Preparation and characteristics of yak casein hydrolysate-iron complex

Abstract

The effect of mass ratio between yak casein hydrolysate and FeSO4, reaction temperature, pH and holding time on ferrous-binding capacity of yak casein hydrolysate was investigated. Iron-releasing percentage and structural characteristics of the formed yak casein hydrolysate-iron complex were also examined. Results showed that casein hydrolysates with different hydrolysis degrees (DH) possessed different ferrous-binding capacities with the highest of 7-h hydrolysate. The optimal binding conditions between yak casein hydrolysate and iron are mass ratio of casein hydrolysate to FeSO4 of 15:1 for 20min at 40°C and pH 6.0. The principal binding site for Fe2+ in yak casein hydrolysate consists of the carboxylate groups and amide groups. Compared with ferrous sulphate, yak casein hydrolysate-iron complex has higher iron-releasing percentage at basic conditions, such as pH 7.0, 7.5 and 8.0. Ferrous-iron enriched casein hydrolysate, i.e. yak casein hydrolysate-iron complex, may have great potential as an effective delivery vehicle of bioavailable iron. © 2011 The Authors. International Journal of Food Science and Technology © 2011 Institute of Food Science and Technology.