High hydrostatic pressure technology promotes the formation of lotus seed starch and epigallocatechin gallate complex: An evaluation of structure and digestive characteristics

The susceptibility of Epigallocatechin-3-gallate (EGCG) to pH changes in digestive juices hampers its potential to regulate the intestinal microecological environment. The study used lotus seed starch (LS) as the embedding carrier and high hydrostatic pressure (HHP) as the non-thermal processing technology to investigate structural changes in LS-EGCG complexes under different pressures and action times, as well as their digestion characteristics. The results indicated that the composite maintained a C-type structure at pressures ranging from 0 - 400 MPa, but the C-type crystal structure disappeared at a treatment pressure of 600 MPa. The swelling and solubility of the complex increased during HHP treatment, while all indexes of pasting properties decreased. Particularly at a pressure of 600 MPa, the pasting properties significantly decreased, indicating enhanced thermal stability and a certain inhibitory effect on aging. The results of in vitro digestion showed that as the intensity of HHP treatment increased, the complex system became more sensitive to digestive enzymes and resulted in an enhanced release of EGCG during digestion. Notably, at 600 MPa for 90 minutes, the intestinal delivery efficiency of EGCG was significantly improved. These findings provide a research foundation for enhancing the bioavailability of EGCG and developing functional prebiotics containing polyphenols. High hydrostatic pressure (HHP) promoted the interaction between lotus seed starch (LS) and EGCG.As the pressure increased and the treatment time increased, the degree of LS gelatinization increased, and the ability to load EGCG increased. The formation of LS-EGCG complex promoted the intestinal delivery efficiency of EGCG, which was beneficial to the improvement of EGCG bioavailability. • HHP facilitated the interaction between LS and EGCG. • The impact of treatment intensity on complex's structural evolution was studied. • The 600MPa condition can effectively promote the binding of LS to EGCG. • HHP treatment improved the EGCG intestinal delivery efficiency.