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 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.