Carbohydrase activity

Exogenous enzymes are those that are added by the brewer rather than those that occur naturally from the malted cereals and yeast. Enzymes are available that exhibit proteolytic, cytolytic (plant cell wall material) and carbohydrase activity. Cost-effective enzyme preparations are not in general pure enzymes, however, a blend is often an advantage, enabling more than one activity to occur. 

Portions (50 mU MCA-hydrolsing activity) of purified CinnAE were incubated at 37°C with SBP (10 mg), both in the presence and absence of other carbohydrases, in 100 mM MOPS (pH 6.0) in a final volume of 1 mL. Incubations containing boiled enzyme were performed as controls. Reactions were terminated by boiling (3 min) and the amount of free ferulic acid determined using a method described previously for de-starched wheat bran [18]. The total amount of alkali-extractable ferulic acid present in the SBP was 0.87% [5]. 

SBP was incubated in the presence of carbohydrases either individually, or in pairs, and in the absence or presence of esterase, and the soluble incubation products assayed for feruloyl groups by HPLC. None of the carbohydrases used contained FAE activity. 

It is important to note that no evidence of maltase activity was found in the amylase preparations even when the highest concentrations used in these comparisons were allowed to react for twenty-four hours with one per cent maltose under the conditions for the hydrolysis of starch. Similarly, no evidence was obtained for the presence of any other contaminating or extraneous carbohydrases in the amylase preparations. Partial inactivation of the amylase under a number of different conditions failed to give any evidence of selective inactivation such as might be expected if more than one enzyme were present. The substrates used for measuring the activity of the partially inactivated amylase were starch and starch hydrolyzates that had already been extensively (58) J. Blom, Agnete Bak and B. Braae, Z. physiol. Chem., 250, 104 (1937). 

A recent study, however, has shown that aminopeptidase activity is present on the surface of porcine buccal mucosa, and that various aminopeptidase inhibitors, including amastatin and sodium deoxycholate, reduce the mucosal surface degradation of the aminopeptidase substrate, leucine-enkephalin [149], Since the peptidases are present on the surface of the buccal mucosa, they may act as a significant barrier to the permeability of compounds which are substrates for the enzyme. In addition to proteolytic enzymes, there exist some esterases, oxidases, and reductases originating from buccal epithelial cells, as well as phosphatases and carbohydrases present in saliva [154], all of which may potentially be involved in the metabolism of topically applied compounds. 

Carbohydrase (Aspergillus oryzae var.) Produced as an off white to tan, amorphous powder or a liquid by controlled fermentation using Aspergillus oryzae var. Soluble in water (the solution is usually light yellow to dark brown), but practically insoluble in alcohol, in chloroform, and in ether. Major active principles (1) a-amylase, (2) glucoamylase (amyloglucosidase), and (3) lactase. Typical applications used in the preparation of starch syrups, alcohol, beer, ale, bakery products, and dairy products. 

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