Fermentation Characteristics Research Articles

Effect of steam explosion pretreatment on the fermentation characteristics of polysaccharides from tea residue

Green tea residues are the by-product of tea processing and they contain a large number of bioactive ingredients. Steam explosion has been recognized as one of the most innovative pretreatments for modifying the physicochemical characteristic of polysaccharides from lignocellulosic materials. However, the comparison of biological activity of steam exploded (SE-GTR) and unexploded (UN-GTR) green tea residue polysaccharides was still unclear, which prompted the determination of the efficacy of steam explosion in tea residue resource utilization. In this study, the effects of two extracted polysaccharides UN-GTR and SE-GTR on human gut microbiota in vitro fermentation were conducted. The results showed that after steam explosion pretreatment, SE-GTR displayed more loose and porous structures, resulting in higher polysaccharide content (2483.44±0.5 μg/mg) compared to UN-GTR (1903.56±2.6 μg/mg). In addition, after 24 h fermentation, gut microbiota produced more beneficial metabolites by SE-GTR. The largest SCFAs produced among samples was acetic acid, propionic acid and butyric acid. Furthermore, SE-GTR could regulate the composition and diversity of microbial community, increasing the abundance of beneficial bacteria, such as Bifidobacterium. These results revealed that steam explosion pretreatment could be a promising and efficient approach to enhance the antioxidant activity and bioavailability of polysaccharides isolated from tea residues.

In Vitro Evaluation of the Antimicrobial, Antioxidant, and Cytotoxicity Potential Coupled with Molecular Docking Simulation of the Dynamic Fermentation Characteristics of Marine-Derived Bacterium Halomonas saccharevitans

A variety of metabolites produced by marine microorganisms are gaining high value for their significant biological properties. Therefore, the search for active secondary metabolites from marine bacteria against pathogenic microorganisms has become essential for alternative and effective strategies. In this study, Halomonas saccharevitans, a marine-derived bacterium, was cultured and fermented on a liquid medium. The ethyl acetate (EtOAc) crude extract was then fractioned yielded five fractions to study their biological effect. Two fractions had significantly higher activity, i.e., absolute n-hexane against Staphylococcus aureus and Pseudomonas aeruginosa and absolute methanol (MeOH) against Escherichia coli and Bacillus subtilis, with promising MIC values. The time–kill kinetics assay for the very susceptible bacteria against active fractions was also examined. The antifungal assay of the active fractions had the highest activity against Aspergillus niger and Candida albicans with the examined variable MFC values. The cytotoxic assay against HepG2 cells showed promising activities, resulting in a 78% inhibition of cell viability. Moreover, the antioxidant activities showed reasonable inhibition values at 21.87 ± 0.85% and 98.25 ± 1.45%, compared to the control. Molecular docking revealed a high affinity between major detected compounds with free binding energies. The active fractions were characterized by the presence of diverse chemically esters, phenolics, essential oils, and other organic compounds detected by GC–MS. In conclusion, H. saccharevitans, derived from the Red Sea, might be useful as an alternative source for the possible production of bioactive substances with a variety of biomedical application.

The Impact of the Inoculation of Different Pied de Cuve on the Chemical and Organoleptic Profiles of Wines.

Controlling the microorganisms involved in alcoholic fermentation during wine production can be achieved by adding a small quantity of spontaneously fermenting must to freshly crushed grapes, a technique known as pied de cuve (PdC). This method not only serves as an inoculation starter but also enhances the microbial footprint unique to each wine region. Recent studies have confirmed that wines inoculated with PdC exhibit efficient fermentation kinetics comparable to those inoculated with commercial strains of Saccharomyces cerevisiae. However, further research is required to draw robust conclusions about the chemical and sensory impacts of PdC-inoculated wines. In this study, we examined the chemical and sensory effects of the PdC technique across three different harvests: Muscat of Alexandria (Spain, harvests 2022 and 2023) and Sauvignon Blanc (Chile, harvest 2023). Each PdC was prepared using various stressors (sulfur dioxide, ethanol, and temperature). Our findings revealed that wines produced with PdC exhibited similar fermentation kinetics and sensory profiles to those inoculated with commercial strains. Notably, PdC fermentations resulted in lower concentrations of acetic acid compared to both the commercial strain and spontaneous fermentations. The sensory analysis indicated that PdC wines significantly differed from those made with commercial strains, with PdC wines displaying more pronounced tropical notes. These results suggest that the PdC technique, particularly when using specific stressors, can maintain desirable fermentation characteristics while enhancing certain sensory attributes, offering a viable alternative to traditional inoculation methods.

Biochemical and chemosensory characterization of doubanjiang fermented via two-stage controlled temperature

This study aimed to elaborate the biochemical and chemosensory characteristics of doubanjiang fermentation via a two-stage controlled temperature. HL group with variable temperature (40 °C → 30 °C) and NTF group fermented following traditional technique were prepared and their volatile and non-volatile metabolites were compared through multivariate statistical analysis. HL group favored the accumulation of amino acid nitrogen, free amino acids and organic acids in the early stage and maintained adequate total acids and biogenic amines in the mid-late stage. HL group also had preferred jiang and fruity flavor through sensory evaluation. A total of 116 volatile metabolites were identified in HL or NTF groups and 22 marker volatile metabolites were screened through the combinational use of OPLS-DA and Random Forest analysis. Stronger anti-oxidant ability was observed in HL group while adequate number of acidic compounds and biogenic amines were ensured. This indicated that the two-stage controlled temperature fermentation was beneficial for doubanjiang fermentation.

Feeding or pen surface application of clinoptilolite with different particle sizes: impact on nitrogen utilization and manure ammonia emissions in feedlot cattle.

This study investigated the effects of feeding clinoptilolite (CLN; 2.5% of diet dry matter) with a particle size of either 30- or 400-µm on ruminal fermentation characteristics, measures of nitrogen (N) utilization, and manure ammonia-N (NH3) emissions in feedlot cattle. The impact of directly applying 30- or 400-µm CLN to the pen surface (2,250kg/ha) on manure NH3-N emissions was also evaluated. Six beef heifers were used in a replicated 3 × 3 Latin square design with 21-d periods. Dietary treatments were 1) finishing ration with no supplement (CON), 2) CON + 30-µm CLN (CLN-30), and 3) CON + 400-µm CL (CLN-400). Intake was measured daily. To evaluate fermentation characteristics, ruminal fluid was collected on day 19. Indwelling pH loggers were used to measure ruminal pH from days 15 to 21. Blood was collected 3-h post-feeding on day 21 for metabolite analysis. Fecal grab and urine spot samples were also collected from days 19 to 21 to measure nutrient digestibility, route of N excretion, and in vitro NH3 emissions. There was no diet effect (P ≥ 0.12) on nutrient intake and apparent total tract digestibility, and ruminal short-chain fatty acid profile and pH. Ruminal NH3 concentration, which was lower (P = 0.04) for CLN-30 than CON heifers, did not differ between CON and CLN-400 heifers. Although there was no diet effect (P = 0.50) on plasma urea-N (PUN) concentration, proportion of urea-N excreted in urine was lower (P = 0.01) for CLN-30 than CON and CLN-400 heifers. Urinary NH3-N excretion, which was greater (P ≤ 0.04) for CLN-400 than CON heifers, did not differ between CLN-30 and CLN-400 heifers. Feeding CLN also increased (P ≤ 0.02) fecal excretion of potassium (K) and iron (Fe) and reduced (P = 0.01) urinary excretion of calcium (Ca). There was a treatment × time interaction (P = 0.01) for NH3 emission rate, which was greatest within the first 36h of incubation and was lower for manure from CLN-400 compared to CON and CLN-30 heifers and pen surface application treatments. Cumulative NH3 emissions were lower (P < 0.01) for manure from CLN-400 compared to CON and CLN-30 heifers and the pen surface application treatments. Although surface application was ineffective, feeding 400-µm CLN to finishing cattle could result in a beneficial decrease in manure NH3 emissions. However, changes in fecal and urine excretion of minerals like K and Ca, which suggest a decrease in bioavailability, need to be considered when feeding CLN in finishing cattle diets.

The Effects of Biscuit on Fermentation Characteristics, Aerobic Stability and In Vitro Organic Matter Digestibility of Alfalfa Silage

The Effects of Biscuit on Fermentation Characteristics, Aerobic Stability and In Vitro Organic Matter Digestibility of Alfalfa Silage

The interaction between Lactobacillus delbrueckii ssp. bulgaricus M-58 and Streptococcus thermophilus S10 can enhance the texture and flavor profile of fermented milk: Insights from metabolomics analysis

Lactobacillus delbrueckii ssp. bulgaricus M-58 (M58) and Streptococcus thermophilus S10 (S10) are both dairy starter strains known for their favorable fermentation characteristics. Therefore, this research aimed to study the effects of 1-d low-temperature ripening on the physicochemical properties and metabolomics of fermented milk. Initially, the performance of single (M58 or S10) and dual (M58+S10) strain fermentation was assessed, revealing that the M58+S10 combination resulted in a shortened fermentation time, a stable gel structure, and desirable viscosity, suggesting positive strain interactions. Subsequently, nontargeted metabolomics analyses using liquid chromatography-MS and GC-MS were performed to comparatively analyze M58+S10 fermented milk samples collected at the end of fermentation and after 1 d of low-temperature ripening. The results showed a significant increase in almost all small peptides and dodecanedioic acid in the samples after 1 d of ripening, although there was a substantial decrease in indole and amino acid metabolites. Moreover, notable increases were observed in high-quality flavor compounds, such as geraniol, delta-nonalactone, 1-hexanol,2-ethyl-, methyl jasmonate, and undecanal. This study provides valuable insights into the fermentation characteristics of the dual bacterial starter consisting of M58 and S10 strains and highlights the specific contribution of the low-temperature ripening step to the overall quality of fermented milk.

European farmhouse brewing yeasts form a distinct genetic group

The brewing industry is constantly evolving, driven by the quest for novel flavours and fermentation characteristics that cater to evolving consumer preferences. This study explores the genetic and phenotypic diversity of European farmhouse yeasts, traditionally used in rural brewing practices and maintained outside of pure culture industrial yeast selection. We isolated landrace brewing yeast strains from diverse geographical locations across Europe, including Norway, Lithuania, Latvia, and Russia, and also included African farmhouse brewing strains from Ghana. Our genomic analysis using long-read and short-read whole genome sequencing uncovered a genetically distinct group that diverges from industrial brewing yeasts. This group, which is closely related to ale brewing strains, is preliminarily named the ‘European Farmhouse’ group and shows greater predicted admixture from Asian fermentation strains. Through genomic and phenotypic analyses, including flavour metabolite analysis via headspace gas chromatography-mass spectrometry, sugar metabolite analysis via high-performance liquid chromatography, and wort fermentation analysis, we found a broad spectrum of fermentation capabilities, from rapid and efficient fermentation to unique aroma and flavour compound profiles, potentially offering novel traits for brewing applications. This study highlights the importance of preservation of brewing cultural heritage knowledge and resources including yeast cultures.Key points• A large set of geographically diverse farmhouse brewing strains were characterized• Norwegian and Baltic farmhouse brewing strains form a distinct genetic group• Farmhouse strains show considerable diversity in fermentation and flavour formation

Characterization and application of Bacillus velezensis D6 co-producing α-amylase and protease.

Research on the co-production of multiple enzymes by Bacillus velezensis as a novel species is still a topic that needs to be studied. This study aimed to investigate the fermentation characteristics of B. velezensis D6 co-producing α-amylase and protease and to explore their enzymatic properties and applications in fermentation. The maximum co-production of α-amylase and protease reached 13.13 ± 0.72 and 2106.63 ± 64.42 U mL-1, respectively, under the optimal fermented conditions (nutrients: 20.0 g L-1 urea, 20.0 g L-1 glucose, 0.7 g L-1 MnCl2; incubation conditions: initial pH 7.0, temperature 41 °C, 8% inoculation size and 30% working volume). Moreover, the genetic co-expression of α-amylase and protease increased from 0 to 24 h and then decreased after 36 h at the transcriptional level, which coincided with the growth trend of B. velezensis D6. The optimal reaction temperature of α-amylase was 55-60 °C, while that of protease was 35-40 °C. The activities of α-amylase and protease were retained by over 80% after thermal treatment (90 °C, 1 h), which indicated that two enzymes co-produced by B. velezensis D6 demonstrated excellent thermal stability. Moreover, the two enzymes were stable over a wide pH range (pH 4.0-8.0 for α-amylase; pH 4.0-9.0 for protease). Finally, the degrees of hydrolysis of corn, rice, sorghum and soybeans by α-amylase from B. velezensis D6 reached 44.95 ± 2.95%, 57.16 ± 2.75%, 52.53 ± 4.01% and 20.53 ± 2.42%, respectively, suggesting an excellent hydrolysis effect on starchy raw materials. The hydrolysis degrees of mackerel heads and soybeans by protease were 43.93 ± 2.19% and 26.38 ± 1.72%, respectively, which suggested that the protease from B. velezensis D6 preferentially hydrolyzed animal-based protein. This is a systematic study on the co-production of α-amylase and protease by B. velezensis D6, which is crucial in widening the understanding of this species co-producing multi-enzymes and in exploring its potential application. © 2024 Society of Chemical Industry.

MBA 포도 첨가에 따른 ALE 맥주의 발효 및 품질 특성

This study investigated the fermentation characteristics and quality attributes of ale beer brewed with MBA grapes to enhance the diversity of Korean domestic ale beers. The grapes were added to the wort in two forms: must and juice, at ratios of 10% and 20%. The results showed that while ale beer with 20% grape addition began fermentation a day later, all samples completed fermentation well on the sixth day. Increasing MBA grape content lowered the pH and increased total acidity and malic acid content without significantly affecting the sour taste. Higher grape addition also decreased the beer’s IBU and bitterness scores in sensory evaluation. The addition of must addition enhanced redness due to anthocyanins, significantly increasing color intensity and EBC value of ale beer. Ale beer with the addition of must exhibited higher antioxidant capacities in total phenolic compound content, DPPH radical scavenging, and FRAP activities compared to that with the addition of juice. Sensory evaluation indicated that ale beer with 20% juice addition was preferred for its color, aroma, sweetness, body, and overall preference. The addition of MBA must improved antioxidant capacity, but ale beer with 20% juice had superior sensory qualities.

MBA 포도 첨가에 따른 ALE 맥주의 발효 및 품질 특성

This study investigated the fermentation characteristics and quality attributes of ale beer brewed with MBA grapes to enhance the diversity of Korean domestic ale beers. The grapes were added to the wort in two forms: must and juice, at ratios of 10% and 20%. The results showed that while ale beer with 20% grape addition began fermentation a day later, all samples completed fermentation well on the sixth day. Increasing MBA grape content lowered the pH and increased total acidity and malic acid content without significantly affecting the sour taste. Higher grape addition also decreased the beer’s IBU and bitterness scores in sensory evaluation. The addition of must addition enhanced redness due to anthocyanins, significantly increasing color intensity and EBC value of ale beer. Ale beer with the addition of must exhibited higher antioxidant capacities in total phenolic compound content, DPPH radical scavenging, and FRAP activities compared to that with the addition of juice. Sensory evaluation indicated that ale beer with 20% juice addition was preferred for its color, aroma, sweetness, body, and overall preference. The addition of MBA must improved antioxidant capacity, but ale beer with 20% juice had superior sensory qualities.

The impact of lactic acid bacteria inoculation on the fermentation and metabolomic dynamics of indigenous Beijing douzhi microbial communities.

Douzhi, a traditional Chinese fermented beverage, features microbial communities primarily composed of lactic acid bacteria (LAB). As fermented foods continue to gain recognition and popularity, douzhi is attracting growing interest. However, investigation of the critical aspects of douzhi's fermentation processes, including fermentation characteristics and microbial community dynamics, remains vital for enhancing food safety and quality for douzhi, as well as for similar fermented food products. In this study, we collected douzhi microbial communities from four chain stores, using them as fermentation starter cultures. The microbial dynamics of the fermentation were analyzed, focusing on the inoculation of LAB strains and the transition from a mung bean-based matrix to skimmed milk. The metabolomic profiles of the fermented mung bean matrices were also studied. Douzhi samples obtained from representative chain stores were found to be overwhelmingly dominated by LAB. When inoculated along with the douzhi community, both LAB strains exhibited notable and substantial reductions in the pH value of the designated mung bean matrices compared to those inoculated indigenous microbiota. Specifically, Lactiplantibacillus plantarum CGMCC 1.1856 retained its population, whereas Pediococcus pentosaceus CGMCC 1.2695 exhibited a decrease in relative abundance. Using skimmed milk as a fermentation substrate instead of the mung bean matrix resulted in significant shifts in microbial communities, particularly leading to an increase in Escherichia sp. The metagenomic analyses and functional predictions illustrated that various metabolic functions were enhanced during the fermentation process due to LAB inoculation. The liquid chromatography-mass spectrometry based metabolomic analysis revealed that the inoculation of Lactiplantibacillus plantarum and Pediococcus pentosaceus in mung bean matrix did not introduce new metabolites but significantly altered the concentration and profile of existing metabolites, especially increased low molecular carbohydrates, which may enhance the nutritional potential of the fermented product. This study examines the microbial dynamics of douzhi microbiota fermentation, emphasizing the role of lactic acid bacteria in enhancing fermentation activity and metabolite profiles. These insights contribute to improving manufacturing processes and ensuring the safety and quality of douzhi and similar fermented foods.

Changes in microbial dynamics and fermentation characteristics of alfalfa silage: A potent approach to mitigate greenhouse gas emission through high-quality forage silage

Feeding ruminants with high-quality forage can enhance digestibility and reduce methane production. Development of high-quality silage from leguminous plants with lactic acid bacteria can improve digestibility and it mitigate the greenhouse gas emissions. In this study, we developed a high-quality alfalfa silage with improved fermentation index and microbial dynamics using Levilactobacillus brevis-KCC-44 at low or high moisture (LM/HM) conditions and preserved it for 75 or 150 days. Alfalfa fermentation with L. brevis enhances acidification and fermentation characteristics primarily due to the dominance of lactic acid bacteria (LAB) L. brevis (>95%) compared to alfalfa fermented with epiphytic LAB. The inoculant L. brevis improved the anaerobic fermentation indexes resulting in a higher level of lactic acid in both high (10.0 ± 0.12 & 8.90 ± 0.31%DM) and low moisture (0.55 ± 0.08 & 0.39 ± 0.0 %DM) in 75 and 150 days respectively, compared to control silage. In addition, the marginal amount of acetic acid (range from 0.23 ± 0.07 to 2.04 ± 0.27 %DM) and a reduced level of butyric acid (range between 0.03 ± 0.0 to 0.13 ± 02 %DM) was noted in silage treated with LAB than the control. The LAB count and abundance of Levilactobacillus were higher in alfalfa silage fermented with L. brevis. Microbial richness and diversity were reduced in alfalfa silage treated with L. brevis which prompted lactic acid production at a higher level even for a prolonged period of time. Therefore, this L.brevis is an effective inoculant for producing high-quality alfalfa silage since it improves fermentation indexes and provides reproducible ensiling properties.

Effects of Lactobacillus plantarum and Cellulase on Mixed Silages of Amaranthus hypochondriacus and Cornmeal: Fermentation Characteristics, Nutritional Value, and Aerobic Stability

In order to develop new feed resources, the aim of this study was to investigate the effects of moisture content, additives, and their interactions on the fermentation quality, aerobic stability, and in vitro digestibility of mixed silage of amaranth and cornmeal. The mass ratios of amaranth and cornmeal were 69:31, 76:24, and 84:16 for adjusting the moisture content of silage to 60% (W1), 65% (W2), and 70% (W3), respectively. The silage treatments included no additives (U), the addition of Lactobacillus plantarum (L), the addition of cellulase (E), and the addition of Lactobacillus plantarum + cellulase (M) mixed reagents. The results revealed that the pH and ammonia nitrogen (NH3-N/TN) ratios were significantly lower in W1 than in W2 and W3 (3.66,19.3 g kg−1 TN vs. 3.70, 3.70, 20.0 kg−1 TN, 25.1 kg−1 TN, p &lt; 0.05). Moreover, dry matter (DM), organic matter (OM), in vitro dry matter digestibility (ivDMD), in vitro organic matter digestibility (ivOMD), and in vitro crude protein digestibility (ivCPD) significantly increased (p &lt; 0.05). Meanwhile, the aerobic stability of mixed silage containing amaranth and cornmeal decreased with increasing water content. The aerobic stability of the L, E, and M treatment groups was improved by 15, 105, and 111 h, respectively, compared with that of the control group at W1. The pH and NH3-N/TN ratios were lower with the addition of E (E and M) than with the absence of E (U and L) (3.73, 20.1 g kg−1 DM vs. 3.64, 22.9 g kg−1 DM, p &lt; 0.05). NDF and ADF were significantly lower with the addition of E than without the addition of E (598 g kg−1 DM, 145 g kg−1 DM vs. 632 g kg−1 DM, 160 g kg−1 DM, p &lt; 0.05). However, CP, ivDMD, ivOMD, and ivCPD were significantly higher (p &lt; 0.05). AA and NH3-N/TN were significantly lower (p &lt; 0.05) with the addition of L (L and M) than without the addition of L (U and E). In conclusion, the best fermentation quality, in vitro digestibility, and aerobic stability of amaranth and cornmeal mixed silage treated with Lactobacillus plantarum + cellulase (M) were achieved at 60% water content. The present study confirmed the potential of amaranth as silage and its potential application for improving feed quality and animal performance.

Rumen microbiota helps Tibetan sheep obtain energy more efficiently to survive in the extreme environment of the Qinghai-Tibet Plateau.

T-sheep and H-sheep exhibit different environmental adaptability and production performance. The rumen microbiome has co-evolved with hosts and plays a vital role in nutrient digestion and energy metabolism. In our previous study, we found that T-sheep have a higher efficiency in energy metabolism than H-sheep, but the rumen microbial community remains unclear. In this study, we determined the rumen bacterial profile and rumen fermentation parameters to reveal the bacterial profiles and predictive functions among breeds and diets with four different energy levels, as well as the correlation between bacterial profiles and rumen fermentation characteristics. The results showed that the rumen total volatile fatty acids (VFAs), acetate, butyrate, total branched-chain VFAs, iso-butyrate, and iso-valerate were higher in T-sheep than H-sheep. The alpha diversity of ruminal bacteria is not affected by dietary energy, but it shows a distinction between the sheep breeds. Specifically, T-sheep rumen bacteria exhibit higher alpha diversity than H-sheep. The beta diversity of ruminal bacteria is not influenced by dietary energy or sheep breeds, indicating similar communities of ruminal bacteria between different diets and sheep breeds. The phyla of Bacteroidetes and Firmicutes predominate in the rumen, with a higher relative abundance of Firmicutes observed in T-sheep than H-sheep. The two most abundant genera in the rumen were Prevotella 1 and Rikenellaceae RC9 gut group. Prevotella 1 is the predominant bacterial genus in the rumen of H-sheep, while the Rikenellaceae RC9 gut group dominates in the rumen of T-sheep. Microbial co-occurrence network analysis reveals that variations in rumen fermentation characteristics result from differences in module abundance, with a higher abundance of VFA-producing modules observed in the rumen of T-sheep. Microbial function prediction analysis showed that dietary energy rarely alters the functional composition of rumen bacteria. However, there were differences in the functions of rumen bacteria between sheep breeds, with T-sheep showing a greater emphasis on energy metabolism-related functions, while H-sheep showed a greater emphasis on protein metabolism-related functions. These findings provide evidence of the special rumen microbial community that helps T-sheep efficiently obtain energy from low-protein and low-energy diets, enabling them to survive in the extreme environment of the Qinghai-Tibet Plateau.

Evaluation of Nutritive Value of Pleurotus tuber-regium Biodegraded Maize Cob using in Vitro Gas Production and Fermentation Characteristics

Evaluation of Nutritive Value of Pleurotus tuber-regium Biodegraded Maize Cob using in Vitro Gas Production and Fermentation Characteristics

Improving Total Mixed Ration Silage: Effects of Lactic Acid Bacteria Inoculants and Antimicrobial Additives on Fermentation Quality and Aerobic Stability

This work aimed to assess microbial inoculants (Lactiplantibacillus plantarum and Lentilactobacillus buchneri), chemical additives (natamycin and hexanoic acid), and their combination on fermentation characteristics and aerobic stability in total mixed ration (TMR) silage. The TMR consisted of 30% water bamboo shell (WBS), 10% alfalfa, 20% rice straw, and 40% concentrate. There were six treatments as follows: (1) deionized water (control, CON). (2) lactic acid bacteria (Lactiplantibacillus plantarum + Lentilactobacillus buchneri; LPB, 1 × 106 cfu/g FW). (3) natamycin (NT, 0.02 g/kg FW). (4) hexanoic acid (HA, 0.02 g/kg FW). (5) lactic acid bacteria + natamycin (SLNT, 0.02 g/kg FW). (6) lactic acid bacteria + hexanoic acid (SLHA, 0.02 g/kg FW). After fermentation, laboratory silos (10 L) were opened to assess fermentation quality, followed by a 6-day aerobic stability test. The results showed that all silages were well fermented with high lactic acid (LA) content, low ammonia nitrogen (NH3-N), and negligible butyric acid (BA) levels. Among all silages, SLNT silage exhibited the greatest LA, acetic acid (AA) levels, LAB counts, and the lowest pH and NH3-N. For aerobic stability, all additives significantly (p &lt; 0.05) enhanced aerobic stability, delayed (p &lt; 0.05) the decrease in LA and water-soluble carbohydrates (WSC) and the increase in pH, and significantly (p &lt; 0.05) minimized yeast proliferation. The SLNT silage showed the best aerobic stability, with SLHA, NT, HA, and LPB following. In conclusion, SLNT is recommended as the optimal additive in improving the fermentation quality and aerobic stability of TMR silage, with SLHA, NT, HA, and LPB following.

Improvement of rheological and sensory properties of Lactobacillus helveticus fermented milk by prebiotics

The fermentation characteristics and aroma-producing properties of Lactobacilli could influence the flavour quality of fermented milk, an important influencing factor of consumers' preference. In this study, fermented milk was prepared using Lactobacillus helveticus and the dynamic changes in the sensory quality of fermented milk throught fermentation were to assess the dynamic changes in sensory quality of fermented milks throughout the fermentation process, including rheological properties and flavour profiles. Styrene, linalool, octanoic acid, and 1-nonanol were considered as the key flavour components during fermentation. The quality of the fermented milk tends to be stabilized after 24-h, showing the minimal off-flavour at 48-h and optimal fermented aroma at 72-h. Three prebiotics (inulin, Galactooligosaccharides and inulin mixed with Galactooligosaccharides) were added to Lactobacillus spiralis fermented milk separately, and the results showed that inulin mixed with Galactooligosaccharides was the most effective group in improving the organoleptic quality of the fermented milk. Overall, the experimental results provide deeper insights into the release and retention of aroma compounds during fermentation and scientific reference for broadening the application of prebiotics and flavour-producing Lactobacilli in fermented milk processing.

Effect of heating treatment on processing characteristics of rice dough

Rice dough is a good source of digestible protein due to its advantages of being gluten-free and hypoallergenic compared to wheat dough, but the poor elasticity, low elongation and adhesion of rice dough limit its application. The effect of heating treatment with different temperature (40–100 °C) on processing characteristics of rice dough was explored. The results of fermentation characteristics showed that the best gas production and gas retention properties of rice dough were achieved at 70 °C. The rheological properties demonstrated a certain degree of deformation resistance at 85 °C, which resulted in the rice dough system exhibiting a tendency to flow at this temperature. Consequently, the blanching dough below 85 °C was deemed preferable for blanching. In addition, with the increase of temperature during blanching., the strength of the rice dough gel network increased. The results of proton distribution showed some of the emi-bound and free water in the rice dough was bound to bound water by exposed hydroxyl groups, leading to an increased bound water content, a decreased adsorbed and free water content. The degree of gelatinization of the rice dough increased gradually with increased blanching temperature, and the stability and resilience of rice dough reached the best at 70 °C. The thermal stability demonstrated that the ungelatinized portion of the rice dough exhibited enhanced structural stability, with the optimal thermal stability attained at 70 °C. It can therefore be concluded that the scalded dough made at 70 °C exhibits superior performance in all aspects and is suitable for subsequent processing of rice dough, which suggests a novel approach to the utilisation of rice dough in the future.

Germination-Induced Enhancement of Brown Rice Noodle Nutritional Profile and Gut Microbiota Modulation.

This study explored how germination influences the starch digestion and intestinal fermentation characteristics of brown rice noodle. The study began with in vitro starch digestion tests to assess how germination affects starch digestibility in brown rice noodles, revealing an increase in rapidly digestible starch content and a decrease in resistant starch content. Subsequently, an in vitro human fecal fermentation model was used to simulate the human intestinal environment, showing that germination altered pH levels and the production of short-chain fatty acids, particularly by increasing propionate while decreasing acetate and butyrate. Additionally, the study noted a decrease in gut microbiota diversity following fermentation, accompanied by an increase in Megamonas growth and a decrease in Bacteroides and Bifidobacterium. In conclusion, these findings suggest that germination could enhance the nutritional value and intestinal probiotic properties of brown rice noodles. This research contributes valuable insights into the role of germination in improving the nutritional properties of rice-based products and provides a foundation for further exploration into the development of health-promoting rice noodles.