Investigating the Effects of Acid Hydrolysis on Physicochemical Properties of Quinoa and Faba Bean Starches as Compared to Cassava Starch

In response to the growing demand for high-quality food ingredients, starches from underutilised sources like quinoa and faba bean are gaining attention due to their unique properties and high tolerance to adverse environmental conditions. Acid hydrolysis is a well-established chemical method for producing modified starch with improved solubility, lower gelatinisation temperature, and reduced pasting viscosity. However, various outcomes can be achieved depending on the type of starch and modification conditions. This study comparatively investigated the effects of acid hydrolysis on the functional and physicochemical properties of emerging starches from quinoa and faba bean, with cassava starch serving as a reference from a leading source. The results demonstrated increased dietary fibre content across all three starches, with faba bean starch showing the most significant rise. Acid treatment also enhanced the crystallinity of the starches, with faba bean starch exhibiting the highest increase in relative crystallinity, which led to a shift towards higher temperatures in their thermal properties. Additionally, water solubility and oil adsorption capacity increased, while swelling power decreased following acid treatment. The acid treatment reduced the pasting properties of all samples, indicating that the modified starches were more resistant to heating and shearing in the rapid visco analyser. While quinoa starch gel remained soft after acid hydrolysis, the gel strength of cassava and faba bean starches improved significantly, making them suitable as plant-based gelling agents.