Effect of Drying Techniques on Functional and Physico-Chemical Properties of Okara

Abstract

The present study was undertaken to study the effect of different drying methods on physicochemical and textural properties of loquat slices. Uniform size of loquat slices were pre-treated with 1% potassium metabisulphite. These slices were dried by using different drying techniques i.e. tray drying (55 °C), vacuum drying (55 °C, at 500 mm Hg) and freeze drying (-40°C,0.006 bar). Physical properties of dried slice were assessed by bulk density (BD), tap density (TD), Carr index (CI), Hausner ratio (HR), porosity, rehydration ratio (RR), coefficient of rehydration (COR), dehydration ratio (RR) and hygroscopicity. Color value was analysed in terms of L*, a*, b*, total color difference (TCD), Hue, Croma and browning index (BI). Hardness was analysed by using texture analyser. It was observed that freeze-dried slices shows decreasing trend of all aspects of physical properties except rehydration ratio and coefficient of rehydration. Freeze-dried samples showed less change in BI and TCD among all the samples. It was found that freeze-dried rehydrated sample reflect lowest hardness than other rehydrated samples.