<i>Moringa oleifera</i> leaf powder colour improvement and lipoxygenase inactivation by different pHs and water-blanching times

Moringa oleifera (MO) leaf powder (MOLP) is a health-functional food ingredient, but the drawbacks are unpleasant colour and flavour contributed by lipoxygenase activity. This study aimed to evaluate the effect of blanching times and pHs on colour improvement, lipoxygenase activity, and phytochemicals of MOLP. The fresh leaves of MO were blanched for 2, 4, 6 min at pH 4–10. The results showed that the appearance of blanched MOLP was greener and darker than non-blanched powder, indicating by higher -a and L values. Acidic pH-induced chlorophyll degradation and alkaline pHs produced lower pheophytin. The composition of chlorophyll and its derivatives resulted in various colour values. Lipoxygenase activity remained high at pH 7, but it was greatly reduced at acidic pH or alkaline pH of 7–9. The identified phytochemical number was affected by pH. The phytochemicals characterized in MO leaves, moringin, mamuroside A, and mamuroside B were still present after blanching.