International Journal of Biological Macromolecules 2012-11-01

Developing an emulsion model system containing canthaxanthin biosynthesized by Dietzia natronolimnaea HS-1.

Seyed Mohammad Taghi Gharibzahedi, Seyed Hadi Razavi, Seyed Mohammad Mousavi

Index: Int. J. Biol. Macromol. 51(4) , 618-26, (2012)

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Abstract

An acceptable strategy to incorporate canthaxanthin (CX) as a natural colorant into products is by means of oil-in-water emulsions. The used CX in this study was produced by bacterium Dietzia natronolimnaea HS-1 using a batch bioreactor system. A central composite rotatable design-response surface methodology (CCRD-RSM) consisting of three-factored factorial design with five levels was applied for analysis of the results to obtain the optimal formulation of emulsions. Three independent variables including fenugreek gum (FG, 0.2-0.5%, w/w), coconut oil (CO, 6-10%, w/w), and CO/CX ratio (10:1-50:1) were transformed to coded values and second-order polynomial models was developed to predict the responses (p<0.0001). The studied independent variables were the stability, viscosity and droplet size properties such as volume-weighted mean diameter (D₄₃), specific surface area (S(v)) and polydispersity index (PDI) of emulsions. The 3-D response surface plot derived from the mathematical models was used to determine the optimal conditions. Main emulsion components under the optimum conditions ascertained presently by RSM: 50:1 CO/CX ratio, 0.49% (w/w) FG content and 6.28% (w/w) CO concentration. At this optimum point, stability, viscosity, D₄₃, S(v) and PDI were 90.6%, 0.0118 Pas, 0.595 μm, 12.03 m²/ml and 1.380, respectively.Copyright © 2012 Elsevier B.V. All rights reserved.