Processing and stability of carotenoid powder from carrot pulp waste

Carrot pulp waste was used as raw material for processing carotenoid powder by spray-drying, and the stability of carotenoid in the powder was studied under light and dark storage at various temperatures. The various carotenoids were analyzed by HPLC with photodiode array detection. Results showed that the most appropriate condition for processing carotenoid powder by spray-drying consists of 15% solid content of feed, with inlet air temperature of 135-145 degrees C and outlet air temperature of 90-100 degrees C. The total amount of all-trans plus cis forms of lutein, alpha-carotene, or beta-carotene in the carotenoid powder decreased with increasing storage time and temperature, and the degradation rate of each fits the first-order model. The major cis isomers formed in the dark were 13-cis-alpha-carotene and 13-cis-beta-carotene, whereas 9-cis isomers of both alpha- and beta-carotene predominated under light. A high correlation was also observed between color changes and carotenoid content.