Infrared pre-treatment effects on phenolic components, Maillard reaction products, antioxidant, functional and physicochemical properties of linseed flour and linseed cake flour

The linseed flour (LF) and linseed cake flour (LCF) varies in nutritional and functional properties and their comparative evaluation is required for proper utilization. In this study, the physicochemical, functional, and antioxidant properties, phenolic profile and Maillard reaction products (MRP) of LF and LCF were investigated and compared after infrared pretreatment (InP) of linseeds at 140 °C, 160 °C, and 180 °C for 5 and 10 min. The control LF and LCF differed in ash, fat, minerals, phenolic and flavonoid content, bound flavonoids, functional and antioxidant characteristics. The protein, mineral (Mg, Ca, Fe and Zn) and ash contents exhibited decline in LF and increment in LCF upon increasing InP conditions. The MRP, phenolic acids (free protocatechuic, syringic, ferulic, vanillic, chlorogenic and cinnammic acid, bound gallic, caeffic, protocatechuic, syringic and p-coumaric acid), flavonoids (bound epicatechin, free catechin and resveratrol) and minerals (P and Na) increased in LF and LCF upon InP for 10 min at 180 °C. However, the moisture, L*, a* and b* value, emulsifying activity, emulsion stability indexes, potassium, selenium, bound phenolics (vanillic acid, chlorogenic acid, catechin and rutin), total bound flavonoids, soluble tryptophan and available lysine exhibited decline in LF and LCF upon increasing InP conditions. In conclusion, the InP modified functional properties, generated MRP, improved phenolic profile and antioxidant properties of LF and LCF. The InP was suggested for improving nutritional value of LF and LCF for possible functional food applications.