Structural, functional properties and in vitro digestibility of maize starch under heat-moisture and atmospheric-cold plasma treatments

Abstract

Maize starch is one of important materials widely used in food applications and other industries. However, natural properties of raw starch can not be suitable for processed foods. So, the modification of starch is very important. In this study, heat-moisture and atmospheric cold argon-plasma treatments were applied in maize starch: then, structural, functional properties and digestibility of modified starch was investigated. Raw starch was heated at 20, 25 and 30 % of moisture content. Subsequently, the samples were then treated under argon-plasma environment at fixed paramenters (137.5 V; 1.0 A for 10 min). The samples were investigated on degree of cross-linking, degree of relative crystallinity (DRC), degree of hydrolysis using alpha-amylase, in vitro digestibility, changes in the hydration properties such as water absorbance index, swelling factor and water solubility index. Results showed that degree of cross-linking, DRC, resistant starch of samples significantly increased under heat-moisture and plasma treatments; especially, sample of 20 % heat-moisture contains 3-folded to 10-folded increase comparing to raw starch base on with or without pre-boiling process. Furthermore, water absorbance index and swelling factor decreased but water solubility index increased under plasma treatment.