Search Results (276)

Maceration techniques like cold maceration before fermentation (CM) and skin-contact fermentation (SF) are widely used in winemaking. However, their application remains limited in white winemaking, representing an important objective for the production of diverse white wines. This study systematically investigated the impacts of CM and SF on phenolics, volatile aromas and sensory properties of Chardonnay and Italian Riesling wines in Yantai wine region. Both CM and SF significantly increased the total phenolic content, especially with gallic acid and quercitrin contents rising 11.65- and 10.02-fold in Chardonnay, as well as catechin and quercitrin increasing 9.05- and 10.82-fold in Italian Riesling under 100% SF. Moreover, 72 h CM and 100% SF showed higher volatile aroma contents in both wines compared to other CM and SF treatments. Esters, including ethyl octanoate, ethyl hexanoate and isoamyl acetate, contributed to the improved floral and fruity aromas in maceration-treated Chardonnay wines, whereas esters and terpenes drove the aromatic profile of Italian Riesling wines, with terpenes rising 1.67- and 3.27-fold after CM and SF. The two varieties differed in wine color, with Italian Riesling wines displaying a stronger yellow hue and reduced lightness under 72 h CM, 50% SF and 100% SF. Sensory evaluation by a panel containing seven trained assessors found that SF-treated wines exhibited more intense flavor and balanced taste and CM-treated wines showed more freshness. These findings provide theoretical support for tailored maceration to enhance varietal expression in the specific region and diversify white wine production. Full article

Kombucha is traditionally produced by fermenting Camellia sinensis tea and sugar in a consortium of microorganisms called SCOBY (Symbiotic Culture Of Bacteria and Yeasts). Short- and medium-chain fatty acids and other organic acids in K are mainly produced by acetic acid bacteria, which contribute to the typical K taste. Coffee is one of the most widely consumed beverages in the world and one of the most traded commodities globally. Harvesting during coffee production generates tons of byproducts generally considered of low value, including cascara (CC), composed of dried pulp and skin, and leaves (CL). To date, few studies have investigated the production of short- and medium-chain fatty acids and monosaccharide’s profile during traditional kombucha fermentation, and their composition in kombuchas prepared from substrates other than C. sinensis is even scarcer. This study followed the changes in sugars and the production of short- and medium-chain fatty acids during K fermentation of black tea (BT), CC, and CL and associated their concentrations with physicochemical parameters (total soluble solids (TSS), pH, and titratable acidity (TA)) and the perceived acidity of the beverages evaluated by a trained panel and untrained consumers. BT K, a SCOBY, and 10% sucrose were added to infusions of arabica CC, CL, or BT. The mixture was fermented for 0, 3, 6, and 9 days. Organic acids were analyzed by GC-MS; sucrose and monosaccharides were analyzed by HPLC-RID. The Rate All That Apply (RATA) test was used for sensory analysis. Results were treated by ANOVA–Fisher and Pearson correlation tests with significance at p < 0.05. Glucose, fructose, arabinose, xylose, cellobiose and glycerol were identified in the infusions. On average, sucrose concentration decreased by 28% up to day 9, considering all K samples, accompanied by TSS decrease. Eight organic acids were semi-quantified, with acetic being the major acid in all beverages (8.4 to 1971 mg L⁻¹) and isovaleric being the lead minor acid (0.7 to 17.7 mg L⁻¹). Additional acids identified were: butanoic, 2-methylpropanoic, pentanoic, 3-methylpentanoic, hexanoic, and octanoic acids. TA values and sourness perceived by consumer assessors increased generally, even though in CC Ks, the acid concentration decreased by day 9. TA, sourness, and sparkling and fizzy mouthfeel correlated positively in all Ks. In general, although the total acid concentration was mainly higher on days 3 or 6, CO₂ formation, among other organic acids, probably increased TA and sourness on day 9. Although it is generally accepted that pH and organic acid concentrations are directly associated with sour taste, it is not possible to accurately predict and modify sour taste intensity in kombucha based only on these parameters, given that other factors, such as the production of CO_2, the existence of buffer systems, and the presence of sugars and other soluble solids, will probably affect the perceived acidity and sourness. Full article

Pigskin, a major byproduct of pork processing, has high protein content and low fat, endowing it with considerable market value for food applications. In this study, bioaugmented fermentation with Latilactobacillus sakei YBZY-W5, a strain previously isolated from traditional fermented pigskin, was applied to pigskin to systematically evaluate its effects on physicochemical parameters, microbial community succession, and volatile flavor compound (VFC) profiles over 20 days. The results showed that moisture and pH significantly decreased, while total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARSs) increased with fermentation time. High-throughput sequencing revealed that Lactobacilli, Fusarium and Aspergillus dominated early fermentation and were gradually replaced by Bacillus, Hanseniaspora and Debaryomyces. A total of 493 VFCs were identified, among which terpenoids, heterocyclic compounds, and alcohols were the most abundant classes. Orthogonal partial least squares discriminant analysis (OPLS-DA) identified numerous differentially changed VFCs (DCVFCs) during fermentation. Odor activity value (OAV) analysis indicated that green, meaty, and woody notes dominated initially, while sour, floral, sweet, and fruity characteristics became increasingly prominent after fermentation. Pearson correlation analysis demonstrated significant associations between key microorganisms (Lactobacilli, Bacillus, Hanseniaspora, Debaryomyces) and DCVFCs (e.g., β-myrcene, ethyl hexanoate, hexanoic acid, ethyl ester, pyrazines). Collectively, bioaugmented fermentation with Ltb. sakei YBZY-W5 effectively modulated the physicochemical and microbial profiles of pigskin, enriched desirable flavor compounds, and reduced unpleasant odor, confirming its feasibility for producing high-quality fermented pigskin products. This study provides an experimental basis for the value-added utilization of pigskin and promotes sustainable development of the pork industry. Full article

The bean bug Riptortus pedestris is one of the principal soybean pests throughout East Asia. Males release an aggregation pheromone consisting of three compounds—(E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H) and myristyl isobutyrate (MI)—in a ratio of 1:5:1. Although pheromone-based baits have been extensively deployed to control the pest for the past three decades, the glands responsible for producing these volatiles have remained unidentified. Our investigations revealed that the metathoracic glands (MTGs) of males synthesized the two pheromonal esters, E2HZ3H and E2HE2H, along with a suite of auxiliary compounds: (E)-2-hexenal, hexanoic acid, (E)-3-hexenoic acid, (E)-2-hexenoic acid, (E)-2-octenal, and (E)-2-hexenyl hexanoate (E2HH). Female MTGs were morphologically similar to those of males and generated the same auxiliary compounds, but lacked the capacity to produce the pheromonal esters E2HZ3H and E2HE2H. MI was released exclusively from the male abdominal sternites. Its quantity was nearly uniform across all sternal segments, implying secretion from an epidermal glandular patch (GP) that was evenly distributed over the sternites. In nymphs, dorsal abdominal glands (DAGs) emitted several volatiles—including (E)-2-hexenal, 4-oxo-(E)-2-hexenal, (E)-2-octenal, and (E)-2-octenoic acid—some of which are characteristic defensive compounds of heteropterans. Thus, our study clarifies how sex- and stage-specific glands contribute to the chemical polymorphism observed in R. pedestris. Full article

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have not been the preferred industrial inoculation strains in both winemaking and brewing sectors. This is mainly due to their slower fermentation rates, lower alcohol tolerance, and limited ability to complete fermentation. This review explores the brewing characteristics of Torulaspora delbrueckii strains, focusing on the aromatic profile of the produced beers, in comparison with the well-known Saccharomyces cerevisiae brewing strains. The effect of fermentation parameters, as well as the use of mono- and mixed cultures with S. cerevisiae, is discussed. Specific T. delbrueckii strains have demonstrated the ability to ferment wort sugars and produce alcohol levels of up to 4–6% (v/v). The main volatile compounds produced include higher alcohols, such as isoamyl and phenyl ethyl alcohol, as well as esters and their acid precursors. Among these, ethyl hexanoate and ethyl octanoate are particularly important due to their contribution to fruity aromas. Mixed fermentations involving T. delbrueckii and S. cerevisiae have been shown to enhance ester production, resulting in improved aromatic complexity in the final product. Full article

Three medium-chain fatty acids (MCFAs), namely decanoic acid, octanoic acid, and hexanoic acid, were identified in ozonated sunflower oil (OSO) using high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC/MS). All three MCFAs exhibited strong in vitro antioxidant activity to enhance high-density lipoprotein (HDL)-associated paraoxonase and protected low-density lipoproteins (LDL) from oxidative damage caused by Cu²⁺ ions. Consistently, MCFAs displayed substantial cellular antioxidant activity and minimized carboxymethyllysine (CML)-induced reactive oxygen species (ROS) generation and apoptotic cell death in zebrafish embryos. In adult zebrafish, MCFAs treatment mitigated CML-induced acute death and swimming abnormalities, and substantially augmented plasma sulfhydryl content, ferric ion reduction ability (FRA), and paraoxonase (PON)-like activity. Also, MCFA-treated zebrafish showed lower blood glucose, total cholesterol (TC) and triglycerides (TG) with raising HDL cholesterol levels. The MCFAs showed substantial inhibition of hepatic ROS generation, neutrophil efflux, interleukin (IL)-6 production, and steatosis, leading to hepatoprotection against CML-triggered adversity. Consistent with hepatic histology results, reduced plasma hepatic function biomarkers aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were observed in MCFA-treated groups than in the CML-treated group. In the kidney, MCFA treatment effectively reduced oxidative stress and cellular senescence and protected against kidney damage induced by exposure to CML. The study concludes the presence of three MCFAs in the OSO, which serve as functional antioxidants and anti-inflammatory agents, accounting for its diverse pharmacological properties. Full article

The clinker grinding stage in Portland cement production is highly energy-intensive, primarily due to particle agglomeration and intensified interparticle attractive forces that hinder efficient comminution. Grinding aids (GAs) are routinely employed to mitigate these issues, enhancing grinding efficiency and improving cement performance. However, the undesirable side effects associated with conventional GAs on cementitious systems have spurred interest in modification strategies that can concurrently optimize grinding efficiency and final product quality. In this study, widely used commercial GAs, triisopropanolamine (TIPA), diisopropanolamine (DEIPA), and diethylene glycol (DEG), were chemically modified via esterification with organic acids of different carbon chain lengths. Cement specimens incorporating these modified GAs were produced at two dosages (0.05% and 0.1% by mass of clinker + gypsum), resulting in 24 distinct Portland cement formulations alongside a control mix. The influence of modification on grinding efficiency, particle size distribution (PSD), and powder flowability was investigated. Furthermore, scanning electron microscopy (SEM) was utilized to analyze particle morphology and concrete microstructural characteristics with powder flow behavior. The results indicate that organic acid modification not only facilitates achieving target fineness with lower energy consumption but also markedly improves both the PSD profile and the powder’s flow properties. Specifically, hexanoic acid-modified TIPA and DEIPA, along with propanoic acid-modified DEG, delivered the most favorable outcomes across the evaluated parameters. These findings underscore the potential of developing next-generation, modified GAs that simultaneously enhance energy efficiency and powder handling in cement grinding operations. Full article

Underutilised, nutrient-dense legumes in their sprouted form provide promising substrates for developing functional fermented foods capable of influencing gut microbial activity and metabolite production. This study evaluated the effects of probiotic lactic acid bacteria-fermented beverages derived from sprouted Bambara groundnut (Vigna subterranea) and cowpea (Vigna unguiculata) on gut microbiota composition and short-chain fatty acid (SCFA) production using an in vitro colonic fermentation model. The beverages were fermented with either Bifidobacterium animalis BB-12 (BCBF24) or Lactiplantibacillus plantarum 75 (BCL7524). During colonic fermentation, at 0, 12, 24, and 38 h, faecal slurries were collected for SCFA analysis using gas chromatography–mass spectrometry (GC-MS) and deoxyribonucleic acid (DNA) sequencing (Oxford Nanopore Technologies). Microbial diversity decreased, indicating selective enrichment of taxa. BCL7524 induced a major shift, significantly (p < 0.05) enriching Bacillota and driving Megasphaera to ~42% dominance within 24 h. This reflected cross-feeding from L. plantarum to lactate-utilising Megasphaera spp. Spearman correlation linked Megasphaera to a broad SCFA profile, including isobutyric, isovaleric, valeric, and hexanoic acids, with a significant (p < 0.05) positive correlation observed for hexanoic acid. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated proteolysis and mapped hexanoic acid to fatty acid biosynthesis pathways, suggesting chain-elongation activity contributing to hexanoate formation. In line with this, BCL7524 produced significantly (p < 0.05) higher levels of hexanoate (3–14 mM) and valerate (10–15 mM), supporting chain-elongation activity within the community. In contrast, BCBF24 enriched Actinomycetota and Bifidobacterium, correlating with acetate production (18–23 mM). This study demonstrates that specific synbiotic beverages can modulate gut microbial ecology and metabolic output under in vitro conditions. Full article

The flavor and scent of Chinese Baijiu are closely linked to the quantity of fatty acid ethyl esters, and their generation is closely associated with Baijiu brewing yeast, most notably ethyl acetate (EA) and ethyl hexanoate (EH). At present, however, the specific mechanism of EA and EH produced by Wickerhamomyces anomalus under ethanol stress during the brewing of Baijiu remains unclear. Our study findings revealed that ethanol stress inhibited the generation of precursor substances (pyruvate and acetyl-CoA) in the fatty acid ethyl ester biosynthesis pathway of W. anomalus NCU003. The high level of EA produced in the fatty acid ethyl ester biosynthesis pathway was associated with the enhanced expressions of ATF1 and EAT1 and the increased activity of C2 esterase under 3% and 6% ethanol stress. The lower EA content was related to the high expression of IAH1 and low activity of C2 esterase under 9% ethanol stress. We also found that the expression of ACC, FAS1, FAS2, EHT1, and EEB1 was up-regulated, which may promote the synthesis of EH under ethanol stress, whereas the activity of C6 esterase may have no effect on the synthesis of EH. Our study results indicated that the above genes and C2 esterase can be modulated in W. anomalus NCU003 under ethanol stress, thus promoting the synthesis of fatty acid ethyl esters during the brewing of Baijiu. Full article

The growing interest in functional beer production has led to the exploration of unconventional raw materials, such as hemp (Cannabis sativa L.), for brewing applications. This study aimed to evaluate the volatile organic compound (VOC) profile and the macro- and microelement composition of barley wort enriched with varying proportions (10% and 30%) of malted and unmalted hemp seeds, using solid-phase microextraction followed by gas chromatography–mass spectrometry (SPME–GC–MS) and atomic absorption spectrometry (AAS). A total of 64 VOCs were identified across four wort variants: control (barley malt only), 10% malted hemp, 30% malted hemp, and 30% unmalted hemp. The aroma profile was significantly influenced by compounds such as 2,3-butanediol, 1-hexanol, 3-methyl-1-butanol, 3-hydroxy-2-butanone, hexanoic acid, and 4-vinylguaiacol (p < 0.001). Principal component analysis (PCA) revealed clear separation between wort types based on the relative abundance of alcohols, acids, ketones, and phenols, indicating a progressive shift from sweet/malty toward acidic, green, and herbal aroma notes as hemp addition increased. Notably, unmalted hemp seeds resulted in a pronounced dominance of hexanoic acid, which may contribute to earthy and rancid sensory attributes. The evaluation of selected mineral elements showed that the key macroelements differentiating the worts were potassium, magnesium, phosphorus, and calcium, while among the microelements the distinguishing elements were manganese, iron, and sodium. These findings demonstrate the strong modulating effect of aromatic hemp-derived materials on the aroma composition and selected mineral content of brewing worts, supporting their targeted use in novel beer formulations. Full article

This study presents the first comprehensive assessment of a bacteriophage P100-activated edible whey-protein solution (WPS) applied to the rind of Sicilian Canestrato Fresco (SCF) cheese. Beyond evaluating its anti-Listeria efficacy in pre- and post-packaging contamination contexts, the work investigates the coating’s effects on chemical composition, volatilome, sensory properties, and consumer responses, including willingness to pay. To assess anti-Listeria activity, all samples were stored at 4 °C for 30 days. Contamination was carried out either before or after coating application, depending on the specific treatment. Listeria monocytogenes was monitored at 0, 1, 3, 7, 15, and 30 days of refrigerated storage. The active coating reduced the pathogen from approximately 3 log CFU/g to undetectable levels (0 log CFU/g) within 3 days, whereas the untreated controls reached about 5 log CFU/g after 30 days. WPS-coated cheeses showed no significant changes in chemical composition (moisture ~33%, protein ~29%, fat ~33%) or fatty acid profile compared to traditional SCF. The volatilome was dominated by hexanoic and butanoic acids and ethyl esters, without significant differences between coated and control samples, as confirmed by Smart Nose^® analysis. Sensory evaluation by trained assessors demonstrated that the bioactive coating did not alter the traditional sensory profile of SCF cheese. A consumer survey conducted with 240 participants from two retail formats revealed significant differences in product familiarity and perceived food safety, while openness to innovation and willingness to pay were similar. More than 90% of respondents were willing to pay a 10% price premium. Overall, phage-based edible coatings appear to be edible, renewable, and biodegradable packaging alternative to improve cheese safety without compromising quality. Full article

The anaerobic digestion process generally generates volatile fatty acids (VFAs) depending upon the metabolic pathway. VFAs are short chain fatty acids containing from one up to eight interlinked carbon atoms. Separation, identification, and quantification of VFAs can enhance metabolic process especially biogas production during anaerobic digestion. Therefore, the continuous monitoring of VFAs is mandatory and is typically performed by liquid chromatography combined with mass spectrometry (LC–MS) and gas chromatography equipped with flame ionization detector (GC–FID) that require sample derivatization and larger sample size of 10–30 mL. Therefore, the current study develops a simple and readily applicable protocol to determine and quantify VFAs (C1–C7) in liquid digestate samples by gas chromatography combined with mass spectrometry (GC–MS) with a reduced sample size of only 0.5 mL. The protocol utilized mix VFAs standard solution for calibration and solvent extraction technique to extract and dissolve VFAs from digestate samples to a volatile solvent dimethyl carbonate (DMC). The results indicate the effective and well separated peaks of all analyte acids from C1 to C7 with regression coefficients r² ≥ 0.98 (C1–C4) and ≥ 0.93 (C5–C7) during calibration. The digestate samples analyzed showed abundance of acetic acid from 4.6 to 11 mM concentration in all four samples followed by propanoic acid (C3) to hexanoic acid (C6) in a range from 0.3 to 4.5 mM concentration. The method is suitable for quantifying all VFAs from C1 to C7 analyte acids as well as the isomers of C4 to C6 analyte acids. Moreover, the method is applicable to a variety of liquid samples from water treatment to energy valorization. Full article

Flavor-relevant trace volatiles and microbial communities were examined in six sauce-aroma high-temperature Daqu samples. Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) quantified 210 trace volatile compounds across 14 chemical classes. Orthogonal partial least squares discriminant analysis (OPLS-DA) with variable importance in projection (VIP) screening was integrated with sensory scoring, correlation analysis, and molecular docking to an olfactory receptor model. Volatile profiles showed clear stratification in total abundance. Pyrazines dominated the high-total group. Tetramethylpyrazine served as a major driver. Sensory evaluation indicated that aroma explained overall quality best. (E)-2-pentenal and dimethyl trisulfide showed significant positive associations with aroma and overall scores. In the olfactory receptor, the polar residue module that provides directional constraints for Daqu odor activation was formed by Ser75, Ser92, Ser152, Ser258, Thr74, Thr76, Thr98, Thr200, Gln99, and Glu94. The hydrogen-bond or charge network was further reinforced by Arg150, Arg262, Asn194, His180, His261, Asp182, and Gln181. The core discriminant set comprised acetic acid, hexanoic acid, (E)-2-pentenal, nonanal, decanal, dimethyl trisulfide, trans-3-methyl-2-n-propylthiophane, 2-hexanone oxime, ethyl linoleate, propylene glycol, 2-ethenyl-6-methylpyrazine, 4-methylquinazoline, 5-methyl-2-phenyl-2-hexenal, and 1,2,3,4-tetramethoxybenzene. Sequencing revealed higher bacterial diversity than fungal. Bacillus and Kroppenstedtia were dominant bacterial genera. Aspergillus, Paecilomyces, Monascus, and Penicillium were major fungal genera. Correlation patterns suggested that Bacillus and Monascus were positively linked to acetic acid and 1,2,3,4-tetramethoxybenzene. Together, these results connected chemical fingerprints, sensory performance, receptor-level plausibility, and microbial ecology. Concrete targets are provided for quality control of high-temperature Daqu. Full article

This study evaluated the suitability of a new glutinous rice cultivar of Gureumchal as a raw material for Makgeolli, a traditional Korean rice wine, by comparing Makgeolli produced from Gureumchal with those made from a non-glutinous rice and another glutinous rice cultivar. Makgeolli was prepared using single and blended rice combinations, and their physicochemical characteristics, amino acids, volatile aromatic compounds, and E-tongue were analyzed. The Gureumchal produced generally higher levels of total amino acids and ester compounds, particularly fruity esters, when compared with the other rice formulations. A volatile aromatic compound analysis indicated that non-glutinous rice favored the formation of acetate esters typically associated with the acetyl-CoA pathway, whereas Gureumchal produced higher levels of fruity acyl-CoA-derived esters, such as ethyl hexanoate and ethyl octanoate. An E-tongue analysis further demonstrated that rice type strongly shaped the Makgeolli’s taste profile: glutinous rice samples, including Gureumchal, exhibited higher sweetness but low umami, whereas non-glutinous rice produced higher acidity and umami. Blended samples confirmed that manipulating the proportion of glutinous and non-glutinous rice allows the systematic adjustment of taste balance. Overall, Gureumchal formed a distinct flavor profile characterized by fruity esters and pronounced sweetness, indicating its potential to diversify Makgeolli quality and support targeted flavor design. Full article

Type 1 Diabetes (T1D) is thought to result from the interaction of genetic and environmental factors, with different studies highlighting a potential role for the gut microbiota and its metabolites in modulating immune responses and disease development. We hypothesized that patients with T1D exhibited altered levels of circulating bacterial metabolites compared with healthy controls (HC), and that these metabolite profiles were associated with key demographic, clinical, and analytical features of the disease. A total of 91 T1D patients and 58 HC were recruited. Plasma samples were collected and analyzed with gas chromatography coupled to mass spectrometry for the detection of the metabolites: short-chain fatty acids (SCFAs: acetate [AA], propionate [PA], isobutyrate [IBA], butyrate [BA], isovalerate [IVA], valerate [VA], and methyl valerate [MVA]), medium-chain fatty acids (MCFAs: hexanoate [HxA] and heptanoate [HpA]) and para-cresol (p-cresol). We also calculated the ratios between the different SCFAs with AA. T1D patients showed significantly higher circulating AA levels than HC, along with reduced PA/AA and IBA/AA ratios, indicating an altered SCFA profile. SCFA diversity was lower in T1D patients, with reduced detection of BA, and total SCFA levels were increased mainly due to elevated AA. AA levels were higher and SCFA ratios lower in women with T1D compared with healthy women, while p-cresol levels were higher in men with T1D than in healthy men. In T1D patients, AA levels positively correlated with HbA1c, whereas PA/AA, IBA/AA, and BA/AA ratios showed negative correlations, particularly in women. MV/AA and non-AA/AA ratios were inversely associated with glucose levels, again, mainly in women. p-cresol levels correlated positively with age and ferritin and were higher in T1D patients with liver dysfunction or hypertension. Therefore, we can conclude that T1D is associated with a marked alteration in circulating gut-derived metabolites, characterized by increased AA levels, particularly in women, and an imbalance in SCFA ratios that correlates with glycemic control. These findings, together with the associations observed for p-cresol and metabolic comorbidities, support a role for the gut microbiota–host metabolic axis in T1D. Full article