Avaliação da digestibilidade in vitro, propriedades estruturais, térmicas e de pasta dos amidos de milho modificados por Heat-moisture treatment (HMT) com adição de ácidos orgânicos

Abstract

Resistant starch (RS) has gained interesting food applications because of its health benefits when properly consumed; the control of diseases such as diabetes and obesity is one of the most important functions. Physical and chemical modifications in starches have been applied in order to improve RS content and increase the range of food applications. The Heat moisture treatment (HMT) modification combined with the addition of organic acids (acetic, citric and lactic) was the aim of this study, which aimed to evaluate the in vitro digestibility and thermal and structural properties of maize starches with different levels of amylose after this treatment, allowing a comparison with native starch. In both botanical sources, the RS content increased significantly from 62.60% to 76.70% for the regular type and from 49.21% to 61.15% for the waxy type. Acid modifications caused a reduction in viscosity, gelatinization enthalpy and relative crystallinity (RC %), but did not cause changes in the X-ray diffraction pattern. Among the acids used, citric acid was more promising in the alterations and in the increase of RS, followed by lactic and acetic acid. These results open excellent opportunities for application of these modified starches in functional foods or in the form of encapsulated starch.