Immobilized transglucosidase in biomimetic polymer–inorganic hybrid capsules for efficient conversion of maltose to isomaltooligosaccharides

Isomaltooligosaccharides (IMOs) are relatively new functional food ingredients which have great potential to improve the quality of many foods due to their low calories, no cariogenicity and safety for diabetics. To convert maltose to IMOs efficiently, α-transglucosidase was immobilized in a kind of alginate–chitosan–calcium phosphate hybrid capsules (Alg–Chi–CaP), which were prepared through a facile bio-inspired mineralization process. The surface morphology of Alg–Chi–CaP capsule and alginate–chitosan capsule (Alg–Chi) was characterized by scanning electron microscopy (SEM). Due to the presence of inorganic shell, immobilization efficiency of transglucosidase in Alg–Chi–CaP capsules was higher than that in Alg–Chi capsules. The optimal temperature (60 °C) and pH (6.0) value for enzymatic conversion catalyzed by transglucosidase immobilized Alg–Chi–CaP capsules were identical to those catalyzed by free transglucosidase. As compared to the free enzyme, transglucosidase in Alg–Chi–CaP capsules exhibited significantly higher recycling stability and storage stability in a broader temperature and pH range.