Curcuma longa L. leaves: Characterization (bioactive and antinutritional compounds) for use in human food in Brazil

This study evaluated the physicochemical characterization of Curcuma longa L. leaves with respect to proximate composition, mineral content, the presence of antinutritional factors, content of bioactive compounds and antioxidant capacity, and color measurements of leaves in natura and leaves subjected to microwave drying, oven drying, and freeze-drying methods. The proximate composition showed appreciable levels of protein (39.5 g.100 g−1), carbohydrates (44.74 g.100 g−1), total fiber (34.47 g.100 g−1), soluble fiber (22.65 g.100 g−1), insoluble fiber (11.81 g.100 g−1), ash (13.81 g.100 g−1), and low lipid contents (2.47 g.100 g−1). No cyanogenic compounds were detected in both samples. Freeze-drying stood out as the method that led to the greatest reductions of the bioactive compounds (33.12-73.86%, dry basis) and antioxidant capacity when compared to the leaves in natura. Microwave drying was the preservation method that produced dry leaves with higher content of bioactive compounds and antioxidant capacity. Therefore, microwave drying produced dehydrated Curcuma longa L. leaves with the highest bioactive compounds and antioxidant activity.