PIGMENT COMPOSITION AND COLOR OF FROZEN AND CANNED KIWI FRUIT SLICES

Qualitative pigment differences between fresh (unripe and ripe), frozen, and canned kiwi fruit slices were determined. Pigments present in fresh and frozen kiwi fruit slices were xanthophylls, chlorophylls and their derivatives, and only one hydrocarbon carotenoid (beta-carotene). The xanthophylls were identified as violaxanthin, neoxanthin, neochrome, auroxanthin, lutein epoxide, and lutein. Neo A and neo B, mono cis isomers of lutein, were observed in the extracts of fresh and frozen slices. The chlorophylls were identified as chlorophyll b and chlorophyll a, and the decomposition product as pheophytin a. The pigment pattern of the canned product showed the formation of zinc complexes, specifically the formation of the metallochlorophyll complexes, Zn-pheophytin a and Zn-pyropheophytin a. Thermal treatment induced the degradation of some xanthophylls, violaxanthin and neoxanthin, to afford neochromes, luteoxanthin and auroxanthin. all-trans-Lutein was accompanied by considerable amount of its 15,15'-isomer in canned kiwi fruit extracts. Large differences in Hunter color value -a (green) were observed between fresh or frozen and canned kiwi fruit slices. Hunter color values of frozen slices approached the color of fresh kiwi fruit.