Evaluation of proximate composition and antioxidant properties in silk-industrial byproduct

The reeling waste silkworm pupae of Bombyx mori, Antheraea mylitta and Antheraea assamensis generated as silk industrial byproduct in India were evaluated for their proximate composition and antioxidant properties. Protein content was found highest in B. mori (55.87%), followed by A. assamensis (52.65%) and A. mylitta (50.82%) while fat content ranged from 23.45 to 28.66%. On an average, silk industrial byproduct exhibited as much as 466 kcal/100 g of energy. Methanolic pupae extract screened separately for antioxidant capacity revealed relatively stronger scavenging activity on DPPH assay in the order of B. mori (IC50 of 28.40 mu g/mL) > A. assamensis (IC50 of 29.31 mu g/mL) > A. mylitta (IC50 of 40.74 mu g/mL). A positive correlation was found among different antioxidant assays. DPPH was significantly correlated with ABTS radical scavenging activity (R-2 = 0.93, p > 0.05) and reducing power assay (R-2 = 0.99, p > 0.05). Maximum phenolic (12.16 mg catechin/g) and flavonoid (6.57 mg quercetin/g) content was found in MPE of B. mori followed by A. assamensis. Total phenolic content was positively correlated (R-2 = 0.99) with DPPH and reducing power assay. The study elucidates that reeling waste pupae could effectively be utilized as natural antioxidant in the development of protein rich food products rendering it profitable for use in animal feed sectors.