Studies on the interactional characterization of preheated silkworm pupae protein (SPP) with anthocyanins (C3G) and their effect on anthocyanin stability

In this paper, the interaction of silkworm pupae protein (SPP) with cyanidin-3-O-glucoside (C3G) was studied the protective anthocyanins stability. Characterization experiments suggested that C3G-SPP complexes mainly through hydrophobic interactions, with a decrease in the α-helix content and increases in the β-sheet and β-turn contents. Fluorescence results revealed that C3G quenched the intrinsic fluorescence of SPP by static quenching. The highest quenching constant, Kq, was recorded to be1.26 × 1012 M−1s−1 for the SPP preheated at 80 °C. Following the C3G-SPP complexes, the degradation rate constant decreased, and the half-life of C3G was prolonged from 64.81 ± 1.07 to 261.99 ± 13.32 min at 80 °C (p < 0.05). The SPP preheated at 80 °C exhibited the highest binding affinity towards C3G and also effectively increased the thermal and oxidative stability of the C3G. The obtained results suggest that the novel protein proposed in this study could expand the application of anthocyanins as stable, functional food ingredients.