Hasil untuk "Fermentation industries. Beverages. Alcohol"

G. Banerjee, Pritam Chattopadhyay

The biotechnological production of fragrances is a recent trend that has expanded rapidly in the last two decades. Vanillin is the second most popular flavoring agent after saffron and is extensively used in various applications, e.g., as a food additive in food and beverages and as a masking agent in various pharmaceutical formulations. It is also considered a valuable product for other applications, such as metal plating and the production of other flavoring agents, herbicides, ripening agents, antifoaming agents, and personal and home-use products (such as in deodorants, air fresheners, and floor-polishing agents). In general, three types of vanillin, namely natural, biotechnological, and chemical/synthetic, are available on the market. However, only natural and nature-identical (biotechnologically produced from ferulic acid only) vanillins are considered as food-grade additives by most food-safety control authorities worldwide. In the present review, we summarize recent trends in fermentation technology for vanillin production and discuss the importance of the choice of raw materials for the economically viable production of vanillin. We also describe the key enzymes used in the biotechnological production of vanillin as well as their underlying genes. Research to advance our understanding of the molecular regulation of different pathways involved in vanillin production from ferulic acid is still ongoing. The enhanced knowledge is expected to offer new opportunities for the application of metabolic engineering to optimize the production of nature-identical vanillin. © 2018 Society of Chemical Industry.

Mingjing Yang, Jintao Wang, Li Li et al.

Compound-fermented wines integrate the aromas, flavor compounds, and nutritional components from several raw materials, enriching the flavor and texture of the final product. This study aimed to explore the influence of edible flowers on the quality of pear wine by evaluating the total phenol and flavonoid contents, antioxidant capacities, and tyrosinase inhibition abilities during the mixed fermentation of pears (P) with Rosa rugosa (PR), Dendrobium candidum (PD), Chrysanthemum morifolium (PC), Lonicera japonica (PL), and Osmanthus fragrans Lour (PO), using standard methods The findings revealed that total phenol and flavonoid contents, antioxidant capacities, and tyrosinase inhibition abilities significantly increased in compound pear-flower wine. Specifically, total polyphenol content (TPC), total flavonoid content (TFC), the DPPH(1,1-diphenyl-2-picryl-hydrazyl radical) radical scavenging activity (DRSA), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) for PR were 580.69 ± 9.51 mg of gallic acid equivalents (GAE) per liter of the sample (mg GAE/L), 600.05 ± 36.6 mg of rutin per liter of the sample (mg RE/L), 0.51 ± 0.00 μmol of Trolox equivalents (TE) per milliliter (μmol TE/mL), 10.11 ± 0.06 μmol TE/mL and 6.35 ± 0.35 μmol of Fe2+ equivalents (FE) per milliliter (μmol FE/mL), respectively. Additionally, we further analyzed the volatile and non-volatile components of P and PR at different fermentation stages. A significant difference was observed between the non-volatile and volatile metabolites, with pear rose wine (PRW) demonstrating superior characteristics compared with pear wine (PW). Phenolic acids and flavonoids were closely associated with the formation of non-volatile metabolites, while esters, hydrocarbons, alcohols, and ketones were significantly linked to volatile formation. Notably, 2(5H)-furanone, 5-ethyl-3-hydroxy-4-methyl-, emerged as a significant aroma contributor with a relative odor activity value (ROAV) of 236,348.11, giving a sweet, fruity, nutty taste. Compared with PR, decanoic acid ethyl ester increased 634.67-fold in PRW. These findings provide a foundation for further exploration into optimized fermentation protocols, mechanistic studies on flavor and bioactive compound formation, and potential commercial applications in the functional beverage industry.

Karina Nascimento Pereira, Handray Fernandes de Souza, Amanda Cristina Dias de Oliveira et al.

Mead is a fermented alcoholic beverage obtained by diluting honey in water and adding yeast. However, the addition of fruit to this beverage gives rise to melomel. In this study we are proposing an interesting novelty which consists of developing cupuaçu (Theobroma grandiflorum) melomel by fermenting Saccharomyces cerevisiae var. boulardii. The aim of this study was to develop cupuaçu (Theobroma grandiflorum) melomel produced by S. boulardii and to evaluate its physicochemical and microbiological characteristics after refrigerated storage at 4 °C. To do this, a central composite design (CCD) was employed, with two independent variables, i.e., the initial soluble solids content of the honey must (°Brix) and the concentration of the cupuaçu pulp (%). A standardized amount of 1 g/L of S. boulardii yeast was used at a temperature of 25 °C and a fermentation time of 30 days. Using the results of the central composite design (CCD), the best conditions for producing the beverage were defined according to the objectives of the study. Thus, the experimental comparison was carried out under the conditions of 25 °Brix of initial soluble solids in the honey must, 10% cupuaçu pulp, and 10 days of fermentation at 25 °C. The cupuaçu melomel exhibited a cell viability of the probiotic yeast S. boulardii above 107 log CFU/mL, with an alcohol content of 8.22% (v/v), a pH of 3.43, a total acidity of 54.8 of (mEq/L), and soluble solids of 12.42°Brix. In addition, the beverage was subjected to simulated gastric and intestinal juices in vitro to evaluate the survival of the microorganisms under these conditions, and a concentration of 106 log CFU/mL of S. boulardii was obtained. In this way, it was possible to produce a probiotic fermented alcoholic beverage made from honey and cupuaçu.

Levent Yurdaer Aydemir, Hande Demir, Zafer Erbay et al.

The growing demand for sustainable plant-based dairy alternatives has spurred interest in valorizing agro-industrial byproducts like hazelnut cake, a protein-rich byproduct of oil extraction. This study developed formulations for vegan ice cream using unfermented (HIC) and <i>Aspergillus oryzae</i>-fermented hazelnut cake (FHIC), comparing their physicochemical, functional, and sensory properties to conventional dairy ice cream (DIC). Solid-state fermentation (72 h, 30 °C) enhanced the cake’s bioactive properties, and ice creams were characterized for composition, texture, rheology, melting behavior, antioxidant activity, and enzyme inhibition pre- and post-in vitro digestion. The results indicate that FHIC had higher protein content (64.64% vs. 58.02% in HIC) and unique volatiles (e.g., benzaldehyde and 3-methyl-1-butanol). While DIC exhibited superior overrun (15.39% vs. 4.01–7.00% in vegan samples) and slower melting, FHIC demonstrated significantly higher post-digestion antioxidant activity (4.73 μmol TE/g DPPH vs. 1.44 in DIC) and angiotensin-converting enzyme (ACE) inhibition (4.85–7.42%). Sensory evaluation ranked DIC highest for overall acceptability, with FHIC perceived as polarizing due to pronounced flavors. Despite textural challenges, HIC and FHIC offered nutritional advantages, including 18–30% lower calories and enhanced bioactive compounds. This study highlights fermentation as a viable strategy to upcycle hazelnut byproducts into functional vegan ice creams, although the optimization of texture and flavor is needed for broader consumer acceptance.

Xinchao Yang, Xinyu Li, Yuanxiu Wang et al.

In this study, we combined the citric acid cycle with the biosynthesis pathways of L-proline and L-hydroxyproline to construct a strain that produces L-hydroxyproline directly from glucose and other raw materials, without the addition of L-proline and α-ketoglutarate. The results showed that the level of L-hydroxyproline production was 550 mg/L. Through the optimization of one-way and orthogonal experiments, the optimal shake flask fermentation conditions were obtained, at which time the production of L-hydroxyproline reached 1800 mg/L, which was 3.3-fold higher. The glutamate permease gene <i>GltS</i> was added to the recombinant plasmid pRSFDuet1-p4h-proBA, and the recombinant plasmid obtained was transformed into <i>E. coli</i> T7E by Gibson seamless cloning to obtain the recombinant strain T7E/pRSFDuet1-p4h-GltS-proBA. Finally, by the addition of 30 mmol/L of sodium glutamate, the recombinant strain achieved a yield of L-hydroxyproline of 2150 mg/L, which was about 1.2-fold higher than the yield of L-hydroxyproline without the addition of sodium glutamate.

Lourdes González-Salitre, Luis Guillermo González-Olivares, Alexis Alejandro Salazar-Navarro et al.

Selenium is an essential micronutrient which is found in many foods and beverages in low concentrations. Craft beer, one of the most widely consumed fermented beverages globally, presents a strategic opportunity for selenium intake through organic nanoparticles. This study aimed to confirm the presence of selenium nanoparticles in the fermentation process of an ale-style beer using <i>S. boulardii</i> yeast selenized with Na₂SeO₃ (74 ppm), through spectroscopic analysis and TEM. The yeast accumulated 5.92 mg/g of dry cell mass, and the beer contained 0.642 mg/g of selenium. UV-VIS detected nanoparticles with a peak at 300 nm and FT-IR at a wavelength of 1398.85 cm⁻¹. The particle size ranged between 74 to 175 nm, with a maximum ζ-potential of −4.2 mV, an electrophoretic mobility of −0.3492 μm × cm Vs⁻¹, and a conductivity of 2.656 mS cm⁻¹. TEM analysis revealed that the nanoparticles exhibited circular/ovoid shapes. The fermentation process, combined with the ingredients used to produce ale-type craft beer, proved to be a feasible method for the biosynthesis of selenium nanoparticles using <i>S. boulardii</i>, offering a reliable option for developing and innovating functional craft beers.

L. Vane

Yulia Miller, Valentina Pomozova, T. Kiseleva

Fermented drinks production is a promising sector of the food industry. Therefore, the new technological solutions development aimed at product quality improvement and production optimization is always relevant. To optimize the fermentation stage and production in general, a man has to identify new resources – new yeast strains. The research aimed at studying the possibility of dry baking yeast “Saf-instant”, “Saf-levur”, “Nevada” and “Angel” use in the fermented grain drinks technology. The developed technology feature was wheat and oat malt use along with traditional barley and rye fermented malt. The authors introduced two formulations of drinks for production with the following composition: the first sample consists of barley malt 45 %, wheat malt 25 %, rye fermented malt 30 %; the second one – barley malt 45 %, oat malt 25 %, rye fermented malt 30 %. The authors optimized the grain wort preparation mode for each formulation with grinding stage adjustment according to temperature and pauses duration. Experimentally, a man established the recommended yeast administration rate at the fermentation stage – 20 million cells/cm3 of wort, optimal temperature (28–30 °C) and stage duration (17–18 hours). As a result, the yeast “Nevada” and “Angel” had the greatest fermentation activity. During fermentation, in drinks, in addition to ethyl alcohol and carbon dioxide, there were higher alcohols (isobutyl, propyl, isoamyl), esters (methyl acetate, isoamyl acetate), and organic acids (succinic, malic, citric, lactic, oxalic, formic, acetic). The organic acids presence enables to improve the beverages quality by its nutritional value increase. The resulting fermented grain drinks meet the standardized requirements for similar beverages fully in terms of quality. The developed technology using new yeast strains can be recommended for introduction into production.

Yupaporn Phannarangsee, Haruthairat Kitwetcharoen, Sudarat Thanonkeo et al.

This study investigated the role of the <i>Zymomonas mobilis recA</i> gene in conferring stress resistance when expressed in <i>Escherichia coli</i>. The <i>recA</i> gene was cloned and expressed in <i>E. coli</i> BL21(DE3), producing a 39 kDa polypeptide. The results of comparative analyses demonstrated that the recombinant strain significantly enhanced survival rates under various stress conditions. In oxidative stress tests, the recombinant <i>E. coli</i> pET-22b(+)-recA exhibited superior survival at 3 mM and 5 mM H₂O₂ concentrations. Heat stress experiments at 50 °C and 55 °C revealed increased survival for the recombinant strain. Under ethanol stress, particularly at 20% (<i>v</i>/<i>v</i>), <i>E. coli</i> pET-22b(+)-recA displayed higher viability than controls. UV-C exposure tests further highlighted the protective effect of <i>recA</i> expression, with the recombinant strain maintaining viability after 60 min of exposure, while control strains showed no survival. These results indicate that the <i>Z. mobilis recA</i> gene product enhances resistance to oxidative, heat, ethanol, and UV-C stresses when expressed in <i>E. coli</i>. This study elucidates the broad stress-protective functions of the RecA protein across bacterial species and suggests potential applications in developing stress-tolerant bacterial strains for biotechnological purposes.

Yeonhee Pyo, Yeon Ja Jung

p-Cymene (p-C) [1-methyl-4-(1-methylethyl)-benzene] is a monoterpene found in a variety of plants and has several biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. This paper explores the microbial fermentation pathways involved in the biosynthesis of p-C, with an emphasis on its potential as a therapeutic agent. Through microbial and biochemical processes, p-C can be produced using renewable precursors such as limonene and 1,8-cineole. Recent advances in fermentation technology have enhanced the efficiency of p-C production, highlighting its role in various industries. Additionally, this paper reviews the antimicrobial bioactivity of p-C, focusing on its ability to inhibit pathogens and modulate immune responses. The integration of microbial biosynthesis and fermentation methods offers a sustainable approach to producing p-C for applications in the perfume, cosmetics, food, and pharmaceutical sectors. Understanding these biosynthetic pathways is crucial for advancing the use of p-C as a bio-based chemical with therapeutic potential. In particular, p-C inhibits the expression of cytokine signal 3 in intestinal inflammation and modulates antioxidant and immunomodulatory systems to protect barrier cells and maintain the mucus layer.

Bin Zhang, Jie Bao

Since its initial discovery in sour milk by Swedish chemist C [...]

Chuang Li, Zhiqi Lu, Ruxin Qi et al.

Silage is the most important component of a ruminant diet and has important production and health significance in ruminant production. The aim of the research was to investigate how the mixed silage of Chinese cabbage waste and rice straw (mixed silage) impacts the fecal microorganisms and metabolites in Hu sheep using Illumina sequencing and metabolomic analysis. A total of 16 Hu sheep (8 rams and 8 ewes) weighing about 39 kg and 5.5 months old were used as experimental sheep and divided into two groups (4 rams and 4 ewes, <i>n</i> = 8) using the principle of randomized trials: the control group with peanut sprouts, corn husks, and sorghum husks as roughage and the silage group with the mixed silage as roughage. There were no significant differences in the average daily gain (ADG), dry matter intake (DMI), or feed conversion rate (FCR) between the control group and the mixed silage groups (<i>p</i> > 0.05). Microbiome results showed that 15 microorganisms such as <i>Ruminococcaceae UCG 010</i>, <i>Breznakia</i>, <i>Erysipelothrix</i>, <i>Desulfovibrio</i>, <i>Succiniclasticum</i>, and <i>Shuttleworthia</i> were significantly different between the two groups. In addition, metabolomics showed that the mixed silage modulated the concentrations and metabolic pathways of metabolites in the manure. Significantly different metabolites were mainly enriched in amino acid anabolism (“glycine, serine, and threonine metabolism”, “valine, leucine, and isoleucine biosynthesis”, “arginine biosynthesis”, etc.), nucleic acid metabolism (pyrimidine metabolism). In conclusion, the addition of mixed silage to the diet of Hu sheep can alter the structure of the hindgut microflora and regulate the metabolism of amino acids and nucleotides, which affects health performance.

P. Vinayamohan, Leya Susan Viju, Divya Joseph et al.

Fermented food products are widely consumed for their nutritional and health-promoting properties, earning them a central place in diets around the globe. However, these foods can present a paradox, as they have the potential to harbor not only beneficial probiotics but also antibiotic-resistant (AR) microbes and genes. The impact of AR microbes and genes in fermented foods has far-reaching implications, such as potential effects on human health, repercussions in the food industry, and environmental consequences. An in-depth analysis of AR microbes and genes in fermented foods, including dairy products, fermented fruits and vegetables, meat products, and beverages, would provide insights into the extent and ramifications of the issue with these foods. Therefore, this review systematically presents the status of AR in fermented foods, with a particular focus on AR bacteria and genes within this category of food products. The review also highlights the complexities of AR in fermented foods, emphasizing the role of bacterial adaptation during the fermentation process and the dynamics of bacterial gene transfer. Various factors contributing to AR microbes and genes are brought into focus, including intrinsic resistance among bacteria in fermented foods and the potential risk of contamination with pathogenic bacteria. Moreover, this review presents a range of mitigation strategies, from the development of novel antimicrobials to advances in fermentation technology and regulatory control. This comprehensive perspective on the intricate interplay between AR and fermented food will potentially pave the way for more targeted research and mitigation strategies in this critical area.

Fatmanur Poyraz, Dilara Yalmanci, Hümeyra İspirli et al.

Bee bread is a product with unique properties for humans and bees that is produced through the fermentation of pollen in the honeycomb, mainly caused by lactic acid bacteria (LAB) and yeast strains present in the environment. It is a rich source of nutrients such as proteins, polyphenols and vitamins. Despite the potential nutritional value of bee bread, it is consumed at low levels, as harvesting bee bread from the hives is costly and difficult. This study aimed to produce a standard bee bread by using different strains of the fructophilic lactic acid bacteria (FLAB) <i>Lactobacillus kunkeei</i> and the yeasts <i>Starmeralla magnolia</i> MP-2 and <i>Zygosaccharomyces siamensis</i> MP-14, previously isolated from bee products. In this context, bee bread was produced from pollen by solid-state fermentation using selected FLAB and yeast species, which were then compared with spontaneously developed and commercially available bee bread in terms of microbial stability, physicochemical properties, total phenolic component amounts, in vitro digestibility and amino acid profiles. As a result, it was determined that bee bread made from bee pollen fermented with starter cultures showed improved characteristics than commercial bee bread and was more advantageous in terms of absorption as well as production processes.

Jie Li, Weiyi Tao, Shenghui Yue et al.

<i>Bacillus subtilis</i> strain 168 is commonly used as a host to produce recombinant proteins and as a chassis for bio-based chemicals production. However, its preferred nitrogen source is organic nitrogen, which greatly increases production costs. In this study, adaptive laboratory evolution (ALE) was used to improve <i>B. subtilis</i> 168 growth using NH₄Cl as the sole nitrogen source. The cell density (OD₆₀₀) of a mutant strain LJ-3 was 208.7% higher than that of the original strain. We also optimized the metal ions in the medium and this resulted in a further increase in growth rate by 151.3%. Reintroduction of the <i>sfp+</i> gene into strain LJ-3 led to the LJ-31 clone, which restored LJ-3’s ability to synthesize surfactin. The fermentation system was optimized (C/N, aeration, pH) in a 5 L bioreactor. Dry cell weight of 7.4 g/L and surfactin concentration of 4.1 g/L were achieved using the optimized mineral salt medium after 22 h of batch fermentation with a Y_P/S value of 0.082 g/g and a Y_P/X of 0.55 g/g. HPLC analysis identified the surfactin isoforms produced by strain LJ-31 in the synthetic medium as C₁₃-surfactin 13.3%, C₁₄-surfactin 44.02%, and C₁₅-surfactin 32.79%. Hence, the variant LJ-3 isolated by ALE is a promising engineering chassis for efficient and cost-effective production of a variety of metabolites.

Chen Liang, Ling-Xiao Liu, Jun Liu et al.

Fermentation technology has a long history and low-temperature fermentation has now become the focus of research. This paper reviews the mechanism and application of low-temperature fermentation and the optimization of relevant strains. Low-temperature fermentation leads to a differential expression of growth in metabolism genes (PSD1, OPI3, ERG3, LCB3 and NTH1). Low-temperature fermentation can be applied to foods and has various advantages, such as increasing changes in volatile flavor compounds and other corresponding metabolic substances of the strain, and inhibited growth of spurious bacteria. The focus of low-temperature fermentation in the long run lies in strain optimization, which is to protect and optimize the strains through a variety of methods. Low-temperature fermentation can greatly improve product quality. At present, the most effective methods to promote low-temperature fermentation are gene knockout and probiotic microencapsulation.

Ulrich H. Engelhardt, Ina Bahar, Ulf Delker

To evaluate mitigation options for both acrylamide and furan and methylfurans a Vietnam Robusta grade 2 and a Brazil Arabica (unwashed) coffee were roasted by tangential, drum and hot air roasting. Three different roasting profiles were followed and three samples (light, medium and dark roast) were obtained per profile. Decaffeinated and steam treated batches of the two coffees were roasted. Special roasts, such as double roast (on 2 days with cooling down in between) or roasting with a sudden temperature change were studied. The contaminants were analyzed by GC-MS – in case of the furans headspace GC-MS – using deuterated standards.The acrylamide contents were highest in light roasts, and decreased after that with longer roasting time. This was true for both the Robusta and Arabica samples. The content of furan and 2-, 3- and 2, 5-methylfurans were low in light roasts and had a maximum in dark roasts. It is possible to minimize the content of either acrylamide and furans, however, a mitigation of both could not be established by changing the roasting parameters or using pretreatments. Among the furans determined, 2-methylfuran was most abundant (average around 70%), followed by furan (average around 20%). The special roasts showed no options to minimize both contaminants as did the pretreatments. In Vietnam Robusta, furan related compounds were measured. 5-hydroxymethylfurfural and 5-hydroxymethylfurfuryl-2-carboxylic acid decreased with the degree of roast and time, while furfuryl alcohol and 2-furoic acid content increased.

Thomas P. West

Pyrimidine biosynthesis and ribonucleoside metabolism in species of <i>Pseudomonas</i> was the focus of this review, in relation to their current taxonomic assignments in different homology groups. It was of interest to learn whether pyrimidine biosynthesis in taxonomically related species of <i>Pseudomonas</i> was regulated in a similar fashion by pyrimidine base supplementation or by pyrimidine limitation of pyrimidine auxotrophic strains. It was concluded that the regulation of pyrimidine biosynthesis in <i>Pseudomonas</i> species could not be correlated with their taxonomic assignment into a specific homology group. Pyrimidine ribonucleoside metabolism in <i>Pseudomonas</i> species primarily involved the pyrimidine ribonucleoside salvage enzymes nucleoside hydrolase and cytosine deaminase, independently of the <i>Pseudomonas</i> homology group to which the species was assigned. Similarly, pyrimidine base catabolism was shown to be active in different taxonomic homology groups of <i>Pseudomonas</i>. Although the number of studies exploring the catabolism of the pyrimidine bases uracil and thymine was limited in scope, it did appear that the presence of the pyrimidine base reductive pathway of pyrimidine catabolism was a commonality observed for the species of <i>Pseudomonas</i> investigated. There also appeared to be a connection between pyrimidine ribonucleoside degradation and the catabolism of pyrimidine bases in providing a cellular source of carbon or nitrogen independently of which homology group the species of <i>Pseudomonas</i> were assigned to.

Petr Gabriel, Robert Král, Roman Beneš

Microbiological contamination of beer is manifested in many cases by the production of CO2 and an increase in its concentration. An increase in the concentration of CO2 in a closed package leads to an increase in internal pressure, which can cause the destruction of the package with dangerous consequences. This case study aimed to verify the applicability of force-displacement measurement for non-destructive monitoring of the internal pressure in beer cans.

Alejandro Plascencia, Alberto Barreras, Yissel S. Valdés-García et al.

The aim of this study was to evaluate the influence of supplemental granulated cane sugar (GCS) levels (0, 13.3, 26.6, and 39.9% on a dry matter basis) in a steam-flaked corn-based finishing diet on measures of ruminal fermentation and the site and extent of nutrient digestion. Four Holstein steers (251 ± 3.6 kg live weight) with “T” type cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate the treatments. The experiment lasted 84 d. Replacing steam-flaked corn (SFC) with GCS linearly decreased the flow of ammonia-N (NH3-N) to the small intestine, increasing the flow of microbial nitrogen (MN; quadratic effect, <i>p =</i> 0.02), ruminal N efficiency (linear effect, <i>p</i> = 0.03) and MN efficiency (quadratic effect, <i>p</i> = 0.04). The ruminal digestion of starch and neutral detergent fiber (NDF) decreased (linear effect, <i>p</i> ≤ 0.02) as the level of GCS increased. The postruminal digestion of organic matter (OM), neutral detergent fiber (NDF), and starch were not affected by the GCS inclusion. However, postruminal N digestion decreased (linear effect, <i>p</i> = 0.02) as the level of GCS increased. There were no treatment effects on total tract OM digestion. However, total tract NDF and N digestion decreased (linear effect, <i>p</i> ≤ 0.02) as the level of GCS increased. The ruminal pH decreased (linear effect, <i>p</i> < 0.01) as the GCS increased in the diet. The ruminal acetate molar proportion decreased (linear effect, <i>p</i> = 0.02) and the ruminal valerate molar proportion tended to increase (linear effect, <i>p</i> = 0.08) as the level of GCS increased. It is concluded that replacing as much as 13% of SFC with GCS in a finishing diet will enhance the efficiency of N utilization (g non-ammonia-N entering the small intestine/g N intake) without detrimental effects on total tract OM digestion. The inclusion of GCS decreased the ruminal proportion of acetate linearly without an effect on the acetate-to-propionate ratio or estimated methane production. Some of the effects on N utilization at a high level of GCS inclusion (27 and 40%) can be magnified by the differences in the CP content between diets. A higher level of GCS supplementation in the diet decreased the ruminal pH below 5.5, increasing the risk of ruminal acidosis.