Assay: loquats are an excellent source of carotenoids and provitamin A. - GreenMedInfo Summary
Carotenoids in white- and red-fleshed loquat fruits.
J Agric Food Chem. 2007 Sep 19;55(19):7822-30. Epub 2007 Aug 21. PMID: 17708644
Laboratory of Fruit Molecular Physiology and Biotechnology, Huajiachi Campus, Zhejiang University, Hangzhou 310029, People's Republic of China.
Fruits of 23 loquat ( Eriobotrya japonica Lindl.) cultivars, of which 11 were white-fleshed and 12 red-fleshed, were analyzed for color, carotenoid content, and vitamin A values. Color differences between two loquat groups were observed in the peel as well as in the flesh. beta-Carotene and lutein were the major carotenoids in the peel, which accounted for about 60% of the total colored carotenoids in both red- and white-fleshed cultivars. beta-Cryptoxanthin and, in some red-fleshed cultivars, beta-carotene were the most abundant carotenoids in the flesh, and in total, they accounted for over half of the colored carotenoids. Neoxanthin, violaxanthin, luteoxanthin, 9- cis-violaxanthin, phytoene, phytofluene, and zeta-carotene were also identified, while zeaxanthin, alpha-carotene, and lycopene were undetectable. Xanthophylls were highly esterified. On average, 1.3- and 10.8-fold higher levels of colored carotenoids were observed in the peel and flesh tissue of red-fleshed cultivars, respectively. The percentage of beta-carotene among colored carotenoids was higher in both the peel and the flesh of red-fleshed cultivars. Correlations between the levels of total colored carotenoids and the color indices were analyzed. The a* and the ratio of a*/ b* were positively correlated with the total content of colored carotenoids, while L*, b*, and H degrees correlated negatively. Vitamin A values, as retinol equivalents (RE), of loquat flesh were 0.49 and 8.77 microg/g DW (8.46 and 136.41 microg/100 g FW) on average for white- and red-fleshed cultivars, respectively. The RE values for the red-fleshed fruits were higher than fruits such as mango, red watermelon, papaya, and orange as reported in the literature, suggesting that loquat is an excellent source of provitamin A.