Search Results (935)

This study evaluates the efficacy of commercial clean-label additives, specifically fermentates, in inhibiting mold growth in vitro and extending the shelf life of preservative-free bread. The mold growth on selected bread was modeled using the time-to-growth approach. The pH, a_w, and moisture content of fresh bread were determined. In addition, selected fermentates were characterized physicochemically. Fermentates, defined as liquid or powdered preparations containing microorganisms, their metabolites, and culture supernatants, were tested at varying concentrations (1% to 12%) to assess their antimicrobial performance and impact on bread quality parameters, including moisture content, water activity, and pH. The results showed significant differences in fermentate efficacy, with Product A as the best mold growth inhibitor in vitro and a clear dose-dependent response. For Penicillium corylophilum, inhibition increased from 51.90% at 1% to 62.60% at 4%, while P. chrysogenum had an inhibition ranging from 32.26% to 34.49%. Product F exhibited moderate activity on both molds at 4%, inhibiting between 28.48% and 46.27%. The two molds exhibited differing sensitivities to the fermentates, with P. corylophilum consistently more susceptible to inhibition. Product A displayed a low pH (2.61) and high levels of lactic acid (1053.6 mmol/L) and acetic acid (1061.3 mmol/L). Product F presented a similar pH but lower levels of lactic and acetic acid. A time-to-growth model, validated by significant coefficients (p < 0.05) and high predictive accuracy (R² > 0.95), was employed to predict the appearance of mold on bread loaves. The model revealed that higher concentrations of fermentates A and F delayed mold growth, with fermentate A demonstrating superior efficacy. At 2% concentration, fermentate A delayed mold growth for 8 days, compared to 6 days for fermentate F. At 8% concentration, fermentate A prevented mold growth for over 25 days, significantly outperforming the control (4 days). Additionally, fermentates influenced bread quality parameters, with fermentate A improving crust moisture retention and reducing water activity at higher concentrations. These findings highlight the potential of fermentates as sustainable, consumer-friendly alternatives to synthetic preservatives, offering a viable solution to the challenge of bread spoilage while maintaining product quality. Full article

Monitoring pH and acidity during yoghurt fermentation is essential for product quality and process efficiency. Conventional measurement methods, however, are invasive and labour-intensive. This study developed artificial neural network (ANN) models to predict pH and titratable acidity during yoghurt fermentation using CIELAB colour parameters (L, a*, b*). Reconstituted milk powder with 12% total solids was prepared with varying protein levels (4.2–4.8%), inoculum concentrations (1–3%), and fermentation temperatures (36–44 °C). Data were collected every 10 min until pH 4.6 was reached. Forty models were trained for each output variable, using 90% of the data for training and 10% for validation. The first two phases of the fermentation process were clearly distinguishable, lasting between 4.5 and 7 h and exceeding 0.6% lactic acid in all treatments evaluated. The best pH model used two hidden layers with 28 neurons (R² = 0.969; RMSE = 0.007), while the optimal acidity model had four hidden layers with 32 neurons (R² = 0.868; RMSE = 0.002). The strong correlation between colour and physicochemical changes confirms the feasibility of this non-destructive approach. Integrating ANN models and colourimetry offers a practical solution for real-time monitoring, helping improve process control in industrial yoghurt production. Full article

The aim of this study was to isolate Weizmannia spp. that produce lactic acid from xylose and use an experimental design to optimize the production of the metabolite. After isolation, the experiments were conducted in xylose-yeast extract-peptone medium. The identification of isolates was performed using the 16S rDNA PCR technique, followed by sequencing. A central composite rotatable design (CCRD) was used to optimize the concentrations of the carbon source (xylose), nitrogen source (yeast extract and peptone), and sodium acetate. Two strains were considered promising for lactic acid production, with W. coagulans BLMI achieving greater lactic acid production under anaerobic conditions (21.93 ± 0.9 g.L⁻¹) and a yield of 69.18 %, while the strain W. ginsengihumi BMI was able to produce 19.79 ± 0.8 g.L⁻¹, with a yield of 70.46 %. CCRD was used with the W. ginsengihumi strain due to the lack of records in the literature on its use for lactic acid production. The carbon and nitrogen sources influenced the response, but the interactions of the variables were nonsignificant (p < 0.05). The response surface analysis indicated that the optimal concentrations of carbon and nitrogen sources were 32.5 and 3.0 g.L⁻¹, respectively, without the need to add sodium acetate to the culture medium, leading to the production of 20.02 ± 0.19 g.L⁻¹, productivity of 0.55 g/L/h after 36 hours of fermentation, and a residual sugar concentration of 12.59 ± 0.51 g.L⁻¹. These results demonstrate the potential of W. ginsengihumi BMI for the production of lactic acid by xylose fermentation since it is carried out at 50 °C, indicating a path for future studies Full article

To explore an industrial fermentation approach for traditional mung bean sour pulp, this study isolated core microorganisms including lactic acid bacteria and yeasts from naturally fermented samples and constructed a synthetic microbial community. The optimized community consisted of Lactiplantibacillus pentosus, Lactococcus garvieae, and Cyberlindnera jadinii at a ratio of 7:3:0.1 and was used to ferment cooked mung bean pulp with a material-to-water ratio of 1:8 and 1% sucrose addition. Under these conditions, the final product exhibited significantly higher levels of protein (4.55 mg/mL), flavonoids (0.10 mg/mL), polyphenols (0.11 mg/mL), and vitamin C (7.75 μg/mL) than traditionally fermented mung bean sour pulp, along with enhanced antioxidant activity. The analysis of organic acids, free amino acids, and volatile compounds showed that lactic acid was the main acid component, the bitter amino acid content was reduced, the volatile flavor compounds were more abundant, and the level of harmful compound dimethyl sulfide was significantly decreased. These results indicate that fermentation using a synthetic microbial community effectively improved the nutritional quality, flavor, and safety of mung bean sour pulp. Full article

Koshu wine, produced from the indigenous Japanese grape Vitis vinifera L. cv. Koshu exhibits a lower pH than other white wines, hindering malolactic fermentation (MLF) by lactic acid bacteria (LAB). Here, we aimed to isolate LAB strains capable of performing MLF under these challenging conditions to improve wine quality. Sixty-four Oenococcus oeni and one Lactobacillus hilgardii strain were isolated from Koshu grapes and wines that had undergone spontaneous MLF. MLF activity was assessed under varying pH, SO₂, and ethanol conditions in modified basal medium (BM) and Koshu model wine media. Expression of stress-related genes was analyzed using real-time PCR. Carbon source utilization was evaluated via API 50CH assays. All isolates degraded malic acid and produced lactic acid at 15 °C and pH 3.2 in BM without reducing sugars. Seven strains, all identified as O. oeni, demonstrated MLF activity at pH 3.0 in modified BM lacking added reducing sugars or tomato juice. Six wine-derived strains tolerated up to 12% ethanol, whereas the grape-derived strain was inhibited at 10%. In a synthetic Koshu wine model (13% ethanol, pH 3.0), wine-derived isolates exhibited higher MLF activity than commercial starter strains. In high-performing strains, mleA was upregulated, and most isolates preferred fructose, arabinose, and ribose over glucose. These findings suggest that indigenous O. oeni strains from Koshu wine possess unique stress tolerance and metabolic traits, making them promising candidates for region-specific MLF starter cultures that could enhance Koshu wine quality and terroir expression. Full article

In recent years, great attention has been paid to second-generation (from agricultural and industrial wastes) lactic acid (LA) production. In the present study, the possibility of two Lactiplantibacillus plantarum strains, namely 53 and 2HS, to produce LA from waste materials was investigated. Distiller’s dried grains with solubles (DDGS), spent coffee grounds (SCG), wood chips, and cheese whey were used as substrates after pretreatment, and the results were compared with those with lactose as a carbon source. Both strains were capable of assimilating sugars from all waste materials. Nearly 20 g/L LA from 23 g/L reducing sugars (RS) obtained from DDGS, 22 g/L LA from 21 g/L RS from SCG, and 22 g/L LA from 21 g/L whey lactose were produced compared to 22 g/L LA obtained from 22 g/L lactose monohydrate in the fermentation broth. The wood chip hydrolysate (WH) contains only 10 g/L RS, and its fermentation resulted in the production of 5 g/L LA. This amount is twice as low as that produced from 11 g/L lactose monohydrate. A mathematical model was constructed based on the Compertz and Luedeking–Piret equations. Full article

This study investigated the effects of Lactococcus lactis subsp. 1.2472 (L)-, Streptococcus thermophilus 1.2718 (S)-, and thermostable Lactobacillus rhamnosus HCUL 1.1901-1912 (T)-fermented rice flour with inoculum levels of 3–11% (w/w) on rice bread staling. Optimal staling resistance was achieved, as follows: 9% L-fermented rice bread (LRB), 7% T-fermented rice bread (TRB), and 5% S-fermented rice bread (SRB). Lactic acid bacteria-fermented rice flour significantly enhanced hydration properties. LF-NMR analysis revealed that T₂₁ (strongly bound water) and T₂₂ (weakly bound water) relaxation times decreased, while T₂₃ (free water) increased with prolonged storage. Fermented-rice-flour groups had significantly more strongly bound water than the control group on 7 d. The optimized formulations exhibited exceptional volumetric stability with specific volume change rates of 17.63% (LRB), 17.60% (TRB), and 19.58% (SRB), coupled with maximal porosities of 10.34%, 9.05%, and 9.41%, respectively. This study provides a theoretical foundation for improving rice bread’s anti-staling properties. Full article

Kombucha is a fermented tea beverage of Asian origin, widely consumed due to its functional properties; yet, it typically lacks sufficient levels of probiotic micro-organisms to be classified as a probiotic product. This review analyzes the occurrence of lactic acid bacteria (LAB) in kombucha, reporting that concentrations rarely exceed 4–5 log CFU/mL and often decline during fermentation or storage. Strategies to enhance probiotic viability, including the use of robust LAB strains and encapsulation technologies, are critically evaluated. Notably, encapsulation using pea and whey protein has been shown to sustain LAB levels above 6 log CFU/mL during fermentation and up to 21 days under refrigerated storage for whey protein. Fortified kombucha beverages with probiotic strains have also been shown to possess enhanced functional and health-promoting benefits compared to traditional control samples. Despite promising approaches, inconsistencies in microbial survival and regulatory constraints remain key challenges. Future research should focus on the optimization of delivery systems for probiotic cultures, identification of kombucha-compatible LAB strains and standardized protocols to validate probiotic efficacy in real-world beverage conditions. Full article

Lactic acid (LA) is a high-value chemical with growing demand for the production of polymers and plastics and in the food and pharmaceutical industries. However, production costs remain a significant constraint when using conventional food-grade substrates. This study investigates Ivorian sugarcane molasses, an abundant agro-industrial by-product, as a low-cost carbon source for LA production via batch fermentation with Limosilactobacillus fermentum ATCC 9338. Molasses was pretreated by acid hydrolysis to improve fermentability, increasing glucose and fructose concentrations. Comparative fermentations using raw and pretreated molasses showed a 75% increase in LA production (32.4 ± 0.03 g/L) after pretreatment. Optimisation using Box–Behnken design revealed that the initial sugar concentration, inoculation rate, and stirring speed significantly influenced lactic acid production. Under optimal conditions, a maximum LA concentration of 52.4 ± 0.49 g/L was achieved with a yield of 0.95 g/g and productivity of 0.73 g/L·h. Kinetic analysis confirmed efficient sugar utilisation under the optimised conditions, and polarimetry revealed a near-racemic lactic acid. A simplified cost analysis showed that molasses could reduce carbon source costs by over 70% compared to refined sugars, supporting its economic viability. This work demonstrates the potential of pretreated molasses under robust fermentation conditions as a sustainable and cost-effective substrate for LA production in resource-limited contexts. The approach aligns with circular bioeconomy principles and presents a replicable model for decentralised bioproduction in a developing country like Côte d’Ivoire. Full article

Winter wheat (Triticum aestivum L.) silage has high feeding value and has become an important roughage resource in China. To recognize the optimal fermentation time of the silage product, this study systematically evaluated the temporal dynamics of microbial communities and metabolic profiles in whole winter wheat silage at days 7, 14, 30, 50, and 70. The dry matter (DM) content slightly fluctuated with the extension of fermentation time, with 28.14% at 70 days of ensiling. The organic matter and neutral detergent fiber content gradually decreased with the extension of fermentation time. A significant decrease in pH was observed at days 30, 50, and 70 compared to days 7 and 14 (p < 0.05), with the lowest pH value of 4.4 recorded at day 70. The contents of lactic acid, acetic acid, butyric acid, and total volatile fatty acids gradually increased with the extension of fermentation time, reaching a maximum at 70 days of ensiling. The dominant bacteria were Proteobacteria and Firmicutes at the phylum level, and the predominant bacteria were Hafnia-Obesumbacterium, Enterobacter, and Lactobacillus at the genus level. The relative abundance of Hafnia-Obesumbacterium and Lactobacillus fluctuated slightly with the duration of fermentation, reaching a minimum for the former and a maximum for Lactobacillus at 50 days of ensiling. By day 70, Sporolactobacillus emerged as a distinct silage biomarker. The dominant fungi was Ascomycota at the phylum level, and the predominant fungi were Fusarium and an unidentified fungus at the genus level. The correlation analysis revealed significant pH–organic acid–microbe interactions, with pH negatively correlating with organic acids but positively with specific bacteria, while organic acids showed complex microbial associations. Collectively, under natural fermentation conditions, the optimal fermentation period for wheat silage exceeds 70 days, and Sporolactobacillus shows potential as a microbial inoculant for whole winter wheat silage. These findings provide a theoretical foundation for optimizing whole winter wheat silage utilization and enhancing fermentation quality. Full article

Coffee kombucha beverages were developed by fermenting various coffee substrates, including instant coffee (I), coffee brews of ground coffee beans (G), and additional spent coffee added ground coffee (GSC) using either SCOBY (S) or Lactiplantibacillus plantarum ELB90 (L), or a combination of both (SL). The combined SL inoculation did not synergistically enhance the growth of acetic and lactic acid bacteria, nor did it increase the acetic and lactic acid concentrations or improve retention of caffeoylquinic acids (CQA) compared to non-fermented controls stored for the incubation period (7 days). Samples fermented with L better preserved the total CQAs during incubation, notably increasing 3-CQA and 4-CQA in L-fermented G and GSC samples by up to 40%, whereas 5-CQA showed a slight decrease (up to 8%) in L-fermented G and GSC samples. After one week, all fermented samples maintained stable levels of 3-CQA compared to the non-fermented SCG control, with significantly elevated 4-CQA. Caffeic acid was detected only in the bound fraction of beans, exhibiting similar concentrations in both fermented and non-fermented samples. SL-fermented coffees showed significant reductions in caffeine contents, except for I coffee substrate, and spent coffee grounds (SCG) filtered from the SL-fermented sample also had significantly lower caffeine content. Panelists preferred coffee kombucha beverages inoculated with S over those fermented with L, which were rated least appealing. The study concludes that fermentation with specific inoculation cultures could mitigate the degradation of coffee phenolic compounds during storage and facilitate the production of beverages with lower caffeine content, potentially enhancing both functional properties and consumer acceptability. Full article

This study aimed to develop a fermented mango-based beverage using Lactiplantibacillus plantarum strains Lp6 and Lp32, focusing on enhancing its functional properties, ensuring microbiological safety, improving nutritional value, and achieving sensory acceptability. A central composite design (CCD) was employed to assess the effects of two factors (fermentation time and inoculum concentration) on several response variables: viable cell concentration (CC), total phenolic compounds (TPCs), total flavonoid compounds (TFCs), and concentrations of L-lactic acid and D-lactic acid. The optimized formulation was achieved using L. plantarum Lp6, with an inoculum concentration of 9.89 Log (7.76 × 10⁹) CFU/mL and a fermentation time of 20.47 h. Under these conditions, the beverage reached the highest values for CC, TPC, TF, and L-lactic acid while minimizing the production of D-lactic acid. Following optimization, the fermented beverage underwent further characterization, including physicochemical analysis, microbiological evaluation, proximate composition analysis, and sensory evaluation. The final product exhibited a viable cell count of 13.01 Log (10.23 × 10¹²) CFU/mL, demonstrated functional potential, complied with microbiological safety standards, and showed adequate nutritional content. Sensory analysis revealed high consumer acceptability, attributed to its distinctive mango aroma and flavor. These findings highlight the potential of this fermented mango-based beverage as a novel functional food with promising market appeal. Full article

In order to achieve the efficient utilization of agricultural by-products and overcome the bottleneck of animal feed shortages in dry seasons, this study utilized corn stover (CS; Zea mays L.) as a material to systematically investigate the dynamic changes in the fermentation quality, bacterial community structure, and pathogenic risk of silage under different fermentation times (0, 3, 7, 15, and 30 days). CS has high nutritive value, including crude protein and sugar, and can serve as a carbon source and a nitrogen source for silage fermentation. After ensiling, CS silage (CSTS) exhibited excellent fermentation quality, characterized by relatively high lactic acid content, low pH, and ammonia nitrogen content within an acceptable range. In addition, neither propionic acid nor butyric acid was detected in any of the silages. CS exhibited high α-diversity, with Serratia marcescens being the dominant bacterial species. After ensiling, the α-diversity significantly (p < 0.05) decreased, and Lactiplantibacillus plantarum was the dominant species during the fermentation process. With the extension of fermentation days, the relative abundance of Lactiplantibacillus plantarum significantly (p < 0.05) increased, reaching a peak and stabilizing between 15 and 30 days. Ultimately, lactic acid bacteria dominated and constructed a microbial symbiotic network system. In the bacterial community of CSTS, the abundance of “potential pathogens” was significantly (p < 0.01) lower than that of CS. These results provide data support for establishing a microbial regulation theory for silage fermentation, thereby improving the basic research system for the biological conversion of agricultural by-products and alleviating feed shortages in dry seasons. Full article

The combined effect of temperature-adapted inocula and anaerobic fermentation (AF) settings (pH 5.1 and 50 °C) were assessed to produce short-chain carboxylates (SCCs). In this study, the AF of carrot pulp was investigated using inocula adapted at different temperatures (25, 35, and 55 °C) with the aim of shifting the microbiome activity from biogas to SCC production. The highest SCC content (17.2 g COD L⁻¹), and bioconversion (26.1%) and acidification efficiency (56.3%) were achieved with 35 °C-adapted inoculum. Lactic acid production prevailed in all reactors, demonstrating a high selectivity in SCC production. Both the microbial richness and diversity sharply diminished in the 35 °C and 55 °C operated reactors, with Firmicutes phylum identified as key players of the lactic acid production in AF. The results demonstrated that the operating temperature played a key role in shaping the microbial structure of inocula, leading to different process performances and highlighting thermophilic AF as a feasible process to produce lactic acid. Full article

This study aimed to ferment protein-rich amaranth flour with different strains of lactic acid bacteria (LAB) and to analyse the fermented dough’s functional properties. The fermented dough analysis was conducted using titrimetric, spectrophotometric, and chromatographic methods. The antioxidant activity of the fermented doughs was evaluated using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) methods, finding ABTS radical scavenging values ranging from 26.00 ± 1.05% to 58.92 ± 6.05%, while the DPPH values ranged from 21.29 ± 0.83% to 28.24 ± 5.48%. By RP-HPLC (Reversed Phase-High Performance Liquid Chromatography) characterisation, several phenolic acids and flavonoids were identified and quantified. Among these compounds, epigallocatechin was the most abundant, with the highest concentration recorded at 7789.88 ± 17.0 ng/µL in the control sample. This was followed by a 6942.47 ± 5.632 ng/µL concentration in the dough fermented with Lacticaseibacillus rhamnosus MIUG BL38 strain and 4983.16 ± 7.29 ng/µL in the dough fermented with Lactiplantibacillus pentosus MIUG BL24 strain. These two LAB strains (Lc. rhamnosus MIUG BL38 and Lp. pentosus MIUG BL24), with probiotic properties previously demonstrated, were selected based on their acidification potential, antioxidant activity, and bioactivity for future optimisation studies. Lactic acid fermentation significantly enhances bioactive characteristics of the amaranth flour, enabling the design of diverse gluten-free products with increased functional properties based on the attributes induced by the prebiotic, probiotic and postbiotic contents (tribiotics). Full article