Preparation and characterisation of an easily absorbabl Mg-casein hydrolysate complex produced through enzymatic hydrolysis and ultrafiltration

Abstract In this study, we synthesised a Mg-casein hydrolysate complex that allowed the effective absorption of Mg. The type of enzyme (papain, alcalase 2.4 L, pepsin, trypsin) and the enzyme/substrate ratio for casein hydrolysis was optimised. When the enzyme/substrate ratio was 30%, the alcalase 2.4 L-hydrolysate showed the highest Mg-chelation efficiency, of 96.1%. To characterise and enhance the function of casein hydrolysate, we fractionated the casein hydrolysate according to molecular weight using ultrafiltration. The Mg-chelation efficiency was increased with the decrease in the molecular-weight range of the hydrolysate fractions. The smallest casein hydrolysate (fraction 5, 1 kDa<) is used for preparation of Mg-casein hydrolysate complex. Synthesised Mg-casein hydrolysate complex (fraction 5) exhibited 100% Mg solubility and 39.5% Mg bioavailability. These results indicated that the Mg-casein hydrolysate remained a stable chelate during simulated gastro-intestinal digestion in vitro. The Mg-casein hydrolysate complex exhibited excellent antioxidant activity as well as Mg binding.