The Effects of Pretreatment on The Qualities of Sweet Potato Flour - A Review

Abstract

Pretreatment is a process that is commonly applied before drying of agricultural products, it inactivates enzymes and improves quality of dried products while accelerating the drying process. This article aims to review the effects of different types of pretreatment on the quality of sweet potato flour. The methods of pretreatment frequently used for the processing of sweet potato prior to drying include Thermal blanching (Hot Water, Steam, Ohmic heater and Microwave), Non thermal blanching (Ultrasound, Freezer, Pulsed electric field and High hydrostatic pressure), Hyperosmotic solutions (Salt, Sugar), Alkaline liquor (Potassium Carbonate, Ethyl oleate solutions), Acid liquor (Citric Acid, Ascorbic Acid), Sulphite solution (Sulphur dioxide gas, Water-soluble sulphide salts for example potassium metabisulphite (K2S2O5), sodium metabisulphite (Na2S2O5)and sodium hydrogen sulphite (NaHSO3).) and Carbonic maseration (Carbon dioxide (CO2). Pretreatment has been proven to retain the colour of sweet potato, enhance nutritional qualities and also improve the functiomal characteristics of sweet potato flour.