INFLUENCE OF PROCESS CONDITIONS ON THE MASS TRANSFER DURING OSMOTIC DEHYDRATION OF COATED PINEAPPLE SAMPLES

Abstract

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.