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

Sunita Kumari, Pankaj Kumar Chaurasia, Shashi Lata Bharati, Sunita Singh


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.

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Neskovic, M., and Culafic, L. (1988). Spinach (Spinacia oleracea L). In: Bajaj, Y. P. S. (eds) Crops 2. Biotechnology in Agriculture and Forestry, 1988, Vol. 6. Springer, Berlin, Heidelberg. http://–3–642–73520–2_18.

Hedges LJ, Lister CE. Nutritional attributes of spinach, silver beet and eggplant. Crop Food Res Confidential Rep. 2007 Jun;1928.

Murcia MA, Jiménez-Monreal AM, Gonzalez J, Martínez-Tomé M. Spinach. InNutritional Composition and Antioxidant Properties of Fruits and Vegetables 2020 Jan 1 (pp. 181–195). Academic Press.


Food Science. 2007 Jul 1;19(3).

Protein and the Body - Oklahoma State University [Internet]. 2021. Available from:

Meyers LD, Hellwig JP, Otten JJ, editors. Dietary reference intakes: the essential guide to nutrient requirements. National Academies Press; 2006 Sep 29.

Young VR. Adult amino acid requirements: the case for a major revision in current recommendations. The Journal of nutrition. 1994 Aug 1;124(suppl_8):1517S–23S.

Genton L, Melzer K, Pichard C. Energy and macronutrient requirements for physical fitness in exercising subjects. Clinical nutrition. 2010 Aug 1;29(4):413–23.

Institute of Medicine (US). Panel on Macronutrients, Institute of Medicine (US). Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. The National Academies Press, Washinton, D. C., 2005.

Chaurasia PK, Bharati SL, editors. The Chemistry inside Spices & Herbs: Research and Development: Volume I. Bentham Science Publishers; 2022 Apr 13.

Chaurasia PK, Bharati SL, editors. The Chemistry inside Spices & Herbs: Research and Development: Volume II. Bentham Science Publishers; 2022 Apr 13.

Johansson I, Larsson C, Ek B, Kjellbom P. The major integral proteins of spinach leaf plasma membranes are putative aquaporins and are phosphorylated in response to Ca2+ and apoplastic water potential. The Plant Cell. 1996 Jul 1;8(7):1181–91.

Ko SH, Park JH, Kim SY, Lee SW, Chun SS, Park E. Antioxidant effects of spinach (Spinacia oleracea L.) supplementation in hyperlipidemic rats. Preventive nutrition and food science. 2014 Mar;19(1):19.

Nykyforuk A, Fira L, Lykhatskyi P, Pyda V. Experimental research of garden spinach extract as a potential anabolic medicinal product. Pharmacia. 2020 Oct 26;67(4):277–82.

El-Sayed SM. Use of spinach powder as functional ingredient in the manufacture of UF-Soft cheese. Heliyon. 2020 Jan 1;6(1).

Thermo Scientific, Extinction coefficient: A Guide to Understanding Extinction Coefficient with Emphasis on Spectrometric Determination of Protein Concentration, Pierce Biotechnology, USA. 2013, pp. 1 3.

Okoronkwo NE, Mba KC, Nnorom IC. Estimation of protein content and amino acid compositions in selected plant samples using UV-Vis spectrophotometeric method. Am. J. Food Sci. Health. 2017;3:41–6.

Yoshikawa H, Hirano A, Arakawa T, Shiraki K. Mechanistic insights into protein precipitation by alcohol. International journal of biological macromolecules. 2012 Apr 1;50(3):865–71.

Morr CV, Lin SH. Preparation and properties of an alcohol-precipitated whey protein concentrate. Journal of Dairy Science. 1970 Sep 1;53(9):1162–70.

Hayes M. Measuring protein content in food: An overview of methods. Foods. 2020 Sep 23;9(10):1340.



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