D-optimal Mixture Design for Optimized Microencapsulation of Vitamin A Palmitate and Its Characterizations

Food fortification is an effective intervention strategy for combating micronutrient deficiencies. Vitamin A can be fortified in a wide range of food vehicles. In this research work, vitamin A in the form of palmitate (VAP) have been microencapsulated by emulsion technology intended for fortification purposes. D-optimal mixture design approach was applied for optimizing the experimental process parameters. Detailed physico-chemical –thermal characterization of the optimized VAP emulsion was done. VAP content was kept constant as per fortification limit. Desirability ramp function graphs and lab experimentations showed maltodextrin (2.5-2.7), OSA starch (1.5-1.6), Tween 80 (1.5-1.7), Span 40 (2.0-2.2) in terms of percentages gave encapsulation efficiency in the range of 98.2-98.8. The optimized VAP emulsion showed particle size in the range of 940-942 nm, polydispersity index 0.41, zeta potential (ζ) value ranging from -31.25 to -32.01 mv; viscosity and interfacial tension was determined to be 1.561±0.03 mPaS and 22.6 mNm−1 respectively. Low temperature DSC studies (-5ºC to 90ºC) of VAP emulsion showed sharp endothermic peaks of vitamin A that disappeared with further elevation in temperature and some flat thermograms of other excipients. The vitamin A content in VAP emulsion was determined to be 88.45±0.03%, the content being reduced to 86.01±0.04% after storage under accelerated conditions (75ºC, 80% RH). The formulated VAP emulsion showed high encapsulation efficiency and significant stability of the emulsion system.