Xanthan-chitosan (XC) and xanthan-chitosan-xanthan (XCX) were employed for microencapsulation of Bifidobacterium bifidum BB01 using extrusion technique. To optimize the process of B. bifidum BB01 microcapsules based on XC hydrogels, response surface methodology was employed to obtain the best possible combination of chitosan concentration, xanthan-B. bifidum BB01 mixture (XBM)/chitosan, stirring time for the maximum viable count and encapsulation yield. The optimum conditions were: chitosan concentration of 0.84 g·mL-1, XBM/chitosan of 1:9.0, stirring time of 60 min with high viable count and encapsulation yield of 1.52 ± 0.15 × 1010 CFU·g-1, 90 ± 0.65%, respectively. In addition, the effective encapsulation system (XC and XCX) resulted in improvement in survival of B. bifidum BB01 compared to non-encapsulated cells during 3 weeks storage at 4 and 25 °C in pure milk.
Keywords: Box–Behnken design; Xanthan–chitosan; microencapsulation; pure milk.