BACKGROUND: New varieties of fruits and vegetables, with higher carotenoid levels, are being developed to improve the potential health benefits to consumers. To assist the development of a new variety of high zeaxanthin sweetcorn, an analytical screening method was developed, including chromameter measurement of hue angle and optimized extraction for HPLC, and applied to 385 lines of a breeding population and six commercial varieties.
RESULTS: Saponification had no effect on carotenoid extraction. In the breeding population, carotenoid levels had a wide range with the highest levels of zeaxanthin being 11.9 mg kg-1 fresh weight, which was at least six times greater than the tested commercial varieties. The regression of hue angle versus zeaxanthin was described by the equation, hue angle = 76.16 + 4.50 × exp(-0.24 × zeaxanthin) + 11.73 × exp(-0.24 × zeaxanthin), r2 of 0.59. The top 6% of lines, with regards to zeaxanthin (zeaxanthin + -cryptoxanthin + -carotene) and total carotenoids, all had hue angles 84.1°.
CONCLUSION: The use of a hue angle of 85° as a maximum cut-off for liquid extraction will allow for much increased efficiency in screening further germplasm for high zeaxanthin lines. There appears to be significant opportunity to further increase the zeaxanthin concentration by selecting for lines which preferentially channel carotenoid synthesis towards zeaxanthin.
Journal of the Science of Food and Agriculture (2010) 90 (1) 91-96 [doi: 10.1002/jsfa.3787]