Hydrothermal and biocatalytic processes on native cassava flours: behavior of the physicochemical, morphological and pasting properties

Abstract

Dual-modification processing was proposed to alter the structural characteristics and improve the physicochemical and techno-functional properties of native cassava flours. This study aimed to evaluate the effect of hydrothermal and biocatalytic processes on the structural and morphological response of native cassava flour, as well as their effect on the behavior of physicochemical, gelatinization, and pasting characteristics. Native cassava flour was modified by hydrothermal processes of heat-moisture treatment (HMT) or annealing (ANN), or combined treatments of hydrothermal modification followed by a debranching enzyme with pullulanase (ANN-P and HMT-P). The results showed that HMT-P (heat-moisture treatment with pullulanase) and ANN-P (annealing with pullulanase) hydrothermal treatments increased the starch and amylose content in the modified flours. Compared with the ANN treatment, HMT produced changes at the morphological level such as fragmented granules or lacerations on the granular surface and reduced paste viscosity. In turn, both ANN and HMT increased the gelatinization properties, with the peak gelatinization temperature reaching values of 82.04 °C and 84.08 °C, respectively. The decrease in the 1047/1022 cm−1 (OM1) ratio and the increase in the relative crystallinity (RC) indicated that the hydrothermal and biocatalytic treatments altered the semicrystalline order of the modified cassava flours. Treatments HMT and HMT-P (dual modification with pullulanase) improved hydrophilic properties such as water absorption capacity (WAC) and cold-water solubility (CWS) and reduced setback viscosity; therefore, these processing technologies are feasible in the development of modified flours with better capacity for gel formation and reduction of the retrogradation phenomenon.