Megazyme® Rapid Integrated Total Dietary Fiber Assay Kit

The Rapid Integrated Total Dietary Fiber (RINTDF) Assay Kit offers the most comprehensive approach to the measurement of total dietary fiber in a wide range of food products, including those that may or may not contain resistant starch. Designed to reflect physiological conditions more closely, the method uses a 4-hour incubation period to simulate digestion in the human small intestine, resulting in more accurate quantification of resistant starch, including phosphate cross-linked starch (RS4).

By increasing the concentrations of key enzymes (α-Amylase and Amyloglucosidase) the method prevents the formation of resistant maltodextrins, which have been observed produced with 16-hour incubation conditions. This adjustment also ensures that the measured levels of resistant starch in control samples are consistent with data obtained from ileostomy studies, enhancing the physiological relevance and accuracy of the results.

The dietary fiber fractions that are measured with this method are:

1. High Molecular Weight Dietary Fiber (HMWDF) including Insoluble Dietary Fiber (IDF) and High Molecular Weight Soluble Dietary Fiber (SDFP; soluble dietary fiber which is precipitated in the presence of 78% aqueous ethanol), and

2. Low Molecular Weight Soluble Dietary Fiber (SDFS; water soluble dietary fiber that is soluble in the presence of 78% aqueous ethanol).

The soluble and insoluble fractions can also be measured individually, offering flexibility for detailed fiber profiling.

The enzymes provided in the kit are of exceptionally high purity, effectively devoid of contaminating enzyme activity on other dietary fiber components such as β-glucan, pectin, and arabinoxylan. Supplied as freeze-dried powders, they support the use of glycerol as an internal standard in the method.

Whether for nutritional labelling, research, or quality control, the RINTDF Assay Kit delivers reliable, physiologically relevant results and broad applicability.

* See McCleary, B. V., Sloane, N & Draga, A. (2015). Determination of total dietary fibre and available carbohydrates: a rapid integrated procedure that simulates in vivo digestion. Starch/Starke, 66, 1-24.

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