Microencapsulation of microbial canthaxanthin with alginate and high methoxyl pectin and evaluation the release properties in neutral and acidic condition.

Canthaxanthin (CX) is an orange-red keto-carotenoid with high antioxidant activity. This functional pigment is sensitive to oxygen, light, pH and heat. In this study, CX was produced by the Dietzia natronolimnaea HS-1 and was encapsulated in Alginate (Alg) and Alg-high methoxyl pectin (HMP) through O/W/O multiple emulsion/external gelation method to developed resistant microparticles among acidic and neutral pHs. Results showed that initial CX concentration had a significant influence on total CX (TCX), surface CX (SCX), microencapsulation efficiency (EE) and particles size. The highest EE% for Alg (60.21 ± 0.18) and Alg-HMP (70.60 ± 0.68) were obtained with CX initial concentration of 11 and 18 μg/mg, respectively. Alg microparticles showed smaller size compare to Alg-HMP microcapsules. Presence of CX in microparticles and good antioxidant activity was confirmed by FT-IR spectroscopy and DPPH assay, respectively. CX in vitro release was 66% and 49% in acidic condition and 76% and 50% in neutral condition for Alg and Alg-HMP, respectively. Thus, Alg-HMP-CX18 microparticles were selected to be used in both neutral and acidic foods such as milk and fermented milks products as an antioxidant and a colorant agent.