Osmotic-air dehydration of cherries and blueberries

Abstract

Major problems associated with air dehydration are poor product quality; considerable shrinkage caused by collapsed cells following the loss of water; poor rehydration of dried product; and unfavorable changes in color, texture, flavor, and nutritive value of dried products. Osmotic dehydration alone or in combination with air drying could improve texture and prevent much of the heat damage to color and flavor commonly associated with air drying. Four skin treatments: steam blanching, hot water dipping, and ethyl myristate and lipase treatments were used to improve the mass transfer during osmotic dehydration of cherries and blueberries. Mass transfer phenomenon during air drying was investigated at 40, 60, and 80$\sp\circ$C in a lab oven dryer which has a fixed air flow velocity of 2.0 m/s. Recovery of anthocyanins was investigated using Amberlite$\sp\circler$ XAD-2, XAD-4, CG-50, XAD7HP, XAD16HP and Duolite$\sp\circler$ XAD765 resins. Computer models were developed using finite elements to predict moisture content during osmotic dehydration and air drying of cherries and blueberries. (Abstract shortened by UMI.)