Bioactive Composition and Free Radical Scavenging Activity of Fresh Orange Maize Hybrids: Impacts of Genotype, Maturity Stages, and Processing Methods

Abstract

Bioactive compounds in foods are responsible for their biological activities, but biotic and abiotic factors may influence their levels. This study evaluated the impact of three genotypes (designated 4, 5, and 7), maturity stages (20, 27, and 34 days after pollination) and processing methods (hydrothermal and dry-heating) on the bioactive constituents (carotenoids, phytate, tannins, vitamin C) and 2,2-diphenyl-2-picrylhydrazyl radical (DPPH*) scavenging activity of fresh orange maize hybrids. Freshly harvested maize cobs of each genotype were subjected to hydrothermal processing at 100°C and dry-heating with husks and without husks. Carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and total β-carotene) contents of fresh and processed samples were analyzed using HPLC; other bioactive constituents and DPPH* scavenging ability were determined using spectrophotometric methods. Genotype had a significant effect on the levels of carotenoids (p < 0.001) and vitamin C (p < 0.05), while genotype (p < 0.001), and processing methods (p < 0.001) had significant effects on DPPH* SC50. Maturity stages, processing methods and their interaction also had significant effects (p < 0.001) on the levels of all the bioactive constituents. A positive moderate to strong correlation was observed between (p < 0.001) α-carotene and the following: lutein (r = 0.57), β-cryptoxanthin (r = 0.69), total β-carotene (r = 0.62). However, the relationship between α-carotene and zeaxanthin was positive but weak (r = 0.39). A positive moderate correlation (p < 0.001) was observed between lutein and the following: β-cryptoxanthin (r = 0.57), total β-carotene (r = 0.58), and zeaxanthin (r = 0.52). A positive strong correlation (p < 0.001) was observed between β-cryptoxanthin and each of total β-carotene (r = 0.92) and zeaxanthin (r = 0.63); total β-carotene and zeaxanthin (r = 0.65); while the association between vitamin C and DPPH* SC50 was negative and weak (r = −0.38). Generally, genotype 4 and harvesting at 34 days after pollination had the best combination of bioactive constituents and DPPH* scavenging ability.

Bioactive components, enzymes inhibitory and antioxidant activities of biofortified yellow maize (Zea mays L.) and cowpea (Vigna unguiculata L. Walp) composite biscuits

“…This ability of the flours and biscuits to inhibit α-glucosidase more than α-amylase suggests that the side effects that characterize the clinical use of acarbose, such as flatulence and abdominal distention, which stem from acarbose's stronger inhibitory effect on α-amylase than on α-glucosidase (Dalar and Konczak, 2013, may not occur in the case of the flours and biscuits. Alamu et al (2021), the YM used in this study had a lower DPPH * SC50 of 52.83 μg/mL (0.05 mg/mL), indicating a stronger DPPH * scavenging activity. Similarly, the DPPH * SC50 of the CP in this study (33.89 μg/mL) is lower than the DPPH * IC50 (48.2 ± 1.9 μg/mL) earlier reported for cowpea flour by Sreerama et al (2012).…”

Antioxidant and Starch-Hydrolyzing Enzymes Inhibitory Properties of Striga-Resistant Yellow-Orange Maize Hybrids

“…The antioxidant properties of the bioactive components, especially the phenolic constituents (flavonoids and tannins) in the Striga-resistant yellow-orange maize hybrids, may also prevent and/or decelerate the oxidative degradation of some endogenous nutrients in the maize that are highly prone to oxidation, such as unsaturated fatty acids and vitamins [16]. Furthermore, the bioactive components in the Striga-resistant yellow-orange maize hybrids may reduce the rate at which some toxic oxidative products are formed, thus maintaining the nutritional quality and extending the shelf-life of food products [26] made from them.…”

Effect of Endogenous Lipids and Proteins on the Antioxidant, in vitro Starch Digestibility, and Pasting Properties of Sorghum Flour

“…The polyphenolic compounds (tannins and flavonoids), for instance, are prominent for their anti-inflammatory, anti-cancer, anti-microbial, anti-Alzheimer's, anti-allergic, anti-diabetic, and anti-hypertensive activities among other health benefits ( 8 , 35 ). Furthermore, the antioxidant properties of these bioactive constituents, especially the phenolic compounds, prevent the oxidative degradation of some nutrients that are highly susceptible to oxidation, such as vitamins and unsaturated fatty acids ( 36 ), and retard the formation of some toxic oxidative products, thereby maintaining the nutritional quality and extending the shelf-life of food products ( 35 ).…”

“…Thus, the ability of the control sorghum flour to chelate Fe 2+ suggests that it can retard and/or inhibit Fe 2+ -catalyzed production of free radicals and ROS, thereby preventing the oxidative damage of biomolecules ( 42 ). In addition to the protective effects of the antioxidant activity of the control flour on the cellular biomolecules, it also helps in preserving some endogenous nutrients from oxidative degradation ( 36 ).…”