Changes in carbohydrate, free amino acids, organic acids, phytate and HCl extractability of minerals during germination and fermentation of finger millet (Eleusine coracana)

Finger millet (Eleusine coracana) also known as 'ragi' in India is a source of carbohydrate, protein and mineral that is comparable to other common cereal grains. However, antinutrients like phytate and tannins reduce the nutrient bioavailability which can be improved by suitable processing methods such as germination and fermentation. In our study, the finger millet was germinated (24 h) and then subjected to fermentation (48 h). Major biochemical changes occurred during fermentation (6-18 h) compared to germination (24 h). The processing decreased the pH from 5.8 to 3.8 and increased the total sugars (2-fold), reducing sugars (13-fold) and free amino acids (10-fold). Lactic acid was the predominant organic acid (3.7%). The phytate content decreased by 60% with an increase in HCl-extractable minerals of 47%. The phytate x Ca/Zn molar ratio decreased from 163 to 66.2, indicative of an increased Zn bioavailability. In conclusion, a combination of germination and fermentation is a potential process for decreasing the antinutrient levels and enhancing digestibility.