100 assays (manual) / 1000 assays (microplate) / 1000 assays (auto-analyser)
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|Content:||100 assays (manual) / 1000 assays (microplate) / 1000 assays (auto-analyser)|
|Storage Temperature:|| Short term stability: 2-8oC, |
Long term stability: See individual component labels
|Stability:||> 2 years under recommended storage conditions|
|Assay Format:||Spectrophotometer, Microplate, Auto-analyser|
|Linear Range:||0.3 to 40 µg of pyruvic acid per assay|
|Limit of Detection:||0.39 mg/L|
|Reaction Time (min):||~ 3 min|
|Application examples:||Wine, beer, fruit juices, soft drinks, cheese, dietary supplements, pharmaceuticals and other materials (e.g. biological cultures, samples, etc.).|
|Method recognition:||Novel method|
For the specific and rapid measurement and analysis of pyruvic acid in beer, wine, fruit juice, food products and bodily fluids.
Note for Content: The number of manual tests per kit can be doubled if all volumes are halved. This can be readily accommodated using the MegaQuantTM Wave Spectrophotometer (D-MQWAVE).
Display our full list of assay kits for various organic acids.
- Very cost effective
- All reagents stable for > 2 years after preparation
- Very rapid reaction (~ 3 min)
- Mega-Calc™ software tool is available from our website for hassle-free raw data processing
- Standard included
- Suitable for manual, microplate and auto-analyser formats
The Impact of Chitosan on the Chemical Composition of Wines Fermented with Schizosaccharomyces pombe and Saccharomyces cerevisiae.
Scansani, S., Rauhut, D., Brezina, S., Semmler, H. & Benito, S. (2020). Foods, 9(10), 1423.
This study investigates the influence of the antimicrobial agent chitosan on a selected Schizosaccharomyces pombe strain during the alcoholic fermentation of ultra-pasteurized grape juice with a high concentration of malic acid. It also studies a selected Saccharomyces cerevisiae strain as a control. The study examines several parameters relating to wine quality, including volatile and non-volatile compounds. The principal aim of the study is to test the influence of chitosan on the final chemical composition of the wine during alcoholic fermentation, and to compare the two studied fermentative yeasts between them. The results show that chitosan influences the final concentration of acetic acid, ethanol, glycerol, acetaldehyde, pyruvic acid, α-ketoglutarate, higher alcohols, acetate esters, ethyl esters, and fatty acids, depending on the yeast species.Hide Abstract
Cyanoflan: A cyanobacterial sulfated carbohydrate polymer with emulsifying properties.
Mota, R., Vidal, R., Pandeirada, C., Flores, C., Adessi, A., De Philippis, R., Nunes, C., Coimbra, M. A. & Tamagnini, P. (2020). Carbohydrate Polymers, 229, 115525.
The extracellular polysaccharides produced by cyanobacteria have distinctive characteristics that make them promising for applications ranging from bioremediation to biomedicine. In this study, a sulfated polysaccharide produced by a marine cyanobacterial strain and named cyanoflan was characterized in terms of morphology, chemical composition, and rheological and emulsifying properties. Cyanoflan has a 71 % carbohydrate content, with 11 % of sulfated residues, while the protein account for 4 % of dry weight. The glycosidic-substitution analysis revealed a highly branched complex chemical structure with a large number of sugar residues. The cyanoflan high molecular mass fractions (above 1 MDa) and entangled structure is consistent with its high apparent viscosity in aqueous solutions and high emulsifying activity. It showed to be a typical non-Newtonian fluid with pseudoplastic behavior. Altogether, these results confirm that cyanoflan is a versatile carbohydrate polymer that can be used in different biotechnological applications, such as emulsifying/thickening agent in food or cosmetic industries.Hide Abstract
Differential cytokine and metabolite production by cervicovaginal epithelial cells infected with Lactobacillus crispatus and Ureaplasma urealyticum.
Cavanagh, M., Amabebe, E. & Anumba, D. O. (2020). Anaerobe, 62, 102101.
Introduction: We sought to quantify targeted metabolites (d-lactate, pyruvate, urea, ammonia) and the cytokine IL-8 produced by human cervicovaginal epithelial cells co-cultured with Ureaplasma urealyticum (a preterm birth-associated bacterium) or Lactobacillus crispatus (a healthy vaginal commensal associated with term birth). Methods: Concentrations of D-lactate, pyruvate, urea and ammonia measured by enzyme-based spectrophotometry and IL-8 by ELISA were determined and compared between monolayer-cultured HeLa cells (ATCC 35241) infected with strains of U. urealyticum (ATCC 27618, 0.5 mL = 3640 CFU/mL, U. urealyticum) or L. crispatus (ATCC 33820, MOI = 10,000, 1000 and 100, L. crispatus) and incubated in 5% CO2 at 37°C for 24 h. Uninfected HeLa cells (Hc) were used as controls and cytotoxicity was determined by the amount (optical density) of lactate dehydrogenase (LDH) released by the dead HeLa cells. Results: The amount of LDH released by untreated Hc (P = 0.002) and U. urealyticum-infected cells (P < 0.0001) was higher than those of L. crispatus-infected cells, with U. urealyticum-infected cells recording the highest % cytotoxicity and L. crispatus-infected cells MOI 10,000 (Lc10,000) the least (P < 0.0001). Though there was no significant difference in the concentration of urea between the samples, U. urealyticum-infected cells showed higher ammonia compared to other samples (p = 0.03). In contrast, all L. crispatus samples had higher D-lactate than untreated Hc (p = 0.01) and U. urealyticum-infected cells (P = 0.01). Also, Lc10,000 had the highest D-lactate (p = 0.001) and lowest pyruvate (P = 0.04, excluding UU) compared to other samples. Furthermore, U. urealyticum-infected cells produced the highest IL-8 (P = 0.01) compared to other samples, with Lc10,000 producing undetectable levels. Conclusion: Infection of cervicovaginal epithelial cells by U. urealyticum stimulates production of ammonia from urea and induces elevated IL-8 production possibly leading to significantly higher cytotoxicity. In contrast, L. crispatus appeared protective against HeLa cell inflammation and death, producing more D-lactate and less IL-8, consistent with a role for L. crispatus in promoting vaginal floral health and reducing infection/inflammation-associated preterm birth.Hide Abstract
Assessment of β-glucans, phenols, flavor and volatile profiles of hulless barley wine originating from highland areas of China.
Zhang, K., Yang, J., Qiao, Z., Cao, X., Luo, Q., Zhao, J., Wang, F. & Zhang, W. (2019). Food Chemistry, 293, 32-40.
Low alcohol hulless barley wine (HW) is a popular beverage among the highland areas in China. It is known to have several health benefits due to the presence of β-glucan and antioxidant compounds. Therefore, the total β-glucan content, total phenols and flavonoids of HW samples from the highland areas of Sichuan province and Tibet were determined in this study. The results indicated that HW is abundant in both β-glucan (54-76 mg/L) and phenolic compounds (131-178 mg/L). Moreover, this study also investigated the flavor and aroma characteristics of HW samples. A total of forty six volatile aroma substances were identified by GC-MS. The HWs could be classified into three distinct groups in terms of the region of origin according to the results of PCA based on the GC-MS data. These findings provide a useful foundation for further study of the health benefits and the flavor characteristics of HW in highland areas.Hide Abstract
Acetate metabolism and the inhibition of bacterial growth by acetate.
Pinhal, S., Ropers, D., Geiselmann, J. & de Jong, H. (2019). Journal of Bacteriology, 201(13).
During aerobic growth on glucose, Escherichia coli excretes acetate, a mechanism called “overflow metabolism.” At high concentrations, the secreted acetate inhibits growth. Several mechanisms have been proposed for explaining this phenomenon, but a thorough analysis is hampered by the diversity of experimental conditions and strains used in these studies. Here, we describe the construction of a set of isogenic strains that remove different parts of the metabolic network involved in acetate metabolism. Analysis of these strains reveals that (i) high concentrations of acetate in the medium inhibit growth without significantly perturbing central metabolism; (ii) growth inhibition persists even when acetate assimilation is completely blocked; and (iii) regulatory interactions mediated by acetyl-phosphate play a small but significant role in growth inhibition by acetate. The major contribution to growth inhibition by acetate may originate in systemic effects like the uncoupling effect of organic acids or the perturbation of the anion composition of the cell, as previously proposed. Our data suggest, however, that under the conditions considered here, the uncoupling effect plays only a limited role.Hide Abstract
Benito, S., Palomero, F., Calderón, F., Palmero, D. & Suárez-Lepe, J. A. (2014). Food Microbiology, 42, 218-224.
This paper describes the selection of Schizosaccharomyces yeasts with adequate oenological suitability and high capacity for the degradation of malic acid. Despite the almost non-existent number of commercial strains, the use of this yeast genus has recently been recommended by the International Organisation of Vine and Wine (OIV, in French). Thus, in the present study, a large number of Schizosaccharomyces strains were isolated using a selective differential medium. Initially, classic parameters of oenological interest for the use of fermentative strains of Saccharomyces cerevisiae (the most frequently used type of yeast) were assessed. Only five strains of moderate acetic acid production lower than 0.4 g/L were obtained at the end of fermentation. Other, more specific features of this yeast genus' physiology were also studied, including urease activity and the production of pyruvic acid and glycerol. Finally, oenological suitability was determined by comparing selected strains with other Schizosaccharomyces reference and S cerevisiae control strains. Schizosaccharomyces strains produced 80% less urea content, four times higher pyruvic acid levels and 1 g higher glycerol contents than the Saccharomyces reference strains. The results confirmed that it is possible to perform selective processes on microorganisms from the genus Schizosaccharomyces using methodology developed in this work to obtain strains of industrial interest.Hide Abstract
Benito, S., Palomero, F., Morata, A., Calderón, F., Palmero, D. & Suárez-Lepe, J. A. (2013). European Food Research and Technology, 236(1), 29-36.
This work studies the physiology of Schizosaccharomyces pombe strain 938 in the production of white wine with high malic acid levels as the sole fermentative yeast, as well as in mixed and sequential fermentations with Saccharomyces cerevisiae Cru Blanc. The induction of controlled maloalcoholic fermentation through the use of Schizosaccharomyces spp. is now being viewed with much interest. The acetic, malic and pyruvic acid concentrations, relative density and pH of the musts were measured over the entire fermentation period. In all fermentations in which Schizo. pombe 938 was involved, nearly all the malic acid was consumed and moderate acetic concentrations produced. The urea content and alcohol level of these wines were notably lower than in those made with Sacch. cerevisiae Cru Blanc alone. The pyruvic acid concentration was significantly higher in Schizo. pombe fermentations. The sensorial properties of the different final wines varied widely.Hide Abstract
Kool, M. M., Schols, H. A., Delahaije, R. J. B. M., Sworn, G., Wierenga, P. A. & Gruppen, H. (2013). Carbohydrate Polymers, 97(2), 368-375.
Differently modified xanthans, varying in degree of acetylation and/or pyruvylation were incubated with the experimental cellulase mixture C1-G1 from Myceliophthora thermophila C1. The ionic strength and/or temperature of the xanthan solutions were varied, to obtain different xanthan conformations. The exact conformation at the selected incubation conditions was determined by circular dichroism. The xanthan degradation was analyzed by size exclusion chromatography. It was shown that at a fixed xanthan conformation, the backbone degradation by cellulases is equal for each type of xanthan. Complete backbone degradation is only obtained at a fully disordered conformation, indicating that only the secondary xanthan structure influences the final degree of hydrolysis by cellulases. It is thereby shown that, independently on the degree of substitution, xanthan can be completely hydrolyzed to oligosaccharides. These oligosaccharides can be used to further investigate the primary structure of different xanthans and to correlate the molecular structure to the xanthan functionalities.Hide Abstract
Sim, M. S., Wang, D. T., Zane, G. M., Wall, J. D., Bosak, T. & Ono, S. (2013). Frontiers in microbiology, 4(171), 1-10.
The sulfur isotope effect produced by sulfate reducing microbes is commonly used to trace biogeochemical cycles of sulfur and carbon in aquatic and sedimentary environments. To test the contribution of intracellular coupling between carbon and sulfur metabolisms to the overall magnitude of the sulfur isotope effect, this study compared sulfur isotope fractionations by mutants of Desulfovibrio vulgaris Hildenborough. We tested mutant strains lacking one or two periplasmic (Hyd, Hyn-1, Hyn-2, and Hys) or cytoplasmic hydrogenases (Ech and CooL), and a mutant lacking type I tetraheme cytochrome (TpI-c3). In batch culture, wild-type D. vulgaris and its hydrogenase mutants had comparable growth kinetics and produced the same sulfur isotope effects. This is consistent with the reported redundancy of hydrogenases in D. vulgaris. However, the TpI-c3 mutant (ΔcycA) exhibited slower growth and sulfate reduction rates in batch culture, and produced more H2 and an approximately 50% larger sulfur isotope effect, compared to the wild type. The magnitude of sulfur isotope fractionation in the CycA deletion strain, thus, increased due to the disrupted coupling of the carbon oxidation and sulfate reduction pathways. In continuous culture, wild-type D. vulgaris and the CycA mutant produced similar sulfur isotope effects, underscoring the influence of environmental conditions on the relative contribution of hydrogen cycling to the electron transport. The large sulfur isotope effects associated with the non-ideal stoichiometry of sulfate reduction in this study imply that simultaneous fermentation and sulfate reduction may be responsible for some of the large naturally-occurring sulfur isotope effects. Overall, mutant strains provide a powerful tool to test the effect of specific redox proteins and pathways on sulfur isotope fractionation.Hide Abstract
Benito, S., Palomero, F., Morata, A., Calderón, F. & Suárez‐Lepe, J. A. (2012). International Journal of Food Science & Technology, 47(10), 2101-2108.
The fermentation of grape must using non-Saccharomyces yeasts with particular metabolic and biochemical properties is of growing interest. In the present work, red grape must was fermented using four strains of Schizosaccharomyces pombe (935, 936, 938 and 2139), Saccharomyces cerevisiae 7VA and Saccharomyces uvarum S6U, and comparisons were made over the fermentation period in terms of must sugar (glucose + fructose), malic acid, acetic acid, ammonia, primary amino nitrogen, lactic acid, urea (a possible fermentation activator or precursor of other metabolites) and pyruvic acid (a molecule affecting vitisin formation and therefore colour stability) concentration. The colour intensity of the fermenting musts was also recorded. The Schizosaccharomyces strains consumed less primary amino nitrogen and produced less urea and more pyruvic acid than other Saccharomyces species. Further, three of the four Schizosaccharomyces strains completed the breakdown of malic acid by day 4 of fermentation. The main negative effect of the use of Schizosaccharomyces was strong acetic acid production. The Schizosaccharomyces strains that produced most pyruvic acid (938 and 936) were associated with better ‘wine’ colour than the remaining yeasts. The studied Schizosaccharomyces could therefore be of oenological interest.Hide Abstract
Marquez, A., Dueñas, M., Serratosa, M. P. & Merida, J. (2012). Journal of Chemistry, 2013, Article ID 274893.
The anthocyanin composition in red grapes dried under controlled conditions has been studied. Pyranoanthocyanins and condensed anthocyanins with flavanols by a methylmethine bridge have been identified. Typically, these compounds appear in wine after the fermentation process, as they require compounds such as pyruvic acid, acetoacetic acid, and acetaldehyde for their formation. During the chamber-drying process a stress situation is originated, inducing significant changes in the grape metabolism from aerobic to anaerobic, and as a result it produces the activation of the alcohol dehydrogenase enzyme (ADH) and others that would cause the formation of these compounds. These derivatives are very interesting because they give greater stability to the color of red wine.Hide Abstract
Morata, A., Benito, S., Loira, I., Palomero, F., Gonzalez, M. C. & Suarez-Lepe, J. A. (2012). International Journal of Food Microbiology, 159(1), 47-53.
Schizosaccharomyces pombe is a non-Saccharomyces yeast strain that can ferment grape musts with high sugar contents — but it also has other metabolic and physiological properties that render it of great interest to wine biotechnologists. This work compares the production of pyranoanthocyanins by S. pombe, Saccharomyces cerevisiae and Saccharomyces uvarum during fermentation. Total pyranoanthocyanins ranged from 11.9 to 19.4 mg/l depending on the strain of S. pombe used. On average, S. pombe produced more pyruvic acid than did either Saccharomyces species; as a consequence it also formed more vitisin A-type pigments. S. pombe 938 produced the largest quantity of vitisin A (11.03 ± 0.82 mg/l). The formation of large amounts of pyranoanthocyanins intensifies the post-fermentation colour of wines somewhat, a phenomenon that helps them maintain their colour over ageing as the natural grape anthocyanins become degraded. Some of the S. pombe strains showed hydroxycinnamate decarboxylase activity, which favours the formation of vinylphenolic pyranoanthocyanins. Fermentation with S. pombe therefore provides an interesting way of increasing the overall pyranoanthocyanin content of red wines, and of stabilising their colour during ageing.Hide Abstract
Marquez, A., Dueñas, M., Serratosa, M. P. & Merida, J. (2012). Journal of Agricultural and Food Chemistry, 60(27), 6866-6874.
This study evaluated the formation of anthocyanin-derived compounds during the production of sweet red wines from Merlot and Syrah grapes previously chamber-dried under controlled-temperature conditions. The musts from both grape varieties were found to contain pelargonidin-3-glucoside throughout the vinification process. Besides, HPLC-DAD-MS revealed the presence of pyranoanthocyanins in unfermented musts from the raisins. These compounds are adducts resulting from the cycloaddition of pyruvic acid (type A vitisins) and acetaldehyde (type B vitisins) to anthocyanin molecules. The analyses additionally revealed the presence of products of the condensation via a methylmethine bridge between anthocyanins and (epi)catechin, which requires the presence of acetaldehyde. The absence of pyruvic acid, acetaldehyde, and ethanol in the musts from fresh grapes and their presence in those from dried grapes support the idea that these compounds result from enzymatic transformations because the vinification of the musts involves no alcoholic fermentation. The drying process alters the permeability of grape membranes by the lipoxygenase activation effect (LOX), a switch to an anaerobic metabolism and the resulting triggering of the alcohol dehydrogenase enzyme (ADH). The activation of these and several other enzymes confirmed the occurrence of enzymatic transformations and the formation of vitisin A, acetylvitisin A, and the B vitisins of malvidin-3-glucoside, peonidin-3-glucoside, peonidin-3-acetylglucoside, and malvidin-3-acetylglucoside, as well as the adducts Pn-3-glc-methylmethine(epi)catechin, Mv-3-glc-methylmethine(epi) catechin, and Mv-3-acetylmethylmethine(epi)catechin.Hide Abstract