Physicochemical characterization and antioxidant activity of decolorized Moringa oleifera Lam leaf flour

Background: Maringa oleifera leaves are rich in antioxidant substances; however, when lyophilized leaves were used in flour form in meat products, they presented no antioxidant effect and even accelerated the oxidation process of the product. Thus, the objective of this study was to evaluate the effect of chlorophyll extraction on the physicochemical composition and antioxidant activity of Moringa leaves. Methods: Moringa leaves were dried and ground in order to obtain uniform flour. A treatment using chlorophyll extraction (decolorized) was tested versus a control treatment (non-decolorized) for proximate composition, instrumental color, and antioxidant activity using ANOVA followed by Tukey’s test. Results: Higher crude fiber, ash, and protein contents were observed for decolorized flour (19.41 and 38.13%, 11.87 and 14.02%, and 28.81 and 31.33%, respectively) when compared to those for the control. Chlorophyll extraction significantly affected (p < 0.05) the instrumental color of the leaves flour. The half maximal effective concentration (EC50) of both decolorized and control flour was 3.74 and 4.30 mg/L, respectively. The equivalent of antioxidant per gram of non-decolorized leaves was higher than that observed for the decolorized leaves (0.36 and 0.32 g/g DPPH, respectively). The antioxidant activity (AA%) of the extract from non-decolorized leaves was higher in the concentrations of 5 and 2.5 mg/0.1 mL, while the decolorized leaves was higher in the extract concentration 5 and 2 mg/0.1 ml. Conclusion: The decolorization process affected the chemical composition and color of Moringa oleifera leaves flours however did not improve its antioxidant activity.