Change in bioaccessible phytonutrients and their bioaccessibility on roasting of whole maize
摘要
Dry heat roasting of maize is a common process that adds convenience. At the same time, roasting could alter the phytonutrients and their bioaccessibility. Therefore, an investigation was conducted to assess the impact of roasting maize at 140 °C on phytonutrients, antioxidant activity and bioaccessibility. The quantity of tocopherols (TP), tocotrienols (TT), and phytosterols was unaffected; methanol soluble and total phenolics, flavonoids and DPPH+ scavenging activity increased, and total carotenoids decreased (p < 0.05) by roasting. The bioaccessible content of α-TP (789 ± 13.44 µg/ 100 g), α-TT (414.03 ± 3.3 µg/ 100 g), γ-TT (408 ± 4.6 µg/ 100 g), δ-TT (31.27 ± 0.45 µg/ 100 g), and flavonoids (25.6 ± 0.5 mg/ 100 g) was higher (p < 0.05) in roasted maize. In contrast, the content of γ-TP, zeaxanthin, β-carotene, and stigmasterol was static in roasted maize. Conversely, the bioaccessible content of δ-TP, lutein, campesterol, and β-sitosterol decreased. The antioxidant activity of the bioaccessible fraction, as measured by reducing power, increased, while total antioxidant activity and DPPH+ scavenging activity remained steady upon roasting. The percentage bioaccessibility of α-TP, α-, γ-, and δ-TT, as well as carotenoids, increased, while it remained constant for γ-TP and δ-TP. In contrast, it decreased for phytosterols, total polyphenols, and flavonoids in roasted maize. Overall, roasting maize at 140 °C retained phytonutrients to a great extent and enhanced both the bioaccessible content and percentage bioaccessibility of phytonutrients, as well as antioxidant activity. Therefore, roasted maize could be used as a functional food ingredient for health benefits.