72 assays (manual) / 720 assays (microplate)
Prices exclude VAT
Available for shipping
|72 assays (manual) / 720 assays (microplate)
| Short term stability: 2-8oC,
Long term stability: See individual component labels
|> 2 years under recommended storage conditions
|0.3 to 25 µg of acetic acid per assay
|Limit of Detection:
|Reaction Time (min):
|~ 4 min
|Wine, beer, fruit and fruit juices, soft drinks, vinegar, vegetables, pickles, dairy products (e.g. cheese), meat, fish, bread, bakery products (and baking agents), ketchup, soy sauce, mayonnaise, dressings, paper (and cardboard), tea, pharmaceuticals (e.g. infusion solutions), feed and other materials (e.g. biological cultures, samples, etc.).
The Acetic Acid (Acetate Kinase Manual Format) test kit is suitable for the measurement and analysis of acetic acid in food and beverages.
This rapid and reliable manual acetic acid kit is simple to perform (only two absorbance readings required), and because a true end-point is measured, does not involve complicated calculations like other kits. This product is very stable both during storage and use (> 2 years), has extended linearity (compared to ACS based kits), contains PVP to prevent tannin inhibition, and is performed at a relatively low pH (7.4), thus minimising ester hydrolysis related interference. This method is suitable for the measurement of acetic acid/acetate in foods, beverages and other materials.
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).
View all of our acetic acid and other organic acid assay kits.
- Improved assay format (only two absorbance readings required)
- All reagents stable for > 2 years after preparation
- PVP incorporated to prevent tannin inhibition
- Very rapid reaction (~ 4 min)
- Mega-Calc™ software tool is available from our website for hassle-free raw data processing
- Very competitive price (cost per test)
- Suitable for manual and microplate formats
- Extended cofactors stability
Megazyme “advanced” wine test kits general characteristics and validation.
Charnock, S. J., McCleary, B. V., Daverede, C. & Gallant, P. (2006). Reveue des Oenologues, 120, 1-5.
Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.Hide Abstract
Grape and wine analysis: Oenologists to exploit advanced test kits.
Charnock, S. C. & McCleary, B. V. (2005). Revue des Enology, 117, 1-5.
It is without doubt that testing plays a pivotal role throughout the whole of the vinification process. To produce the best possible quality wine and to minimise process problems such as “stuck” fermentation or troublesome infections, it is now recognised that if possible testing should begin prior to harvesting of the grapes and continue through to bottling. Traditional methods of wine analysis are often expensive, time consuming, require either elaborate equipment or specialist expertise and frequently lack accuracy. However, enzymatic bio-analysis enables the accurate measurement of the vast majority of analytes of interest to the wine maker, using just one piece of apparatus, the spectrophotometer (see previous issue No. 116 for a detailed technical review). Grape juice and wine are amenable to enzymatic testing as being liquids they are homogenous, easy to manipulate, and can generally be analysed without any sample preparation.Hide Abstract
Effect of spray drying conditions on physicochemical and functional properties of apple cider vinegar powder.
Altay, I., Reimer Stubbe, P. & Mohammadifar, M. A. (2023). JSFA Reports, 3(6), 271-281.
Background: Apple cider vinegar (ACV) contains many health benefits due to its antioxidant and acetic acid content. However, the adverse effects of directly consuming the vinegar should be eliminated to make it possible to regulate its intake as a dietary supplement. The objective of the study is to optimize the spray drying operating conditions to produce ACV powder with health benefits. A central composite design (CCD) of response surface methodology (RSM) was used to optimize the spray drying process of ACV. The influences of inlet temperature (130°C–170°C), gum Arabic concentration (5%–15% w/w), and feed flow rate (1–2 kg/h) on some product and process aspects were investigated. Spray-dried powders were evaluated for their moisture content, process yield, acetic acid content, solubility, and antioxidant content. Results: The relationships between the model factors and final powder properties were established with ANOVA and multiple regression analysis. The model factors affected the investigated powder properties at different significance levels, where carrier concentration was the main influencing factor. Gum Arabic contributed to the retention of volatile and heat-sensitive compounds providing health benefits. All powders showed high solubility (>94%) and high antioxidant recovery, and most treatments achieved a drying yield of higher than 50%. Conclusion: Optimization of spray drying process was achieved with application of RSM and relationships between model factors and powder properties were established. This study highlighted the feasibility of the development of ACV-based functional powder as a dietary supplement.Hide Abstract
Water-soluble biopolymers from heat-treated and high pressure homogenized vegetable purées: investigating their emulsion forming and stabilizing capacities.
Santiago-Alumbro, J. S., Van Loey, A. & Hendrickx, M. (2023). Journal of Food Science and Technology, 60(12), 3043-3053.
The emulsion forming and stabilizing capacities of water-soluble biopolymers originating from the aqueous (serum) phase of heat-treated and high pressure homogenized purées were investigated. The serum biopolymers were characterized and then utilized as emulsifier/stabilizer in simple oil-in-water emulsions. The resulting emulsions were stored at 4°C and monitored for 2 weeks. Results revealed that carrot and tomato sera contained higher amounts of pectin and lower protein compared to broccoli. The serum pectic biopolymers exhibited distinct molecular structures, depending on the vegetable origin. Given these natural biopolymer composition and characteristics, emulsions with small droplet sizes were observed at pH 3.5. However, emulsions at pH 6.0 showed large mean droplet sizes, except for the emulsion formulated with carrot serum. Regardless of the pH, emulsions containing carrot serum biopolymers exhibited high capacity to form fine emulsions that were stable during the 2-week storage period at low temperature. This study clearly shows the capacity of natural water-soluble biopolymers isolated from the serum phase of vegetable purées to form fine emulsion droplets and maintain its stability during storage, especially in the case of carrot serum biopolymers.Hide Abstract
Physicochemical changes during controlled laboratory fermentation of cocoa (CCN-51) with the inclusion of fruits and on-farm inoculation.
Peña González, M. A., Ortiz Urgiles, J. P., Santander Pérez, F. A., Lazo Vélez, M. A. & Caroca Cáceres, R. S. (2023). Brazilian Journal of Food Technology, 26, e2023013.
Fermentation is key to developing the organoleptic characteristics of cocoa beans, as dynamic changes in metabolites have a significant impact on flavors and aromas, hence modifications of this process have been investigated. In this research, the mucilage of CCN-51 cocoa beans was replaced by a mixture of passion fruit (Passiflora edulis) and plantain (Musa paradisiaca L.) pulp, and a controlled fermentation of this mixture was carried out after its spontaneous on-farm inoculation. The physicochemical changes and correlations during the five days of fermentation were evaluated. At the end of the process, the temperature reached 47 ºC in the fermentation mass and pH 5.64 was recorded in the cotyledon. In the first 48 hours, citric acid and fructose were high but at the end of fermentation were 71% and 41.17% lower than at the start of fermentation, respectively. As glucose and fructose were consumed during fermentation, acetic acid and lactic acid levels increased from day two onward, reaching values at the end of the process of 22.48 mg/g and 16.01 mg/g, respectively. In contrast, the bromatological parameters did not show greater variability when comparing each day of fermentation. The data generated and results presented in this study will contribute to the knowledge of possible sensory improvements achieved with the inclusion of pulp fruits in the fermentation stage.Hide Abstract
Acss2/HIF-2 signaling facilitates colon cancer growth and metastasis.
Garcia, J. A., Chen, R., Xu, M., Comerford, S. A., Hammer, R. E., Melton, S. D. & Feagins, L. A. (2023). Plos one, 18(3), e0282223.
The microenvironment of solid tumors is characterized by oxygen and glucose deprivation. Acss2/HIF-2 signaling coordinates essential genetic regulators including acetate-dependent acetyl CoA synthetase 2 (Acss2), Creb binding protein (Cbp), Sirtuin 1 (Sirt1), and Hypoxia Inducible Factor 2α (HIF-2α). We previously shown in mice that exogenous acetate augments growth and metastasis of flank tumors derived from fibrosarcoma-derived HT1080 cells in an Acss2/HIF-2 dependent manner. Colonic epithelial cells are exposed to the highest acetate levels in the body. We reasoned that colon cancer cells, like fibrosarcoma cells, may respond to acetate in a pro-growth manner. In this study, we examine the role of Acss2/HIF-2 signaling in colon cancer. We find that Acss2/HIF-2 signaling is activated by oxygen or glucose deprivation in two human colon cancer-derived cell lines, HCT116 and HT29, and is crucial for colony formation, migration, and invasion in cell culture studies. Flank tumors derived from HCT116 and HT29 cells exhibit augmented growth in mice when supplemented with exogenous acetate in an Acss2/HIF-2 dependent manner. Finally, Acss2 in human colon cancer samples is most frequently localized in the nucleus, consistent with it having a signaling role. Targeted inhibition of Acss2/HIF-2 signaling may have synergistic effects for some colon cancer patients.Hide Abstract
Cellulose Isolation from Tomato Pomace Pretreated by High-Pressure Homogenization.
Pirozzi, A., Ferrari, G. & Donsì, F. (2022). Foods, 11(3), 266.
This work proposes a biorefinery approach for the utilization of agri-food residues, such as tomato pomace (TP), through combining chemical hydrolysis with high-pressure homogenization (HPH), aiming to achieve the isolation of cellulose with tailored morphological properties from underused lignocellulose feedstocks, along with the valorization of the value-added compounds contained in the biomass. Cellulose was isolated from TP using sequential chemical hydrolysis in combination with mechanical pretreatment through HPH. The chemical and structural features of cellulose isolated from TP pretreated by HPH were compared with cellulose isolated from untreated TP through light scattering for particle size distribution, optical and scanning electron microscopy, and Fourier-transform infrared spectroscopy (FT-IR) analysis. HPH pretreatment (80 MPa, 10 passes) not only promoted a slight increase in the yield of cellulose extraction (+9%) but contributed to directly obtaining defibrillated cellulose particles, characterized by smaller irregular domains containing elongated needle-like fibers. Moreover, the selected mild chemical process produced side streams rich in bioactive molecules, evaluated in terms of total phenols and reducing activity. The liquors recovered from acid hydrolysis of TP exhibited a higher biological activity than those obtained through a conventional extraction (80% v/v acetone, 25°C, 24 h at 180 rpm).Hide Abstract
Effects of supplemental calcium gluconate embedded in a hydrogenated fat matrix on lactation, digestive, and metabolic variables in dairy cattle.
Seymour, D. J., Sanz-Fernandez, M. V., Daniel, J. B., Martín-Tereso, J. & Doelman, J. (2021). Journal of Dairy Science, 104(7), 7845-7855.
There is growing evidence suggesting that by improving gut integrity and function, less energy is partitioned toward immune responses related to xenobiotic infiltration, sparing energy for productive purposes. Gluconic acid and its salts have previously shown prebiotic effects in the lower gut of nonruminant animals, where they serve as a precursor for butyrate, although evidence in ruminants is limited. Butyrate and its fermentative precursors have demonstrated multiple beneficial effects to gastrointestinal ecology, morphology, and function, such as the stimulation of epithelial cell proliferation and improvement of gut barrier function and ecology. The objective of this study was to evaluate changes in milk production, milk fatty acid composition, and fecal and blood parameters in lactating dairy cattle fed a hydrogenated fat-embedded calcium gluconate (HFCG) supplement designed to target the hindgut for calcium gluconate delivery. In addition, the effects of a compound feed processing method (i.e., incorporated into a mash or an extruded pellet) were tested to evaluate the effect of extrusion on product efficacy. Forty-five lactating Holstein cows at approximately 165 d in milk were used in a 3 × 3 Latin square consisting of three 28-d periods, during which animals were offered a basal ration mixed with 3 different compound feeds: a negative control in mash form containing no HFCG, or the HFCG supplement fed at a target rate of 16 g/d, delivered in either a mash or pelleted form. Supplementation of HFCG tended to increase yields of milk fat and fat- and energy-corrected milk. Total yields and concentrations of milk fatty acids ≥18 carbons in length tended to increase in response to HFCG. Plasma nonesterified fatty acids and milk urea increased in HFCG treatments. No differences were observed in fecal pH or fecal concentrations of volatile fatty acids, with the exception of isobutyrate, which decreased in HFCG-fed cows. Changes in milk fatty acid profile suggest that increased milk fat yield was driven by increased incorporation of preformed fatty acids, supported by increased circulating nonesterified fatty acid. Future research investigating the mode of action of HFCG at the level of the hindgut epithelium is warranted, as measured fecal parameters showed no response to treatment.Hide Abstract
Impact of Lachancea thermotolerans strain and lactic acid concentration on Oenococcus oeni and malolactic fermentation in wine.
Snyder, E. C., Jiranek, V. & Hranilovic, A. (2021). OENO One, 55(2), 365-380.
The yeast Lachancea thermotolerans can produce lactic acid during alcoholic fermentation (AF) and thereby acidify wines with insufficient acidity. However, little is known about the impact of L. thermotolerans on Oenococcus oeni, the primary lactic acid bacterium used in malolactic fermentation (MLF). This study explored the impact of sequential cultures of L. thermotolerans and Saccharomyces cerevisiae on MLF performance in white and red wines. Four L. thermotolerans strains were tested in Sauvignon blanc with sequential S. cerevisiae inoculation, compared to an S. cerevisiae control and the initially un-inoculated treatments. The L. thermotolerans wines showed large differences in acidification, and progression of MLF depended on lactic acid production, even at controlled pH. The highest and lowest lactic acid producing strains were tested further in Merlot fermentations with both co-inoculated and sequentially inoculated O. oeni. The low lactic acid producing strain enabled successful MLF, even when this failed in the S. cerevisiae treatment, with dramatically quicker malic acid depletion in O. oeni co-inoculation than in sequential inoculation. In contrast, a high lactic acid producing strain inhibited MLF irrespective of the O. oeni inoculation strategy. In a follow-up experiment, increasing concentrations of exogenously added lactic acid slowed MLF and reduced O. oeni growth across different matrices, with 6 g/L of lactic acid completely inhibiting MLF. The results confirm the inhibitory effect of lactic acid on O. oeni while highlighting the potential of some L. thermotolerans strains to promote MLF and the others to inhibit it.Hide Abstract
Multiscale analysis of lignocellulose recalcitrance towards OrganoCat pretreatment and fractionation.
Weidener, D., Dama, M., Dietrich, S. K., Ohrem, B., Pauly, M., Leitner, W., de María, P. D., Grande, P. M. & Klose, H. (2020). Biotechnology for Biofuels, 13(1), 1-13.
Background: Biomass recalcitrance towards pretreatment and further processing can be related to the compositional and structural features of the biomass. However, the exact role and relative importance to those structural attributes has still to be further evaluated. Herein, ten different types of biomass currently considered to be important raw materials for biorefineries were chosen to be processed by the recently developed, acid-catalyzed OrganoCat pretreatment to produce cellulose-enriched pulp, sugars, and lignin with different amounts and qualities. Using wet chemistry analysis and NMR spectroscopy, the generic factors of lignocellulose recalcitrance towards OrganoCat were determined. Results: The different materials were processed applying different conditions (e.g., type of acid catalyst and temperature), and fractions with different qualities were obtained. Raw materials and products were characterized in terms of their compositional and structural features. For the first time, generic correlation coefficients were calculated between the measured chemical and structural features and the different OrganoCat product yields and qualities. Especially lignin-related factors displayed a detrimental role for enzymatic pulp hydrolysis, as well as sugar and lignin yield exhibiting inverse correlation coefficients. Hemicellulose appeared to have less impact, not being as detrimental as lignin factors, but xylan-O-acetylation was inversely correlated with product yield and qualities. Conclusion: These results illustrate the role of generic features of lignocellulosic recalcitrance towards acidic pretreatments and fractionation, exemplified in the OrganoCat strategy. Discriminating between types of lignocellulosic biomass and highlighting important compositional variables, the improved understanding of how these parameters affect OrganoCat products will ameliorate bioeconomic concepts from agricultural production to chemical products. Herein, a methodological approach is proposed.Hide Abstract
Reduced photosynthesis in Arabidopsis thaliana atpme17. 2 and atpae11. 1 mutants is associated to altered cell wall composition.
Roig‐Oliver, M., Rayon, C., Roulard, R., Fournet, F., Bota, J. & Flexas, J. (2020). Physiologia Plantarum, In Press.
The cell wall is a complex and dynamic structure that determines plants' performance by constant remodeling of its compounds. Although cellulose is its major load‐bearing component, pectins are crucial to determine wall characteristics. Changes in pectin physicochemical properties, due to pectin remodeling enzymes (PRE), induce the rearrangement of cell wall compounds, thus, modifying wall architecture. In this work, we tested for the first time how cell wall dynamics affect photosynthetic properties in Arabidopsis thaliana pectin methylesterase atpme17.2 and pectin acetylesterase atpae11.1 mutants in comparison to wild‐type Col‐0. Our results showed maintained PRE activities comparing mutants with wild‐type and no significant differences in cellulose, but cell wall non‐cellulosic neutral sugars contents changed. Particularly, the amount of galacturonic acid (GalA) - which represents to some extent the pectin cell wall proportion – was reduced in the two mutants. Additionally, physiological characterization revealed that mutants presented a decreased net CO2 assimilation (AN) because of reductions in both stomatal (gs) and mesophyll conductances (gm). Thus, our results suggest that atpme17.2 and atpae11.1 cell wall modifications due to genetic alterations could play a significant role in determining photosynthesis.Hide Abstract
Portuguese cacholeira blood sausage: A first taste of its microbiota and volatile organic compounds.
Belleggia, L., Ferrocino, I., Reale, A., Boscaino, F., Di Renzo, T., Corvaglia, M. R., Cocolin, L., Milanović, V., Cardinali, F., Garofalo, C., Clementi, F., Aquilanti, L. & Osimani, A. (2020). Food Research International, 136, 109567.
Among typical Portuguese sausages, the cacholeira blood sausage undoubtedly represents one of the most popular preparations. To the authors’ knowledge, a lack of information on both the microbiota and the volatile organic compounds (VOCs) of this blood-containing sausage emerges from the available scientific literature. This study represents the first characterization of physico-chemical, microbiological and volatile traits of Portuguese cacholeira blood sausage. To this end, ready-to-eat cacholeira blood sausages were collected from two production batches manufactured in summer (batch 1) and autumn (batch 2). Viable counts showed active microbial communities mainly composed by lactic acid bacteria, coagulase negative cocci, enterococci and eumycetes. The metataxonomic approach showed a simple bacterial composition, which was dominated by Lactobacillus sakei in both the analyzed batches (1 and 2) considered. Carnobacterium, Enterococcus, Kluyvera, Lactococcus and Serratia were found as minor genera. The mycobiota varied according to the production season. Batch 1 was dominated by Starmerella apicola, Debaryomyces hansenii and Candida tropicalis, whereas batch 2 was dominated by D. hansenii. Moreover, Aspergillus spp., Kurtzmaniella zeylanoides, Saccharomyces cerevisiae, Kurtzmaniella santamariae, Brettanomyces bruxellensis and Pichia kluyveri were detected in both the batches as minority species. Seventy-two volatile compounds were identified, including esters, phenols, terpenoids, acids, alcohols, ketones, aldehydes, lactones, furans, sulphur and nitrogen compounds. Significant differences were seen in the amount of some compounds, as a feasible consequence of differences in the raw materials, artisan production and seasonality.Hide Abstract
Assessing population diversity of Brettanomyces yeast species and identification of strains for brewing applications.
Colomer, M. S., Chailyan, A., Fennessy, R. T., Olsson, K. F., Johnsen, L., Solodovnikova, N. & Forster, J. (2020). Frontiers in Microbiology, 11, 637.
Brettanomyces yeasts have gained popularity in many sectors of the biotechnological industry, specifically in the field of beer production, but also in wine and ethanol production. Their unique properties enable Brettanomyces to outcompete conventional brewer’s yeast in industrially relevant traits such as production of ethanol and pleasant flavors. Recent advances in next-generation sequencing (NGS) and high-throughput screening techniques have facilitated large population studies allowing the selection of appropriate yeast strains with improved traits. In order to get a better understanding of Brettanomyces species and its potential for beer production, we sequenced the whole genome of 84 strains, which we make available to the scientific community and carried out several in vitro assays for brewing-relevant properties. The collection includes isolates from different substrates and geographical origin. Additionally, we have included two of the oldest Carlsberg Research Laboratory isolates. In this study, we reveal the phylogenetic pattern of Brettanomyces species by comparing the predicted proteomes of each strain. Furthermore, we show that the Brettanomyces collection is well described using similarity in genomic organization, and that there is a direct correlation between genomic background and phenotypic characteristics. Particularly, genomic patterns affecting flavor production, maltose assimilation, beta-glucosidase activity, and phenolic off-flavor (POF) production are reported. This knowledge yields new insights into Brettanomyces population survival strategies, artificial selection pressure, and loss of carbon assimilation traits. On a species-specific level, we have identified for the first time a POF negative Brettanomyces anomalus strain, without the main spoilage character of Brettanomyces species. This strain (CRL-90) has lost DaPAD1, making it incapable of converting ferulic acid to 4-ethylguaiacol (4-EG) and 4-ethylphenol (4-EP). This loss of function makes CRL-90 a good candidate for the production of characteristic Brettanomyces flavors in beverages, without the contaminant increase in POF. Overall, this study displays the potential of exploring Brettanomyces yeast species biodiversity to find strains with relevant properties applicable to the brewing industry.Hide Abstract
Influence of sugars and pH on the citrate metabolism of different lactic acid bacteria strains in a synthetic wine matrix.
Pretorius, N., Engelbrecht, L. & Du Toit, M. (2019). Journal of Applied Microbiology, 127(5), 1490-1500.
Aims: This study investigated the influence of sugars (glucose and fructose) and pH on the gene expression of cite (citrate lyase β‐subunit) and the subsequent formation of metabolites associated with citrate metabolism. Methods and Results: Different levels of glucose (2·5, 50 and 115 g l−1), fructose (2·5, 50 and 115 g l−1) and pH (3·0, 3·5, 4·0 and 5·0) were evaluated for their effect on cite expression in four different lactic acid bacteria strains. Two Oenococcus oeni strains and two Lactobacillus plantarum strains were used, of which one strain of each species screened positive for the cite gene. Among the factors tested, fructose had the biggest influence on the relative expression of cite in O. oeni. In addition, the citrate‐positive strains produced high concentrations of diacetyl and acetoin. Conclusions: This study gives an overview of how sugar, pH and different lactic acid bacteria strains influence cite gene expression and the formation of metabolites associated with citrate metabolism closely linked to malolactic fermentation (MLF). Significance and Impact of the Study: These results can be used to make informed decisions regarding MLF when aiming to create a wine with a buttery aroma or not.Hide Abstract
Assays for the enzymes catalyzing the O-acetylation of bacterial cell wall polysaccharides.
Brott, A. S., Sychantha, D. & Clarke, A. J. (2019). “Bacterial Polysaccharides”, Humana Press, New York, NY, 115-136.
The polysaccharides that comprise bacterial cell walls are commonly O-acetylated. This modification confers resistance to hydrolases of innate immune systems and/or controls endogenous autolytic activity. Herein, we present protocols for the compositional analysis of bacterial cell wall O-acetylation, and assays for monitoring O-acetyltransferases and O-acetylesterases. The assays are amenable for the development of high-throughput screens in search of inhibitors of the respective enzymes.Hide Abstract