A Study on the Photo-Stability of Spray Dried Bixin That is Encapsulated with Carbohydrates

Abstract: Bixin is a carotenoid which is extracted from annatto (Bixa orellana). Its main application is as a coloring agent. It consists of conjugating double bonds with a carboxylic end, making it prone to degradation by oxygen, light and heat. This study investigates the light stability of bixin encapsulated with maltodextrin (MD), sucrose and whey by spray drying. MD was added with additives such as carboxymethylcellulose (CMC), gum arabic (GA) and pectin to examine their interaction effects. Two sets of samples were used; one with pure bixin and carbohydrates, and the other, with non-filtered bixin encapsulated with the same set of carbohydrates and a carbohydrate naturally present in the seeds named botanical tissue. The samples were illuminated using a plasma sulfur lamp for a period of 30 days. UV-Visible spectrometer was used to keep track of the degradation. Statistic tests such as Shapiro-Wilk, ANOVA and t-test were used to confirm that the degradation was linear and that they follow first order decay. Quantum yields of photo-bleaching were calculated and compared between samples. Lower the quantum yield, higher the light stability. The presence of carbohydrates significantly improved the stability of bixin in comparison with non-encapsulated samples. The non-encapsulated samples lost their color completely by day 9 while the others lasted till 30 days. Sucrose showed the highest degradation rate in the absence of botanical tissue. Although sucrose and whey showed highest stability towards light in the presence of botanical tissue, the mix of MD and CMC worked better without botanical tissue. Botanical tissue seems to play a complex role in protecting bixin as the results varied with different carbohydrates.