Protection of lipase by self-assembled microgels under high-pressure

Abstract

Chestnut is very susceptible to pests and diseases caused the waste of resources, so achieving a high value of chestnut utilization is imperative. In this study, a novel type of microgels (MGs) was successfully prepared by using chestnut starch (CS) and casein (CA) under high-pressure homogenization. Thermodynamic analyses showed that CS interacts with porous starch (PS) to form the MGs process, and the binding is spontaneous and robust (ΔG<0). Furthermore, ΔH<0 and ΔS<0 indicate that the binding process is exothermic and enthalpy-driven, and the main interaction forces are hydrogen bonding and hydrophobic forces. Molecular docking predicted the lowest binding energy of −2.90 kcal/mol and localized the casein-protein and PS binding within the amino acid sequence residues 20 to 55. Spectroscopy revealed that high-pressure homogenization increases the α-helical and β-folding content of proteins and decreases the randomly curled structure by 58.81%; the CA molecules are more ordered and tightly packed. The MGs can efficiently load lipase and blueberry anthocyanin, significantly improving their stability while realizing slow release in vitro. Compared with casein-chestnut starch microgels, the anthocyanin encapsulation efficiency and loading capacity of casein-porous starch microgels were increased by 55.49% and 49.96%, respectively. Therefore, the MGs have superior biocompatibility and high loading capacity, which can effectively address the challenges of instability and low solubility of traditional bioactive compounds.