Ferments, action

Starkenstein, E., Ferment action and the influence upon it of neutral salts, Biochem. Z., 24, 210-218, 1910. 

Further enzymatic conversions (ferment actions) observed in that early period, summarized in Frankland s list of soluble ferments (1885) and by Sumner and Somers (1953) are summarized in Table 1.1. 

Spoilage symptoms dominant feature fermentation Action points ... 

J, Chem. Soc., 1898, Ixxiii, 634 (Reversible Zymohydrolysis) 1903, Ixxxiii, 578 (Reversibility of Enzyme or Ferment Action). 

Tlic enzyme method of fat-splitting is carried out by melting the fat in a pan with a conical bottom and fitted with a steam coil, the temperature not being raised too high, since the best temperature lor the ferment action lies between 25 and 3D , while... 

In enzymes, this folding process is crucial to their activity as catalysts, with part of the structure as the center of reactivity. Heating enzymes (or other treatments) destroys their three-dimensional structure so stops further action. For example, in winemaking, the rising alcohol content eventually denatures the enzymes responsible for turning sugar into alcohol, and fermentation stops. 

Fiber components are the principal energy source for colonic bacteria with a further contribution from digestive tract mucosal polysaccharides. Rate of fermentation varies with the chemical nature of the fiber components. Short-chain fatty acids generated by bacterial action are partiaUy absorbed through the colon waU and provide a supplementary energy source to the host. Therefore, dietary fiber is partiaUy caloric. The short-chain fatty acids also promote reabsorption of sodium and water from the colon and stimulate colonic blood flow and pancreatic secretions. Butyrate has added health benefits. Butyric acid is the preferred energy source for the colonocytes and has been shown to promote normal colonic epitheUal ceU differentiation. Butyric acid may inhibit colonic polyps and tumors. The relationships of intestinal microflora to health and disease have been reviewed (10). 

Currently, a-amino acids are prepared by several routes such as by the fermentation of glucose, by enzyme action on several substances and by the hydrolysis of proteins. Many methods for synthesising the polymers are known, of which the polymerisation of A -carboxyanhydrides is of particular interest, as it yield-products of high molecular weight (Figure 18.24). 

Addition of acetic or mineral acid to skimmed milk to reduce the pH value to 4.6, the isoelectric point, will cause the casein to precipitate. As calcium salts have a buffer action on the pH, somewhat more than the theoretical amount of acid must be used. Lactic acid produced in the process of milk souring by fermentation of the lactoses present by the bacterium Streptococcus lactis will lead to a similar precipitation. 

Neutral salts and aqueous solutions of various acids generally follow the acid action. Aluminum has no apparent action or microbiological processes (i.e., the production of antibiotics by deep-vessel fermentation). Fermentation tanks, as well as various absorbing and extracting units, can be made from aluminum. 

There are many reactions in which the products formed often act as catalysts for the reaction. The reaction rate accelerates as the reaction continues, and this process is referred to as autocatalysis. The reaction rate is proportional to a product concentration raised to a positive exponent for an autocatalytic reaction. Examples of this type of reaction are the hydrolysis of several esters. This is because the acids formed by the reaction give rise to hydrogen ions that act as catalysts for subsequent reactions. The fermentation reaction that involves the action of a micro-organism on an organic feedstock is a significant autocatalytic reaction. 

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