Effect of Processing on Major Carotenoid Levels in Corn (Zea mays) and Selected Vegetables: Bioavailability of Lutein and Zeaxanthin from Processed Corn in Mice

Corn and vegetables are good sources of vitamins, minerals, and carotenoids. This study reports (1) the effect of processing-blanching, drying, and milling on major carotenoids-lutein (L), zeaxanthin (Z), and beta-carotene levels in corn (Zea mays), onion stalk (Allium cepa L), broccoli (Brassica oleracea L), and capsicum (Capsicum annum L), and (2) the bioavailability of L and Z from processed corn in mice. A group of mice were fed with diet containing processed or unprocessed corn (L + Z source) or purified L (control) for 3 weeks. Results from HPLC analysis indicate that the levels of L + Z (19.6-118.5%) and beta-carotene (1-84%) were higher in blanched samples compared to fresh samples whereas drying resulted in lower L + Z level in onion stalk (45.5%) and capsicum (36.4%) and was higher in corn (22%) and broccoli (14%) over blanching. The level of beta-carotene was slightly higher in broccoli on drying than blanching. Milling did not alter carotenoid levels in any of the samples. Feeding processed corn (blanched + dried + milled) resulted in nonsignificant change in the plasma L + Z level but significantly higher in liver (58.7%) than in control group. Similarly, the level of L + Z in plasma (12.1%) and liver (14.9%) of mice fed on processed corn was higher compared to unprocessed-corn-fed group. Based on the above results, it is concluded that the extractability and bioavailability of L + Z can be improved by blanching corn before its consumption.