Influence of Process Conditions on the Mass Transfer During Osmotic Dehydration of Coated Pineapple Samples

Abstract

The study investigated the combined treatment of edible coatings and osmotic dehydration (OD) of pineapple samples. Pineapple samples were coated with 0.5% to 5.0% (w/v) sodium alginate solution by dipping for 60 s and 120 s and then dried at 50C for 10 and 40 min. OD in sucrose solution was carried out for coated and uncoated samples and water loss (WL), solid gain (SG), performance ratio (PR) and weight reduction (WR) were measured. There was a difference of 13.76 (g/100 g fresh sample) in the rates of WL between its highest and lowest value. The lowest value of 6.15 (g/100 g fresh sample) of SG and the highest value of PR of 7.32 was observed in the sample dipped in coating solution of 2% concentration for 120 s followed by drying for 40 min. WL increased whereas SG decreased up to a certain level of concentration of coating solution. PRACTICAL APPLICATIONS The treatment of coating may provide a solution to the problem of solid gain without affecting water removal during osmotic dehydration. The application of coating before osmotic dehydration (OD) will help in retaining nutrients and flavor than those without coating. The coated osmotically dehydrated fruits after rehydration can be added in ice cream, yogurt and confectionary products. Limited information is available in the literature combining coating with OD of fruits. Results of this study will be helpful in exploring the application of coating in pineapples. The combination of coating and OD may provide a practical method for the preservation of pineapple with better quality characteristics.

Response surface optimization of osmotic dehydration process for aonla slices

“…The diffusion of water is accompanied by simultaneous counter diffusion of solutes from solution into tissue (Lazarides et al 1995). Leakage of natural solutes from plant tissue occurs because the cell membranes of plant tissue responsible for osmotic transport is not perfectly selective but this fl ow is negligible, although it may be important for the organoleptic and nutritional properties of the product (Heng et al 1990, Mizrahi et al 2001, Sahoo et al 2007, Singh et al 2008. The food which has been osmotically dehydrated, can be further processed by freezing, freeze drying vacuum drying and air drying (Nanjundaswamy et al 1978).…”

Formulation of osmo -dehydrated cashew apple (<italic>Anacardium occidentale</italic> L.)

“…Observations on kinetics of osmo-dehydration such as Percent Solid Gain (SG), Per cent Water Loss (WL) and Per cent Weight Reduction (WR) were recorded using the following formulae (Singh et al, 2008).…”

Effect of pectin coating on colour and quality of dehydrated pineapple during storage

“…The processing parameters optimized were sucrose concentration of the osmotic solution, temperature during OD, time and fruit-solution ratio, whereas the response variables kept were water loss, solid gain and ratio of water loss to solid gain (WL/SG) with desired conditions of maximum water loss, minimum solid gain and maximum WL/SG ratio during the OD. The optimized conditions obtained after the experiment were: 62°Brix sucrose concentration, temperature of 30°C for 6 hours using 1:6 fruit-solution ratio (Singh et al, 2008). After OD, samples were taken out of the osmotic medium, drained, gently blotted with filter paper to remove adhering solution and weighed.…”

“…Edible coatings are thin layers of edible material applied directly and formed on the surface of lightly processed fruits and vegetables (by immersing, spraying or wrapping) to provide a selective mechanical barrier against transmission of gases, vapours and solutes (Gennadios and Weller, 1990;Singh et al, 2010) and as such improve their shelf-life and sensory properties.…”