Physically inaccessible starch

The non-break down of physically inaccessible starch explains why wheat is ground into flour in the first place. This may also explain the claims that modern flour with its very small particle size is less healthy than the sort of flour produced by ancient wind and water mills. The resistant nature of ungelatinised starch also explains why starch-based foods were baked in the first place. 

Physically inaccessible starch Raw starch granules Nongranular, retrograded, or crystalline starch Chemically modified starches... 

Food starches can be classified according to the way they are metabolized by the human small intestine into those that are rapidly digested, those that are slowly digested, and those that are resistant to digestion. Similarly, resistant starch has been classified into three types physically inaccessible starch, resistant starch granules, and retrograded starch (Table 1). 

RSi, physically inaccessible starch RS2, resistant granules RS3, retrograded starch. 

Physically inaccessible starch (RSi) Type I resistant starch is physically inaccessible and is protected from the action of a-amylase, the enzyme that hydrolyzes the breakdown of starch in the human small intestine. This inaccessibility is due to the presence of plant cell walls that entrap the starch, for example, in legume seeds and partially milled and whole grains. RSi can also be found in highly compact processed food like pasta. The RSj content is affected by disruption of the food structure during processing (e.g., milling) and, to some extent, by chewing. 

Most foods are heat processed prior to consumption. Although heat processing increases the availability of starch to enzyme, a fraction of starch remains resistant to amylase hydrolysis in the human gastrointestinal tract. This fraction is called resistant starch (RS). RS has been classified107 into three groups (a) RSI starch that is physically inaccessible to digestive enzymes due to enclosure in structures such as... 

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