Effect of various processing techniques on nutritional, techno-functional, structural, and molecular interactions of finger millet (Eleusine coracana)

To determine the impact of anti-nutritional factors, in vitro protein and starch digestibility, in vitro protein bio-accessibility, techno-functional properties, and the structural and molecular interactions of finger millet due to soaking, germinating, fermenting, and a combination of aforesaid processing techniques were assessed with time in this study. Alterations in techno-functional properties were determined as water absorption capacity, water solubility index, oil absorption capacity, paste clarity, swelling power, emulsion activity, emulsion stability, and viscosity. Structural variations and the macromolecular arrangement of processed finger millet flours were assessed by using a Scanning Electron Microscope (SEM) and Fourier Transform Infrared spectroscopy (FTIR). Replicates were taken and their mean and standard deviation were calculated and presented by using SPSS software. Tannin and phytate content showed a reduction pattern in soaking, fermentation and the combination of soaking, germination, and fermentation treatments. However, saponin content increased (p < 0.05) with time in the germinated finger millet samples (2.03 – 2.50%). The most profound in vitro starch digestibility effect was obtained by the combination of treatments (25.45 ± 0.01^e g/100g). Soaking, germination, fermentation, and treatment combination significantly increased (p<0.05) water sorption isotherm and oil absorption capacity compared to the control sample and slightly modified the swelling power, emulsion capacity, and emulsion stability of finger millet flour. The treatment combination greatly improved most of the functional properties compared with each processing technique alone. SEM images of the combination of treatments showed the most uniform structural assembly and particle size distribution of starch granules with the most drastic degradation. In conclusion, the treatment combination has been found as the best way to improve the properties of finger millet flour. The increased levels of these constituents in the processed finger millet flours suggest their potential as functional ingredients in the development of novel bakery products and other food applications.