Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation.

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

Physicochemical, in vitro antioxidant and cytotoxic properties of water-soluble chitosan-lactose derivatives.

In this study, water-soluble chitosan (Ch) derivatives were synthesized by the Maillard reaction between Ch and lactose. The Ch derivatives were characterized by FT-IR, 1H-NMR and SLS to determine their structure, degree of deacetylation (DD), and molecular weight (Mw). The solubility at physiological pH, the in vitro antioxidant activity against hydroxyl radical, anion superoxide radical and ABTS cation radical, and the cytotoxicity against epithelial cells of the rat ileum (IEC-18) were also evaluated. The Maillard reaction, derivatives with lower Mw and DD and greater solubility than Ch were obtained. The biological properties of the derivatives were dependent on the concentration, Mw and DD, with antioxidant activity greater than or equal to that of Ch and non-cytotoxic in a wide range of concentrations. The results indicate that Ch derivatization with lactose produces new water-soluble polysaccharides, with antioxidant activity and non-cytotoxic, which can be used as biomaterials for food and pharmaceutical applications.