QuantiQuik™ Malic Acid Quick Test Strips

Protocol SDS

Application

• For rapid, direct determination of malic acid concentrations in food and beverage samples as well as biological samples. Note: Requires access to pipettes for dilution. We offer pipettes that can be purchased separately: 20 uL Pipettes (Catalog: TP-20), 100 uL Pipettes (Catalog: TP-100), or 400 uL Pipettes. (Catalog: TP-400)

Key Features

• Fast and sensitive. Use of 20 or 100 µL sample. Semi-quantitative measurement between 0-500 mg/L (undiluted) malic acid.
• Convenient. No expensive lab equipment needed.
• Sample treatment and assay can be performed in under 15 minutes.

Method

• Visual

Samples

• Wine, beer, milk, etc

Species

• All

Procedure

• Approximately 15 min

Size

• 10 tests

Shelf Life

• 6 months

More Details

L-MALIC ACID, or L-malate, is a dicarboxylic acid that is made by all living organisms and plays an important role in the Calvin and Krebs Cycle. Malic acid is frequently used in food and beverage industries as an additive in products such as wine, beer, candies, etc. It can be used as an acidity regulator, preservative, or simply added for flavor. In the wine industry, decreasing levels of L-malic acid and increasing levels of L-Lactic Acid are monitored during malolactic fermentation. As L-malic acid is converted to L-lactic acid, the overall acidity of the wine is reduced which can lead to the improvement of the flavor of the wine.BioAssay Systems QuantiQuik™ L-Malic Acid Test Strips are based on L-malate dehydrogenase catalyzed oxidation of L-malic acid in which the formed NADH reduces a chromogenic reagent. The intensity of the product color is directly proportional to the L-malic acid concentration in the sample.

What samples have you tested?

The strips have been tested on red wine, white wine, homogenized whole milk, cultured buttermilk, almond milk, yogurt, beer, apple juice, lemonade, grape juice, orange juice, cranberry juice, lime and lemon juice.

My sample turns the strip very dark purple, how can I determine the D-lactate concentration?

Very dark purple indicates that the diluted sample concentration is greater than 500 mg/L. To obtain a more accurate concentration, the sample should be further diluted and retested. For example, if the sample was diluted 5&times, try diluting 21×.

I don’t have access to a pipetteman. How can I accurately measure out my samples?

We offer exact volume transfer pipettes as an accessory. For samples requiring a 21× dilution, order the 20 µL transfer pipettes (TP20). For samples requiring a 5× dilution, order the 100 µL transfer pipettes (TP100).

In your product information about the QuantiQuik L-Lactic Quick Test Strips, you indicate that there is information on how to prepare yogurt products for analysis with the Quick Test strips. How do I prepare my yogurt sample?

Previously, we have tested the QQLLAC test strips with greek yoghurt and buttermilk. Since yoghurt is a solid sample, it cannot be diluted in the same way as liquids, so sample spoons with defined volumes were used to measure the amount of sample to dilute in water. If you have access to a scale, you can also weigh out your sample. Our yoghurt required a 5x dilution, but different samples may vary.

I am working with Sour Beer samples and the edges are dark purple while the center is pale yellow. Is this normal? I tried D-Lactic & L-Lactic and had similar results

The color on the strip should be uniform. Sometimes the strip will not develop a uniform color if the sample is too acidic, and I suspect that this is your problem. In this case, you can either dilute your sample further than 5x, or if you have access to pH measuring equipment and a strong base like NaOH, you can adjust the pH of your sample to ~7 and rerun the sample.

Can I store unused reagents for future use?

Yes, unused reagents can be stored according to the assay protocol. The strips should be kept in a dry, cool location and protected from light.

No citations for this new product. Please check back later. You may click here to check if citations are available, but are not listed here yet.

If you or your labs do not have the equipment or scientists necessary to run this assay, BioAssay Systems can perform the service for you.

– Fast turnaround
– Quality data
– Low cost

Please email or call 1-510-782-9988 x 2 to discuss your projects.