Effect of processing treatments on the carotenoids composition of dehydrated carrots

Effect of different blanching (steam. water and microwave) and drying (cabinet and fluidised-bed-drying) methods on the stability of total carotenoids in carrots and their composition was studied. Apparant increases in total carotenoids. when expressed on dry weight basis were found to be due to leaching of soluble solids, which ranged from 3.9 to 11.0%. When expressed on total insoluble solids basis, the total carotenoids decreased by 9.9 to 10.6% during blanching operations. Losses of total carotenoids were higher in unblanched carrots as well as in fluidized bed-dried samples as compared to blanched and cabinet-dried ones, respectively. During storage, the losses were higher in fluidized-bed-dried samples than cabinet-dried ones. Also, carotenoid degradation was fastest In water-blanched samples and least in steam-blanched samples. Of the carotenoids, beta-carotene degraded fastest, while lutein degraded slowest during storage. Development of non-enzymatic browning (NEB) during storage was also influenced by the blanching treatments. Water-blanched samples turned brown at the slowest rate, while unblanched samples browned at the fastest rate.