Analysis of rancidity characteristics of different foxtail millet flour during accelerated aging storage

Although foxtail millet is popular for its rich nutritional components and climate-resilient advantages, the influence of rancidity on the changes in the quality of foxtail millet flour remains unclear. Herein, an accelerated aging storage experiment was conducted in this study to analyze the physiochemical parameters of lipid hydrolysis and lipid oxidation, and the change in surface morphology and flavor of three foxtail millet flour varieties. Results showed that the fatty acid value of foxtail millet flour significantly increased during storage. Lipid peroxides and carbonyl compounds were formed by lipid oxidation, which altered the flavor of foxtail millet flour. Among these, hexanal, benzaldehyde, Z-2-heptenal, and heterocyclic compounds were the main volatile compounds that contributed to the rancid flavor. Physicochemical indexes including fatty acid value, activity of catalase and lipoxygenase and flavor profile including volatile compounds were the main factors contributing to differences in rancidity characteristics in foxtail millet flour. This study indicated that the fat rancidity is the main reason for the quality deterioration of foxtail millet flour during storage, and JG-49 showed significantly different rancidity characteristics compared with other millet flour varieties, providing important references for extending the shelf life and developing other new products of millet flour.