AOAC RI ERP E-Book - DS DF

K-RINTDF.2016_11_K-RSTAR.DATA.NEW 27/09/2016 11:54 Page 4

OMAMAN-38 C: Instructions for Use Expert Review Panel Use Only September, 2017

fractions, pheno lic compounds, waxes, saponins, phytates, cutin, phyto stero ls, etc.) intimately “associated” w ith plant po lysaccharides in the AO A C 991.43 method. b Decision on whether to include carbohydrates o f 3 to 9 monomeric units should be left up to national autho rities.” A method for the measurement of TDF as defined by CODEX Alimentarius, which measures both RS and NDO, was published in 2007 15 , and this method has been successfully evaluated in interlaboratory studies under the auspices of AOAC International (Method 2009.01 16 ) and AACC International (AACC Method 32- 45.01). A modified method for separately measuring insoluble dietary fiber ( IDF ), dietary fiber soluble in water, but precipitated in 78% aqueous ethanol ( SDFP ) and dietary fiber soluble in water and not precipitated in 78% aqueous ethanol ( SDFS ) has also been successfully evaluated (AOAC Method 2011.25 and AACC Method 32-45.01). SDFP is also termed high molecular weight soluble dietary fiber ( HMWSDF ) and SDFS is also termed low molecular weight soluble dietary fiber ( LMWSDF ) and is also referred to as non- digestible oligosaccharides ( NDO ). AOAC Method 2009.01 (AACC Method 32-45.01) has been adopted as a CODEX Alimentarius Type I Method). In the application of AOAC Methods 2009.01 and 2011.25 to a diverse range of plant based foods and food ingredients, several analytical challenges were identified: (1) in AOAC Methods 2009.01 and 2011.25, the incubation time with pancreatic α -amylase (PAA) and amyloglucosidase (AMG) is 16 h, while the likely time of residence of food in the human small intestine is approx. 4 + 1 h; 17 (2) under the extended incubation conditions of AOAC Method 2009.01 and 2011.25, there is excessive hydrolysis of phosphate crosslinked starch (RS 4 ) and to a lesser extent native high amylose maize starch (RS 1 ), giving underestimation of these components; 18 (3) during hydrolysis of various starch containing foods, a small amount of resistant maltodextrins are produced by the combined action of PAA and AMG under the conditions employed. 18, 19 Since these resistant maltodextrins are rapidly hydrolysed by the mucosal α -glucosidase complex in the brush border lining of the small intestine 18 , they should not be included as DF; (4) fructotriose (F3), present in commercial FOS that are produced by enzymic hydrolysis of fructan, elutes at the same point as disaccharides from a Waters Sugar-Pak ® HPLC column; in contrast, complete separation can be achieved on a TOSOH TSK ® gel permeation column. In the “Rapid” Integrated TDF procedure (RINTDF) described here, each of these challenges/limitations of AOAC Methods 2009.01 and 2011.25 have been addressed and resolved 20 . Incubation with higher concentrations of PAA and AMG preclude the formation of resistant maltodextrins (Figure 3, page 13), and the shorter incubation time, AOAC Research Institute ERP Use Only

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