Comparative Foodomic Profiling of Free Amino Acids in Stem and Root of Rubus idaeus L. and Rubus caesius L. Using HPLC

Abstract

Objective: The present work was to comparatively determine the free amino acid content in stem and root of Rubus idaeus L and Rubus caesius L using high-performance liquid chromatography [HPLC] and the application of this material in terms of biologically active components of functional and nutraceutical foods.
Materials And Methods: The stem and root organs [above-ground and underground] of plants Rubus idaeus L and Rubus caesius L, which grow in the Fergana region of Uzbekistan, were collected, cleaned, dried in shade and ground. Free amino acids in proteins were precipitated by 20% trichloroacetic acid [TCA], and the extracted amino acids were derivatized with phenylisocyanate [to phenylthiocarbamyl derivatives, PTC] then analyzed by high-performance liquid chromatography on the diode-array detection system with the column Discovery HS C18. Amino acids were identified and quantified using retention time [RT] based on the established chromatographic conditions using a standard mixture of amino acids. The quantitative estimation of amino acids was carried out by comparison of peak areas using standard amino acid mixtures under similar conditions. Results are expressed as the average ± standard deviation [SD] [n = 3].
Results: Based on the conducted HPLC analysis, 20 free amino acids were identified in plants Rubus idaeus L. And Rubus caesius L. In Rubus idaeus L., highest concentration of amino acids detected were cysteine [2.397 mg/g DW], threonine [0.931 mg/g DW], proline [0.910 mg/g DW], glutamine [0.816 mg/g DW] and arginine [0.659 mg/g DW], while in Rubus caesius L. They were serine [1.525 mg/g DW], valine [1.068 mg/g DW], asparagine [0.971 mg/g DW], glutamine [1.125 mg/g DW], and aspartic acid [0.775 mg/g DW]. The total amount of amino acids was higher in Rubus caesius [9.342 mg/g DW] than in Rubus idaeus [8.15 mg/g DW]. Amino acids, including essential ones like threonine, valine, methionine, leucine, isoleucine, tryptophan, phenylalanine and lysine, have been found in both plants.
Conclusion: The investigation has revealed that plants Rubus idaeus L. And Rubus caesius L. Possess diverse array of amino acid profile which may have nutritive and biological importance. These amino acids present in stem and root of plants demonstrate good potential to be employed as unexploited resources for functional foods and nutraceuticals. This investigation supports the general trends of the application of foodomics techniques to profile the nutritional and bioactive constituents of unexploited plant sources.