Effect of endogenous proteins and lipids on yam flour during radio frequency explosion puffing: Characterization, microstructure, function, and in vitro digestibility.

Radio frequency explosion puffing (RFEP) can improve yam flour properties, in which endogenous proteins and lipids play an important role, but the action mechanism is unclear. In this study, native yam flour was defatted and/or deproteinized and then treated with RFEP. The results indicated that RFEP caused protein covering layers on the starch surface to become loose, and these loose layers interacted with lipids and then rewrapped tightly around the starch surface to form compact matrixes. The existence of lipids prevented the shedding of protein covering layers from starch surface during RFEP. The compact matrixes caused decrease in intermolecular hydrogen bonds and relative crystallinity and changes in structure of protein peptide group and protein amide II bands. The compact matrixes reduced the contact of water molecules and enzyme with starch, inhibiting the gelatinization, swelling, and digestibility. Endogenous proteins had a greater impact on yam flour properties during RFEP. These findings offer new insights for the development of yam flour products and the extensive application of RFEP technology in the food industry.