What does diastase mean?
Diastase is an enzyme — more precisely, a mixture of amylases — that converts starch into maltose and other simpler sugars. The term originated in nineteenth-century science, when it was applied to the starch-digesting substance extracted from malted barley, and it holds the distinction of being among the first enzymes ever named. Today the word appears mainly in technical settings: brewers rely on the diastatic power of malt to produce fermentable sugars, bakers use diastase-rich preparations to improve dough, and pharmaceutical formulations of fungal diastase have long served as digestive aids. Although modern biochemistry generally prefers the specific term 'amylase,' 'diastase' survives in industry and in older literature. Its name derives from the Greek 'diastasis,' meaning separation, reflecting its ability to break large starch molecules apart. Because of its similar spelling to the unrelated medical terms 'diastasis' and 'diastole,' care is needed in reading older scientific and medical texts where all three words may appear.
nounA mixture of amylase enzymes, originally obtained from germinating grain such as malted barley, that converts starch into maltose and other sugars. More broadly, the term refers to any diastatic enzyme preparation that breaks down starch.
- An enzyme or enzyme mixture, chiefly amylase, that hydrolyses starch into maltose and other sugars; originally prepared from malt.
- A pharmaceutical or industrial preparation containing such enzymes, used in digestion aids, brewing, and food processing.
"The brewer relied on the natural diastase in malted barley to convert the grain's starch into fermentable sugars."
"Saliva contains a diastase that begins breaking down starchy foods as soon as you start chewing."
"Early twentieth-century pharmacists sold fungal diastase as a digestive aid for patients who struggled to digest starch."
Rarely pluralized; the plural may appear in technical literature referring to different diastase preparations or enzyme mixtures, but diastase is normally treated as uncountable.
"Various commercial diastases are available for use in brewing and baking."
Named from the Greek for 'separation,' diastase was the first enzyme ever given a name — back in 1833, when scientists still called these mysterious substances 'ferments.'
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of diastase
Diastase entered English in the early nineteenth century, coined by French chemists Anselme Payen and Jean-François Persoz, who isolated the substance from malt in 1833 and named it after the Greek 'diastasis,' meaning separation or division — a reference to its splitting of starch molecules. The same Greek root gives English 'diastasis,' used medically for the separation of body parts, and 'diastole,' the relaxing phase of the heart's cycle, making these close cognates despite their very different meanings. The suffix '-ase,' later standardized for naming enzymes, ultimately became the hallmark of enzyme nomenclature.
Related word forms
How diastase is actually used
Diastase is a technical term found chiefly in biochemistry, brewing, baking, and historical pharmacy texts; in modern scientific writing it has largely been replaced by the more precise term 'amylase.' It functions as a mass noun and is not typically used in the plural except in laboratory contexts referring to different preparations. It should not be confused with the medical term 'diastasis.'
Easily confused with diastase
Diastasis is a medical term for the abnormal separation of parts of the body normally joined together, whereas diastase is a starch-digesting enzyme.
Diastole refers to the relaxation phase of the heartbeat, while diastase is an enzyme that breaks down starch into sugar.