Resistant Starch Assay Kit (Rapid)
The Resistant Starch Assay Kit (Rapid) method is suitable for the measurement of resistant starch in pure starch, cereal and legume seeds and food samples. This method is an update of the method of McCleary et al. 1 (AOAC Method 2002.02, AACC Method 32-40.01) employing incubation conditions similar to those used in AOAC Method 2017.16 for dietary fiber. The enzyme mixture employed [pancreatic α-amylase (PAA) and amyloglucosidase (AMG)] are those used by Englyst et al.2 except that both enzymes have been purified, standardised and stabilised. Digestion is performed using saturating levels of PAA and AMG with stirring at pH 6 and 37oC for 4 h, to simulate in vivo conditions in the human small intestine. Recent studies on the hydrolysis of “newer” resistant starch materials such as phosphate crosslinked starch (RS4) indicated that these incubation conditions are an essential requirement to obtain meaningful physiologically relevant values for RS.
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 service the definition of DF announced by Codex Alimentarius in 2009.
1. McCleary, B.V., McNally, M. & Rossiter, P. (2002). Measurement of Resistant Starch by Enzymic Digestion in Starch and Selected Plant Materials - Collaborative Study. J. AOAC Int., 85, 1103-1111.
2. Englyst, H.N., Kingman, S.M. & Cummings, J.H. (1992). Classification and measurement of nutritionally important starch fractions. Eur. J. Clin. Nutr., 46 (Suppl. 2), S33-S50.
Colourimetric method for the determination of resistant starch (RS) in cereal products, foodstuffs, feeds and other materials.
(PAA + AMG, pH 6.0, 37°C, 4 h)
(1) Starch + H2O → D-glucose + RS
Recovery of RS:
(Ethanol or IMS)
(2) Reaction mixture → soluble D-glucose + RS pellet
(AMG, pH 4.5, 50°C, 30 min)
(3) Dissolved RS pellet + H2O → D-glucose
(4) D-Glucose + H2O + O2 → D-gluconate + H2O2
(5) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine → quinoneimine + 4H2O
Kit size: 100 assays
Method: Spectrophotometric at 510 nm
Total assay time: ~ 5 h
Detection limit: 2-100% of sample weight
Plant materials, starch samples and other materials
An updated modification of: AOAC Method 2002.02; AACC Method 32-40; CODEX Type II Method