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

Abstract

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 β-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 β-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 β-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.