FUNCTIONAL PROPERTIES AND POTENTIAL UTILIZATION OF STARCH ISOLATED FROM CHAYOTE FRUIT

Abstract

Chayote, Sechium edule (Jacq.) Sw., is anoverlooked food plant despite its various potentialities. This study investigated the characteristics of starch isolated from chayote fruit cultivated in Algiers which is known for its Mediterranean climate. The granules morphology, functional properties and amylose content of Algerian chayote fruit starch were examined. Spherical, oval and polygonal shapes and smooth surface were observed using three imaging techniques: a normal and polarized light microscopy with Lucia software and Scanning Electron Microscopy (SEM). Starch granules size was in the rang 3.56-37.24 μm, and for the chayote tubers, it was 7-50 μm. The amylose content (20.36%) is different from that of the chayote tubers (12.81%), but close to those of conventional sources. The Algerian chayote fruit starch showed higher swelling strength and lower melting index. The Rapid Visco Analyzer pasting profile revealed a lower peak viscosity (2158.3 cP) than that from chayote tubers (14746 cP). However, Differential Scanning Calorimetry analysis showed higher gelatinisation temperatures (66.89 °C) and transition enthalpy (15.79 J/g). X-ray diffraction profile showed B-type. The digestibility (D∞), hydrolysis index, HI, and average glycemic index,,)GI( were estimated at 50.66 %, 52.16% and 70.16% respectively. The results showed that starch has an acceptable nutritional value with significant in vitro digestion properties and it is suitable for human health and nutrition. The starch of Algerian chayote fruit showed interesting functional characteristics which makes it suitable for relevant applications in both the field food and cosmetics industries. It can, also, be a raw material for starch processing.