Impacto da secagem em leito de jorro e das modificações com calor-umidade e pressão osmótica nas propriedades do amido da semente de abacate cv. Breda.

Abstract

The present work aimed to extract starch from avocado seeds and evaluate the impact of drying temperatures (50, 60, 70 and 80 °C) in a spouted bed and the effect of single and double modifications by heat-moisture (HMT) and osmotic pressure (OPT) regarding the physicochemical, physical and functional, textural, morphological (SEM), structural (XRD and FT-IR) and thermal (DSC) properties of starch. The results demonstrated that spouted bed drying is an alternative and viable technique for drying avocado seed starch pastes (yield between 52.3-58.5%), however, the process conducted at 70 °C is stood out for presenting the highest contents of starch, amylose and amylopectin, good flow characteristics and swelling power greater than 50%. Furthermore, all samples presented smooth particles, without cracks or cavities, classified as type B, with relative crystallinity between (23.29-24.27%) and without the formation of new functional groups. When evaluating the effect of physical modifications (HMT, OPT, HMT+OPT and OPT+HMT) a reduction in physicochemical and functional, textural, structural and thermal parameters was observed, however, there was an increase in particle diameter when evaluating its morphological aspects, and the combined treatments (HMT+OPT and OPT+HMT) presented the highest values for this parameter. HMT presented the lowest syneresis values, and the OPT treatment presented the highest crystallinity value (23.55%). The samples were classified as type A starch, and there was also no formation of new functional groups after modification, and the combination in the order OPT+HMT presented the lowest intensities among the treatments. Therefore, the spouted bed provides a simple and efficient route for drying starch, ensuring fast and uniform drying. Furthermore, physical modifications by heat-moisture and osmotic pressure are innovative methods to alter the functionalities of avocado seed starch and be directed to suitable food applications, resulting in high-quality final products and superior yield.