Qualitative and quantitative analysis for the content of benzoic, salicylic, sorbic and glycyrrhizic acids in an aqueous extract of alfalfa

The article presents the results of experimental studies on the assessment of the content of benzoic, salicylic, sorbic and glycyrrhizic acids in the aqueous-alcoholic extract of alfalfa (Medicago sativa L.) and in its condensed extract (BAA «Erakond»), belonging to the class of preservatives of natural origin. Qualitative and quantitative analysis was carried out by high performance liquid chromatography (HPLC) on a Waters Breeze chromatograph (Waters, USA). The content of acids endowed with antiseptic and fungicidal properties in the air-dry raw material of alfalfa was, mg/g: benzoic - 3.2 ± 0.3; salicylic - 1.8 ± 0.2; sorbic - 0.15 ± 0.11; glycyrrhizin - 2.0 ± 0.3. The technology of hydrobaric extraction, used in the industrial production of the dietary supplement «Erakond» from alfalfa, ensured the concentration of the analyzed acids in the finished product: the content of benzoic acid in the dietary supplement «Erakond» was 26.0 ± 3.0 mg/g, salicylic acid - 2.9 ± 0.3 mg/g, sorbic - 0.22 ± 0.03 mg/g, glycyrrhizin - 5.2 ± 0.6 mg/g. The mechanisms of implementation of the antioxidant properties of polyphenolic compounds of alfalfa, which exhibit a synergistic preservative effect together with identified organic acids, are disclosed. Relatively high concentration of polyphenolic compounds in Erakond dietary supplement (naringenin - 0.05 ± 0.0006; rutin - 8 ± 3; licuraside - 3.5 ± 0.4; quercetin - 0.04 ± 0.001; fisetin - 0.35 ± 0.01; naringin - 0.5 ± 0.0006; dihydroquercetin - 0.20 ± 0.002) provides high stability of Eracond-containing food products during long-term storage with preservation of nutritional, taste and biological properties. The combined antiseptic and antioxidant action in vitro of organic acids, polyphenolic compounds, essential oils, coumarins and plant saponins ensures the effectiveness of the use of natural preservatives in food industry technologies.