Diastaseresistant

Diastaseresistant refers to substances that resist hydrolysis by diastase, an enzyme (alpha-amylase) found in saliva and used in laboratory assays to break down starch into smaller sugars. When a material is diastase-resistant, it remains largely intact after exposure to this enzyme under specified conditions.

In starch science and nutrition, diastase resistance is closely related to the concept of resistant starch, the portion of dietary starch not digested in the small intestine. Several structural factors contribute to diastase resistance, including high amylose content, crystalline or ordered starch architecture, the formation of amylose–lipid complexes, and physical entrapment of starch within cell walls or retrograded (recrystallized) starch. These features impede access of amylases to the starch polymer.

Measurement of diastase resistance typically involves an in vitro digestion where a test sample is incubated with diastase under defined pH and temperature, followed by quantification of the remaining undigested starch or produced glucose. Results are often expressed as a percentage of resistant starch relative to the original starch. The term is sometimes used interchangeably with diastase-resistant starch, though methods and conditions can vary between protocols.

Applications include evaluating and engineering food ingredients to achieve lower glycemic responses, enhance dietary fiber content, or tailor starch digestibility. It is important to note that diastase resistance in vitro does not always fully predict in vivo digestibility, as human digestion involves additional enzymes and microbial fermentation in the gastrointestinal tract.

See also: resistant starch, alpha-amylase, diastase, retrogradation.