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Nowadays, the wine industry carries out fermentations at low temperatures because this oenological practice clearly improves the aromatic complexity of the final wines. In addition, nitrogen content of the must also influences the quality of the wine. In this study, we carried out a phenotypic and fermentative analysis of two industrial wine Saccharomyces cerevisiae strains (P5 and P24) at 15 and 28 °C and three nitrogen concentrations (60, 140 and 300 mg N/L) in synthetic must. Our results show that both parameters, temperature and nitrogen, are interrelated and clearly determine the competitiveness of the wine strains and their ability to adapt at low temperatures. The best adapted strain at low temperatures decreased its competitiveness at lower nitrogen concentrations. In addition, our results show that it is not only the quantity of nitrogen transported that is important but also the quality of the nitrogen source used for wine yeast adaptation at low temperatures. The presence of some amino acids, such as arginine, branched chain amino acids, and some aromatic amino acids can improve the growth and fermentation activity of wine yeasts at low temperatures. These results allow us to better understand the basis of wine yeast adaptation to fermentation conditions, providing important information for winemakers to help them select the most appropriate yeast strain, thus reducing the economic costs associated with long and sluggish fermentations. The correlation between some amino acids and better yeast fermentation performance could be used in the future to design inactive dry yeast enriched in some of these amino acids, which could be added as a nutritional supplement during low temperature fermentations. [ABSTRACT FROM AUTHOR]

The study explored using a hot-air oven at various temperatures (35, 45, and 55 °C) as a promising alternative to traditional sun-drying for salted shrimp paste production. Comparing drying profiles, fermentation rate, quality, and acceptability with conventional sun-drying (CON), it was found that the alternative hot-air oven led to lower enzymatic activities and degree of hydrolysis during a 30-day fermentation (p < 0.05). Consequently, the alternative samples exhibited lower development of distinctive characteristics (color, browning intensity, formal, ammonia, nitrogen contents, and antioxidant capabilities) resulting in lower sensory scores compared to CON (p < 0.05). Interestingly, microbial populations in hot-air-dried samples were also lower than CON (p < 0.05). Based on PCA biplots and drying duration, drying at 45 °C with a hot-air oven seemed optimal for shrimp paste production. However, adjustments, such as prolonging fermentation or using a starter culture, are needed to make the alternative process comparable to the traditional product. [ABSTRACT FROM AUTHOR]

Nowadays, the wine industry carries out fermentations at low temperatures because this oenological practice clearly improves the aromatic complexity of the final wines. In addition, nitrogen content of the must also influences the quality of the wine. In this study, we carried out a phenotypic and fermentative analysis of two industrial wine Saccharomyces cerevisiae strains (P5 and P24) at 15 and 28 °C and three nitrogen concentrations (60, 140 and 300 mg N/L) in synthetic must. Our results show that both parameters, temperature and nitrogen, are interrelated and clearly determine the competitiveness of the wine strains and their ability to adapt at low temperatures. The best adapted strain at low temperatures decreased its competitiveness at lower nitrogen concentrations. In addition, our results show that it is not only the quantity of nitrogen transported that is important but also the quality of the nitrogen source used for wine yeast adaptation at low temperatures. The presence of some amino acids, such as arginine, branched chain amino acids, and some aromatic amino acids can improve the growth and fermentation activity of wine yeasts at low temperatures. These results allow us to better understand the basis of wine yeast adaptation to fermentation conditions, providing important information for winemakers to help them select the most appropriate yeast strain, thus reducing the economic costs associated with long and sluggish fermentations. The correlation between some amino acids and better yeast fermentation performance could be used in the future to design inactive dry yeast enriched in some of these amino acids, which could be added as a nutritional supplement during low temperature fermentations.

In this study, changes in physicochemical characteristics, microbial communities, and metabolites were investigated to identify the fermentation characteristics of radish kimchi according to the size of radish cubes used. The small-sized radish kimchi group showed the highest hardness value and glucose content in the early stages of fermentation. The relative abundance of major lactic acid bacteria, including Leuconostoc, Weissella, and Lactobacillus, was the highest in the small-sized radish kimchi group on day 5 of fermentation, which resulted in rapid production of lactic acid, thereby causing a decrease in pH and an increase in titratable acidity. The size of the radish in kimchi plays a pivotal role in determining various factors, most notably during the first 5 days of fermentation, leading to marked metabolic changes. A total of 17 metabolites, including glucose, sucrose, lactic acid, malic acid, citric acid, and GABA, exhibited significant differences in the small-size radish kimchi group. Interestingly, the sucrose content was higher in the large-sized radish group at the beginning of fermentation. This study revealed that ingredient size can selectively affect the growth of specific microorganisms in an environment where several microorganisms coexist, which could change the quality of radish kimchi.

Honey is a product of high nutritional value, used as a raw material for obtaining mead. However, adding fruit juices, including chokeberry juice, can improve mead quality. This paper aims to assess the effects that adding different quantities of chokeberry juice, with the variation of 3 amounts of inoculated yeast, has on the fermentation and physicochemical, antioxidant, and antimicrobial properties of mead. The parameters analyzed are the dry matter content, pH value, and content of volatile acids, ethanol and methanol, total phenols and flavonoids, FRAP, DPPH, and ABTS tests, and antimicrobial properties. The results obtained in this paper show that adding chokeberry juice improves the antioxidant properties of the final product and positively affects the course of mead fermentation, i.e., it has led to an increase in the maximum concentration of ethanol. Regarding the chemical composition of mead, there is no significant difference, except in the obtained ethanol content, which is the highest in samples with 10% of added chokeberry juice. Furthermore, the control sample showed the best antimicrobial activity, while the sample with 5% added chokeberry juice showed the weakest effect. Finally, the strongest effect was seen in the sample with 20% of added chokeberry juice.

The article presents data on the study of the influence of hydrocolloids and protein additives on the technological aspects of gluten-free rice bread production. The method of full-factor experiment PFE 2 3 determined the optimal conditions for bread production – the amount of yeast 1.5% by flour weight, dough moisture 60%, duration of fermentation, and proofing 70 minutes. The prescribed amount of yeast, salt, agar, and gelatin was dissolved in water at 35 ºC and mixed with the specified amount of rice flour. The dough was kneaded for 15 minutes. The dough was placed in the mould and left to ferment for 40 minutes and stand for 30 minutes at the temperature of 30 ºC. After fermentation, the dough was divided into pieces weighing 50 grams, placed in baking tins, and baked for 35 – 40 minutes at the temperature of 180 ºC. Since adding polysaccharides and protein improvers to the recipe of gluten-free dough to regulate its technological properties can significantly affect the intensity of fermentation and the activity of amylolytic enzymes of flour, studied the dynamics of carbon dioxide release gluten-free rice dough. It was found that additives of protein nature increase the amount of carbon dioxide accumulation in gluten-free dough by 33 – 44%. It is experimentally substantiated that the recommended duration of fermentation of rice flour dough with the addition of gelatin is 45 – 50 min, with the addition of agar 25 – 30 min, and the mixture of gelatin and agar 35 – 45 min. It is established that to achieve full readiness of bread based on rice flour, it is possible after 35 minutes of baking at 200 ºC. When extending the duration of heat treatment, the quality of bread does not change, so long-term heat treatment is not economically feasible.

Saccharomyces cerevisiae is a microorganism of remarkable biotechnological interest, owing to its involvement in bioethanol production, as well as in beverages and bread production. High ethanol concentration during alcoholic fermentation constitutes a major stress for yeast cells, leading to decreased fermentation rate and reduced ethanol production. Herein we describe an innovative Adaptive Laboratory Evolution (ALE) strategy for the acquisition of S. cerevisiae populations more tolerant to ethanol toxicity. In this strategy, a weak selective pressure environment (encouraging diversity) is alternated by a strong selective pressure environment (eliminating low-tolerant clones). Two different parental strains, named S. cerevisiae CFB and S. cerevisiae BLR, were used and the resulting evolved populations obtained after 100 generations of evolution were proven capable of surviving at 23% v/v ethanol for 1 h and at 25% v/v ethanol for 2 h, respectively. Two evolved populations originated from S. cerevisiae CFB and S. cerevisiae BLR after 150 and 200 generations of evolution respectively, exhibited higher fermentation rates than their parental strains in synthetic broth with 200 g/l glucose, completing the fermentation 166 h and 130 h earlier, respectively. The evolved populations derived after 100 generations of evolution produced 94.77 and 98.67 g/l ethanol, for S. cerevisiae CFB and S. cerevisiae BLR, respectively, in comparison with 84.91 and 78.09 g/l of their parental strains. Contrary, the maximum specific growth rate (μ max) was improved solely in S. cerevisiae BLR, reaching the value of 0.25 1/h after 100 generations of evolution in comparison with 0.12 1/h of the parental strain. It is concluded that the fermentation ability of the two S. cerevisiae strains was significantly improved through evolution using ethanol as a selective factor. [Display omitted] • High ethanol concentration in fermentation broth leads to decreased fermentation rate and ethanol production. • An Adaptive Laboratory Evolution strategy for the acquisition of ethanol tolerant Saccharomyces cerevisiae populations was developed. • Using evolved populations fermentation rate and ethanol yield were significantly improved. [ABSTRACT FROM AUTHOR]

Nitrogen addition is a viable strategy for preventing sluggish or stuck fermentation and enhancing aroma profiles in the winemaking industry. Herein, nitrogen, in the form of amino acids mixture or diammonium hydrogen phosphate (DAP), was added at different fermentation periods to investigate its effects on the fermentation characteristics, non-volatile compounds and aroma profiles of kiwi wines. Both the amino acids mixture and DAP shortened fermentation time by 1–2 days and balanced organic acid proportion by reducing malic acid content and increasing citric acid content. Adding DAP significantly decreased higher alcohols content, whereas higher alcohols content was remarkably increased with amino acids mixture supplementation. Furthermore, nitrogen addition during the stationary phase was most conducive to synthesizing other beneficial aromas, especially acetate esters and medium-chain fatty acid ethyl esters (MCFAEEs), and improving the perception of tropical fruity and cream aromas in kiwi wines. Partial least-squares regression (PLSR) results showed there was a tight correlation between amino acids and volatile compounds. This study provides an insight into the development of high-quality kiwi wine and should serve as the theoretical foundation to support the application of nitrogen addition in the wine industry. [Display omitted] • The addition time and type of nitrogen affected the characteristics of kiwi wine. • Nitrogen addition cut fermentation time and improved aroma profiles in kiwi wine. • Nitrogen addition increased tropical fruity and cream aromas of kiwi wine. • The promotion effect was most conducive during addition in the stationary phase. [ABSTRACT FROM AUTHOR]

Cili (Roxburgh rose) wine, which is rich in ascorbic acid, flavones, and polyphenols, presents unique challenges in wine production, including oxidation, aroma loss, and SO 2 residues. This study investigated the effects of three antioxidants (SO 2 , glutathione (GSH), and GSH-rich inactive dry yeast (g-IDY)) on the fermentation properties of cili wine and evaluated the potential of g-IDY for addressing the aforementioned issues. g-IDY significantly enhanced the fermentation rate, as evidenced by increased CO 2 production within 48 h, and maintained high levels of GSH, total phenolics, total flavones, and ascorbic acid, contributing to the antioxidant capacity and overall stability of the wine. g-IDY also improved the retention and concentration of key aromatic compounds, including higher alcohols, esters, and terpenes, thereby enhancing the sensory profile of the wine. Principal component analysis confirmed that different antioxidants significantly altered the volatile profile, with g-IDY demonstrating distinct improvements. The optimal concentration was 400 mg/L g-IDY. Compared with traditional antioxidants like SO 2 and pure GSH, g-IDY offers a safer and more effective solution for preserving the quality of cili wine. This study provides experimental evidence for refining the fermentation process and promotes the use of g-IDY for enhancing the antioxidant capacity and sensory attributes of cili wine. • Effects of different antioxidants on cili-wine fermentation were investigated. • Key challenges in wine production were addressed. • Using g-IDY improved the antioxidant capacity. • g-IDY positively influenced the concentrations of key volatile aroma compounds. • Insights were provided for optimizing brewing methods for cili wine using g-IDY. [ABSTRACT FROM AUTHOR]

Antibiotics adversely affect intestinal communities and prebiotic fibers are effective to counteract the side effects of antibiotics. The effects of prebiotic fibers vary due to their molecular characteristics. This study compared the effects of three fibers with different fermentation rates on fecal microflora with the perturbance of antibiotics in vitro. The results showed that supplementation of the low-fermentable fiber (konjac glucomannan, KGM) enhanced the viability of several gut bacterial groups and increased the production of acetic acid and total SCFAs better than the high- (galactooligosaccharides, GOS) and moderate-fermentable fibers (inulin, INU) with antibiotic disturbance. The relative abundance of Bacteroidetes was significantly lowered after fermentation with GOS compared with KGM and INU in the presence of ampicillin. KGM fermentation also maintained the relative abundance of possible butyric acid producer Clostridium. These results suggest that low-fermentable carbohydrates confer better effects to relieve or counteract antibiotic influence on gut microbiome.

Introduction. Mead, one of the oldest alcoholic beverages that man consumed is obtained by fermentation of honey solution, and contains from 8 to 18% vol. ethanol. Honey can be considered as an excellent source of carbohydrates for the fermentation process, but low concentrations of other substances in the honey can slow down the process. Blackberry (Rubus fruticosus L.) contains dietary fibers, vitamin C (ascorbic acid), vitamin A, vitamin E, potassium and calcium, along with the phenolic metabolites that are a source of possible health benefits. Study objects and methods. In this study was investigated the influence of blackberry juice addition on mead fermentation process, chemical composition and antioxidative activity. Dynamics of the fermentation process were controlled based on weighing the flasks in time on a scale every 24 h throughout the alcoholic fermentation. At the end of fermentations, oenological parameters of mead: dry matter content, pH, volatile acidity and ethanol content and reducing sugars. For the determination of antioxidative capacity the content of total phenolics, total flavonoids and total flavonols were measured and two tests were performed: DPPH and ABTS. Results and discussion. Addition of blackberry juice had a positive effect on fermentation dynamics (almost 25% higher rate of fermentation than in control samples), and improved all physicochemical characteristics and composition of resultant meads. Also, meads with the addition of blackberry juice had a significantly higher concentration of total phenolics, total flavonoids and total flavonols and significantly stronger antioxidative properties compared to the control meads without juice addition. The highest total phenolics, total flavonoids and total flavonols content was determined in the mead with the maximum addition of blackberry juice (B20W): it reached 490.88, 50.34 and 62.57 μgQE.mL–1, respectively, and was 6-fold higher for total phenolics and total flavonoids content, and 10-fold higher for total flavonols content than in the mead without juice addition (CW). The strongest antioxidative activity was determined in the B10W mead; it accounted for 6.98 μgTE.mL–1 (DPPH assay) and 0.65 μgTE.mL–1 (ABTS assay), what was 1.5-fold and 3-fold higher, respectively, than in the mead without juice addition (CW). Conclusion. The conducted study demonstrated that the use of blackberry juice influenced the course of fermentation of meads as well as their physicochemical and antioxidative properties (positive effect on fermentation dynamics – almost 25% higher rate of fermentation than in control samples, and improvement of all physicochemical characteristics and composition of resultant meads).

Kimchi products are often discarded by burst package due to the excessive fermentation during long-term distribution. In this study, supercooling storage was approached to prevent deterioration during distribution by regulating fermentation rate and maintaining quality of products by lowering storage temperature. Herein, cut cabbage kimchi (CCK) products were stored in the supercooling condition by stepwise temperature control algorithm for 12 weeks. During storage, the temperature of CCK was strictly followed the algorithm, maintaining −3.5 °C at the lowest step without ice nucleation. The supercooled CCK were reduced in the LAB growth comparing to the refrigerated CCK, presenting superior quality. Further, heterofermentative LABs were dominant in supercooled CCK after 12 weeks, maintaining the earlier stage of fermentation. Reversely, homofermentative LABs were dominant in refrigerated CCK, meaning the latter stage of fermentation. Freezing suppressed the growth of aerobic bacteria and LAB in CCK and lost the physicochemical qualities by damages from freezing and thawing. Thus, supercooling storage could help maintain the original qualities of CCK to control fermentation rate at −3.5 °C for long-term storage in the static condition. Further studies can be conducted at −3.5 °C reflecting practical conditions. • Supercooling storage of CCK was achieved by stepwise temperature control algorithm. • Supercooling reduced the number of LAB in CCK compared to refrigeration. • Supercooling regulated fermentation rate of LAB in CCK, maintaining its quality. • Refrigerated CCK was overmatured. [ABSTRACT FROM AUTHOR]

[Objectives] To explore the influence of emulsifier on the fermentation performance of wine active dry yeast. [ Methods] Angel active dry yeast RV002 was selected as the test strain, and the simulated grape juice was used as the fermentation medium to investigate the fermentation rate, the yeast cell number and morphology, and the physicochemical indexes of the produced wine. [ Results] It was found that the viable cell rate of the active dry yeast without the emulsifier was significantly reduced, and the fermentation rate was significantly slowed down. However, the emulsifier had no significant effect on the morphology of yeast cells, the fermentation cycle, the final number of viable cells, and the quality of the produced wine. [Conclusions] The active dry wine yeast without emulsifier can reduce the formation of grape juice foam and reduce the risk of grape juice spillover. [ABSTRACT FROM AUTHOR]

The article presents data on the study of the influence of hydrocolloids and protein additives on the technological aspects of gluten-free rice bread production. The method of full-factor experiment PFE 2 3 determined the optimal conditions for bread production - the amount of yeast 1.5% by flour weight, dough moisture 60%, duration of fermentation, and proofing 70 minutes. The prescribed amount of yeast, salt, agar, and gelatin was dissolved in water at 35 °C and mixed with the specified amount of rice flour. The dough was kneaded for 15 minutes. The dough was placed in the mould and left to ferment for 40 minutes and stand for 30 minutes at the temperature of 30 °C. After fermentation, the dough was divided into pieces weighing 50 grams, placed in baking tins, and baked for 35 - 40 minutes at the temperature of 180 °C. Since adding polysaccharides and protein improvers to the recipe of gluten-free dough to regulate its technological properties can significantly affect the intensity of fermentation and the activity of amylolytic enzymes of flour, studied the dynamics of carbon dioxide release gluten-free rice dough. It was found that additives of protein nature increase the amount of carbon dioxide accumulation in gluten-free dough by 33 - 44%. It is experimentally substantiated that the recommended duration of fermentation of rice flour dough with the addition of gelatin is 45 - 50 min, with the addition of agar 25 - 30 min, and the mixture of gelatin and agar 35 - 45 min. It is established that to achieve full readiness of bread based on rice flour, it is possible after 35 minutes of baking at 200 °C. When extending the duration of heat treatment, the quality of bread does not change, so long-term heat treatment is not economically feasible. [ABSTRACT FROM AUTHOR]

Tannic acid could inhibit the α-amylase activity secreted from gut microbiota and regulate the microbial composition. As a result, tannic acid could delay the metabolism of resistant starch, thereby probably delivering resistant starch to the distal colon. [Display omitted] • Tannic acid could delay the metabolism of resistant starch. • Tannic acid inhibited the activity of α-amylase secreted by gut microbiota. • Tannic acid delayed the enrichment of starch-degrading bacteria. • Tannic acid improved the prebiotic activity of resistant starch. This work investigated the effect of tannic acid on the fermentation rate of resistant starch. It was found that 1.0 and 1.5 μmol/L tannic acid decreased the rate of producing gas and short-chain fatty acids (SCFAs) from fermentation of resistant starch, and 1.5 μmol/mL tannic acid had a more profound effect, which confirmed that tannic acid delayed the metabolism of resistant starch. Moreover, tannic acid significantly inhibited the α-amylase activity during fermentation. On the other hand, tannic acid delayed the enrichment of some starch-degrading bacteria. Besides, fermentation of the resistant starch/tannic acid mixtures resulted in more SCFAs, particularly butyrate, and higher abundance of beneficial bacteria, including Bifidobacterium , Faecalibacterium , Blautia and Dorea, than fermentation of resistant starch after 48 h. Thus, it was inferred that tannic acid could delay the metabolism of resistant starch, which was due to its inhibitory effect on the α-amylase activity and regulatory effect on gut microbiota. [ABSTRACT FROM AUTHOR]

To accelerate the fermentation rate and reduce the adverse effects of undesirable microorganism contamination on rice noodle quality, the pure inoculum fermentation method was used to produce fermented rice noodles. The results indicated that the pure inoculum fermented rice slurry required 10 h to reach a stable pH value. While, the pH value of the natural, pure and natural inoculum fermented rice slurries required 54, 18 and 20 h to stabilize, respectively. Free amino acids and lactic acid concentrations of the pure inoculum fermented rice slurry were higher than those of the natural and natural inoculum fermented rice slurries. The pure inoculum fermentation modified the proximate composition and lowered the pasting viscosities of the rice flour. The texture, cooking and eating qualities of the pure inoculum fermented rice noodles were similar to those of the natural fermented ones. In addition, the pure inoculum fermented rice noodles had higher relative contents of aldehydes than other fermented rice noodles and thus had a better flavor. Therefore, pure inoculum fermentation accelerated the fermentation rate and improved the rice noodle flavor while maintaining the texture, cooking and eating qualities of the rice noodles. [ABSTRACT FROM AUTHOR]

Nitrogen content management before fermentation is often used in cider production to avoid sluggish fermentations. In addition to enhanced fermentation rates, the proper nitrogen content in the apple must may have an impact on the flavour characteristics of cider. This research aimed to assess yeast performance in two different commercially available musts with similar non-limiting yeast available nitrogen (YAN) content. In addition to fermentation kinetics, volatile ester production by yeast, and sensory properties of the final product were evaluated. The results showed that the fermentation rate and consumption of sugar and nitrogen sources by yeast did not vary between the two different musts. Yeasts consumed more malic acid in the environment of higher initial malic acid content. The content of volatile esters and sensory properties of the final products varied significantly. The occurrence of intense sulfur off-flavour was noted in one of the products. [ABSTRACT FROM AUTHOR]

Corn grits are commonly used adjuncts in the brewing industry in the United States, especially for lager beers. The major challenge of using a high amount of adjuncts in the brewing process is reduced levels of nutrients available to yeast during fermentation, which negatively affects the growth and functioning of yeast, and results in sluggish fermentation. The problem is usually addressed by adding external nutrition. The objective of this work was to assess the suitability of corn components other than brewer's grits to improve the fermentation rates. Water obtained after soaking of corn germ, a vital source of lipids and soluble proteins, was investigated as a source of nutrient during brewing of 40:60 (w/w) corn grits and malt mixture. Performance of water-soluble nutrients from germ of two corn verities, yellow dent corn and flint corn, was investigated. Germ soak water was added during corn grits slurry formation before mashing. The addition of germ water increased the free amino nitrogen levels by 37% and Zn concentrations by 3.6 times in the wort, which resulted in up to a 28% higher fermentation rate (between 48 to 72 h of fermentation) and shortened the fermentation time from 120 to 96 h. The use of water obtained from the soaking of flint corn germ resulted in a similar shortening of fermentation time. In another approach, nutrient-rich concentrated germ soak water was directly added into the wort, which also resulted in similar improvements in the fermentation rate as those from adding germ soak water during slurry formation. Due to leaching of micronutrients and soluble proteins, the oil concentrations in the germ increased by more than 30%, enhancing its economic value. [ABSTRACT FROM AUTHOR]

The selection of yeast with good fermentation characteristics is critical for producing beer with desirable qualities. A yeast population was selected with an enhanced fermentation rate, referred to as high‐fermentation yeast (HFY), which was derived from the wild‐type Sacchromyces pastorianus yeast population (WTY). To identify genes that contribute to the fermentation performance, we compared the genetic profiles of the WTY and HFY populations by next‐generation sequencing. Several chromosomal regions were found to exhibit markedly different sequence coverage, suggesting chromosomal duplications and deletions, which might have occurred during selection of the HFY population. Among the genes with altered coverage, the copy number of the Saccharomyces eubayanus‐type YCK1 (SeYCK1) gene was almost two times higher in the HFY population than in the WTY population. The gene which is involved in glucose sensing in Saccharomyces cerevisiae was at a higher level in the HFY population throughout fermentation. These findings suggest that the chromosomal duplication of a region including the SeYCK1 gene locus of the HFY population is at least partially responsible for the differences in the fermentation properties between the WTY and HFY populations. © 2018 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The fermentation of sodium alginate at different colon regions are expected to be regulated using cross-linking strategy to release SCFAs at different colon regions. [Display omitted] • The Ca2+ cross-linked sodium alginates were still producing more SCFAs in the later fermentation stages in comparison to sodium alginate. • The Ca2+ cross-linking exerted a more restricting effect than a delaying effect on the in vitro fermentation of sodium alginate. • Bacteroides_xylanisolvens were highly correlated to the Ca2+ cross-linking density but not Ca2+ concentration. Slow fermentable dietary fibers can be utilized by human gut microbiota in the distal region of the colon and thus exert a sufficient short-chain fatty acids (SCFAs) supplement in the distal region of the human colon. Alginate (Alg) based microgels are widely fabricated and used to control their digestion by digestive enzymes releasing active substances site-specifically. Herein, sodium alginate microgels with gradient calcium-ion (Ca2+) cross-linking densities were developed, restricting their degradation by gut microbiota. Alg microgels were prepared using high-speed shearing after Alg was cross-linked with 10, 40, and 60 mmol/L Ca2+, respectively (named 10-Alg, 40-Alg, and 60-Alg). The fluorescence and atomic force microscopic results showed that the 40-Alg particle has the densest structure among the three cross-linked Alg. In vitro human fecal fermentation results revealed that the Ca2+ cross-linking exerted more restricting effects than delaying effects on the fermentation of Alg, and the 40-Alg exhibited the slowest fermentation rate and the least fermentation extent, by characterizing the residual total carbohydrate content, residual monosaccharide content, pH, and total short-chain fatty acids. The 16S rRNA gene sequencing results indicated that cross-linking structures shaped a high specifical Bacteroides -type microbial community and that OTU205 (Bacteroides_xylanisolvens) highly correlated to the cross-linking density (R = 0.65, p = 0.047). In sum, Ca2+ cross-linking generated a dense and compact structure of sodium alginate that facilitated a more restricted fermentation property and specificity-targeting microbial community structure in comparison to the original sodium alginate. [ABSTRACT FROM AUTHOR]

High fiber diets are known to have many benefits to sows (e.g., improving reproductive performance such as vitality of piglets, stimulating gut health, and improving well-being), and due to their fermentation properties, they may have different functions in lactating sows. Fast fermentable fiber favors the growth of beneficial microbiota which contributes to improved gut health, and slow fermentable fiber increases the fecal mass and provides a delayed release of some nutrients which benefits the farrowing process of sows. On the other hand, high fiber diets may reduce feed intake and nutrient digestibility. The objective of this study was to investigate the effects of dietary fiber concentration and fermentation rate on lactating sow performance, nutrient digestibility, and immunity. Four diets were formulated with increasing fast fermentable fiber, with diets 1 and 2 formulated at low (15%) total dietary fiber (TDF) and diets 3 and 4 at high (25%) TDF. The proportion of fast fermentable fiber in total diet of 4 treatments were 1.25%, 2.5%, 3.75%, and 5% respectively. The main fiber sources were sugar beet pulp, oat hull, and barley. Digestible energy, crude protein, and lysine levels were comparable among each treatment group. A total of 136 lactating sows (Landrace × Large White) were blocked by parity, body weight (BW), and back fat (BF), and then randomly assigned to each block (8 blocks). Feed allowance was set to increase from 3 kg/d (primiparous) or 3.5 kg/d (multiparous) at farrowing to a maximum of 7 kg/d or 8 kg/d at 7d or 8d post farrowing. Results showed that sows in high fiber groups had an increased litter weight gain and BF loss (P < 0.05), and sows in fast fiber groups showed a decreased BW and protein loss (P < 0.05). Low fiber fed sows showed a significantly increased digestibility of protein, gross energy (GE), and dry matter compared with high fiber ones (P < 0.05). Sows fed with slow fermentable fiber in the low fiber groups showed greater digestibility of GE, protein, and dry matter compared with the ones fed with fast fermentable fiber; however, the opposite was true in high fiber groups. Fiber concentration and fermentation rate did not show significant effects on serum IL-8, IL-10, TNF-a, or endotoxin of sows (P > 0.05). In conclusion, high fiber diet increased BF loss and negatively influenced nutrient digestibility while having positive effects on litter growth. The negative effects of fiber were partially compensated by increasing the soluble fraction. Based on the current study, when feeding lactating sows a diet with high fiber, a relative increase of fast fermentable fiber is the most favorable feeding strategy. [ABSTRACT FROM AUTHOR]

In this study, changes in physicochemical characteristics, microbial communities, and metabolites were investigated to identify the fermentation characteristics of radish kimchi according to the size of radish cubes used. The small-sized radish kimchi group showed the highest hardness value and glucose content in the early stages of fermentation. The relative abundance of major lactic acid bacteria, including Leuconostoc , Weissella , and Lactobacillus , was the highest in the small-sized radish kimchi group on day 5 of fermentation, which resulted in rapid production of lactic acid, thereby causing a decrease in pH and an increase in titratable acidity. The size of the radish in kimchi plays a pivotal role in determining various factors, most notably during the first 5 days of fermentation, leading to marked metabolic changes. A total of 17 metabolites, including glucose, sucrose, lactic acid, malic acid, citric acid, and GABA, exhibited significant differences in the small-size radish kimchi group. Interestingly, the sucrose content was higher in the large-sized radish group at the beginning of fermentation. This study revealed that ingredient size can selectively affect the growth of specific microorganisms in an environment where several microorganisms coexist, which could change the quality of radish kimchi., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

High solid fermentation during bioethanol production is a promising process engineering strategy to reduce total energy use and water requirements, and to improve productivity. However, ethanol toxicity at higher concentrations restricts the corn solids to 30–32% ( w /w) during dry grind corn ethanol process. This work, using in situ ethanol removal, results in two big improvements in the fermentation process: 1) achieve complete fermentation of high solids slurries (up to 42%) at typical commercial enzyme dosages, and 2) fasten the fermentation process for currently used process with 32% solids. Application of vacuum at optimal times during fermentation (1 h at 12, 24, 36, and 48 h) of 40% corn solids resulted in complete fermentation, compared to about 12% residual glucose in the conventional process. The ethanol yield of 0.42 L/kg of dry corn with about 80% ethanol conversion efficiency was 88% higher than that of the conventional process at 42% solids (0.22 L/kg dry corn). Application of 1.5 h of vacuum at 18 and 24 h of fermentation with 32% solids resulted in high fermentation rates and decreased the fermentation time by more than 50%. Shorter fermentation times can allow processing of more material with the same equipment and allow smaller fermentation tanks in new plants, which would lead to both, lower capital and operating cost. [ABSTRACT FROM AUTHOR]

Corn grits are commonly used adjuncts in the brewing industry in the United States, especially for lager beers. The major challenge of using a high amount of adjuncts in the brewing process is reduced levels of nutrients available to yeast during fermentation, which negatively affects the growth and functioning of yeast, and results in sluggish fermentation. The problem is usually addressed by adding external nutrition. The objective of this work was to assess the suitability of corn components other than brewer’s grits to improve the fermentation rates. Water obtained after soaking of corn germ, a vital source of lipids and soluble proteins, was investigated as a source of nutrient during brewing of 40:60 (w/w) corn grits and malt mixture. Performance of water-soluble nutrients from germ of two corn verities, yellow dent corn and flint corn, was investigated. Germ soak water was added during corn grits slurry formation before mashing. The addition of germ water increased the free amino nitrogen levels by 37% and Zn concentrations by 3.6 times in the wort, which resulted in up to a 28% higher fermentation rate (between 48 to 72 h of fermentation) and shortened the fermentation time from 120 to 96 h. The use of water obtained from the soaking of flint corn germ resulted in a similar shortening of fermentation time. In another approach, nutrient-rich concentrated germ soak water was directly added into the wort, which also resulted in similar improvements in the fermentation rate as those from adding germ soak water during slurry formation. Due to leaching of micronutrients and soluble proteins, the oil concentrations in the germ increased by more than 30%, enhancing its economic value.

BACKGROUND Fungicide residues on fruit may adversely affect yeast during cider fermentation, leading to sluggish or stuck fermentation or the production of hydrogen sulfide ( H2S), which is an undesirable aroma compound. This phenomenon has been studied in grape fermentation but not in apple fermentation. Low nitrogen availability, which is characteristic of apples, may further exacerbate the effects of fungicides on yeast during fermentation. The present study explored the effects of three fungicides: elemental sulfur ( S0) (known to result in increased H2S in wine); fenbuconazole (used in orchards but not vineyards); and fludioxonil (used in post-harvest storage of apples). RESULTS Only S0 led to increased H2S production. Fenbuconazole (≥0.2 mg L−1) resulted in a decreased fermentation rate and increased residual sugar. An interactive effect of yeast assimilable nitrogen ( YAN) concentration and fenbuconazole was observed such that increasing the YAN concentration alleviated the negative effects of fenbuconazole on fermentation kinetics. CONCLUSION Cidermakers should be aware that residual fenbuconazole (as low as 0.2 mg L−1) in apple juice may lead to stuck fermentation, especially when the YAN concentration is below 250 mg L−1. These results indicate that fermentation problems attributed to low YAN may be caused or exacerbated by additional factors such as fungicide residues, which have a greater impact on fermentation performance under low YAN conditions. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the nitrogen content in different varieties of apple musts and to study the effect of different nitrogen concentrations in apple wine fermentation. The average total nitrogen content in 51 different apples juices was 155.81 mg/L, with 86.28 % of the values above 100 mg/L. The apple must with 59.0, 122.0 and 163.0 mg/L of total nitrogen content showed the maximum population of 2.05x 10(7); 4.42 x 10(7) and 8.66 x 10(7) cell/mL, respectively. Therefore, the maximum fermentation rates were dependent on the initial nitrogen level, corresponding to 1.4, 5.1 and 9.2 g/L.day, respectively. The nitrogen content in the apple musts was an important factor of growth and fermentation velocity.

[Display omitted] • Low temperatures along with multiple strains and culture media were considered. • Temperature, strain and medium exert effect jointly on low-temperature winemaking. • Similar metabolite compositions at 10 and 15 °C are distinguished from 20 °C. • Lower temperatures improved ethanol, ethyl acetate, and ethyl butanoate synthesis. • Lower temperatures reduced acetic acid, phenylethanol, phenylethyl acetate synthesis. Low-temperature fermentation is considered to enrich the aroma of wine. The metabolism of Saccharomyces cerevisiae responding to low temperatures is intricate and this complexity is further enhanced by various strains and culture media. However, the real effects of low-temperature fermentation on yeast metabolism are unclear. Aiming to clarify the yeast-derived metabolite formation in a low-temperature winemaking range, fermentations were performed at 10, 15, and 20 °C, using five wine yeast strains in two media respectively. Tolerance toward low temperatures and metabolite compositions (including basic chemical compositions and volatile aroma compounds) of wine yeasts were analyzed. Results showed that ethanol, ethyl acetate, and ethyl butanoate increased with the temperature decreasing, while acetic acid, phenylethanol, phenylethyl acetate, ethyl decanoate, and ethyl hexadecanoate decreased with decreasing temperature. The linear relationship between fermentation temperature and the formation of ethanol, acetic acid, and phenylethanol might be fundamentally due to the growth changes caused by temperature. The enhanced production of ethyl acetate and ethyl butyrate followed by decreasing temperature probably resulted from low-temperature-stimulated enzymes in metabolic pathways. These findings reveal a typical profile of yeast-derived metabolites at low-temperature fermentation and provide evidence to support the application of low-temperature winemaking in the wine industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metabolic characteristics of Lactococcus lactis strains are described. • Fermentation profile correlates with metabolic profile. • Peptides, esters and tributyrin may affect the growth of Lactococcus lactis strains. • Peptides, esters and tributyrin can be used as markers for fast acid-producing strains. The bacterial starter has a crucial role in fermentation of dairy products; however, knowledge about metabolic differences in Lactococcus (L.) lactis subsp. lactis strains with different fermentation rates is limited. We analyzed the fermentation capacity and metabolic profiles of 17 L. lactis subsp. lactis strains through ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry Elevated Energy. Metabolomics results revealed significant differences in metabolites between the fast group (fermentation time < 16 h) and slow group (fermentation time ≥ 16 h). In the fast group, 98 and 55 metabolites were increased and decreased, respectively. The fast group was enriched with peptides and lipids, and we found that peptides, esters, and tributyrin can be used as biomarkers to distinguish between groups. Our results implicated that tributyrin plays a role in regulating strain growth. This study provides a novel insight into the metabolic cause of different acid production rates between individuals L. lactis subsp. lactis strains. [ABSTRACT FROM AUTHOR]

[Display omitted] • The utilization rate is GOS > INU > KGM > MC by fecal microflora. • Low-fermentable fiber enhanced the viability of gut bacteria better with antibiotic perturbance. • High- and moderate-fermentable fibers lowered the microbial diversity with antibiotic perturbance. • Low-fermentable fiber induced higher productions of acetic acid and total SCFAs. Antibiotics adversely affect intestinal communities and prebiotic fibers are effective to counteract the side effects of antibiotics. The effects of prebiotic fibers vary due to their molecular characteristics. This study compared the effects of three fibers with different fermentation rates on fecal microflora with the perturbance of antibiotics in vitro. The results showed that supplementation of the low-fermentable fiber (konjac glucomannan, KGM) enhanced the viability of several gut bacterial groups and increased the production of acetic acid and total SCFAs better than the high- (galactooligosaccharides, GOS) and moderate-fermentable fibers (inulin, INU) with antibiotic disturbance. The relative abundance of Bacteroidetes was significantly lowered after fermentation with GOS compared with KGM and INU in the presence of ampicillin. KGM fermentation also maintained the relative abundance of possible butyric acid producer Clostridium. These results suggest that low-fermentable carbohydrates confer better effects to relieve or counteract antibiotic influence on gut microbiome. [ABSTRACT FROM AUTHOR]

During fermentation, the nature and amount of nitrogen added into grape must affect the fermentation rate and secondary aroma production. Timing of addition is also relevant for the resultant wine. The wine industry uses different nitrogen preparations to avoid nitrogen deficiency in wine fermentations. However, it is important to know the proper way to carry out additions. In this work, we studied the effect of nitrogen addition to three commercial wine strains in the stationary phase of synthetic must fermentations. We analyzed the impact of the concentration and source of nitrogen on fermentation activity and aroma production. Nitrogen addition stimulates the fermentation rate, mainly in N-deficient medium. Moreover, aroma synthesis changes with nitrogen additions. The use of ammonium and arginine as additives produces wines with lower higher alcohol content and higher ester concentration respectively. The results indicate that different wine strains and nitrogen sources can be used to produce wines with divergent aroma profiles to meet consumer demands for diversified products. [ABSTRACT FROM AUTHOR]

Abstract: Fermentation of sugars into CO2, ethanol and secondary metabolites by baker's yeast (Saccharomyces cerevisiae) during bread making leads to leavening of dough and changes in dough rheology. The aim of this study was to increase our understanding of the impact of yeast on dough related aspects by investigating the effect of harvesting yeast at seven different points of the growth profile on its fermentation performance, metabolite production, and the effect on critical dough fermentation parameters, such as gas retention potential. The yeast cells harvested during the diauxic shift and post-diauxic growth phase showed a higher fermentation rate and, consequently, higher maximum dough height than yeast cells harvested in the exponential or stationary growth phase. The results further demonstrate that the onset of CO2 loss from fermenting dough is correlated with the fermentation rate of yeast, but not with the amount of CO2 that accumulated up to the onset point. Analysis of the yeast metabolites produced in dough yielded a possible explanation for this observation, as they are produced in different levels depending on physiological phase and in concentrations that can influence dough matrix properties. Together, our results demonstrate a strong effect of yeast physiology at the time of harvest on subsequent dough fermentation performance, and hint at an important role of yeast metabolites on the subsequent gas holding capacity. [Copyright &y& Elsevier]

The objective of this study was to evaluate the nutritive value of maize stover silage diets containing pig excreta (PE), poultry litter (PL) or urea as nitrogen (N) sources, and sugarcane molasses (MOL) or bakery by-products (BBP) as energy sources. The study was designed as a 6 x 6 Latin square with six ruminal cannulated Hampshire rams (56 ± 5.7 kg body weight) in a 3 x 2 factorial arrangement of treatments. The quality of silages was good because of acceptable pH (4.1), texture and odour. Gas production was higher for diets with silage containing PL than that containing PE (287 vs. 269 mL/g DM). The fermentation rate of diets with MOL was higher than with BBP (0.07 vs. 0.05/h). The in vitro degradation, feed intake and N excretion of diets that contained PL were higher than with PE silage. Feed intake for diets with silage that contained BBP and PL or PE was lower than that containing MOL. Rumen pH was increased in lambs fed diets with silage that contained urea (6.38) or PL (6.25), compared with lambs fed diets containing PE silage (6.04). Dry matter (DM) and organic matter (OM) disappearances were higher for diets with silage containing PL compared with those containing PE or urea (650 vs. 606 and 594 g/g DM; 620 vs. 574 and 594 g/g OM, respectively). The N retention and total tract digestion were similar for all treatments. It was concluded that diets with PL and MOL silage had higher nutritive values than those containing PE or urea. [ABSTRACT FROM AUTHOR]

Fermentations carried out at low temperatures, that is, 10-15 °C, not only enhance the production and retention of flavor volatiles, but also increase the chances of slowing or arresting the process. In this study, we determined the transcriptional activity of 10 genes that were previously reported as induced by low temperatures and involved in cold adaptation, during fermentation with the commercial wine yeast strain QA23. Mutant and overexpressing strains of these genes were constructed in a haploid derivative of this strain to determine the importance of these genes in growth and fermentation at low temperature. In general, the deletion and overexpression of these genes did affect fermentation performance at low temperature. Most of the mutants were unable to complete fermentation, while overexpression of CSF1, HSP104, and TIR2 decreased the lag phase, increased the fermentation rate, and reached higher populations than that of the control strain. Another set of overexpressing strains were constructed by integrating copies of these genes in the delta regions of the commercial wine strain QA23. These new stable overexpressing strains again showed improved fermentation performance at low temperature, especially during the lag and exponential phases. Our results demonstrate the convenience of carrying out functional analysis in commercial strains and in an experimental set-up close to industrial conditions. [ABSTRACT FROM AUTHOR]

Vacuolar H+-ATPase (V-ATPase) is thought to play a role in stress tolerance. In this study it was found that bottom-fermenting yeast strains, in which the V-ATPase-related genes DBF2, VMA41/CYS4/NHS5 and RAV2 were overexpressed, exhibited stronger ethanol tolerance than the parent strain and showed increased fermentation rates in a high-sugar medium simulating high-gravity fermentation. Among the strains examined, the DBF2-overexpressing bottom-fermenting yeast strain exhibited the highest ethanol tolerance and fermentation rate in YPM20 medium. Using this strain, high-gravity fermentation was performed by adding sugar to the wort, which led to increased fermentation rates and yeast viability compared with the parent strain. These findings indicate that V-ATPase is a stress target in high-gravity fermentation and suggests that enhancing the V-ATPase activity increases the ethanol tolerance of bottom-fermenting yeast, thereby improving the fermentation rate and cell viability under high-gravity conditions. Copyright © 2012 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each strain, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast strains. This task was carried out using statistical modeling techniques. The strains PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than strains ARM and TTA. Likewise, the strains PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively due to the increase in biomass because the strain TTA, which showed the worst growth behavior, had the best fermentation activity. Some strains may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the strains showed the better and worse fermentation performance with arginine and ammonium, respectively. [Copyright &y& Elsevier]