英文名：Fructan Assay Kit
规格：100 assays per kit
英文名称：Fructan Assay Kit
The Fructan test kit is suitable for the specific measurement and analysis of fructan in plant extracts and food products containing starch, sucrose and other sugars.
Colourimetric method for the determination of Fructan in plant
products, foodstuffs and other materials
(1) Sucrose + H2O → D-glucose + D-fructose
(β-amylase + maltase + pullulanase)
(2) Starch + maltosaccharides + H2O → D-glucose
(3) D-Glucose + D-fructose → D-sorbitol + D-mannitol
(exo-inulinase + endo-inulinase)
(4) Fructan + H2O → D-glucose + D-fructose
(100°C, 6 min)
(5) D-Glucose + D-fructose + PAHBAH → PAHBAH colour complex
Kit size: 100 assays
Method: Spectrophotometric at 410 nm
Total assay time: ~ 90 min
Detection limit: 1-100% of sample weight
Flours, plant materials (e.g. onion), food products and other materials
AOAC (Method 999.03), AACC (Method 32-32.01) and CODEX
(Type III Method)
- Very cost effective
- All kit reagents stable for > 2 years after preparation
- Unaffected by high sucrose / reducing sugar concentrations
- Fructan kits are only available from Megazyme
- Simple format
- Mega-Calc™ software tool is available from our website for hassle-free raw data processing
- Standard included
Q1. Should the pH of the sample be adjusted even for samples in acidic media?
The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.
Q2. Does the fructanase enzyme hydrolyse Neosugar?
Q3. When measuring fructan in starch containing samples, i.e. maize, is there a possibility of incomplete starch hydrolysis in step B?
From our experience, the level of beta-amylase/pullulanase etc. added is more than adequate to completely hydrolyse any starch likely to be present. However, if there is a suspicion of incomplete starch hydrolysis, you can check this by running the hydrolysis with the pullulanase/beta-amylase etc. over a range of incubation times and comparing the results.
Q4. Could you tell me whether this method simply gives a gross measure of the fructan content, or whether it is possible to specifically determine the inulin content of the material?
The method measures inulin and cereal fructans.
Q5. What typical absorbance values are obtained for fructan control and fructose control?
Fructan Control Flour (29.6%) 0.496 0.498
Fructose Control 1.133 1.135.
Q6. What is the precision of the method for measurement of fructans?
Our reproducibility is usually +/- 5 to 7% of the fructan value.
Q7. Do you have statistics for the variability of your diagnostic test kits? I would like to get an idea what typical %RSD values would be for your oligofructan test kit.
With all our kits we can obtain approx. 5% c.v. in interlaboratory studies. In-house these values are closer to 3%.
Q8. Can I detect the levan content of some plant materials by use of your fructan kit?
The fructanase in the kit will completely hydrolyse the fructans in plants. These are either inulin type or "branched" type (as in oat or wheat stems). We do not know if the enzymes would act on pure levan.
Q9. What actually is the factor value (F)? Is it always 54.5 or does it change depending on the fructose content?
The value of 54.5 is the actual amount of fructose standard used. This amount of fructose will give a certain colour in the PAHBAH assay.
Thus; F = factor = [54.5 (micrograms of fructose)] divided by the absorbance value obtained for 54.5 micrograms of fructose in the PAHBAH method.
Q10. Is it possible to buy Fructanase separate from the kit?
Yes. The best enzyme to use for analytical purposes is exo-Inulinase (E-EXOIAN).
Q11. We need to analyse sucrose in extracts of chicory roots and the sucrase used in your fructan assay procedure may solve the problem. Do you think that it would be possible to use sucrase instead of invertase in the sucrose assay?
Yes, the sugar enzyme can be used to measure sucrose. The enzyme is an alpha-glucosidase, so it will also hydrolyse maltose if this is present.
Q12. Is it possible to do the weighing and hot extraction the day before the actual assay?
Extract solutions are best made and analysed the same day (not stored overnight). But if they are stored overnight in a refrigerator, heat them to 80˚C, and cool before analysing (to ensure all fructan has re-dissolved).
Q13. Can the fructan method be used to measure inulin in starch-containing products, i.e. Cornflakes?
Q14. There is an issue with the performance of the kit; the results are not as expected.
If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:
- Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
- Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (firstname.lastname@example.org). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
- State the kit lot number being used (this is found on the outside of the kit box).
- State which assay format was used (refer to the relevant page in the kit booklet if necessary).
- State exact details of any modifications to the standard procedure that is provided by Megazyme.
- State the sample type and describe the sample preparation steps if applicable.
Q15. Sucrase is specific for the cleavage of sucrose without hydrolysing any of the other potentially present oligo/polysaccharides (mixed linked glucan, soluble starch, fructan of any size & structure). Is this correct? Do you sell the enzyme separately?
Yes , the sucrase does hydrolyse sucrose only and has no action on the other carbohydrates that you mention. The “sucrase” enzyme is an alpha-glucosidase which we sell as Alpha-Glucosidase (Maltase) E-MALTS.
Q16. Fructan Assay Procedure “Further treatment of extracts” Step 3, Pg 8 "if sample is cooled, it must be re-heated to 80˚C to ensure fructans redissolve". If frozen to –20˚C, thawed quickly & re-heated to 80˚C, will the fructans re-dissolve completely?
Fructans are very soluble and will redissolve very readily. They may precipitate on freezing (at least the polymeric portion) but they will easily re-dissolve at 80˚C.
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