Butyric acid, a representative short-chain fatty acid, has gained considerable attention due to its noteworthy health benefits and widespread application. Nonetheless, the majority of commercially available butyric acid is currently synthesized through environmentally harmful chemical synthesis methods, which pose a significant obstacle to the development of the butyric acid industry. Therefore, there is a need to develop cost-effective, efficient, and environmentally friendly methods for butyric acid production. This review commences with a systematic evaluation of the health effects and mechanisms of action of butyric acid. Subsequently, it outlines the advantages and disadvantages of different sources of butyric acid, including chemical synthesis and biosynthesis, along with their development trends. Finally, the review delves into high-efficiency strategies to enhance butyric acid production through targeted biosynthesis. This review not only serves as a valuable reference for researchers and practitioners interested in the diverse aspects of butyric acid but also offers insights into future trends in the development of butyric acid.

In this study, aroma profiles of fresh and fermented chili pepper from nine Capsicum frutescens cultivars were compared using untargeted analysis based on headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Furthermore, multivariate data analysis was adopted to identify the characteristic aroma compounds of fermented chili pepper. The results showed that esters and terpenes were the major characteristic volatile components in fresh chili pepper. The number and amount of esters and terpenes increased significantly after fermentation (P < 0.05). Ocimene, hexanal, (E)-2-hexanal, 1-hexanol, linalool, methyl salicylate, and 4-methylpentyl 3-methylbutanoate were common to fresh chili pepper from the nine cultivars, while the volatile aroma compounds common to fermented chili pepper were (E)-2-heptanal, (E)-2-octenal, 1-octene-3-one, (E)-linalool oxide (furanoid), ethyl salicylate and α-terpineol. 1-Octene-3-one and (Z)-3-hexenyl hexanoate were the most predominant aroma-active compounds in fresh and fermented chili pepper, respectively. Moreover, a significant difference was observed among cultivars in terms of the profile of aroma compounds. The multivariate data analysis indicated that esters (benzyl 2-methylbutanoate, pentyl 3-methylbutanoate, benzyl pentanoate) and terpenes (D-limonene, ocimene, anethole) contributed to the difference in the flavor of fermented chili pepper among cultivars. The aroma profile of fermented chili pepper described in this study can provide theoretical support for flavor evaluation of and variety selection for fermented chili pepper.