To examine flavor variations in Xuanwei ham due to different cooking methods, we selected one-year cured Xuanwei ham and applied four techniques: dry frying (DF), baking (BA), steaming (ST), and boiling (BO). Organoleptic evaluation revealed ST received the highest overall sensory score. High-performance liquid chromatography (HPLC) revealed that the total nucleotide content was significantly different (P < 0.05), lactic acid predominated the measured organic acids. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and chromatography-electronic nose (GC-E-Nose) data indicated that ST resulting in significantly higher total volatile compounds than the other methods (P < 0.05). SPME-GC-MS detected 55 volatile compounds, and 12 characteristic flavor substances were identified using orthogonal partial least squares discriminant analysis (OPLS-DA) (VIP > 1). This study aimed to support comprehensive research on the flavor characteristics of cooked Xuanwei ham and guide the selection of appropriate processing methods.

With the increasing awareness of health, more people have shown a preference for low-alcohol beverages. Seeking various methods to improve the quality of kiwi wine is now a major research interest in the wine industry. In this study, kiwi wine was fermented by Saccharomyces cerevisiae and different non-Saccharomyces strains (Torulaspora delbrueckii, Kluyveromyces thermotolerans, Pichia fermentans) in three methods (pure fermentation, simultaneous, and sequential co-fermentation). The physicochemical characteristics, color parameters, phenolic profiles, total phenolic content (TPC), antioxidant activities, organic acids, and taste sense of the different wines were evaluated to determine the effects of different yeasts and fermentation methods on the quality of the kiwi wine. Results indicated that co-fermentation reduced the contents of alcohol while enhancing the lightness of the kiwi wine. The TPC of sequential co-fermentation with K. thermotolerans/S. cerevisiae was significantly higher than that of their simultaneous co-fermentation. Compared to K. thermotolerans/S. cerevisiae, the antioxidant activities were increased by co-fermentation of T. delbrueckii/S. cerevisiae and P. fermentans/S. cerevisiae. Principal component analysis showed that kiwi wines fermented by different yeasts and inoculation methods could be separated and grouped. Correlation analysis presented positive correlations of phenolic composition, antioxidant activities, and color intensity. This study provided theoretical guidance for co-fermentation of non-Saccharomyces/S. cerevisiae and accelerated the industrialization process of kiwi wine.

Alcoholic beverages have developed unique flavors over millennia, with sourness playing a vital role in their sensory perception and quality. Organic acids, as crucial flavor compounds, significantly impact flavor. This paper reviews the sensory attribute of sour flavor and key organic acids in alcoholic beverages. Regarding sour flavor, research methods include both static and dynamic sensory approaches and summarize the interaction of sour flavor with aroma, taste, and mouthfeel. In addition, this review focuses on identifying key organic acids, including sample extraction, chromatography, olfactometry/taste, and mass spectrometry. The key organic acids in alcoholic beverages, such as wine, Baijiu, beer, and Huangjiu, and their primary regulatory methods are discussed. Finally, future avenues for the exploration of sour flavor and organic acids by coupling machine learning, database, sensory interactions and electroencephalography are suggested. This systematic review aims to enhance understanding and serve as a reference for further in-depth studies on alcoholic beverages.

Every year, approximately 2 billion tons of plant-derived waste (such as straw and crop residues) are generated globally, most of which are either incinerated, dumped, or landfilled without proper planning, leading to severe environmental pollution and resource wastage. Plant-derived waste exhibits potential advantages as a growing media component in various aspects. However, numerous studies have also indicated that plant-derived waste generally possesses strong phytotoxicity, which must be removed or reduced before being utilized as a growing media component. Therefore, accurately assessing their phytotoxicity and appropriately modifying it to ensure their support for plant growth when used as a growing media component is crucial. This paper reviews the manifestation and assessment methods of phytotoxicity in plant-derived waste; systematically summarizes the phytotoxicity sources of three common types of plant-derived waste (garden waste, crop straw, and spent mushroom substrate), as well as the toxic mechanisms of two representative phytotoxic substances (phenolic compounds and organic acids); and proposes some insights into further research directions. By consolidating insights from these studies, this review aims to deepen our understanding of phytotoxicity and its implications, and offer valuable references and guidance for future research endeavors and practical applications.

This article employs six organic acids to selectively dissolve Mo, Ni and V from spent catalysts, and the most effective acid is identified. Then, the effects of key leaching parameters, including acid concentration, temperature, and S/L ratio, on metal leaching are systematically explored to determine the leaching mechanism. The results demonstrate that the leaching ability of organic acids followed the order: oxalic acid > citric acid > tartaric acid > malonic acid > acetic acid > formic acid. The leaching process of metals was jointly influenced by acidolysis and complexolysis. Among them, more than 93.07 % of Mo, 86.64 % of V, and 74.21 % of Ni were selectively leached with oxalic acid at the optimum condition: S/l: 1/20, oxalic acid: 1.0 mol/L, temp: 60 °C. From the correlation coefficients, the resulting activation energies, and n values, it was demonstrated that Mo and V followed the Avrami dissolution reaction model, V leaching was controlled by the diffusion mode, and Mo leaching was controlled by a mixed mode of chemical reaction and diffusion. The dissolution behavior of both metals consistently adhered to the linear trend of the Avrami kinetic model under varying S/L ratios and oxalic acid concentrations.

In recent years, the research on the conversion of chitin to high value-added chemicals has attracted more and more attention. At present, the method of preparing lactic acid from chitin mostly uses strong base or catalyst. The reaction system under alkaline condition not only corrodes the container but also easily harms the human body. Herein, a simple and effective method to convert chitin to organic acids in catalyst and base-free conditions is developed. The use of H2O2 only can efficiently convert chitin to organic acids in the absence of bases and catalysts. Under the optimal conditions of 30 mg chitin, 2.1 mL water, 0.9 mL H2O2 at 230 °C for 1.5 h, the lactic acid yield of chitin can reach 58.2 % and the total organic acid yield can reach 84.0 %. This work provides an efficient method for the resource utilization of chitin biomass.

Moringa oleifera leaves (MOL) are native to India and have high biological activities. To better understand the basic pharmacodynamic materials, the chemical components in MOL and their pharmacokinetic properties were studied and quantitated using UPLC-Q-Exactive Orbitrap-MS. Forty-two compounds were identified, including phenolic acids and their derivatives, flavonoids, isothiocyanates, nucleosides, alkaloids, and other compounds. Two phenolic acids and six flavonoids were studied for their pharmacokinetic properties using UHPLC-MS/MS. Precision, accuracy, stability, matrix effects, and extraction recovery were verified. All substances that were measured reached their maximum within 0.5 h. Vicenin-2 had a high peak concentration and bioavailability. Kaempferol-3-O-rutinoside had a longer biological half-life than other components. The results from this study provide the data basis for subsequent comprehensive qualitative evaluation and potential MOL use in clinical applications.

Anaerobic methane oxidation (AOM) can drive soil arsenate reduction, a process known as methane-dependent arsenate reduction (M-AsR), which is a critical driver of arsenic (As) release in soil. Low molecular weight organic acids (LMWOAs), an important component of rice root exudates, have an unclear influence and mechanism on the M-AsR process. To narrow this knowledge gap, three typical LMWOAs-citric acid, oxalic acid, and acetic acid-were selected and added to As-contaminated paddy soils, followed by the injection of 13CH4 and incubation under anaerobic conditions. The results showed that LMWOAs inhibited the M-AsR process and reduced the As(III) concentration in soil porewater by 35.1-65.7 % after 14 days of incubation. Among the LMWOAs, acetic acid exhibited the strongest inhibition, followed by oxalic and citric acid. Moreover, LMWOAs significantly altered the concentrations of ferrous iron and dissolved organic carbon in the soil porewater, consequently impacting the release of As in the soil. The results of qPCR and sequencing analysis indicated that LMWOAs inhibited the M-AsR process by simultaneously suppressing microbes associated with ANME-2d and arrA. Our findings provide a theoretical basis for modulating the M-AsR process and enhance our understanding of the biogeochemical cycling of As in paddy soils under rhizosphere conditions.

The direct synthesis of 1,2-pentanediol (1,2-PeD) from renewable xylose and its derivatives derived from hemicellulose is appealing yet challenging due to its low selectivity for the target product. In this study, one-pot catalytic conversion of xylose to 1,2-PeD was performed by using nitrogen-doped carbon (NC) supported Pt catalysts with the assistance of organic acids. A remarkable yield of 49.3% for 1,2-PeD was achieved by reacting 0.1869 g xylose in 30 mL water at 200 °C under a hydrogen pressure of 3 MPa for 8 h in the presence of 0.1 g of 2.5Pt/NC600 catalyst and 0.1869 g propanoic acid co-catalyst. The presence of vicinal Pt-acid pair sites on the surface of the 2.5Pt/NC600 catalyst exhibited a synergistic effect in promoting the hydrogenation of furfural to furfuryl alcohol intermediate and subsequent hydrogenation and ring-opening reactions leading to the formation of 1,2-PeD. The addition of organic acids, may serve as both acid catalyst for dehydration of xylose and hydrogen donor for hydrogenation of furfural and furfuryl alcohol, thereby promoting the one-pot conversion of xylose to 1,2-PeD. Remarkably, the 2.5Pt/NC600 catalyst demonstrated outstanding catalytic performance and good reusability over five consecutive cycles without significant deactivation.

BACKGROUND: Yeast culture (YC) is a product fermented on a specific medium, which is a type of postbiotic of anaerobic solid-state fermentation. Although YC has positive effects on the animal growth and health, it contains a variety of beneficial metabolites as dark matter, which have not been quantified. In the present study, liquid chromatography-tandem mass spectrometry is employed to identify the unknown metabolites. Following their identification, the important chemicals are quantified using HPLC-diode array detection methods.
RESULTS: Non-targeted metabolomics studies showed that 670 metabolites in total were identified in YC, of which 23 metabolites significantly increased, including organic acids, amino acids, nucleosides and purines, isoflavones, and other substances. The chemical quantitative analysis showed that the contents of succinic acid, aminobutyric acid, glutamine, purine and daidzein increased by 84.42%, 51.07%, 100%, 68.85% and 4.60%, respectively.
CONCLUSIONS: Therefore, the use of non-targeted metabolomics combined with chemical quantitative analysis to reveal the nutritional and functional substances of YC could help to elucidate the postbiotic mechanism and provide theoretical support for the regulation of the directional accumulation of beneficial metabolites. © 2024 Society of Chemical Industry.