engleski

Bioaccessibility of maize carotenoids as prerequisite for their utilization in egg yolk pigmentation

Yellow maize is recognized worldwide as a source of carotenoids, fat-soluble pigments that contribute to the pigmentation of poultry products and improve their health. At high levels in hen diet, maize is a natural alternative to synthetic pigments in egg yolk pigmentation. Besides carotenoid profile, maize pigmentation potential is determined by the release of carotenoids from the grain matrix and incorporation into micelles during digestion. The aim of the study was to investigate the carotenoid profile and their digestibility and bioaccessibility in commercial maize hybrids. Representative samples of 105 maize hybrids were collected from nine seed companies in the same county in Central Croatia during 2019 season. Carotenoid profile was determined by reversed-phase HPLC method, which was also used to determine the profile of digested and micellar carotenoids in a standardized INFOGEST in vitro procedure mimicking digestion in the stomach and small intestine. Possible relationships between the levels in grain and digested/micellar carotenoids were tested using the SAS statistical package. The tested hybrids showed the following ranges (μg/g DM): 3.47-13.04 for lutein, 4.72- 23.87 for zeaxanthin, 0.30-3.34 for α- cryptoxanthin, 4.47-4.62 for βcryptoxanthin and 0.21-2.09 for β-carotene. The proportions of both digested and micellar carotenoids decreased in the order: lutein>zeaxanthin> β- carotene>βcryptoxanthin>α-cryptoxanthin (on average 62.2, 50.4, 42.5, 32.0 and 30.5% for digested and 52.7, 42.8, 33.6, 26.9 and 25.6% of grain content for micellar, respectively). The amount of both digested and micellar carotenoids increased with increasing content in the grain (r>0.60 for all carotenoids, P<0.0001), indicating that hybrids with higher carotenoid content will have their higher content for absorption and deposition in the yolk. However, the slopes of a linear regression between grain and digested/micellar carotenoids are below 0.5, indicating that the efficiency of digestion and micellarization decreases with increasing content in grain. In conclusion, the variability in the carotenoid profile of the tested hybrids shows a high potential for yolk pigmentation. Lutein and zeaxanthin have high digestion and micellarization efficiency, suggesting that high amounts of these carotenoids could be deposited in the yolk. Less polar α- and β-cryptoxanthin and β-carotene are less bioaccessible but could still contribute to yolk pigmentation.

Laying hens ; Carotenoids ; Bioaccessibility ; Yellow maize

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