Abstract: Polymerized whey protein (PWP), a thermally induced polymer, has good film-forming properties and gel properties. In this study, we attempted to fabricate microcapsules containing tartary buckwheat flavonoids with PWP as the wall material by piercing-solidifying incuber method. The optimization of process parameters for improved microencapsulation efficiency was done using one-factor-at-a-time method and response surface methodology. It turned out that the optimal experimental conditions were as follows: ratio of core to wall materials, 1:9.24 (g/g); concentration of CaCl2, 1.43% and stirring time, 52.23 min. Under these conditions, microcapsules with microencapsulation efficiency of 92.85%, drug-loading efficiency of 9.29%; and moisture content of 7.10% were obtained as spherical particles with a loose and porous surface. The microencapsuled tartary buckwheat flavonoids had good sensory quality, storage stability and sustained release capacity. It was rarely released in the gastric juice environment but exhibited good release performance in the intestinal environment. Thus, PWP could be used in the food industry as a novel microcapsule wall material.

Key words: polymerized whey protein, tartary buckwheat flavonoids, microcapsules, sustained release