Changes in free amino acids of fermented minced peppers during natural and inoculated fermentation process based on HPLC‐MS/MS

Abstract

Free amino acids (FAAs) participate in the synthesis of quality characteristic ingredients and taste substances in fermented minced peppers (FMPs), and they can be affected by fermentation method and time. In this study, changes in FAAs of FMP during natural fermentation (NF) and inoculated fermentation (IF) process were characterized by HPLC‐MS/MS. The results showed that a total of 20 FAAs were identified, including 8 essential amino acids (AAs), 2 semiessential AAs, and 10 nonessential AAs. Comparing with other FAAs, Gln, Arg, and Asn presented higher content in the whole NF or IF periods. The FAAs content of NF and IF samples showed similar tendency during fermentation process, which first increased and then decreased. The highest content of most FAAs in IF and NF samples was obtained on the 18‐ and 12‐day, respectively. Moreover, the FAA content in IF samples was higher than that in NF ones at the same fermentation time. The taste AAs content accounted for 23.3% to 50.0% in total FAAs, and taste activity value of bitter and umami was higher than sweet and aromatic ones. Based on principal component analysis, comprehensive analysis ranking, and heat map clustering analysis, FMP obtained by IF posed better FAAs quality than NF samples during fermentation process. Practical Application Free amino acids (FAAs) participate in the synthesis of quality characteristic ingredients and taste substances in fermented minced peppers (FMPs), and they can be affected by fermentation method and time. Changes in FAA varieties and level in FMP during natural fermentation (NF) and inoculated fermentation (IF) process were analyzed using HPLC‐MS/MS. Then, they were performed by principal component analysis (PCA), and clustered with the heat map. The results showed that FMP obtained by IF posed better FAAs quality than NF samples in the whole fermentation. HPLC‐MS/MS was a reliable and effective mean for determining the FAAs and could provide regulation guidelines for improving the quality of FMP during fermentation process.

Investigating the mechanism of the flavor formation in Sichuan sun vinegar based on flavor-orientation and metagenomics

“…Fermentation is the main stage for the formation of other amino acids; the concentration of serine and threonine positively correlated with the fermentation stage, reaching 0.35 ± 0.02g/100g and 1.57 ± 0.03g/100g dry weight on day 17 of fermentation, respectively. Proteases produced by microorganisms that hydrolyze proteins into amino acids also contribute to the increase in amino acid content ( Wang et al, 2020 ). Furthermore, after 1.5 years of aging, the serine concentration reached 0.58 ± 0.02g/100g dry weight and then declined continuously.…”

Insights into the metabolic profiling of Polygonati Rhizoma fermented by Lactiplantibacillus plantarum under aerobic and anaerobic conditions using a UHPLC-QE-MS/MS system

“…20,000 mg/L ( 23 ). During the fermentation process of peppers, the arginine content was higher in peppers inoculated with lactic acid bacteria than that of the control group without inoculation of lactic acid bacteria ( 24 ). Also, other studies ( 25 , 26 ) also show that during L. plantarum fermentation, the amino acid content of the fermentation system was significantly increased ( p < 0.05), which is consistent with the results of this study.…”

“…This could be attributed to the fact that the enzymatic activities of PPYAT are activated by oxygen under aerobic conditions, and vice versa. Previous study have demonstrated that the activity of PPYAT could be influenced by different substances; for example, its activity on S. cerevisiae was higher in cassava beer than The top-class of the KEGG enrichment pathway and pharmacological action of nine main compounds produced by Lactiplantibacillus plantarum during fermentation of Polygonati Rhizoma; *information on the pharmacological action is obtained from the literature (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38).…”

Anti-obesity effect of Angelica keiskei Jiaosu prepared by yeast fermentation on high-fat diet-fed mice

“…In addition, the fermentation process also produces free amino acids, active peptides, polysaccharides, and other substances. Wang et al employed the HPLC-MS method to prove that the components of fermented chili powder (FMPs) were transformed during fermentation, and FMPs had the higher quantity of free amino acids ( 28 ). The results of Liu et al indicated that fermentation enhanced the anti-obesity effect of pepper on the HFD mice ( 29 ).…”