Structural and functional properties of raw and defatted flaxseed flour and degradation of cynogenic contents using different processing methods

Flaxseed contains valuable nutritional composition with functional and bioactive properties. These characteristics make flaxseed an attractive source of functional ingredient for the preparation of foodstuffs. An extensive comparative study was conducted using raw and defatted flaxseed flours (DFF), investigating their functional properties, antioxidant potential (ABTS, DPPH, and FRAP assays), thermal properties by differential scanning calorimeter, microstructure by scanning electron microscope (SEM), and Fourier transformed infrared (FTIR) spectroscopic analysis. Flaxseed flour contains a considerable amount of cyanogen glycosides that have certain harmful effects on human health. Therefore, different processing methods (microwave processing, water boiling, autoclaving, soaking, solvent extraction, and ultrasound-assisted detoxification) were compared to reduce this harmful compound in DFF. As seen in results, significant increase in proximate composition was observed in DFF. Similarly, DFF showed better antioxidant activity and functional properties. FTIR spectra revealed that the characteristic peaks associated with protein and carbohydrates were more prominent in DFF. Additionally, all tested detoxification methods significantly depleted HCN content. Among all, water boiling method found to be higher in reduction of HCN content followed by ultrasound assisted detoxification method. These findings revealed that DFF possess good nutritional, functional, and antioxidant properties, suggesting the potential application as a functional ingredient and as a supplement in foods. Practical Applications Flaxseed has been considered as a rich source of oil, protein and other beneficial components. The presence of cyanogenic components (mainly HCN) limits its application in food products. Therefore, the current study is conducted with a view of providing beneficial knowledge concerning potential applicability of flaxseed flour on industrial scale. It will also be supportive for establishing strategies to reduce HCN content from DFF and subsequently providing a safer toxin free flour with high nutrition value that could supplement other cereal or tuber flours.