Influence of heat and moisture treatment on carotenoids, phenolic content, and antioxidant capacity of orange maize flour

The aim of this work was to study the effect of heat and moisture treatment (HMT) on carotenoids, phenolic content and antioxidant capacity of ground, orange maize. Total carotenoid content (TCC) of untreated sample (53.39 mg/kg) was 2.2 times higher than measured in treated orange maize f (24.61 mg/kg). The rates of degradation with HMT were in the following order: β-carotene > β-cryptoxanthin > zeaxanthin > lutein. There was a significant interaction between longer heating time and higher moisture content on carotenoid degradation (p < .05). Total phenolic content (TPC) in raw sample (1664.74 mg/kg) was two-fold higher than in treated orange maize (827.89 mg/kg). Ferulic acid was the most abundant and stable phenolic acid in raw and treated orange maize. The antioxidant capacity of orange maize was higher in methanol than in butanol extracts. The highest correlation (0.924) was observed between TPC and ABTS+ scavenging capacity of methanol extracts.

Provitamin A potential of landrace orange maize variety (Zea mays L.) grown in different geographical locations of central Malawi

The provitamin A potential of landrace orange maize from different locations (A, B, C and D) of central Malawi has been evaluated. Physicochemical compositions, color, total carotenoid content (TCC), carotenoid profiles, and oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity as antioxidant capacities of maize were determined. Color values of orange maize had correlations with β-cryptoxanthin (r>0.36). TCC of white and orange maize averaged 2.12 and 59.5 mg/kg, respectively. Lutein was the most abundant carotenoid (47.8%) in orange maize, followed by zeaxanthin (24.2%), β-carotene (16.4%) and β-cryptoxanthin (11.6%). Location D showed the highest levels of lutein, zeaxanthin and antioxidant capacity. Provitamin A content of orange maize met the target level (15 μg/g) of biofortification. Retinol activity equivalent (RAE) from β-cryptoxanthin and β-carotene in orange maize averaged 81.73 μg/100g. In conclusion, orange maize has the potential to be a natural source of provitamin A.