Based on coffee’s unique and fascinating flavor, coffee has become the most popular nonalcoholic drink in the world and is a significant agricultural economic crop in tropical- and subtropical-planted coffee countries and regions. It is also beneficial for human health because of its rich active compounds, such as caffeine, chlorogenic acids, trigonelline, tryptophan alkaloids, diterpenes, melanoidins, etc. These compounds often relate to the prevention of cardiovascular disease, Alzheimer’s disease, and antibacterial, anti-diabetic, neuroprotection, and anti-cancer activities. The formation of coffee’s flavor results from various influence factors, including genetics, shade, elevation, post-harvest processing, fermentation, roasted methods, etc. The first stage of coffee production is obtaining green coffee beans through the primary process. Fermentation is critical in the primary process of coffee, which is often related to yeasts, bacteria, and filamentous fungi. Therefore, microorganisms play a key role in coffee fermentation and coffee flavor. To provide an understanding of the role of microorganisms in coffee fermentation, the coffee fermentation overview and microbial characteristics in different coffee primary processing methods and different coffee fermentation regions were reviewed in this paper. Brazil and China are the main study countries in coffee fermentation, which contribute a large number of technologies and methods to improve coffee flavor by fermentation. Different primary processing methods (wet, dry, or semi-dry processing) and coffee producer countries had obvious microbial community characteristics. Moreover, the application of yeast and bacteria for improving coffee flavor by microbial fermentation was also introduced.

The primary processing method of coffee plays a crucial role in determining its flavor profile. In this study, roasted coffee beans were subjected to three primary processing methods, i.e., natural processing (SC), washed processing (WC), and honey processing (MC), that were analyzed by LC-MS/MS and GC-MS metabolomics. Additionally, sensory evaluation was conducted by the Specialty Coffee Association of America (SCAA) to assess coffee flavor characteristics. The results showed that 2642 non-volatile compounds and 176 volatile compounds were detected across the three primary processing methods. Furthermore, significant differentially changed non-volatile compounds (DCnVCs) and volatile compounds (DCVCs) were detected among SC/WC (137 non-volatile compounds; 32 volatile compounds), MC/SC (103 non-volatile compounds; 25 volatile compounds), and MC/WC (20 non-volatile compounds; 9 volatile compounds). Notable compounds, such as lichenin, 6-gingerdiol 5-acetate, 3-fluoro-2-hydroxyquinoline, and 4-(4-butyl-2,5-dioxo-3-methyl-3-phenyl-1-pyrrolidiny)benzenesulfonamide, were identified as important DCnVCs, while ethyl alpha-D-glucopyranoside, 2,3-butanediol, maltol, and pentane-1,2,5-triol were identified as significant DCVCs in SC/WC. In MC/SC, 3-fluoro-2-hydroxyquinoline, etimicin, lichenin, and imazamox were important DCnVCs, whereas ethyl alpha-D-glucopyranoside, 2-pyrrolidinone, furfuryl alcohol, and pentane-1,2,5-triol were import DCVCs. Lastly, MC/WC samples exhibited notable DCnVCS, such as (S)-2-hydroxy-2-phenylacetonitrile O-[b-D-apiosyl-1->2]-b-D-glucoside], CMP-2-aminoethyphosphonate, talipexole, and neoconvallatoxoloside, along with DCVCS including citric acid, mannonic acid, gamma-lactone, 3-(1-hydroxy-1-methylethyl)benzonitrile, and maltol. Therefore, the primary processing method was a useful influence factor for coffee compositions.

Coffee fermentation is crucial for flavor and aroma, as microorganisms degrade mucilage and produce metabolites. This study aimed to provide a basis for understanding the impact of microorganisms on Coffea arabica from Yunnan, China, during washed processing. The microbial community structure and differentially changed metabolites (DCMs) of C. arabica beans during washed processing were analyzed. The results indicated that the top five predominant microorganisms at the genera level were Achromobacter, Tatumella, Weissella, Streptococcus, and Trichocoleus for bacteria and Cystofilobasidium, Hanseniaspora, Lachancea, Wickerhamomyces, and Aspergillus for fungi. Meanwhile, the relative content of 115 DCMs in 36 h samples decreased significantly, compared to non-fermentation coffee samples (VIP > 1, p < 0.05, FC < 0.65), and the relative content of 28 DCMs increased significantly (VIP > 1, p < 0.05, FC > 1.5). Furthermore, 17 DCMs showed a strong positive correlation with microorganisms, and 5 DCMs had a strong negative correlation (p < 0.05, |r| > 0.6). Therefore, the interaction and metabolic function of microbiota play a key role in the formation of coffee flavor, and these results help in clarifying the fermentation mechanisms of C. arabica and in controlling and improving the quality of coffee flavor.

The phytochemical investigation of Veratrum mengtzeanum Loes. roots resulted in the isolation and characterization of two novel, namely Mengtzeanines A (1), Mengtzeanines B (2), and eight known steroidal alkaloids (3–10). Their structural properties were assessed though extensive spectroscopic techniques. All constituents 1–10 were analyzed for suppression of NO formation in LPS-induced RAW264.7 macrophages. Among them, constituent 6 (Verazine) showed inhibition against LPS-induced NO production (IC₅₀ = 20.41 μM). Additionally, compound 6 could inhibit the secretion of IL1β, IL6, and TNFα, and downregulate the productions of iNOS and COX2 in LPS-induced RAW264.7 macrophages. Further experiments revealed that 6 exhibited a potent anti-inflammatory level in LPS-stimulated RAW264.7 macrophages via inhibiting NF-κB, and triggering of Keap1/Nrf2/HO-1 axis, implying that compound 6 may be a promising candidate for treating inflammatory disorders.

Dendrobium officinale flowers (DOF) have previously been established as a promising source of natural antioxidants, and it is ideally suited for processing to prepare functional foods and food additives. The precise extraction processes employed, however, can alter the composition and antioxidant properties of the resultant products, and the characteristic compounds associated with the active fractions prepared from DOF or their mechanisms of action have yet to be reported. To clarify the molecular mechanisms through which these active fractions function for the first time, chromatography was used to separate DOF extracts, yielding five fractions (Fr. (a—e)). Analyses of the antioxidant activity for these different fractions revealed that Fr. (d) presented with the most robust bioactivity. Levels of total flavonoids were then measured, revealing that antioxidant activity levels were positively correlated with total flavonoid content. Fr. (d) was found to contain 20 flavonoids in HPLC-Triple-TOF-MS/MS analyses. At the cellular level, Fr. (d) was found to induce increases in the levels of protective antioxidant factors (SOD and GSH-Px) while reducing the levels of reactive oxygen species (ROS), damage-associated factors (MDA, NO, TNF-α, IL-1β, and IL-6), and inducible nitric oxide synthase (iNOS) expression in C2C12 cells that had been stimulated with H₂O₂. These data thus provided support for Fr. (d) prevention of oxidative stress and inflammation. Network pharmacology analyses further suggested that Fr. (d) can help protect against oxidative stress through its effects on PI3K/Akt-related signaling activity. Fr. (d) was subsequently found to upregulate PI3K/Akt pathway-related proteins, nuclear transcription factor 2 (Nrf2), and heme oxygenase 1 (HO-1) in addition to suppressing Kelch-like epoxide-related protein 1 (Keap1) expression. In summary, Fr. (d) was found to suppress PI3K/Akt/Nrf2 pathway activation, ultimately alleviating inflammation and oxidative stress as predicted with a network pharmacology approach. Future studies aimed at clarifying the composition and mechanistic activity of DOF Fr. (d) will likely help establish it as a functional food capable of promoting health and longevity.

The semi-dry fermentation processing (SFP) of Coffea arabica is a traditional primary processing method in the coffee industry, which crucially impacts the coffee’s flavor. To further obtain useful information on microbial communities and chemical compounds during the SFP of C. arabica from Yunnan, China, the microbial community structures and the differentially changed non-volatile compounds (DCnVCs) were comprehensively analyzed. The results showed that Tatumella, Staphylococcus, Klebsiella, Brevundimonas, and Gluconobacter were the most prevalent bacteria genera, and Candida, Hannaella, Hanseniaspora, Pichia, and Lachancea were the most abundant fungal genera. Furthermore, 117 DCnVCs were found in the fermentation-finished samples compared to the raw materials. Therefore, this study can provide useful information for understanding the SFP of coffee beans, and its impact on coffee’s quality parameters.