Search Results (328)

Malolactic fermentation (MLF), a key enological process for wine deacidification and aroma and flavor development, is predominantly mediated by lactic acid bacteria. This study characterized 342 indigenous Lactiplantibacillus plantarum (L. plantarum) isolates, a potential starter species underexploited for MLF, from China’s Jiaodong Peninsula wine regions through polyphasic analysis. Thirty strains with high tolerance to wine stress conditions and efficient malate metabolism were selected. Among these, two high-performance strains, P101 and J43, exhibited superior MLF kinetics. Their applications had almost no effect on the wine’s basic physicochemical parameters, color parameters, and individual phenolic contents. Solid-phase microextraction–gas chromatography–mass spectrometry (SPME-GC-MS) analysis revealed that these strains significantly enhance key aroma compound contents in wines, including ethyl acetate, ethyl lactate, ethyl 2-methylbutyrate, and nerol, contributing more floral and fruity aroma characteristics. These indigenous L. plantarum strains, novel microbial starter cultures, demonstrate dual functionality in enhancing wine quality through controlled fermentation while supporting microbial biodiversity through the development of region-specific strain resources. Full article

Carob pulp flour (Ceratonia siliqua) is gaining attention as a sustainable ingredient with nutritional and functional potential. This study evaluated the partial replacement of soft wheat flour with 10% carob pulp flour in breadmaking, focusing on the role of different leavening strategies: commercial baker’s yeast (LB), a selected starter culture, Lactiplantibacillus plantarum SL31 and Saccharomyces cerevisiae SY17 (LI), and a type I sourdough (LS). Dough rheology, microbial dynamics, bread quality, acceptability, and shelf-life were assessed. Results showed that the inclusion of carob pulp flour enhances the nutritional profile while maintaining satisfactory technological performance. The leavening strategy strongly influenced the final products: breads made with commercial yeast displayed high volume and softness but were less stable during storage; LS breads achieved greater microbial stability but were limited by excessive acidity and reduced sensory acceptance; breads obtained with the selected starter culture offered the most balanced outcome, combining moderate structure with enhanced flavor and consumer preference. Overall, the findings demonstrate the feasibility of incorporating carob pulp flour into bakery products and highlight the potential of tailored starter cultures as a promising compromise between technological performance, sensory quality, and shelf-life. Future work should optimize fermentation approaches to further enhance consumer appeal and support industrial application. Full article

Sauce-flavor Daqu is the solid-state fermentation starter for sauce-flavor Baijiu. Its microbial community influences flavor formation, yet links between community change, process conditions, and flavor development during high-temperature fermentation remain unclear. We investigated Daqu fermentation by integrating high-throughput sequencing, monitoring of physicochemical parameters, and analysis of volatile compounds. Fermentation temperature showed three phases: rapid rise, fluctuating plateau, and gradual decline. High temperatures were associated with increased thermophilic microbes such as Bacillus and Thermoascus and with higher levels of reducing sugars and amino acid nitrogen; amylase, protease, and other hydrolase activities were detected. Bacterial composition varied more than fungal composition; Firmicutes and Ascomycota were the dominant phyla, and Bacillus and Thermoascus were abundant genera. Canonical correspondence analysis associated reducing sugars, acidity, and moisture with early community shifts, and amino acid nitrogen with later shifts; reducing sugars and moisture showed the strongest associations. Filamentous fungi and Bacillus correlated with pyrazine-type compounds. These results link microbial composition, process parameters, and flavor profiles, and may inform the standardization and mechanization of Daqu production. Full article

Dairy products harbor complex and dynamic microbial communities that contribute to their sensory properties, safety, and cultural distinctiveness. Raw milk contains a diverse microbiota shaped by seasonality, storage conditions, lactation stage, animal health, farm management, and genetics, serving as a variable starting point for further processing. Fermentation, whether spontaneous or starter driven, selects for subsets of lactic acid bacteria (LAB), yeasts, and molds, resulting in microbial succession that underpins both artisanal and industrial products such as kefir and cheese. Kefir represents a balanced LAB–yeast symbiosis, with species composition influenced by grain origin, milk type, and processing parameters, whereas the cheese microbiota reflects the interplay of starter and non-starter LAB, coagulants, ripening conditions, and “house microbiota”. Methodological factors—including DNA extraction, sequencing platform, and bioinformatic pipelines—further impact the reported microbial profiles, highlighting the need for standardization across studies. This review synthesizes current knowledge on raw milk, kefir, and cheese microbiomes, emphasizing the biological, technological, environmental, and methodological factors shaping microbial diversity. A holistic understanding of these drivers is essential to preserve product authenticity, ensure safety, and harness microbial resources for innovation in dairy biotechnology. Full article

Nong-flavor (NF) Daqu, a critical fermentation starter for traditional Baijiu, harbors diverse starch-degrading enzymes with poorly characterized functional dynamics. This study transcended traditional quality assessments by developing molecular approaches to dissect starch-hydrolyzing enzyme genes. Specific and degenerate primers targeting glucoamylase, α-amylase, and α-glucosidase genes were designed, and key genes were qualitatively identified with distinct distributions among NF Daqus and unique presences between JXL and HB Daqu. Quantitative PCR revealed six genes with elevated expression in JXL Daqu versus HB Daqu, and which peaked during late fermentation in both Daqus. Metagenomics identified greater enzymatic diversity in HB Daqu. Phylogenetic clustering confirmed evolutionary conservation (GH13/GH15/GH31 families) and specificity of core enzyme genes across both Daqus. Enzymatic assays demonstrated the dominance of saccharification over α-glucosidase activity in both Daqus, with significantly higher α-glucosidase activity in JXL than HB Daqu. Divergent starch degradation strategies emerged: JXL prioritized high enzyme expression/activity, while HB utilized broader gene abundance. Based on Pearson correlation analysis, the saccharification activity showed the highest but weak correlation with α-glucosidase gene_15963 (r = 0.26), and was also positively correlated with the expression of all other enzyme genes except one glucoamylase gene. Meanwhile, α-glucosidase activity was most strongly linked to glucoamylase gene_22243 (r = 0.76), with additional correlations with two α-glucosidase genes being observed. This establishes RNA-based biomarkers for real-time quality control. Our findings decode divergent microbial strategies (JXL: high-expression/high-activity vs. HB: high-diversity) and provide a molecular framework for optimizing starch utilization in Baijiu fermentation. This technology holds potential to enable precision-driven standardization of traditional food production, which would reduce processing waste and enhance resource efficiency. Full article

The research aimed to examine the effects of fermentation and enzymatic hydrolysis of cottonseed protein on body weight changes, serum biochemistry, rumen function, intestinal health, and liver metabolism of suckling lambs. A total of twelve 7-day-old healthy male Hu sheep body weights (5.27 ± 0.48 kg) were randomly distributed into two groups. Starter feed regimens containing microbial fermentation of cottonseed protein (MFCP) or enzymatic hydrolysate of cottonseed protein (EHCP) were administered to lambs during the initial 60-day period. Results showed that compared with EHCP group, the serum glucose, ruminal acetic, propionic, butyric and valeric acids concentrations, jejunal immunoglobulin G content and mRNA expressions of Claudin 1 and Occludin, as well as the relative abundance of actinobacteriota and pseudoscardovia in the rumen were significantly increased in the MFCP group (p < 0.05), whereas an opposite trend was observed in the jejunum. α-amylase and trypsin enzymatic activities were observed between the two groups. Relative to EHCP treatment, the MFCP group exhibited 69 elevated and 103 reduced hepatic metabolites, and these metabolites displayed distinct enrichment patterns within specific metabolic networks, including fructose and mannose metabolism (p = 0.003), arachidonic acid metabolism (p = 0.017), glycerophospholipid metabolism (p = 0.036), and the cAMP signaling pathway (p = 0.047). Overall, microbial fermentation of cottonseed protein may be beneficial for strengthening intestinal barrier function and facilitating hepatic lipid metabolism and immune regulation, while enzymatic hydrolysis of cottonseed protein enhances gastrointestinal digestive enzyme activity, thereby promoting nutrient digestion of suckling lambs. Full article

The black soldier fly (Hermetia illucens) has become one of the most promising alternative protein sources in the feed and food industry. The aim of this work was to utilize microbial fermentation to enhance the nutritional properties of black soldier fly larvae (BSFL) as a food ingredient for human consumption by optimizing the amino acid profile and small peptide content. Free amino acids (FAA) have a critical role in human nutrition and bioavailability. Unlike whole proteins that require enzymatic breakdown in the digestive tract, FAA are directly absorbable by the small intestine, allowing for rapid utilization in protein synthesis and metabolic functions. BSFL pastes were fermented using Lacticaseibacillus paracasei (PCB 030) or a mixed starter culture preparation, and results were compared to pea protein and BSFL pastes that were enzymatically hydrolyzed. The resultant hydrolyzed BSFL pastes were analyzed for free amino acids and small peptides. The L. paracasei PCB 030 fermented BSFL pastes yielded significantly higher amounts of free amino acids than the control or pastes fermented using a commercial starter culture (named F-LC). The increased FAA availability in fermented BSFL makes it a more efficient protein source for human consumption. The L. paracasei PCB 030 fermented pastes showed an increase in small peptides after three days fermentation; nearly 80% of normalized abundances of small peptides increased by over 100 times compared to day zero (before the fermentation started). Over 90% of these small peptides consisted of more than 50% hydrophobic amino acids, which may contribute to their antioxidant and antibacterial properties. This study provides a promising and industrially practical process for hydrolyzing BSFL protein to yield a functional protein hydrolysate with an enhanced nutritional profile. Full article

Sea grape kombucha has been known to exhibit high antioxidant activity due to its elevated total polyphenol content. This study aims to identify and characterize the active microbial community involved in the fermentation of kombucha using sea grapes (C. racemosa) as the primary substrate. Furthermore, it evaluates the effects of different Symbiotic Culture of Bacteria and Yeast (SCOBY) starter concentrations on the physicochemical properties and antioxidant activity of sea grape kombucha. Our results showed that the pH of the kombucha was higher after 7 days of fermentation compared to later time points. The microbial community was composed of 97.08% bacteria and 2.92% eukaryotes, divided into 10 phyla and 69 genera. The dominant genus in all samples was Komagataeibacter. Functional profiling based on 16S rRNA data revealed that metabolic functions accounted for 77.04% of predicted microbial activities during fermentation. The most enriched functional categories were carbohydrate metabolism (15.70%), cofactor and vitamin metabolism (15.54%), and amino acid metabolism (14.24%). At KEGG Level 3, amino acid-associated pathways, particularly alanine, aspartate, and glutamate metabolism (4.24%), were predominant. The fermentation process in sea grape kombucha is primarily driven by carbohydrate and amino acid metabolism, supported by energy-generating and cofactor biosynthesis pathways. Our findings indicate that different metabolic pathways lead to variations in kombucha components, and distinct fermentation stages result in different metabolic reactions. For instance, early fermentation stages (Day 7) are dominated by amino acid metabolism, whereas the late stages (Day 21) show increased activity in carbohydrate and sulfur metabolism. Metabolomic analysis revealed that increasing the SCOBY starter concentration significantly influenced pH, soluble solid content, vitamin C, tannin, and flavonoid content. These variations suggest that fermentation duration and microbial composition significantly influence the spectrum of bioactive metabolites, which synergistically provide functional benefits such as antimicrobial, antioxidant, and metabolic health-promoting activities. For example, sample K1 produced more fatty acids and simple sugar alcohols, sample K2 enriched complex lipid compounds and phytosterols, while sample K3 dominated the production of polyols and terpenoid compounds. Full article

Kefir is a historic dairy-fermented beverage produced using lactic acid bacteria and yeast as a starter culture and is considered nutritious with a good taste. Many studies have been conducted to incorporate various possible functional materials into kefir to enhance its nutritional value. This study aims to enrich kefir with 0.25% and 0.5% of Stinging nettle (Sn) powder before fermentation to improve its nutritional value. Stinging nettle (Urtica dioica) is a nutritious and multifunctional herb with a variety of healthful components such as fibers and polyphenols; it has significant potential as a useful food functional ingredient. The physicochemical, microbial, and nutritional properties of kefir fortified with Sn were examined weekly during refrigerated storage for 21 days. The results showed that adding Stinging nettle significantly (p < 0.05) increased the probiotic counts from 7.90 ± 0.22 log to 8.46 ± 0.19 log CFU/g, antioxidant activity (4%), and total polyphenol contents (5%) in kefir yogurt after 12 days of refrigerated storage. The addition of Sn also had a positive effect on the acidity of kefir and increased the viscosity and the syneresis to a certain extent. Furthermore, adding Sn increased lactic acid bacteria counts and the production of short-chain fatty acids after in vitro digestion and colonic fermentation. The results of this study indicated the potential use of Sn powder as a functional ingredient in kefir yogurt and other similar products. Full article

Lactobacillus-enriched yogurt is in increasingly high demand due to its health benefits, but the product stability requires an understanding of the microbial dynamics during fermentation and storage. This study investigated the interactions between probiotic pairs (L. paracasei L9 and L. acidophilus LAC) and starter culture (HYY) through fermentation kinetics, microbial viability, organic acid profiles, and metabolomics. The results demonstrated that L. paracasei L9 significantly increased the titratable acidity from 25.20 ± 7.01 °T to 36.56 ± 3.47 °T at 3 h and reduced the fermentation time by 0.5 h, whereas L. acidophilus LAC showed minimal effects. L. paracasei L9 achieved higher viability (8.4 lg CFU/g) via the high-affinity lactose transport and Leloir pathway, whereas the L. acidophilus LAC growth remained limited (6.9 lg CFU/g). The metabolomic investigation revealed the L9 + HYY upregulated glycerophospholipid metabolism and pantothenate/CoA biosynthesis to support rapid biomass accumulation. In contrast, LAC + HYY modulated the arginine and branched-chain amino acid metabolism for acid tolerance. During 21 days of storage, there were no significant differences in final TA values and lactic acid content among the probiotic supplementation groups. L9 + HYY remained stable (>9.0 lg CFU/g) by upregulating the aromatic amino acid biosynthesis and suppressing the purine/sulfur metabolism, whereas L. acidophilus LAC decreased to 6.02 lg CFU/g. These findings demonstrate the dual role of L. paracasei L9 in accelerating the fermentation and maintaining the microbial stability through metabolic reprogramming, which guides the development of improved probiotic yogurts. Full article

Plant-based yogurts are increasingly recognized as sustainable and health-conscious alternatives to dairy-based products, driven by environmental, ethical, and nutritional motivations. Pistachio milk, derived from an efficient and resilient crop, emerges as a promising raw material for yogurt production, offering unique sensory qualities and a dense nutritional profile. Rich in unsaturated fatty acids, bioactive compounds, and essential nutrients, pistachios are ideal for fermentation with lactic acid bacteria (LAB). In this study, a novel pistachio-based yogurt analog (PBYA) was developed using lactic acid fermentation, with a yogurt commercial starter, of pistachio milk. The production process was optimized to create an additive-free, clean-label formulation without the use of stabilizers or thickeners. The physicochemical, microbiological, and sensory properties of the PBYA were evaluated over refrigerated storage. The final product exhibited high levels of protein (5.6%), fat (5.4–6.8%), and total solids (20.5–21.4%), along with desirable texture and flavor characteristics. Notably, PBYA presented significantly higher concentrations of total free amino acids (754 mg/L) compared to commercial soy (557 mg/L) and cow’s milk yogurts (390 mg/L), particularly in essential amino acids such as lysine, methionine, and tryptophan. This enhanced free amino acid profile contributes to the product’s functional and nutritional value. Sensory analysis revealed good acceptance of the product, with improvements in viscosity and firmness over time, likely due to microbial exopolysaccharide production. Overall, the findings highlight the feasibility and commercial potential of PBYA as a clean-label, plant-based fermented product that meets current consumer demands for sustainability, nutrition, and sensory quality. Full article

The citrus processing industry is an economically important agro-industrial sector worldwide; however, it produces significant amounts of waste annually. The biorefinery concept and the recovery of bio-based materials from agro-industrial residues, including citrus processing waste, are emphasized in the European Green Deal, reflecting the EU’s commitment to fostering circularity. Biotreatment of citrus processing waste, including bioconversion into biomethane, biohydrogen, bioethanol and biodiesel, has been applied to valorize biomass for energy recovery. It can also be composted into a valuable soil conditioners and fertilizers, while raw and fermented citrus residues may exhibit phytoprotective activity. Citrus-derived residues can be converted into materials such as nanoparticles with adsorptive capacity for heavy metals and recalcitrant organic pollutants, and materials with antimicrobial properties against various microbial pathogens, or the potential to remove antibiotic-resistance genes (ARGs) from wastewater. Indeed, citrus residues are an ideal source of industrial biomolecules, like pectin, and the recovery of bioactive compounds with added value in food processing industry. Citrus processing waste can also serve as a source for isolating specialized microbial starter cultures or as a substrate for the growth of bioplastic-producing microorganisms. Solid-state fermentation of citrus residues can enhance the production of hydrolytic enzymes, with applications in food and environmental technology, as well as in animal feed. Certain fermented products also exhibit antioxidant properties. Citrus processing waste may be used as alternative feedstuff that potentially improves the oxidative stability and quality of animal products. Full article

Microorganisms play a crucial role in food processes, safety, and quality through their dynamic interactions with other organisms. In recent years, biosensors have become essential tools for monitoring these processes in the dairy, meat, and fresh produce industries. This review highlights how microbial diversity, starter cultures, and interactions, such as competition and quorum sensing, shape food ecosystems. Diverse biosensor platforms, including electrochemical, optical, piezoelectric, thermal, field-effect transistor-based, and lateral flow assays, offer distinct advantages tailored to specific food matrices and microbial targets, enabling rapid and sensitive detection. Biosensors have been developed for detecting pathogens in real-time monitoring of fermentation and tracking spoilage. Control strategies, including bacteriocins, probiotics, and biofilm management, support food safety, while decontamination methods provide an additional layer of protection. The integration of new techniques, such as nanotechnology, CRISPR, and artificial intelligence, into Internet of Things systems is enhancing precision, particularly in addressing regional food safety challenges. However, their adoption is still hindered by complex food matrices, high costs, and the growing challenge of antimicrobial resistance. Looking ahead, intelligent systems and wearable sensors may help overcome these barriers. Although gaps in standardization and accessibility remain, biosensors are well-positioned to revolutionize food microbiology, linking ecological insights to practical solutions and paving the way for safer, high-quality food worldwide. Full article

CRISPR technology, which is derived from the bacterial adaptive immune system, has transformed traditional genetic engineering techniques, made strain engineering significantly easier, and become a very versatile genome editing system that allows for precise, programmable modifications to a wide range of microbial genomes. The economies of fermentation-based manufacturing are changing because of its quick acceptance in both academic and industry labs. CRISPR processes have been used to modify industrially significant bacteria, including the lactic acid producers, Clostridium spp., Escherichia coli, and Corynebacterium glutamicum, in order to increase the yields of bioethanol, butanol, succinic acid, acetone, and polyhydroxyalkanoate precursors. CRISPR-mediated promoter engineering and single-step multiplex editing have improved inhibitor tolerance, raised ethanol titers, and allowed for the de novo synthesis of terpenoids, flavonoids, and recombinant vaccines in yeasts, especially Saccharomyces cerevisiae and emerging non-conventional species. While enzyme and biopharmaceutical manufacturing use CRISPR for quick strain optimization and glyco-engineering, food and beverage fermentations benefit from starter-culture customization for aroma, texture, and probiotic functionality. Off-target effects, cytotoxicity linked to Cas9, inefficient delivery in specific microorganisms, and regulatory ambiguities in commercial fermentation settings are some of the main challenges. This review provides an industry-specific summary of CRISPR–Cas9 applications in microbial fermentation and highlights technical developments, persisting challenges, and industrial advancements. Full article

Cheese ripening involves microbial changes, with starter lactic acid bacteria (SLAB) initiating fermentation and nonstarter lactic acid bacteria (NSLAB) driving flavor and texture development. However, heat-resistant spores of Clostridium and Bacillus can survive pasteurization and cause spoilage during ripening. This study evaluated NSLAB dynamics in the presence of spores during cheese ripening. Cheddar cheese samples at pilot-scale level (110 L) with four treatments, namely control, with spores of B. licheniformis (T1), with spores of Cl. tyrobutyricum (T2), and both spores (T3) at 2.0 Log₁₀ CFU/mL, were ripened at 7 °C for six months. SLAB declined from 8.0 to 0.2 Log₁₀ CFU/g, while NSLAB increased from 2.0 to 8.5 Log₁₀ CFU/g by month three and maintained their counts up to six months, unaffected by spore presence. Spore counts were ≤1.45 Log₁₀ CFU/g in controls but reached 2.94 ± 0.02 (T2) and 2.48 ± 0.03 (T3), correlating with spoilage signs after five months. MALDI-TOF identified L. rhamnosus (up to 37%) and L. paracasei (up to 25%) as dominant NSLAB across treatments. Physicochemical parameters were not significantly affected by higher spore levels. While NSLAB dominated, they were inadequate to prevent spoilage in spore-inoculated samples exceeding 2.0 logs during cheese ripening. Full article