Roasting effect on anti-nutritional factors of the Moringa oleifera leaves

The Moringa oleifera leaves are a preferred feedstock for animal feed, but also for human consumption. They contain anti-nutritional factors that inhibit the bioavailability of its nutrients. Among traditional treatments applied to food, roasting is as easily applicable treatment, which may reduce the anti-nutritional factor and make bioavailable the nutrients. However, these effects on the products depend of the temperature and the treatment duration. Acentered composite experimental design on two factors (temperature: 50-100 ° C, Time: 20-120 min) was use in this work to study the effect of the two parameters on the anti-nutritional factors on the Moringa oleifera leaves. The results show that the time and roasting temperature have a negative influence on the water content, oxalate, phytate and total phenols. With a water content between 6.43 and 14.3%, the contents in phytate, oxalate and phenol of the roasting Moringa oleifera leaves were respectively ranging from 0.15 to 1.87%, 0.54 to 2.4% and from 1.21 to 3.21%. The lower contents oxalate (1.2 ? g/100g DM) were obtained for roasting time greater than 100 minutes at temperatures higher than 90°C and lower than 60°C. In the same way, the lowest contents of phytate (< 0.3g/100g) are obtained for samples roasted during at least 40 minutes at temperatures between 70 and 80°C. Finally roasting Moringa oleifera leaves in excess of 65 ° C for at least 90 minutes gives lower levels of phenols (<1.5% gallic acid).