Resistant starch method

Goni I, Garcia-Diz L, Manas E and Saura-Calixto F. 1996. Analysis of resistant starch A method for foods and food products. Food Chem 56 445 149. 

Resistant starch will serve as primary source of substrate for colonic microflora and may have important physiological benefits. On this basis resistant starch can be classified as a dietary fibre. The Association of Official Agricultural Chemists (AOAC) method of determining dietary fibre will measure some resistant starch as dietary fibre. 

Dietary Fibre. An area of some contention is what should be included as dietary fibre. There are several different methods of measuring dietary fibre and all of them will give different results on the same sample. The EU favours the Association of Analytical Chemists (AOAC) method, which includes lignin and resistant starch, while the UK has preferred the Englyst method and has defined fibre as nonstarch polysaccharides from cell walls as the only substances that count as fibre. 

The protocol developed by Holm et al. (1986) was evaluated by analysis of starch content in wheat starch, white wheat flour, whole-grain wheat, and industrially processed wheat products. The major advantage of this protocol over the Basic Protocol is its reduced cost. The chemicals for the reagent preparations and the enzymes are purchased directly from the companies that produce them. The original method did not include RS3 (resistant starch) in its quantitation. A DMSO treatment step has been added (step 4) to solve this problem. 

Sieved, D. and Pomeranz, Y. 1989. Enzyme-resistant starch. I. Characterization and evaluation by enzymatic, thermoanalytical, and microscopic methods. Cereal Chem. 66 342-347. 

Bond Joint Resistance Test, Method TM-PT-15, Ablestik Laboratories, a National Starch and Chemical Company (Sep. 15,1993)... 

Kapelko M, Zi ha T, Golachowski A, Gryszkin A. Effect of the production method on the properties of RS3/RS4 type resistant starch. Part 1. Properties of retrograded starch (RS3) produced under various conditions and its susceptibility to acetylation. Pood Chem 2012 135 1494-1504. 

Saura-Calixto, R, Goni, L, Bravo, L., and Manas, E. 1993. Resistant starch in foods Modified method for dietary fiber residues. J. Food Sci. 58 642-643. 

In recent years, there has been increasing interest in those carbohydrates that escape absorption in the small intestine and enter the colon, where they may have specific health benefits due to their fermentation by the colonic microflora and their effect on gut physiology. This entry considers the definition, classification, dietary sources, methods of analysis, colonic fermentation, and health benefits of both resistant starch and oligosaccharides, and compares them with those of dietary fiber. 

The definition of resistant starch is based on its physiological behavior in the human small intestine, i.e., resistant starch is a heterogeneous group of molecules from small monosaccharides to large polymers with different molecular weight, degree of polymerization, and supramolecular architecture. This complexity makes it difficult to quantify accurately. All in vitro methods therefore need to be corroborated against in vivo models however, in vivo models are also very difficult to validate. 

Table 4 Comparison between different methods to measure resistant starch in vitro... 

Quantification of modified starch intake is even more difficult. First, food labels do not usually provide information about the nature of the modification used. Second, the commonly used method to estimate resistant starch can underestimate any nondigestible fractions that became soluble in water because of the... 

The bomb method for sulfur determination (ASTM D129) uses sample combustion in oxygen and conversion of the sulfur to barium sulfate, which is determined by mass. This method is suitable for samples containing 0.1 to 5.0% w/w sulfur and can be used for most low-volatility petroleum products. Elements that produce residues insoluble in hydrochloric acid interfere with this method this includes aluminum, calcium, iron, lead, and silicon, plus minerals such as asbestos, mica, and silica, and an alternative method (ASTM D1552) is preferred. This method describes three procedures the sample is first pyrolyzed in either an induction furnace or a resistance furnace the sulfur is then converted to sulfur dioxide, and the sulfur dioxide is either titrated with potassium iodate-starch reagent or is analyzed by infrared spectroscopy. This method is generally suitable for samples containing from 0.06 to 8.0% w/w sulfur that distill at temperatures above 177°C (351°F). 

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