Comparative behaviour of cellulosic and starchy plant materials during osmotic dehydration

Abstract

Osmotic dehydration studies on two cellulosic plant materials – Golden Delicious and Cox apple – and two starchy plant materials – banana and potato – showed that the amount and rate of water loss occurred in the following descending order: Golden Delicious > Cox > potato > banana. Temperature, concentration and immersion time of samples in the osmotic solution played a significant effect on amount and rate of water loss in all commodities in a descending order as follows: 55 > 40 > 32.2 ◦C; 0.70 > 0.60 > 0.50 > 0.40 g kg−1; and 30 > 60 > 90 > 120 min, respectively. A corresponding uptake of solids from the osmotic solution occurred, the rate been greatest over the first 30min, before declining significantly thereafter. The diffusion coefficients for water loss (Deff,w) measured by the method of slopes on the water loss rate curves conducted at 32.2, 40 and 55 ◦C for 0.40, 0.50, 0.60 and 0.70 g kg−1 sucrose concentration solutions were higher for cellulosic plant materials than starchy plant materials. Significant variations occurred in efficiency index (WL/SG) between cellulosic and starchy plant materials