Effect of Fermentation Time on the Functional Properties, Proximate and Anti-Nutrients Composition of Groundnut Hull

This study determined the functional, proximate and anti-nutrient content of fermented groundnut hull flour. 1kg of groundnut hull was sorted, washed, and then soaked in a bucket of 1 litre of water for one hour. A measured weight of 20g of tempeh yeast (Rhizopus oligosporus) was added, thoroughly mixed manually and divided into 7 equal portions (as per experimental design). They were put in plastic buckets, closed at a temperature of 29±2°C and allowed to ferment for 0, 8, 16, 24, 32, 40 and 48 h, respectively. The fermented hulls were dried for 12 h at 60℃, cooled, milled and stored in a high-density polyethylene. The results showed that proximate composition (%) of the samples ranged: moisture content 1.50 - 3.33, ash 2.00 - 4.50, fibre 6.80 - 12.00, fat 0.40 - 3.20, protein 0.50 - 1.24 and carbohydrate 78.53 - 86.00. The moisture content of the sample was significantly (p < 0.05) influenced by fermentation time and the fermented groundnut sample contained higher ash in comparison to the control sample (unfermented). Fermented samples had significantly (p<0.05) higher fiber (8.80 - 12.00%) and protein (0.79 - 1.24%). Functional properties of the samples showed that the water absorption capacity ranged from 1.00 - 1.50 mL/g, oil absorption capacity 0.47 - 2.33 mL/g and bulk density 0.56 - 0.63 g/mL, with high significance differences (p < 0.05) being observed when compared to the unfermented sample. All the samples were high in phytochemicals, tannin 579.94 - 586.87 mg/g and saponin 168.00 - 264.00 mg/g with high significance differences (p < 0.05). The high dietary flavonoid obtained in this study can help in reducing the risk of chronic conditions like cardiovascular disease, cancer, and neurodegenerative diseases. These improvements are essential for various food applications, making it a suitable ingredient for functional foods.