Influence of pretreatments combined with extrusion on γ-amino butyric acid, nutritional composition and physicochemical properties of foxtail millet (Setaria italica)

Extrusion processing deals with a compromise between better texture and less nutrition. Therefore, present study was conducted to assess the combine effect of pretreatments (germination, fermentation and sonication) and extrusion on γ-amino butyric acid (GABA), total phenolic content, antioxidant activity and physicochemical properties of foxtail millet. The GABA content significantly (P < 0.05) increased in pretreated extrudates whereas highest content was revealed in germinated millet extrudates (7.24 mg/100 g) followed by germinated-sonicated millet extrudates (6.15mg/100 g) as compared to native millet extrudates and native millet flour. Pretreated extrudates maintained higher total phenolic compounds (TPC) and antioxidant activity than native millet extrudates. Among pretreated extrudates, germinated millet extrudates retained highest level of TPC (30.54 mg GAE/g), DPPH scavenging activity (15.51%) and ABTS (2.97 mg Trolox E/g). Moreover, oleic acid, palmitic acid and linolenic acid were increased, while linoleic acid content decreased in pretreated extrudates. Additionally, pretreated extrudates had higher water absorption and solubility index, while lower bulk density was recorded as compared to native millet extrudates. Extrudates obtained from pretreated millet under optimum conditions improved nutritional, functional and physiochemical characteristic. Therefore, this approach may help food industries to develop gluten free and healthy extrudates by incorporating pretreated foxtail millet in human diet.