Sweet Potato Protein Hydrolysates Solidified Calcium-Induced Alginate Gel for Enhancing the Encapsulation Efficiency and Long-Term Stability of Purple Sweet Potato Anthocyanins in Beads

Abstract

Based on the previous research, this work aimed to reveal the effect of sweet potato protein hydrolysates (SPPHs) with different molecular weights (1000, 3000, and 8000 Da) at 0.5% on the gelation behavior of calcium-induced sodium alginate (SA), and the encapsulation efficiency and storage stability of purple sweet potato anthocyanins (PSPA) in calcium-induced alginate gel beads was determined. Results indicated that SPPHs with a molecular weight of 8000 Da significantly strengthened the gel and filled its pores effectively. The effect of SPPHs added at 0.5% was more effective than that at 0.25% of the same molecular weight. The highest encapsulation efficiency was achieved at 87.27%, compared to 61.73% without SPPHs. Additionally, stored at 37℃ for 21 days after commercial sterilization, the residual concentration of PSPA with SPPHs was 2.50 times higher than that without SPPHs. SPPHs can enhance the encapsulation efficiency of PSPA and retard their release in gel beads.

Keywords: sodium alginate, sweet potato protein hydrolysates, purple sweet potato anthocyanins, encapsulation efficiency, long-term stability