Comparative Analysis of Protein and Prediction of Amino Acids in Different Extracts of Local Spinach Leaves

Abstract

In this study, spinach leaves from the local source have been selected for its comparative analysis of protein concentrations using UV-Visible spectrophotometer in three different solvents viz. double distilled water (ddH2O), ethanol (C2H5OH), and methanol (CH3OH). Different amino acids in different solvents have also been predicted based on the peaks obtained at different wavelengths in UV-region and compared. For the solvent-extraction of spinach, the final spinach: solvent ratio was 1:20 (w/v). Before the insertion of the sample in PC-based double beam spectrophotometer 2206 (Systronics; Bandwidth 1 nm), a solution has been filtered off and the filtrate solution was subjected to the 5 minutes of centrifugation at >4000 rpm value in a centrifugation machine (REMI R-8C) in order to eliminate the possibility of the presence of any interfering particles. Finally, extracted and filtered samples were studied with spectra received as well as absorbance obtained at 280 nm using UV-Visible spectrophotometer. Protein concentration (mg/mL) in spinach dried leaves as determined by the study at 280 nm were 7.430 mg/mL, 6.15 mg/mL, and 4.055 mg/mL in ddH2O, C2H5OH, and CH3OH, respectively while the percentage concentrations were calculated as 0.1486%, 0.1230%, and 0.0811% in ddH2O, C2H5OH, and CH3OH, respectively. Spectral studies for all three solvents showed fairly considerable absorption peaks in the range of 200-400 nm. As per the peak’s studies obtained for the spinach in water, amino acids like tyrosine, tryptophan, and histidine were predicted while for the spinach in ethanol, amino acids like phenylalanine, tryptophan, histidine, and cysteine were predicted and for the spinach in methanol, amino acids like tyrosine, tryptophan, histidine, and phenylalanine were predicted. In this study, the highest protein concentration was found for the water as solvent followed by the ethanol and methanol while methanolic and ethanolic extract showed the maximum amino acids composition.