Protein Determination and Soluble Amino Acids Prediction in Various Solvents Extracted Solutions of Indigenous Red Lentil and Moong Pulse through Direct UV- Visible Spectrophotometer Technique: A Comparative Study
In this comparative study, direct protein determination have been done for indigenous Red lentil (Lens culinaris) and Moong pulse (Vigna radiata) (obtained from Muzaffarpur, Bihar) by UV-Visible spectroscopy in three different solvents viz. double distilled water (ddH2O), ethyl alcohol (C2H5OH), and methyl alcohol (CH3OH). A few amino acids in solutions have also been predicted (not characterized) based on their peaks observed in UV-region by comparing them with reported range of wavelengths. Protein concentrations in red lentil for ddH2O, C2H5OH, and CH3OH extracted solution were 7.480, 1.205, and 0.835 mg/mL, respectively. While, in case of moong pulse, protein concentrations in ddH2O, C2H5OH, and CH3OH extracted parts were 6.415, 1.150, and 3.485 mg/mL, respectively. In both cases, ddH2O extracted part showed highest concentration of proteins while red lentil showed higher concentration in C2H5OH followed by CH3OH and moong pulse showed higher concentration in CH3OH followed by C2H5OH. During comparison with known wavelength ranges for amino acids peaks, red lentil in ddH2O showed peaks for cysteine, phenylalanine, tryptophan, and tyrosine; in C2H5OH peaks were only for cysteine and traces of phenylalanine; while in CH3OH, peaks were for cysteine, phenylalanine, tryptophan, and tyrosine. Whereas, moong pulse in ddH2O showed peaks for cysteine, phenylalanine, tryptophan, and tyrosine; in C2H5OH and CH3OH peaks were observed only for cysteine and phenylalanine. This method concludes that local pulses are rich in protein and amino acids and aqueous solutions showed highest protein concentration in each case. This direct method of protein quantitation is effective in the determination of protein at wavelength 280 nm as well as prediction of a few amino acids based on their specific peaks in UV-region.
