Effect of Fomesafen on the Nutritional Quality and Amino Acids of <i>Vigna angularis</i> Based on Metabonomics

At present, fomesafen is widely used to control weeds in <i>Vigna angularis</i> fields. To explore the effect of fomesafen (FSA) on the nutritional value and amino acids of <i>Vigna angularis</i>, the protein, fat, water, ash, sand yield, and hundred-grain weight of <i>Vigna angularis</i> were measured using <i>Vigna angularis</i> sprayed with or without FSA. A non-targeted metabonomics and a high-throughput targeted amino acid analysis of <i>Vigna angularis</i> were performed using the metabonomics technology of liquid chromatography–mass spectrometry (LC-MS). The results showed that the protein (23.39 ± 0.16%) and fat (0.49 ± 0.05%) in sprayed <i>Vigna angularis</i> (Z-2-GS-2) were significantly different from the protein (19.88 ± 0.05%) and fat (0.71 ± 0.06%) in non-sprayed <i>Vigna angularis</i> (GS), indicating that a certain amount of FSA could promote the synthesis of protein in <i>Vigna angularis</i> and inhibit the formation of fat. A total of 63 metabolites with significant differences were screened from the non-targeted metabonomic analysis, including isoprene lipids, carboxylic acids, organic oxygen compounds, and carboxylic acid derivatives. Seventeen metabolic pathways were enriched. Five metabolic pathways with significant differences were screened according to <i>p</i> < 0.05, including alanine, aspartic acid, glutamic acid metabolism, tryptophan metabolism, and arginine biosynthesis, indicating that FSA had a significant effect on amino acid metabolism in <i>Vigna angularis</i>. Through targeted amino acid analysis, 21 different amino acids in <i>Vigna angularis</i> were accurately determined qualitatively and quantitatively. Among them, the contents of Asp and Glu increased under the influence of FSA, while the contents of Phe, His, and Ile decreased, which proved that FSA would cause the sweet taste of <i>Vigna angularis</i> to increase, reducing the flavor. Use of FSA will lead to the increase in protein content, ash content, and sand yield of <i>Vigna angularis,</i> while also leading to the decrease of fat content, water content, and hundred-grain weight. The use of FSA will also have a particular impact on the nutritional value, health care efficacy, and taste of <i>Vigna angularis</i>. The results of this study provide new ideas for follow-up research on the rational use of FSA in the field of <i>Vigna angularis</i> and the development of <i>Vigna angularis</i> health food.