The key odorants of Cayenne pepper fermentation: from chili peppers to the condiment
Creators: name: Cannon, Robert J.
Publisher: name: No Publisher Supplied
Year: 2022

description: As one of the oldest and widely cultivated crops, chili peppers (Capsicum annuum L.) are in ever increasing demand and utilized in a diverse range of culinary applications to impart color, flavor, and texture. The last decade has witnessed a massive influx of Hispanic cuisine and ethnic food options into the United States, including the spicy and bold flavors of chili peppers and hot sauce. Surprisingly, only a few published reports in the literature discuss the flavor chemistry of Cayenne peppers. Even fewer reports reference the flavor changes that fresh peppers undergo during fermentation, aging and bottling into a finished hot sauce condiment. The objective of this study is to develop food omics approaches to identify the aroma and flavor actives in fresh Cayenne peppers, fermented pepper mash, and hot sauce. Targeted, sensory-guided methods, including multidimensional gas chromatography-mass spectrometry-olfactometry, were deployed for the identification and quantitation of the key aroma compounds. Application of aroma extract dilution analysis (AEDA) on Cayenne peppers from two different locations revealed 18 aroma-active compounds with flavor dilution (FD) factors ranging between 2 to 1024. These odorants were quantitated in the extracts and odor activity values (OAVs) were calculated. The odorants with the highest OAVs in the Cayenne peppers were 2-isobutyl-3-methoxypyrazine (OAV 12950), ethyl 2-methylbutyrate (OAV 277), (Z)-3-hexenal (OAV 158), 2-methyl-3-furanthiol (OAV 157), and hexanal (OAV 136). Application of AEDA on the fermented Cayenne pepper mash revealed 29 aroma-active compounds with FD factors ranging between 2 to 8192. The odorants with the highest OAVs in the 12-month fermented and aged pepper mash were (E)-β-damascenone (OAV 4850), 2-isobutyl-3-methoxypyrazine (OAV 2700), (Z)-1,5-octadien-3-one (OAV 1333), ethyl 2-methylbutyrate (OAV 715), and 5-ethyl-4-hydroxy-2-methyl-3(2H)-furanone (OAV 478). The key odorants in three stages of pepper mash fermentation and aging were quantitated, including a discussion on the importance of both microorganism and acid-catalyzed-reactions of labile precursors. A total of eight volatile compounds were reported for the first time in the Capsicum genus from these studies. Finally, application of AEDA on fermented Cayenne hot sauce revealed 35 aroma-active compounds with FD factors ranging between 8 to 8192. The odorants with the highest OAVs in the hot sauce included (E)-β-damascenone (OAV 6250), acetic acid (OAV 1553), 2-isobutyl-3-methoxypyrazine (OAV 1550), (Z)-1,5-octadien-3-one (OAV 556), and 3-(methylthio)-propanal (OAV 406). Multivariate data analysis measured the changes of both volatile and non-volatile (amino acids, sugars, thiamine, ferulic acid) constituents in fresh chili peppers from different locations and during fermentation of chili pepper mash. In order to mimic plant and microbial glycosidases and the non-enzymatic conditions to ferment and bottle the finished condiment, glycosidic precursor extracts obtained from the chili peppers were introduced to enzymatic hydrolysis (AR2000, pH 5, 16 h) and acid hydrolysis (pH 2.5, 100 °C, 1 h). A total of twenty-one volatile aglycones were identified for the first time in chili pepper. The results demonstrated that enzymatic hydrolysis was more effective at liberating volatile aglycones compared to acid hydrolysis. The biogenesis and mechanisms of formation for the major classes of released compounds and flavor actives will be discussed. These learnings will help to improve breeding and fermentation practices, as well as establish parameters for the quality, stability, and consumer liking of chili pepper products.