Preparation and stability of butterfly pea color extract loaded in microparticles prepared by spray drying

Butterfly pea is one of the most interesting sources of natural color used in food and cosmetics. Anthocyanins are the main coloring compounds in its petals and could be extracted easily with water. The pH of medium, temperature, and light were found to affect stability of the color aqueous extract from butterfly pea petals. Acidity and alkalinity of the solvent did not only change shade of the color but also affected the color stability. The color presented the most stable in pH 4 solution under darkness and the least stable in pH 7 solution under UV light. The higher the temperature the more the color loss. In an attempt to improve the color stability, microparticulated system prepared by spray drying technique was employed in this study. Hydroxylpropylmethyl cellulose (HPMC) and gelatin were used as carrier polymers. The operating condition providing optimum production yield was determined using 2 3 factorial design. The factors were % solid in the feed solution, inlet temperature, and solution feed rate. The optimized condition was 5% w/w of solid in the feed solution, 130 I inlet temperature, and 10 ml/min of solution feed rate for both HPMC and gelatin. Color stability of the microparticulated particles was studied under heat and UV light. Gelatin microparticulated system presented better protection against UV light than HPMC microparticulated system and aqueous color solution. Therefore, polymer type should be carefully selected for preparing the microparticulated particles. However, no protection against thermal degradation was observed in both gelatin and HPMC microparticulated systems.