DEGRADATION KINETICS AND COLOR STABILITY OF SPRAY-DRIED ENCAPSULATED ANTHOCYANINS FROM HIBISCUS SABDARIFFA L.

Dry powder of red color from roselle calyces, which can be used as natural colorant and functional food ingredient, was produced using microencapsulation technique. Four different matrices, i.e., maltodextrin, gum Arabic, combination of maltodextrin and gum Arabic, and soluble starch were used for encapsulation study. Identification and measurement of anthocyanins in encapsulated roselle was made by high-performance liquid chromatography. Encapsulation efficiencies were determined and compared with storage analysis data. The stability of encapsulated pigments was investigated during storage under three different storage temperatures (4, 25 and 37C) until 105 days. The four type of matrices largely increased the half-life of the pigments during storage especially at 37C (P < 0.05) compared with the non-encapsulated roselle extract. Storage temperature did not significantly (P > 0.05) effect the L*, a* and b* values. However, type of encapsulation agent and storage time significantly (P < 0.05) affected the color changes. The L* and a* values were decreased during storage whereas the b* value was increased. Combination of maltodextrin and gum Arabic showed the highest encapsulation efficiencies (99.87 +/- 0.04%), lower degradation rate in 4C (3.7 +/- 0.3) and had smaller changes in a* and b* values among the four matrices. PRACTICAL APPLICATIONS A spectrum of natural, red-hue primer colorants derived from roselle plant extracts, substantially free of alkaloids, enzymes, aroma or solvent residuals, and microencapsulated to ensure good stability and shelf life. This study measures the storage stability and suitability of the microencapsulated natural colorants. The colorants are for functional use in the food, pharmaceuticals, cosmetics and other industries.