Effects of fermentation time on the chemical composition of condiment (Ogiri-Asala) from Conophour nut (Tetracarpidium conophorum)

Abstract

Oilseeds are a crucial source for plant-based proteins, especially in developing countries where protein intake is often insufficient. The conophor nut, though frequently overlooked, is rich in high-quality protein and oil. The study investigated the impact of fermentation on the chemical composition of Ogiri-asala, a local condiment produced from conophor nut. Conophor nuts were processed and fermented for varying durations (48, 72, and 96 h) to produce ogiri-asala. Proximate composition, mineral contents, amino acid profile, antinutritional factors and sensory acceptability of the samples of ogiri-asala were evaluated. Results showed that fermentation significantly increased protein content from 26.71% to 30.96%. Fermentation also reduced anti-nutrients which included phytic acid, tannin, saponin, and trypsin inhibitor. There was a notable increase in mineral elements such as calcium (325 to 395 ppm), magnesium (385 to 413 ppm), iron (6.6 to 14.0 ppm), and manganese (15.9 to 21.0 ppm). The sample fermented for 96 h (sample HYF) showed the highest value of protein contents, highest macronutrient levels and lowest antinutritional factors. The overall indispensable amino acids and overall amino acids ratio of all the samples (36.46%, 37.50%, 37.62% and 38.01%) were below 39%, nonetheless, sufficient only for children and adult and not infants. The sample fermented for 96 h (sample HYF) was most accepted by the panelists, in terms of aroma, taste and texture. In conclusion, fermentation enhances the nutritional values of conophor nut and the Ogiri-asala produced could serve as an alternative to the conventional ogiri.