Auxiliary materials. Inversion catalysts.
The substances which catalyze the cleavage of sucrose and starch.
Inversion, or invert sucrose by reaction proceeds
С12Н22011 + N20 - »C6Н12Ое + C6Н)206
Sucrose glucose fructose
The reaction is known as inversion, as a result of its changes in direction of rotation of the polarization plane. If the initial sucrose rotates the plane of polarization to the right, then the resulting mixture of monosaccharides - left. The resulting reaction mixture of equal parts of glucose and fructose is called invert sugar, and its aqueous solution - invert syrup (see Appendix 2..).
Invert Syrup is highly hygroscopic.
By reducing the pH of the medium velocity inversion increases dramatically. With increasing concentration of sucrose in the sugar solution decreases the rate of inversion.
Inversion acid catalysts are: inorganic (hydrochloric acid, sulfuric acid) and organic (lactic, citric, tartaric, acetic), as well as the enzyme invertase.
By selecting the type of raw materials and catalysts, the catalyst concentration, process temperature and duration can change the depth of the reactions to the splitting of starch dextrin, maltose or glucose to B.
Of great importance for the food industry are products of carbohydrate digestion in the presence of dilute acids. The raw materials used starches: corn, rice, wheat, tapioca and potato. Partial hydrolysis products are powders (dextrins, maltooligosaccharides, maltotriose, maltose) and liquid (glucose and maltose syrups). Complete hydrolysis of starch by reaction proceeds
(C6Нш05) n + (i - 1) N20 -> n • C6Н1206
Hydrochloric and sulfuric acids, sometimes nitric and acetic, are most often used as the catalysts for the breakdown of carbohydrates. Dosage of 0,1-0,3% in terms of starch. The reaction rate depends on the ratio of amylose and amylopectin and on the presence of impurities. Linear molecules of amylose hydrolyze much slower than branched molecules of amylopectin. Different kinds of starch contain different amounts of impurities: proteins, fats and minerals. Corn starch, containing a small amount of phosphate, hydrolyzes faster than others. Potato is especially rich in phosphoric acid residues, capable of binding cations, so it is more difficult to hydrolyze corn.
Enzymes and enzyme preparations
Enzymes - biological catalysts of protein nature, are capable of many times to speed up chemical reactions occurring in the animal and plant world. Enzymes have a number of advantages over non-biological catalysts. Firstly, the enzymatic catalysis reactions accelerated by several orders of magnitude (from 103 to 109), Secondly, most of them have an exceptionally high substrate specificity; thirdly, the enzymes catalyze reactions under mild conditions: at normal pressure, temperature from 20 to 70 ° C, pH from 4 to 9. In the food industry, enzymes are used in the form of enzyme preparations, which, as a rule, are multienzyme complexes and contain, in addition to the active protein, various ballast substances. A large number of enzyme preparations are obtained on an industrial scale using microorganisms - active producers of the corresponding enzymes.