that significantly affect the aforementioned parameters. It was concluded that OD using alternative osmotic agents is an efficient method with respect to product colour and texture retention, allowing for the production of novel products with extended shelf life. © 2018 Society of Chemical Industry.

Modeling of Osmotic Dehydration of Apples in Sugar Alcohols and Dihydroxyacetone (DHA) Solutions

The purpose of this paper is twofold: on the one hand, we verify effectiveness of alternatives solutes to sucrose solution as osmotic agents, while on the other hand we intend to analyze modeling transfer parameters, using different models. There has also been proposed a new mass transfer parameter-true water loss, which includes actual solid gain during the process. Additional consideration of a new ratio (Cichowska et al. Ratio) can be useful for better interpretation of osmotic dehydration (OD) in terms of practical applications. Apples v. Elise were dipped into 30% concentrated solutions of erythritol, xylitol, maltitol, and dihydroxyacetone (DHA) to remove some water from the tissue. To evaluate the efficiency of these solutes, 50% concentrated sucrose solution was used as a control. All of the tested osmotic agent, except maltitol, were effective in the process as evidenced by high values in the true water loss parameter. Solutions of erythritol and xylitol in 30% concentrate could be an alternative to sucrose in the process of osmotic dehydration. Peleg's, Kelvin⁻Voigt, and Burgers models could fit well with the experimental data. modeling of mass transfer parameters, using Peleg's model can be satisfactorily supplemented by Kelvin⁻Voigt and Burgers model for better prediction of OD within the particular periods of the process.

Efficiency of Osmotic Dehydration of Apples in Polyols Solutions

The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.