L. indica L. cv. Mengzao, a medicinal plant of the Ixeris genus, is rich in flavonoids. In order to thoroughly analyze the the distribution and dynamic change of major flavonoids in its various parts from different growth periods, the flavonoids extracted from L. indica L. cv. Mengzao were identified and quantitatively analyzed by ultra-high-performance liquid chromatography mass spectrometer (LC-MS/MS). Results indicated that 15 flavonoids were identified from L. indica L. cv. Mengzao, and rutin, luteolin, luteolin-7-O-glucoside, kaempferol, quercetin, and apigenin are the major flavonoids in L. indica L. cv. Mengzao. In general, the total flavonoids’ content in different parts of L. indica L. cv. Mengzao followed the order flowers > leaves > stems > roots. Flowers and leaves are the main harvesting parts of L. indica L. cv. Mengzao, and the flowering period is the most suitable harvesting period. This study provides valuable information for the development and utilization of L. indica L. cv. Mengzao and determined the best part to harvest and the optimal time for harvesting.

During aerobic exposure of silage, the fatty acid and amino acid composition may alter the quality and palatability, resulting in economic losses in livestock production. The objective of this study was to evaluate the effects of Lactiplantibacillus plantarum (LP), Lenti Lentilactobacillus buchneri (LB), and a mixture of LP and LB (PB) on the fatty acids, amino acids, and antioxidant capacity of Leymus chinensis silage during aerobic exposure. The lactic acid bacteria were added at 1 × 10⁶ CFU/g. The silage treatments were opened after 60 days of fermentation, and sampled on days 0, 4, and 8 of aerobic exposure. The LB group had higher total fatty acid and polyunsaturated fatty acid content, and less decrease in amino acid content and antioxidant capacity, while the LP group had a higher monounsaturated fatty acid content but a larger decrease in all indicators after exposure. Correlation analysis showed that Lactobacillus, Cryptococcus, Penicillium, and Thermoascus were more correlated with fatty acid changes, and that Lactobacillus, Actinomyces, Clostridium, and Penicillium were more correlated with amino acid changes. In conclusion, Lentilactobacillus buchneri could effectively improve the antioxidant capacity and fatty acid and amino acid contents of Leymus chinensis silage during aerobic exposure, while Lactiplantibacillus plantarum could effectively improve the content of each index of Leymus chinensis silage at opening, but deterioration was faster during aerobic exposure.

In this study, the triterpenoids in the leaves of Lactuca indica L.cv. Mengzao (LIM) were extracted via microwave-assisted ethanol extraction, and the optimum extraction conditions for triterpenoids were determined through single-factor experiments and the Box–Behnken method. The effects of three factors (solid–liquid ratio, microwave power and extraction time) on the total triterpenoids content (TTC) were evaluated. The TTC of different parts (roots, stems, leaves and flowers) of LIM in different growth stages was studied, and the scavenging effects of the highest TTC parts on DPPH, ABTS and hydroxyl free radicals were investigated. The results showed that the optimum extraction conditions for microwave-assisted extraction of total triterpenoids from LIM leaves were as follows: solid–liquid ratio of 1:20 g/mL; microwave power of 400 W; and extraction time of 60 min. Under these conditions, the TTC was 29.17 mg/g. Compared with the fresh raw materials, the TTC of the materials increased after freeze drying. The leaves of LIM had the highest TTC, and the flowering stage was the best time. The triterpenoids from the leaves had a strong ability to eliminate DPPH and ABTS free radicals, and the elimination effect of dried leaves was better than that of fresh leaves, while the elimination effect of hydroxyl free radicals was not obvious. The tested method was used to extract total triterpenoids from LIM using a simple process at low cost, which provides a reference for developing intensive processing methods for L. indica.

High‐quality silage enhances palatability and feed intake; however, the effects of co‐fermentation with flavouring agents and lactic acid bacteria (LAB) on its flavour quality, core microbiota, and taste‐active amino acids remain unclear. This study investigated the effects of fermentation using Lactiplantibacillus plantarum (LP) alone or in combination with phenethyl acetate (LPP) on the flavour profile of alfalfa silage and its subsequent influence on feed intake. Both LP and LPP significantly improved fermentation quality versus control (CK), with markedly higher feed intake—LP > CK and LPP > LP. Key flavour compounds, including dimethyl trisulfide, 4‐ethylphenol and β‐damascenone, were significantly increased in the LP alone group. Contrarily, essential taste‐related amino acids including aspartic acid, alanine, proline, histidine, isoleucine, and valine were decreased, except for arginine. These metabolic shifts collectively contributed to enhanced feed intake. The addition of LPP increased phenylethyl alcohol, benzyl alcohol and hexanal, and decreased arginine, contributing to enhanced palatability. Aryl alcohol dehydrogenase, proline aminopeptidase, histidine dehydrogenase, and branched‐chain amino acid transaminase from LP played a crucial role in the formation of phenylethyl alcohol, proline, histidine and isoleucine during fermentation. These results provide insights into how LAB and flavouring agents jointly regulate flavour development in high‐quality alfalfa silage.