ferment : Idioms & Phrases

volatile oils produced by the fermentation of plants, and not originally contained in them. These were the quintessences of the alchenists.

. Fermentations of this class are purely chemical reactions, in which the ferment acts as a simple catalytic agent. Of this nature are the decomposition or inversion of cane sugar into levulose and dextrose by boiling with dilute acids, the conversion of starch into dextrin and sugar by similar treatment, the conversion of starch into like products by the action of diastase of malt or ptyalin of saliva, the conversion of albuminous food into peptones and other like products by the action of pepsin-hydrochloric acid of the gastric juice or by the ferment of the pancreatic juice.

(Physiol. Chem.), a ferment which makes its appearance in the blood shortly after it is shed, and is supposed to be the active agent in causing coagulation of the blood, with formation of fibrin.

(Physiol. Chem.), a ferment, enzyme, or chemical ferment, which acts only in the presence of water, and which causes the substance acted upon to take up a molecule of water. Thus, diastase of malt, ptyalin of saliva, and boiling dilute sulphuric acid all convert starch by hydration into dextrin and sugar. Nearly all of the digestive ferments are hydrolytic in their action.

an organized ferment (Bacterium lacticum ∨ lactis), which produces lactic fermentation, decomposing the sugar of milk into carbonic and lactic acids, the latter, of which renders the milk sour, and precipitates the casein, thus giving rise to the so-called spontaneous coagulation of milk.

(Physiol. Chem.), a ferment, present in rennet and in variable quantity in the gastric juice of most animals, which has the power of curdling milk. The ferment presumably acts by changing the casein of milk from a soluble to an insoluble form.

a soluble ferment formed by certain bacteria, which, however, yield the ferment from the body of their cells only after they have been killed by alcohol. It causes urea to take up water and decompose into carbonic acid and ammonia. Many different bacteria possess this property, especially Bacterium ureæ and Micrococcus ureæ, which are found abundantly in urines undergoing alkaline fermentation.