Effects of heat-moisture treatment on the thermal, functional properties and composition of cereal, legume and tuber starches-a review

Abstract

Several methods are currently employed in the modification of starch obtained from different botanical sources. Starch in its native form is limited in application due to retrogradation, syneresis, inability to withstand shear stress as well as its unstable nature at varying temperatures and pH environment. Modification of starch is therefore needed to enhance its food and industrial application. A primary and safe means of modifying starch for food and industrial use is through hydrothermal methods which involves heat-moisture treatment and annealing. Heat-moisture treatment (HMT) is a physical modification technique that improves the functional and physicochemical properties of starch without changing its molecular composition. Upon modification through HMT, starches from cereals, legumes and tuber crops serve as important ingredients in diverse food, pharmaceutical and industrial processes. Although changes in starch initiated by HMT have been studied in starches of different plant origin, this work further provides insight on the composition, thermal and functional properties of heat-moisture treated starch obtained from cereals, legumes and tuber crops.

Keywords: Functional properties; Heat-moisture treatment; Hydrothermal modification; Starch; Starch modification; Thermal properties.

Fig. 1

Reaction pattern of amylases on amylose and amylopectin. a semicrystalline structure of native granule; b dispersed amylopectin molecules; and c dispersed amylose molecules. Arrows shows access points of amylases towards the negative granules (a), isolated amylopectin (b) and amylose (c) of starches. Source: Naguleswaran et al. (2014)

Fig. 2

Noodles produced from native (corn and grain amaranth) and heat-moisture treatment starches. CS—Noodles = corn starch noodles; AS—Noodles = amaranth starch noodles; HMT-AS—Noodles = heat-moisture treated amaranth starch noodles. Source: Chandla et al. (2017)

Fig. 3

Structural improvement on annealing. a lengthening of the double helices by twisting of the ends of the chains; b improved parallel packing of double helices; c co-crystallization of tie chains and amylopectin. Upright arrows in (a) and (b) depicts that annealing increases the crystalline thickness and thus the enthalpy of gelatinization. Source: Vamadevan et al. (2014)