In this study, the volatile composition and characteristic flavor compounds of Changsha stinky tofu brine during fermentation were analyzed and identified by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) with internal standards based on odor activity values (OAV). The dominant microbiota was investigated by shotgun metagenomic sequencing, and the correlation between the dominant microbiota and the characteristic flavor substances was analyzed by calculating Pearson’s correlation coefficients. Results showed that a total of 75 volatile flavor compounds were identified during the 120-day fermentation period, including phenols, indoles, alcohols, acids, aldehydes, ketones, esters, and ethers. Phenol, p-cresol, indole, 3-methylindole, butyric acid, isovaleric acid, 4-ethylphenol, trimethylamine, 3-methyl-1-butanol, 2-heptanol, 1-hexanol, 3-octanol, 1-octen-3-ol, 2-undecanol, phenethyl alcohol, (E,E)-farnesol, ethyl 3-phenylpropionate, 4-dodecanolide and 1-nonanal were identified as the characteristic flavor substances in the whole fermentation process. The predominant microorganisms identified were Clostridium bacterium SYSU GA17129, Clostridiales unclassified, Clostridium ultunense, Sporanaeromonas acetenes, Keratinibaculum paraultunense, Massiilibacterium senegalense, Aneurinibacillus aneurinilyticus, Pseudogracilibacillus auburnensis, Paencaligenes hominis, Ignatzschineria sp. F8392, and Ignatzschineria indica. Moreover, C. bacterium SYSU GA17129, A. aneurinilyticus, and S. acetigenes had significant correlations with 12 characteristic flavor components (P < 0.05), which were the major microbiota associated with the flavor of Changsha stinky tofu brine. This study provides a theoretical basis for promoting the stability of the flavor quality of Changsha stinky tofu.

The dominant spoilage bacteria in chicken feet with pickled peppers were analyzed by high-throughput sequencing technology and isolated by the traditional culture method to evaluate their spoilage capacity by back inoculation. The results showed that the dominant genus identified was Bacillus, and four dominant strains were identified including B. methylotrophicus, B. velezensis, B. subtilis and B. safensis. All these strains were able to produce protease and lipase activity. Among them, B. safensis showed the strongest protease activity (51.19 U/mL), while B. methylotrophicus showed the strongest lipase activity (3.75 U/mL). The pH, total volatile basic nitrogen (TVB-N) content and thiobarbituric acid reactive substances (TBARS) value of the samples inoculated with each of the four Bacillus strains were higher than those of the uninoculated control group, indicating that all four Bacillus strains had spoilage capacity. This study will provided a theoretical basis for preventing and controlling the spoilage of chicken feet with pickled peppers and extending its shelf life.

With the gradual advancement of the Healthy China strategy, the comprehensive healthcare industry represented by “homology of medicine and food” has gradually become a hot topic. As one of the most consumed condiments in China, chili can be used for medicinal and culinary purposes. Capsaicin (CAP), a major bioactive substance in chili, possesses biological effects such as analgesic, antioxidant, anti-inflammatory, anti-cancer, anti-obesity and cardioprotective and has been extensively studied for its pharmacological functions and potential action mechanisms. Considering that the application of CAP has some problems including high irritation, poor water solubility and low bioavailability, this paper reviews the evaluation of novel delivery systems for improving the oral bioavailability of capsaicin, including liposomes, micelles, micro/nanoemulsions, Pickering emulsions and nanoparticles based on stability, encapsulation rate and biological properties. This review aims to provide a theoretical basis for the development of capsaicin into functional nutraceuticals.

In order to investigate changes in the quality, flavor and major aroma components of pickled chilies in ceramic jars during fermentation, this study used headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to analyze the volatile substances of pickled chilies in ceramic jars from a certain producer after storage for 1–5 years and determined their physicochemical indexes and total bacterial counts. The results showed that the levels of soluble salt-free solids, total acids, total esters, amino nitrogen and total colony count of chopped chili peppers kept changing with storage time, and the quality and aroma kept improving in the first three years, and then the quality declined in the fourth year. A total of 112 volatile compounds were detected, including 22 acids, 12 alcohols, 36 esters, 5 ketones, 9 aldehydes, 5 phenols, 18 hydrocarbons, and 5 other compounds. The volatile composition and content varied with storage time, and 36 volatile compounds with odor activity values (OAVs) greater than 1 were found, which played an important role in the overall aroma of chopped chili peppers. Among them, linalool and methyl salicylate, ethyl salicylate, 4-ethyl-2-methoxyphenol were common to all samples. The samples stored for 1–3 years were superior in terms of organoleptic quality, physicochemical properties and volatile components, while those stored for more than 3 years had a strong aroma but poorer texture.