Enzymatic Debranching and High Hydrostatic Pressure Synergistically Enhance the Encapsulation of Conjugated Linoleic Acid in Lotus Seed Starch Microcapsules for Oxidative Stability

Abstract

Modified lotus seed starch (LS) through enzymatic debranching (ED) and high hydrostatic pressure (HHP) treatment demonstrates enhanced microencapsulation performance for conjugated linoleic acid (CLA). This study systematically investigated the structural and functional modifications of LS under ED treatment (0-12 h) combined with HHP (300-600 MPa). ED treatment induced significant chain-length redistribution, increasing A-chain (15.3% to 24.6%) and B1-chain (42.1% to 51.3%) proportions while decreasing B2 (23.4% to 15.1%) and B3 chains (19.2% to 9.0%). The modified starch (P-LS) exhibited 47.3% higher solubility with reduced swelling power (8.35 g/g) and adhesiveness (2.2 mm). Optimal microencapsulation efficiency (92.7%) and oxidative stability were achieved at 3-6 h ED combined with 300-600 MPa HHP. SEM characterization revealed HHP-induced formation of a porous network structure in P-LS-CLA microcapsules, accompanied by improved thermal stability (ΔH increased by 28.6%) compared to native starch. These findings establish the synergistic mechanism between enzyme modification and HHP processing for developing starch-based delivery systems, particularly highlighting HHP's potential for thermosensitive ingredient encapsulation in functional food applications.

Keywords: Enzymatic debranching, High hydrostatic pressure, conjugated linoleic acid, Starch microcapsules, Oxidative stability