Nutritional and Techno-Functional Properties of Flours Processed from Dioscorea bulbifera Fermented with Edible Calocybe indica and Pleurotus ostreatus

Abstract

A medicinal and nutritional value product that is underutilised is Dioscorea bulbifera (air yam). Its usage as a potential and functional foods have been compromised due to traditional belief and preparation challenges. This study aimed to enhance the nutritional, functional, and antioxidant properties of D. bulbifera by fermenting it with edible mushrooms, Calocybe indica and Pleurotus ostreatus. The treatment of D. bulbifera bulbils were segregated into four; A control thus unfermented (UDB), submerged fermented (FDB), fermented with C. indica (DBC), and fermented with P. ostreatus (DBP). The phytochemical composition, nutritional composition, protein digestibility, amino acid profiles, starch digestibility, antioxidant activity, colour indices, and functional properties of the samples were evaluated using standard analytical methods. The nutritional and functional qualities of D. bulbifera flours were improved significantly through fermentation. The amino acid phenylalanine and Leucine increased by 15.1 % and 32.5–32.8 % in DBC and DBP respectively as compared to UDB. In addition, the slowly digestible starch (SDS) content rose by 8.3–11.49 % in DBC and DBP as shown in UDB. The functional properties were also elevated in the treatment as compared to the control, with water absorption capacity and water solubility index increased by 131.3 % and 76.1 % in DBP as compared to UDB. However, there was decrease in the Bulk density of the fermented samples implying the flour has low texture. The study suggests that fermented D. bulbifera flours could be used to manage chronic conditions such as diabetes and oxidative stress because of enhanced antioxidant activity observed in the treatment (p < 0.05). Fermenting D. bulbifera flour with edible mushrooms have shown an improvement in nutritional and functional properties of the D. bulbifera flour and could be use as functional food. The study also sought to address nutritional and health challenges in relation to chronic conditions such as diabetes and oxidative stress.