Composition and Antioxidant Properties of Guanacaste (Enterolobium cyclocarpum) Fruit: A Promising Legume

Background: Legumes are a significant part of the diets of numerous regions worldwide. However, only a limited number of species are cultivated, traded, and consumed. Guanacaste (Enterolobium cyclocarpum) remains underutilized and insufficiently studied. Objective: This research aims to assess the nutritional composition and antioxidant properties of this undervalued legume. Methods: Physical characterization, proximate analysis, and quantification of phenolic compounds, flavonoids, and antioxidant activity were performed on both the pods and seeds to explore their potential for human consumption. Results: The pod pulp had 59% soluble solids, a pH of 5.6, a notable content of total phenolics (1826.62 mg GAE/100 g) and flavonoids (165.75 mg QE/100 g), and high antioxidant activity (129, 113 and 156 μmol TE/g, by ABTS, DPPH and FRAP, respectively). The seed showed high protein content (34.5%), and a good level of phenolics, flavonoids, and antioxidant capacity (427.97 mg GAE/100 g, 160.69 mg QE/100 g, and 28.20 μmol TE/g, respectively). Both the pod and seed extracts exhibited more than 89% chelating activity (IC50 of 0.017 and 0.037 mg/mL, respectively). HPLC analysis identified catechin, epicatechin, p-coumaric acid, rutin, and quercetin in the pod; while gallic acid, catechin, epicatechin, p-coumaric acid, rutin, and quercetin were found in the seed. Pods and seeds presented significant amounts of dietary fiber (28.9% and 17.5%, respectively), and, regarding sugar content, sucrose predominated, followed by fructose and glucose. Conclusions: These findings suggest that this legume has potential for commercial exploitation as a functional food, which would result in economic benefits for the communities that produce it.