FTIR and multivariate analysis of total phenolic content, antioxidant and anti-amylase activities of extracts and milk of Glycine max L. and Phaseolus vulgaris L.

Abstract

Background: Alpha-amylase is a digestive enzyme which hydrolyses the glycosidic bonds in polysaccharides into monosaccharides. Inhibition of α-amylase can help to retard carbohydrate digestion in the small intestine and decrease blood glucose level. The effect of solvent extraction and milk processing on total phenolic content (TPC), antioxidant and anti-amylase activities, and Fourier-transform infrared (FTIR) spectra of Glycine max L. and Phaseolus vulgaris L. were estimated by Principal Component Analysis (PCA) and Partial Least Squares Structural Equation Modelling (PLS-SEM). Results: The result showed that the aqueous extract of P. vulgaris L. had the greatest antioxidant activity and anti-amylase activity, while the ethanol extract of G. max L. showed the greatest TPC. Interestingly, the milk of P. vulgaris L. seed showed the greatest level of TPC, antioxidant activity and anti-amylase activity. Mixed milk of G. max L. and P. vulgaris L. (8:2 v/v) showed high anti-amylase activity, while the mixed milk (5:5 v/v) showed high TPC and antioxidant activity. The FTIR result showed five wavenumber ranges associated with functional groups of phenolic compounds. Moreover, the PLS-SEM result revealed a significant positive correlation between TCP and FTIR data (β = 0.335, t = 2.112, p-value < 0.05), and between TCP and antioxidant activity (β = 0.346, t = 2.150, p-value < 0.05). Conclusions: The result indicated that the solvent types and cooked beans could affect the biological activities and chemical content. The application of chemical content, biological activities, and FTIR technique combined with PLS-SEM and PCA analysis could discriminate bean types, solvent types, and between raw and cooked beans. How to cite: Thummajitsakul S, Paensanit P, Saeieo T, et al. FTIR and multivariate analysis of total phenolic content, antioxidant and anti-amylase activities of extracts and milk of Glycine max L.and Phaseolus vulgaris L. Electron J Biotechnol 2023;64. https://doi.org/10.1016/j.ejbt.2023.04.001. © 2023 The Authors