Digestible and Resistant Starch Assay Kit

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The Digestible and Resistant Starch Assay Kit (K-DSTRS) method is based on the research of Englyst et al. (Ref) with some modifications. Digestion is performed using saturating levels of pancreatic α-amylase (PAA) and amyloglucosidase (AMG), but in stirred containers rather than shaken tubes, to simplify sample removal.

In line with Englyst definitions:

Rapidly digestible starch (RDS) is that starch which is digested within 20 min.

Slowly digestible starch (SDS) is that starch which is digested between 20 and 120 min.

A new term, ‘Total digestible starch (TDS)’ is introduced (and measured) to cover all starch that is digested within 4 h (the average time of residence of food in the human small intestine).

Resistant starch (RS) then, is that starch which is not digested within 4 h.

The incubation conditions parallel those used in AOAC Method 2017.16, a new, rapid integrated procedure for the measurement of total dietary fiber (Megazyme method K-RINTDF). This method is physiologically based and designed to fit the definition of DF announced by Codex Alimentarius in 2009.

Product Code
Content/size
Stock
Price
Qty
K-DSTRS
40 assays of each per kit
$260.00

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Colourimetric method for the determination of digestible starch (RDS, SDS and TDS) and resistant starch (RS) in cereal products, foodstuffs, feeds and other materials. 

Principle:

                             (PAA + AMG, pH 6.0, 37°C, 20 min)
(1) Rapidly digestible starch + H2O → D-glucose

                                (PAA + AMG, pH 6.0, 37°C, 120 min)
(2) Slowly digestible starch + H2O → D-glucose

                      (PAA + AMG, pH 6.0, 37°C, 4 h)
(3) Total digestible starch + H2O → D-glucose

Removal of 4 mL aliquot for RS determination:

(4) Aqueous ethanol wash + centrifugation to remove D-glucose

(5) Dissolution of resistant starch pellet in NaOH and neutralisation

               
                (AMG, pH 4.5, 50°C, 30 min)
(6) Dissolved resistant starch + H2O → D-glucose

                                    (glucose oxidase)
(7) D-Glucose + H2+ O2 → D-gluconate + H2O2

                                    
(peroxidase)
(8) 2H2O2 + p-hydroxybenzoic acid 4-aminoantipyrine
 → quinoneimine + 4H2O

Kit size:                               40 assays
Method:                               Spectrophotometric at 510 nm
Total assay time:                ~ 360 min
Detection limit:                   2-100% of sample weight
Application examples: 
Plant materials, starch samples and other materials