Effect of detoxification on the functional and nutritional quality of proteins of karanja seed meal

Meal from karanja, an unconventional oilseed, is a good source of proteins (33.2%). The presence of anti-nutritional constituents, such as phytates, tannins and protease inhibitors, glabrin and karanjin (a furano-flavonoid) is a formidable constraint. The effects of various treatments on the “functional and nutritional” quality of the proteins were evaluated. Treatments, such as water leaching, mild acid and mild alkali were found to bring down the levels of anti-nutrient components, while 2% hydrochloric acid improved the nutritional value by reducing the content of phytate (81%), tannin (69%) and trypsin inhibitor activity (84%). Effective removal of the residual oil from the meal ensured complete reduction of karanjin, a fat-soluble constituent. The functional characteristics of proteins are affected with respect to solubility at various pH values from 2 to 11. There is a decrease in water and fat absorption capacities (50% and 35%). Emulsification capacity is found to reduced by 50% while the foam capacity decreases drastically (>60%). The available lysine content (3.46%) in acid-treated meal was comparable with the control (3.6%). The amino acid composition of the meal was not affected by the treatments. The protein digestibility corrected amino acid score (PDCAAS) of the meal was 0.6. Detoxification methods may potentially lead to effective value addition to these agro-resources.