Effect of Ultrasound and Chemical Cross-Linking on the Structural and Physicochemical Properties of Malanga (Colocasia esculenta) Starch

Abstract

Starch extracted from malanga (Colocasia esculenta) is a biopolymer with considerable industrial potential thanks to its high starch content (70–80% on a dry basis) and small granule size, which give it distinctive functional properties. To expand its applications in advanced processes such as encapsulation, it is necessary to modify its structural and physicochemical characteristics. This study evaluated the effects of ultrasound (US) and chemical cross-linking (CL) on the properties of this starch. US was applied at various times and amplitudes, while CL was performed using sodium trimetaphosphate and sodium tripolyphosphate, with sodium sulfate as a catalyst. US treatment reduced particle size and increased amylose content, resulting in lower viscosity and gelatinization temperature, without affecting granule morphology. Meanwhile, CL induced phosphate linkages between starch chains, promoting aggregation and reducing amylose content and enthalpy, but increasing the gelatinization temperature. The modified starches exhibited low syneresis, making them potentially suitable for products such as pastas, baby foods, and jams. Additionally, ultrasound modification enabled the production of fine starch microparticles, which could be applied in the microencapsulation of bioactive compounds in the food and pharmaceutical industries. These findings suggest that modified malanga starch can serve as a functional and sustainable alternative in industrial applications.