Change in Flavonoid Composition and Antioxidative Activity during Fermentation of Onion (Allium cepa L.) by Leuconostoc mesenteroides with Different Salt Concentrations

Phenolic metabolites changes during baijiu fermentation through non-targeted metabonomic

To investigate the changes of phenolic metabolite during different grains fermentation stages of Chinse Baijiu, the ultra-performance liquid chromatography-quadrupole time of-flight mass spectrometry (UHPLC-QTOF-MS) was applied to identify and analyze the different phenolic metabolites, combined with principal component analysis and partial least squares discriminant analysis. Results indicated that significant differences in phenolic metabolites during different fermentation stages were found. Among the 231 phenolic metabolites detected, 36, 31, 19, 23, 14, and 50 differential phenolic metabolites were screened between different groups using partial least squares discriminant analysis. Twelve metabolic pathways with high correlation of differential phenolic metabolites and 23 main participating differential metabolites were identified through KEGG metabolic pathway enrichment analysis. The present study preliminarily revealed the differences of phenolic metabolites at different fermentation stages, and providing a theoretical basis for the further improving of the taste and quality of Chinese Baijiu.

Quercetin-4'-O-β-D-glucopyranoside inhibits podocyte injury by SIRT5-mediated desuccinylation of NEK7

Diabetic kidney disease (DKD) is a complication of diabetic mellitus. New treatments need to be developed. This study aimed to investigate the effects of quercetin-4'-O-β-D-glucopyranoside (QODG) on podocyte injury. Podocytes were cultured in high glucose (HG) medium, treated with QODG, and overexpressing or knocking down SIRT5. Oxidative stress indicators were assessed using corresponding kits. Pyroptosis was detected by flow cytometry and western blot analysis. Succinylation modification was detected using immunoprecipitation (IP) and western blot analysis. The interaction between NEK7 and NLRP3 was determined by co-IP. The results indicated that QODG inhibited oxidative stress and pyroptosis of podocytes induced by HG. Besides, QODG suppressed succinylation levels in HG-induced podocytes, with the upregulation of SIRT5. Knockdown of SIRT5 reversed the effects of QODG on oxidative stress and pyroptosis. Moreover, SIRT5 inhibited the succinylation of NEK7 and the interaction between NLRP3 and NEK7. In conclusion, QODG upregulates SIRT5 to inhibit the succinylation modification of NEK7, impedes the interaction between NEK7 and NLRP3, and then inhibits the pyroptosis and oxidative stress injury of podocytes under HG conditions. The findings suggested that QODG has the potential to treat DKD and explore a novel underlying mechanism of QODG function.

Unlocking Flavor Potential Using Microbial β-Glucosidases in Food Processing

Aroma is among of the most important criteria that indicate the quality of food and beverage products. Aroma compounds can be found as free molecules or glycosides. Notably, a significant portion of aroma precursors accumulates in numerous food products as nonvolatile and flavorless glycoconjugates, termed glycosidic aroma precursors. When subjected to enzymatic hydrolysis, these seemingly inert, nonvolatile glycosides undergo transformation into fragrant volatiles or volatiles that can generate odor-active compounds during food processing. In this context, microbial β-glucosidases play a pivotal role in enhancing or compromising the development of flavors during food and beverage processing. β-glucosidases derived from bacteria and yeast can be utilized to modulate the concentration of particular aroma and taste compounds, such as bitterness, which can be decreased through hydrolysis by glycosidases. Furthermore, oral microbiota can influence flavor perception by releasing volatile compounds that can enhance or alter the perception of food products. In this review, considering the glycosidic flavor precursors present in diverse food and beverage products, we underscore the significance of glycosidases with various origins. Subsequently, we delve into emerging insights regarding the release of aroma within the human oral cavity due to the activity of oral microbial glycosidases.

Synergistic Antioxidant and Anti-Inflammatory Activities of Kale Juice Fermented with Limosilactobacills reuteri EFEL6901 or Limosilactobacills fermentum EFEL6800

This study investigates the synergistic impact of fermenting kale juice with Limosilactobacillus strains on its antioxidant and anti-inflammatory properties. Kale's rich nutrient profile, especially its flavonoids, offers potential health benefits. Probiotic lactic acid bacteria are employed in kale fermentation to enhance nutrient bioavailability and generate bioactive compounds. Kale juices fermented with L. reuteri EFEL6901 or L. fermentum EFEL6800 exhibited superior microbial growth. Free sugars and amino acids were converted to alcohols and organic acids, affecting the organoleptic and health-related properties of the product. In addition, fermentation increased quercetin and kaempferol content, indicating improved availability. Furthermore, the fermented juice exhibited notable antioxidant activity and suppressed nitric oxide (NO) production, revealing anti-inflammatory potential. Gene expression analysis confirmed reduced pro-inflammatory markers such as iNOS, COX-2, IL-6, and IL-1β and elevated anti-inflammatory cytokines, including IL-10. This research highlights the promising potential of fermented kale juice, enriched with Limosilactobacillus strains, as a functional food with combined antioxidant and anti-inflammatory benefits.

Genome-Wide Comparative Analysis of Lactiplantibacillus pentosus Isolates Autochthonous to Cucumber Fermentation Reveals Subclades of Divergent Ancestry

Lactiplantibacillus pentosus, commonly isolated from commercial cucumber fermentation, is a promising candidate for starter culture formulation due to its ability to achieve complete sugar utilization to an end pH of 3.3. In this study, we conducted a comparative genomic analysis encompassing 24 L. pentosus and 3 Lactiplantibacillus plantarum isolates autochthonous to commercial cucumber fermentation and 47 lactobacillales reference genomes to determine species specificity and provide insights into niche adaptation. Results showed that metrics such as average nucleotide identity score, emulated Rep-PCR-(GTG)₅, computed multi-locus sequence typing (MLST), and multiple open reading frame (ORF)-based phylogenetic trees can robustly and consistently distinguish the two closely related species. Phylogenetic trees based on the alignment of 587 common ORFs separated the L. pentosus autochthonous cucumber isolates from olive fermentation isolates into clade A and B, respectively. The L. pentosus autochthonous clade partitions into subclades A.I, A.II, and A.III, suggesting substantial intraspecies diversity in the cucumber fermentation habitat. The hypervariable sequences within CRISPR arrays revealed recent evolutionary history, which aligns with the L. pentosus subclades identified in the phylogenetic trees constructed. While L. plantarum autochthonous to cucumber fermentation only encode for Type II-A CRISPR arrays, autochthonous L. pentosus clade B codes for Type I-E and L. pentosus clade A hosts both types of arrays. L. pentosus 7.8.2, for which phylogeny could not be defined using the varied methods employed, was found to uniquely encode for four distinct Type I-E CRISPR arrays and a Type II-A array. Prophage sequences in varied isolates evidence the presence of adaptive immunity in the candidate starter cultures isolated from vegetable fermentation as observed in dairy counterparts. This study provides insight into the genomic features of industrial Lactiplantibacillus species, the level of species differentiation in a vegetable fermentation habitat, and diversity profile of relevance in the selection of functional starter cultures.

Identification of a candidate gene responsible for the G locus determining chartreuse bulb color in onion (Allium cepa L.) using bulked segregant RNA-Seq

A gene encoding a laccase responsible for chartreuse onion bulb color was identified. Markers tagging this gene showed perfect linkage with bulb colors among diverse germplasm. To identify a casual gene for the G locus determining chartreuse bulb color in onion (Allium cepa L.), bulked segregant RNA-Seq (BSR-Seq) was performed using yellow and chartreuse individuals of a segregating population. Through single nucleotide polymorphism (SNP) and differentially expressed gene (DEG) screening processes, 163 and 143 transcripts were selected, respectively. One transcript encoding a laccase-like protein was commonly identified from SNP and DEG screening. This transcript contained four highly conserved copper-binding domains known to be signature sequences of laccases. This gene was designated AcLAC12 since it showed high homology with Arabidopsis AtLAC12. A 4-bp deletion creating a premature stop codon was identified in exon 5 of the chartreuse allele. Another mutant allele in which an intact LTR-retrotransposon was transposed in exon 5 was identified from other chartreuse breeding lines. Genotypes of molecular markers tagging AcLAC12 were perfectly matched with bulb color phenotypes in segregating populations and diverse breeding lines. All chartreuse breeding lines contained inactive alleles of DFR-A gene determining red bulb color, indicating that chartreuse color appeared when both DFR-A and AcLAC12 genes were inactivated. Linkage maps showed that AcLAC12 was positioned at the end of chromosome 7. Transcription levels of structural genes encoding enzymes in anthocyanin biosynthesis pathway were generally reduced in chartreuse bulk compared with yellow bulk. Concentrations of total quercetins were also reduced in chartreuse onion. However, significant amounts of quercetins were detected in chartreuse onion, implying that AcLAC12 might be involved in modification of quercetin derivatives in onion.

Effects of Anaerobic Fermentation on Black Garlic Extract by Lactobacillus: Changes in Flavor and Functional Components

The purpose of this study is to investigate the potential application of probiotics in the development of novel functional foods based on black garlic. The single-factor analysis (extraction temperatures, solid-to-liquid ratios, and extraction times) and the response surface methodology were firstly used to optimize hot water extraction of soluble solids from black garlic. The optimal extraction conditions were temperature 99.96°C, solid-to-liquid ratio 1:4.38 g/ml, and extracting 2.72 h. The effects of Lactobacillus (Lactobacillus plantarum, Lactobacillus rhamnosus, and co-culture of them) fermentation on the physicochemical properties of black garlic extract broth were studied for the first time. Artificial and electronic sensory evaluations demonstrated that fermentation significantly influenced the sensory characteristics. The variations of metabolites in different broth samples (S1, unfermented; S2, 1-day fermentation by L. plantarum; S3, 2-day fermentation by L. rhamnosus; and S4, 1-day fermentation by co-cultured Lactobacillus) were further investigated by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry/mass spectrometry analysis. As a result, Lactobacillus fermentation significantly reduced the pH; increased the contents of the total acid, amino nitrogen, total polyphenol, and total flavonoid; and reduced the content of 5-hydroxymethylfurfural (a carcinogenic component) by 25.10-40.81% in the black garlic extract. The contents of several components with unpleasant baking flavors (e.g., furfural, 2-acetylfuran, and 5-methyl furfural) were reduced, whereas the contents of components with green grass, floral, and fruit aromas were increased. More importantly, the contents of several functional components including lactic acid, Gly-Pro-Glu, sorbose, and α-CEHC (3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-propanoic acid) were increased after Lactobacillus fermentation. The results demonstrated the potential of probiotic fermentation to improve the quality of black garlic. This work will provide an insight into the strategic design of novel black garlic products and facilitate the application of black garlic in functional foods.

Allium Flavonols: Health Benefits, Molecular Targets, and Bioavailability

Allium species are revered worldwide as vegetables, condiments, and spices as well as the therapeutic agents in traditional medicine. The bioactive compounds in alliums mainly include organosulfur compounds, polyphenols, dietary fibers, and saponins. Flavonoids, particularly flavonols from alliums, have been demonstrated to have the antioxidant, anticancer, hypolipidemic, anti-diabetic, cardioprotective, neuroprotective, and antimicrobial activities. However, flavonols are mostly characterized from onions and have not been comprehensively reviewed across different species. This article therefore focuses on flavonol profiles from different Allium species, their health effects, underlying molecular mechanisms, and bioavailability. Intriguingly, the functional health effects of flavonols were mainly ascribed to their antioxidant and anti-inflammatory activities involving a cascade of multiple signaling pathways. Although the Allium-derived flavonols offer tremendous potential in preventing chronic disease risks, in-depth studies are needed to translate their clinical application.

Effects of different processing methods on the antioxidant and immune stimulating abilities of garlic

In this study, we determined the antioxidant and immune stimulating abilities of a garlic product developed by freeze drying, heat drying, and solid-state fermentation of heat-dried garlic. Lactobacillus plantarum KCTC21004 and Leuconostoc mesenteroides KCTC13302 were used for the sample fermentation. The optimum conditions for fermentation were 50% (v/w) moisture, a fermentation time of 48 hr and a temperature of 37°C. Heat-dried garlic samples fermented with L. plantarum KCTC21004 (HD21004) and L. mesenteroides KCTC13302 (HD13302) showed the highest flavonoid contents while heat-dried garlic (HD) had the lowest flavonoid content. HD21004 contained the highest phenolic compounds, showed the highest antioxidant activity and demonstrated a strong immune stimulating effect while freeze-dried garlic showed the lowest flavonoid and polyphenolic contents. Overall, the heat-dried garlic samples (fermented and unfermented) contained about three times more S-Allylcysteine (SAC) than the freeze-dried samples (FD). The current study demonstrates that heat drying and subsequent fermentation of garlic with L. plantarum KCTC21004 can improve its therapeutic effects.

Phenolics and eudesmanolide from aged common sage exudate with sugar

Nineteen compounds including one new flavanone were isolated from the juice of aged common sage exudate with sugar (ACSE). The isolated compounds were identified by NMR and MS analyses as levodopa methyl ester (1), 3,4-dihydroxybenzoic acid (2), (S)-8-hydroxy-4-hydroxy-phenylpropanoic acid (3), 4-hydroxybenzoic acid ethyl ester (4), cis-caffeic acid (5), trans-caffeic acid (6), esculetin (7), (S)-8-hydroxy-3,4-dihydroxy-phenylpropanoic acid ethyl ester (8), cis-rosmarinic acid (9), trans-rosmarinic acid (10), trans-rosmarinic acid methyl ester (11), 6-methoxy-7,8,3',5'-tetrahydroxyflavanone (12), nepetin (13), trans-caffeic acid ethyl ester (14), luteolin (15), cis-caffeic acid ethyl ester (16), 6-methoxynaringenin (17), 1α-acetoxy-2-oxo-eudesman-3,7(11)-dien-8β,12-olide (18), and hispidulin (19). Compound 12 was isolated for the first time from nature and seven compounds (1, 3, 4, 7, 8, 14, and 18) were newly identified from common sage. Of them, 15 isolated phenolic compounds (1-3, 5-8, 10-15, 17, and 19) were detected in ACSE juice, while only 10 was detected in the fresh common sage.

Glu-Phe from onion (Allium Cepa L.) attenuates lipogenesis in hepatocytes

A Glu-Phe (EF) was isolated from onion (Allium cepa L. cv. Sunpower). The chemical structure of EF was determined by nuclear magnetic resonance and electrospray ionization-mass (ESI-MS) spectroscopy. We showed that EF reduced lipid accumulation in mouse hepatocytes by inhibiting the expression of sterol regulatory element-binding protein-1c (SREBP-1c) and its lipogenic target genes. We also found that AMP-activated protein kinase (AMPK) was required for the inhibitory effect of EF on lipid accumulation in mouse hepatocytes. Furthermore, EF was qualified in nine onion cultivars by selective multiple reaction-monitoring detection of liquid chromatography-ESI-MS. These results suggest that EF could contribute to the beneficial effect of onion supplement in maintaining hepatic lipid homeostasis.

Enhancement of antioxidative and antimicrobial activities of immature pear (Pyrus pyrifolia cv. Niitaka) fruits by fermentation with Leuconostoc mesenteroides

Immature pear (Pyrus pyrifolia cv. Niitaka) fruits were fermented with Leuconostoc mesenteroides and Aspergillus oryzae, which are commonly used as starters for manufacturing fermented foods. Fermented immature pear fruit extracts (FIPF) by L. mesenteroides showed significantly higher radical-scavenging activity using DPPH, ABTS, superoxide anion, and hydroxyl radicals and reducing power capacity than unfermented immature pear fruit extracts. L. mesenteroides-FIPF more effectively inhibited the formation of cholesteryl ester hydroperoxide in copper ion-induced rat blood plasma. In addition, the L. mesenteroides-FIPF strongly inhibited tyrosinase activity and the growth of pathogenic skin bacteria. In contrast, enhanced antioxidative and antibacterial activities were not apparent in A. oryzae-FIPF. The antioxidative and antimicrobial activities of the fermented and unfermented immature pear fruits were correlated with the flavonoid contents. These results indicate that fermentation enhances antioxidative and antimicrobial activities of immature pear fruits.