Oxidized high-amylose starch macrogel as a novel delivery vehicle for probiotic and bioactive substances

Abstract Oxidized high-amylose starch macrogels (OHASMs) were successfully prepared and, for the first time, used as novel delivery vehicles for nutraceuticals. Oxidized high-amylose starch (OHAS) fabricated by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation could crosslink Ca2+, Al3+, Fe2+, Fe3+, Cu2+, Zn2+ and Ba2+. For OHASM, the oxidation degree (DO) of OHAS had great effects on its morphology and controlled release properties except for the variety and concentration of metal ions. OHASM, formed by Zn2+ crosslinking OHAS (DO~90%), was suitable for encapsulating various nutraceuticals, such as hydrophobic and hydrophilic bioactive substances as well as probiotics, evidenced by 62.4%, 77.9% and 88.8% encapsulation efficiency for β-carotene, tea polyphenols and Lactobacillus paracasei, respectively. Furthermore, the outstanding pH-responsiveness and resistance of OHASM against gastric acid, bile salt, and digestive enzymes were demonstrated by swelling and simulative digestive experiments in vitro. The development of OHASM in this study suggests an attractive strategy for designing potential vehicles to encapsulate a variety of nutrients in food industries.