L-Malic Acid Assay Kit (Analyser Format)
245.5 mL of prepared reagent (e.g. 1116 assays of 0.22 mL)
| Content: | 245.5 mL of prepared reagent (e.g. 1116 assays of 0.22 mL) |
| Shipping Temperature: | Ambient |
| Storage Temperature: |
Short term stability: 2-8oC, Long term stability: See individual component labels |
| Stability: | > 2 years under recommended storage conditions |
| Analyte: | L-Malic Acid |
| Assay Format: | Auto-analyser |
| Detection Method: | Absorbance |
| Wavelength (nm): | 340 |
| Signal Response: | Increase |
| Linear Range: | up to 80 μg/mL of L-malic acid in final reaction solution |
| Limit of Detection: | 20 mg/L |
| Reaction Time (min): | ~ 3 min |
| Application examples: | Wine, beer, fruit juices, soft drinks, candies, fruit and vegetables, bread, cosmetics, pharmaceuticals and other materials (e.g. biological cultures, samples, etc.). |
| Method recognition: | Methods based on this principle have been accepted by AOAC, EEC, EN, NF, NEN, DIN, GOST, OIV, IFU, AIJN, NBN, ISO and MEBAK |
The L-Malic Acid (Analyser Format) test kit is an analyser format for the specific measurement and analysis of L-malic acid (L-malate) in beverages and food products. On calibration, the prepared reagent is linear to > 80 micrograms of L-malic acid per mL of assay solution.
View more assay kits on our organic acid list.
- Extended cofactors stability. Dissolved cofactors stable for > 1 year at 4oC.
- PVP incorporated to prevent tannin inhibition
- Very stable reagent when prepared for auto-analyser applications
- Linear calibration (R2 ~ 0.9994) up to 80 μg/mL of L-malic acid in final reaction solution
- Validated by the University of Wine, Suze la Rousse, France
- Very competitive price (cost per mL of reagent)
- Both enzymes supplied as stable suspensions
- Very rapid reaction (~ 3 min)
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.
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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.
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Portugal, I., Ribeiro, S. C., Xavier, A. M. R. B., Centeno, F. & Strehaiano, P. (2011). International Journal of Food Science & Technology, 46(2), 284-289.
Maloalcoholic fermentation (MAF) of grape must by Schizosaccharomyces pombe immobilised in calcium-alginate double-layer beads (ProMalic®) was studied in Erlenmeyer flasks and in a total recycle fixed-bed reactor operating in batch mode. The reaction is pseudo-first order with respect to L-malic acid and under similar conditions deacidification is faster in the recycle reactor. This was attributed to mass transfer limitations which were confirmed in the recycle reactor by studying the influence of yeast load on the rate of MAF. Mass transfer limitations are also responsible for the lower activation energy of fermentation with the immobilised yeast (67 ± 9 kJ mol-1) in comparison with the free cells (126 ± 19 kJ mol-1). Alcoholic fermentation and MAF were performed simultaneously, both in the recycle reactor and in the industrial trials, confirming the efficacy of immobilised S. pombe to reduce grape must acidity without interfering with the main fermentation. Altogether, the present results are useful for the scale-up of a recycle reactor to process large volumes of grape must.
Hide Abstract| Symbol : | GHS07 |
| Signal Word : | Warning |
| Hazard Statements : | H302, H412 |
| Precautionary Statements : | P264, P270, P273, P301+P312, P330, P501 |
