Search Results (88)

Recent studies have shown that the use of non-Saccharomyces yeasts, either alone or in co-fermentation with Saccharomyces cerevisiae, can enhance the development of specialty beers with distinctive compositional characteristics. This study aimed to evaluate the main compositional and sensory differences between American Pale Ale (APA) beers produced using the commercial strain S. cerevisiae US-05 as a single starter (Test 1), and those produced through sequential inoculation with Metschnikowia pulcherrima 62 followed by S. cerevisiae US-05 (Test 2). Analyses focused on key chemical parameters and volatile compounds at the end of primary fermentation (F1) and after 20 days of refermentation at 20 °C (F2). After F1, Test 2 samples showed higher concentrations of glycerol and higher alcohols (isoamyl alcohol, benzeneethanol) and lower concentrations of esters (isoamyl acetate, ethyl hexanoate, ethyl octanoate) compared to Test 1. After F2, the differences in higher alcohol content became less significant, whereas ester concentrations, particularly ethyl acetate and ethyl octanoate, were significantly higher in Test 2. Sensory evaluation revealed that beers from Test 2 exhibited more pronounced floral and fruity notes and achieved higher overall scores in the panel assessment. These findings indicate that sequential inoculation with M. pulcherrima 62 followed by S. cerevisiae enhances both the chemical complexity and sensory appeal of APA beers, highlighting the strain’s potential as a valuable tool for developing specialty beers with unique aromatic profiles. Full article

The craft beer market is continually expanding, driven by the consumers’ demand for product diversification, which leads to innovation in the brewing industry. While traditional brewing focuses on consistency and high-volume efficiency using standard yeasts, craft brewing prioritizes small-batch experimentation and flavor complexity. Traditionally, Saccharomyces cerevisiae (Ale beer) and Saccharomyces pastorianus (Lager beer) yeast are used in brewing. The craft brewing revolution introduced the use of non-conventional yeast. These yeasts possess distinct technological characteristics compared to commercial starters, such as a richer enzyme profile. This biological diversity produces beers with novel, complex aroma profiles, and opens exciting avenues for flavor creation. Recently, non-alcoholic beer and low-alcoholic beer (NABLAB), and functional beer have become the new horizons for the application of non-conventional yeasts. In recent years, the brewing potential of these alternative yeasts has been extensively explored. However, some aspects relating to the interactions between yeast and raw materials precursors involved in the aroma of the final beer, and the management of yeasts in fermentation, remain unexplored. This review systematically outlines the various innovative ways in which non-conventional yeasts are applied in brewing, including healthier beer. Here, we explore how these yeasts can foster innovation in the beer sector and provide the possibility for sustainable development in contemporary brewing. Full article

From the first spontaneous fermentations of early civilizations to the precision of modern biotechnology, natural starter cultures have remained at the heart of fermented food and beverage production. Composed of complex microbial communities of lactic acid bacteria, yeasts, and filamentous fungi, these starters transform raw materials into products with distinctive sensory qualities, extended shelf life, and enhanced nutritional value. Their high microbial diversity underpins both their functional resilience and their cultural significance, yet also introduces variability and safety challenges. This review traces the historical development of natural starters, surveys their global applications across cereals, legumes, dairy, vegetables, beverages, seafood, and meats, and contrasts them with commercial starter cultures designed for consistency, scalability, and safety. Within the context of organic food production, natural starters offer opportunities to align fermentation with principles of sustainability, biodiversity conservation, and minimal processing, but regulatory frameworks—currently focused largely on yeasts—pose both challenges and opportunities for broader certification. Emerging innovations, including omics-driven strain selection, synthetic biology, valorization of agro-industrial byproducts, and automation, offer new pathways to improve safety, stability, and functionality without eroding the authenticity of natural starter cultures. By bridging traditional artisanal knowledge with advanced science and sustainable practices, natural starters can play a pivotal role in shaping the next generation of organic and eco-conscious fermented products. Full article

This study investigated the effects of direct vat set commercial yoghurt starter (B) and yeast starter (Y) on the quality of fermented large yellow croaker surimi balls, with natural fermentation (CTR) as a control. Surimi products were inoculated and fermented at 25 °C for 4 h, then analyzed for physicochemical, sensory, and oxidative properties. Yoghurt starter significantly inhibited protein oxidation, as indicated by the highest sulfhydryl content (9.10 nmol/mg protein, p < 0.05), improved textural properties (hardness was 28% higher than CTR, p < 0.05), and promoted a balanced flavor profile, accompanied by the highest equivalent umami concentration (1.66%, p < 0.05). However, B also caused the greatest MDA accumulation (1.49 mg/kg, p < 0.05), reflecting enhanced lipid oxidation. By comparison, Y enhanced umami primarily through significant enrichment of aspartic acid (53.88 mg/100 g, p < 0.05) and accelerated nucleotide degradation, resulting in the highest AMP and hypoxanthine levels (p < 0.05). These advantages were offset by severe protein carbonylation (54.32 nmol/mg protein, p < 0.05) and evident color deterioration. Sensory analysis revealed no significant difference between B and CTR (p > 0.05), whereas Y received significantly lower acceptance scores (p < 0.05) due to impaired color and taste. These findings suggest that B is a promising starter for improving texture and flavor in fermented surimi balls, while Y, despite enhancing umami and controlling lipid oxidation, negatively affects color, texture, and protein stability. Full article

Debaryomyces hansenii has the potential to enhance the flavor profile of traditional fermented meat products. This study investigates the impact of the D. hansenii LY090 strain on the microbial community, lipidome, flavor profiles, and sensory properties of Sichuan bacon. Inoculation with LY090 significantly inhibited the relative abundance of other yeasts, except for Debaryomyces, and altered bacterial community composition. The presence of LY090 led to a notable reduction (p < 0.05) in the levels of ceramide and phosphatidylcholine, resulting in an excessive inhibition of lipid degradation. This further affected the development of flavor and color in Sichuan bacon. However, the concentrations of aldehydes (249.80 μg/kg), ethyl 3-methylbutyrate (81.01 μg/kg), and acetoin (223.91 μg/kg) were all found to be abundant, and the bacon achieved the highest overall acceptance scores when inoculated with both LY090 and commercial starter culture FAST301. Correlation analysis indicated that the differential metabolites exhibited a stronger association with the yeast community, which plays a vital role in the flavor development of Sichuan bacon. These detailed investigations provide meaningful implications for D. hansenii LY090 implementation strategies in the Sichuan bacon industry. 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

This study aimed to identify and evaluate yeasts and lactic acid bacteria (LAB) isolated from Mexican cocoa mucilage (Theobroma cacao) and coffee pulp (Coffea arabica) for their potential use as sourdough starter co-cultures to improve bread quality. Functional screens included assessments of amylolytic, proteolytic, and phytase activities, CO₂ production, acidification capacity, and exopolysaccharide (EPS) synthesis. Saccharomyces cerevisiae YCTA13 exhibited the highest fermentative performance, surpassing commercial baker’s yeast by 52.24%. Leuconostoc mesenteroides LABCTA3 showed a high acidification capacity and EPS production, while Lactiplantibacillus plantarum 20B3HB had the highest phytase activity. Six yeast–LAB combinations were formulated as mixed starter co-cultures and evaluated in sourdough breadmaking. The B3Y14 co-culture (LABCTA3 + YCTA14) significantly improved the bread volume and height by 35.61% and 17.18%, respectively, compared to the commercial sourdough starter, and reduced crumb firmness by 59.66%. Image analysis of the bread crumb revealed that B3Y14 enhanced the crumb structure, resulting in greater alveolar uniformity and a balanced gas cell geometry. Specifically, B3Y14 showed low alveolar regularity (1.16 ± 0.03) and circularity (0.40 ± 0.01), indicating a fine and homogeneous crumb structure. These findings highlight the synergistic potential of selected allochthonous yeast and LAB strains in optimizing sourdough performance, positively impacting bread texture, structure, and quality. 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

Malolactic fermentation conducted by lactic acid bacteria is essential for enhancing wine’s sensory qualities. Although this process can occur spontaneously through the action of native lactic acid bacteria (LAB) from the grapes and cellar, it carries risks such as increased volatile acidity, consumption of residual sugars, and the formation of undesirable metabolites like biogenic amines. This study evaluated the oenological potential of three innovative native malolactic fermentation starters (MLFS) on a pilot scale, aiming to offer local wineries cost-effective MLFS with native LAB strains. Alcoholic fermentation of Malbec grapes was carried out using a commercial yeast starter, followed by a sequential inoculation of native malolactic starters formulated with (i) mesophilic Lactiplantibacillus plantarum UNQLp11 and Oenococcus oeni UNQOe73.2, both from the Province of Río Negro; (ii) psychrotrophic Lentilactibacillus hilgardii UNQLh1.1 and Oenococcus oeni UNQOe19, both from the Province of Río Negro; (iii) mesophilic Lactiplantibacillus plantarum UNQLp1001, from the Province of Buenos Aires; and (iv) a commercial malolactic started, which served as a control. Malic acid was consumed by all starters. RAPD-PCR using M13 primer showed the native LAB’s capability for implantation in wine. A sensory analysis revealed distinct profiles for each formulation, despite having been inoculated at the end of the same alcoholic fermentation. These MLFS could replace imports, enhancing the region’s unique terroir. Full article

Roasted carob flour is a sustainable ingredient rich in dietary fiber, polyphenols, and pinitol, offering potential for both food and pharmaceutical applications. However, its high sugar content and the presence of undesirable compounds such as furans present challenges for its use in bread making. This study evaluated the effects of prolonged sourdough fermentation on roasted carob flour, with a focus on microbial dynamics and its functional and technological properties. Carob and carob–wheat sourdoughs were prepared using a mixed starter culture comprising three lactic acid bacteria (Lactiplantibacillus plantarum, Fructilactobacillus sanfranciscensis, and Lactobacillus helveticus) and three yeast species (Saccharomyces cerevisiae, Kazachstania humilis, and Torulaspora delbrueckii). The sourdoughs underwent six consecutive refreshment cycles and were analyzed to determine their pH, microbial and biochemical composition, gassing power, and volatile organic compounds (VOCs). The carob–wheat sourdough exhibited faster acidification and higher lactic acid bacteria (LAB) activity, resulting in a 90–98% reduction in the sugar content, compared to 60% in the carob sourdough. Microbial sequencing revealed that L. plantarum was the dominant species in all samples, while K. humilis and S. cerevisiae were enriched in carob and carob–wheat sourdough, respectively. Both types of sourdough demonstrated effective leavening in bread dough without the addition of commercial yeast. Fermentation also modified the VOC profiles, increasing esters and alcohols while reducing acids, aldehydes, ketones, and furans. While the antioxidant activity showed a slight decline, the pinitol content remained unchanged. These findings suggest that extended sourdough fermentation, supported by multiple refreshments, enhances the baking suitability of roasted carob flour and supports its application as a functional, sustainable ingredient. Full article

The spoilage of wine caused by Brettanomyces bruxellensis and Hanseniaspora uvarum poses a significant challenge for winemakers, necessitating the development of effective and reliable strategies to control the growth of these yeasts, such as grape must bioprotection. Despite evidence that certain microorganisms can inhibit the growth of Brettanomyces bruxellensis and Hanseniaspora uvarum, the specific mechanisms driving this inhibition remain unclear. The primary objective of this study is to elucidate the underlying mechanisms responsible for this inhibitory effect. We analyzed one Metschnikowia pulcherrima (Mp2) and two Lachancea thermotolerans (Lt29 and Lt45) strains, all of which demonstrated significant killing and inhibitory effects on Brettanomyces bruxellensis (B1 and B250) and Hanseniaspora uvarum (Hu3137) in synthetic must at pH 3.5 and 22 °C. The effectiveness of these two strains exhibited varying inhibition kinetics. The strains were monitored for growth and metabolite production (L-lactic acid, ethanol, and acetic acid) in both single and co-cultures. The low levels of these metabolites did not account for the observed bioprotective effect, indicating a different mechanism at play, especially given the different growth profiles observed with added L-lactic acid and ethanol compared to direct bioprotectant addition. Following the production, purification, and quantification of killer toxins, different concentrations of toxins were tested, showing that the semi-purified Mp2Kt, Lt29Kt, and Lt45Kt toxins controlled the growth of both spoilage yeasts in a dose-dependent manner. These bioprotectant strains also showed compatibility with Saccharomyces cerevisiae in co-cultures, suggesting their potential use alongside commercial starter cultures. Full article

Significant advances in winemaking equipment and processes, as well as a deeper understanding of the role of yeast, have significantly improved wine quality throughout history. This paper examines critical aspects related to the use of commercial wine yeast starter cultures in the fermentation of grape and fruit wines, with a focus on berry wines and blackberry wine, which is the most predominant berry wine in Croatia. While the production of grape wines remains the most significant, fruit wines are gaining importance due to their composition, which contains a variety of bioactive compounds. Although spontaneous fermentation is still preferred by some winemakers, controlled or inoculated fermentation, based on the use of wine yeast starter cultures, is predominantly employed in modern winemaking. The selection of suitable yeast strains for grape wines is easier than for fruit wines, as the broader availability of commercial yeasts for grape wines contrasts with the limited selection offered for fruit wine production due to the smaller fruit wine market. The selection of Saccharomyces and, more recently, non-Saccharomyces yeast strains with desirable characteristics are crucial for the production of high-quality wines. Selection criteria for wine yeasts have evolved to meet modern consumer preferences and focus on technological properties, secondary flavor development and health effects. Full article

The effects of spontaneous fermentation and the inoculation of grape must with a flocculant yeast starter culture, together with the supplementation of must with a commercial organic nitrogen compound (ONC), were analyzed. The microbiome during fermentation was tracked, and volatile compounds in the resulting wines were identified and quantified using gas chromatography and mass spectrometry (GC-MS). Volatile compound concentrations were then subjected to statistical analysis. No significant differences in pH, titratable and volatile acidity, and ethanol and lactic acid were observed among the four wines analyzed. However, the musts supplemented with the ONC slightly increased the fermentation rate of the flocculant yeast, and, also, this additive reduced the volume of lees in the spontaneous fermentation and flocculant yeast by 1.2% and 0.6%, respectively. The concentrations of 11 major and 28 minor volatiles were significantly influenced (p-value ≤ 0.05) by the inoculation strategy, while 8 major and 28 minor volatiles were affected by ONC supplementation. This supplementation significantly decreased the Odor Activity Values and, consequently, the values of the odorant series established in wines from spontaneous fermentation. On the contrary, those from flocculant yeast showed a significant increase in all the odorant series except for the waxy series, leading to a more balanced aroma profile. Additionally, lower scores were recorded for the green, creamy, citrus, chemical, and honey series compared to wines from spontaneous fermentation. Overall, the commercial ONC extract contributed to a content increase in volatiles that provided desirable aromatic notes to the wines made with flocculant yeast, although the organoleptic evaluation showed no significant statistical differences in the attributes evaluated at the 95% confidence level. Full article

The community of epibiotic yeasts significantly influences the quality of Docynia delavayi (Franch.) Schneid. wine. The yeast diversity in four different Docynia delavayi (Franch.) Schneid. wines during the brewing stage was investigated using pure culture methods and high-throughput sequencing technology. A total of 229,381,292 sequencing bases were generated, yielding 323,820 valid sequences with an average length of 708 nt and identifying 93 operational taxonomic units (OTUs) from naturally fermented samples of Docynia delavayi (Franch.) Schneid. wine for classification purposes. At the early fermentation stage, Hanseniaspora sp. was identified as the dominant species, whereas at the late fermentation stage, Hanseniaspora sp., Saccharomyces sp., and Candida californica became predominant. From these samples, a total of 109 yeast strains were isolated from Docynia delavayi (Franch.) Schneid. wine. Three specific strains—LZX-76, LZX-89, and LZX-104—were further selected based on their growth characteristics along with hydrogen sulfide production, ester production, ethanol production, and tolerance levels. Through morphological examination and molecular biology techniques, these strains were identified as Pichia fermentans and Hanseniaspora spp. Additionally, a total of 29 volatile compounds were detected through simulated fermentation processes; these included 12 esters, 6 alcohols, 2 acids, 4 aldehydes, and 5 other compounds. When compared to commercial yeasts used as starters in winemaking processes, it was observed that utilizing yeast strains LZX-76, LZX-89, and LZX-104 resulted in an increased number of volatile compounds, which enhanced the aromatic profile characteristics of Docynia delavayi (Franch.) Schneid. wine by making its aroma richer and more complex. The findings from this study hold significant potential value for both the production practices and research endeavors related to Docynia delavayi (Franch.) Schneid. wine. Full article

Lactic acid bacteria (LAB) are widely used to produce various food products, adding flavor, texture, and health benefits. The bacteria are commonly grown on expensive nutrients like glucose, sucrose, and yeast extracts, which makes them commercially unappealing. In the current study, Lactobacillus acidophilus TISTR 1338 culture was studied using spent cell yeast as a nitrogen source and molasses as a carbon source. The drying process used to create starter cultures of Lactobacillus acidophilus TISTR 1338 was vacuum drying. After vacuum drying, this bacterium had a survival rate of 8.08 log CFU/g. The dried strain survived for four months at 37 °C. With wasted cells at 0.5%, molasses concentration at 11% at 2.14 109 CFU/mL at 22 h, precise growth rate at 0.39 h⁻¹, and yield cell mass at 1.67 1011 CFU/g sugar, yeast produced the maximum cell mass. The lower viability of the tested strain was induced by a higher temperature during this prolonged storage. Meanwhile, dehydrated starter culture was subjected to accelerated storage testing at 50, 60, and 70 °C. To determine the vacuum-dried Lactobacillus acidophilus TISTR 1338′s long-term storage viability, a temperature-dependent prophecy model was created. Molasses and spent cell yeast serve as promising carbon and nitrogen sources when optimized conditions are employed. The study also suggests that vacuum drying is a promising method for producing dried cells suitable for non-refrigerated storage conditions. Full article