Storage stability and in vitro release characteristics of black rice anthocyanins microencapsulated by pectin and sodium carboxymethyl cellulose

Abstract

To improve the stability of black rice anthocyanins (ANS), microcapsules based on ANS, pectin, or/and sodium carboxymethyl cellulose (CMC) were successfully prepared. The encapsulation efficiency (EE), FTIR, color, storage stability, antioxidant activity, and release character of encapsulated anthocyanins during in vitro digestion were determined. The results indicated that the EE using pectin, CMC, and pectin/CMC were 81.6 ± 0.3%, 70.4 ± 0.4%, and 79.4 ± 0.2%, respectively. The microcapsules showed a red-purple color, and the interactions between ANS and pectin/CMC were confirmed by FTIR analysis. The retention rate of anthocyanins was 53.8%, 58.7%, 75.6%, and 85.2% in the sample of ANS, pectin, CMC, and pectin/CMC microcapsules, respectively, after 60 days of storage. Furthermore, encapsulation also decreased the loss of antioxidant activity of ANS, and the pectin and CMC combination at a ratio of 1:1 showed a better protective effect than the individual using of pectin or CMC. The in vitro release experiments revealed that the ANS was majorly released in the intestine, and the release rate in pectin microcapsules was lower than that in CMC microcapsules. In conclusion, compared with the individual wall material, microencapsulation using the combination of pectin and CMC improved the storage stability to protect against the degradation of ANS.