Nutritional composition and antioxidant potential of different seed parts of Nigerian Malabar chestnut (Pachira glabra Pasq.)

Aim: Malabar chestnut seed from Nigeria is an underutilized seed in Africa that possesses different nutritional, functional, and medicinal characteristics. Nevertheless, there is no quality information on the antioxidant properties of the embryo, the whole seed, and the seed coat of the Pachira glabra. This research investigated the nutritional composition and antioxidant properties of the Malabar chestnut embryo (MCE), whole Malabar chestnut (WMC), and Malabar chestnut seed coat (MCSC). Methods: The nuts were sorted, and the seed coat was separated from the embryo. This was processed to get the WMC, MCE, and MCSC flours, and they were analyzed for proximate composition, minerals, amino acid profiles, antinutrients, and antioxidant properties. Results: The proximate composition (g/100 g) showed high protein and fat content, total ash (2.50–3.50), crude fiber (2.04–11.43), moisture (3.62–7.93), and carbohydrate (13.29–37.92). The results also showed higher deposition of minerals in the seed coat, with phosphorus (2.82–5.26) and potassium (2.77–4.90) being the most abundant. This indicates that the seed can be used as a supplement for these nutrients. Low lead content was recorded in all samples. The antinutritional compositions were relatively lower in the embryo compared to the seed coat and whole seed. Furthermore, the high ratio of essential amino acids to non-essential amino acids (0.63–0.87), particularly in MCE, positions the seed as a potential high-quality protein source. The antioxidant properties demonstrated a high scavenging power, with a viable level of total phenol (198.65–330.41) mg GAE/g, total flavonoid (30.74–86.49) mg QE/g, as well as ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl). Conclusions: The seed coat and the embryo of the Malabar chestnut showed superior nutritional composition and antioxidant properties; therefore, they can be used for medicinal purposes and as an antioxidant in the management of chronic diet-based diseases.