Effect of processing variables on the stability of β‐Carotenes and xanthophylls of dehydrated parsley

Abstract

AbstractCurled‐ and plain‐leaf parsley were analysed for β‐carotene, xanthophyll and the stereo‐isomers of β‐carotene, before and after various combinations of freezing, blanching, sulphiting and air‐drying. Heating of parsley by blanching or by dehydration of unblanched samples generally resulted in an increased retention of β‐carotene. Dried samples contained a higher percentage of the cis‐isomer and neo‐β‐carotene b but a lower percentage of the all‐trans‐isomer. Freezing unblanched parsley reduced total carotene content 8–13 %. Xanthophyll changes were similar to those for total carotene except that dried samples contained 2–28 % less xanthophyll than fresh parsley. Sulphited samples retained 8–30 % more carotenoid pigments than the non‐sulphited samples. Total β‐carotene of dried parsley stored for 3 months in air and in nitrogen at 22° decreased 10‐15%and 3·5‐10%, respectively, while that stored at –18° showed no change. The stereo‐isomer ratio did not change. Blanching had no apparent effect on carotene stability in storage. Carotene loss in fresh parsley, additional extractions, and enzymic destruction of added carotene were also investigated.