Tannases

In addition, pectinolytic enzymes play an important role in food processing, increasing the yield of fruit and vegetable juices and the yield of oil from olive fruits. 

For example, preparations from Aspergillus niger prevent the development of turbidity in cold tea extracts. 

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Recovery of mycelium-bound tannase from Aspergillus niger fermentation broth [84]... 

Instant tea produced as described above will dissolve completely in hot water but not in cold water, as the caffeine-polyphenol complexes are insoluble under those conditions. Since virtually all instant tea manufacture in the U.S. is for iced tea preparation, process modification is required. This initial extract may be cooled to 5 to 10°C and the cold water insoluble material or cream be allowed to precipitate. Under these conditions, 20 to 35% of the extract solids may be separated by centrifugation. The supernatant solids will reconstitute in cold water after concentration and drying.105 It is also possible to process the cream to make a portion of it compatible with the product and thereby retain the caffeine and some polyphenolic components that are present in this fraction.106 Commercial use of the enzyme Tannase, which removes gallic acid from gallated tea polyphenols107 and reduces cream formation108 can be used to reduce cream losses and manufacture instant teas retaining more of the natural polyphenol content. 

In 1913, Knudson (17) reported that tannic acid (the commercial name of the Chinese gall tannin) could be degraded by a strain of Aspergillus niger previously the French scientist Pottevin (in 1900) had named this enzyme tannase (10). Since then, most of the progress on elucidating the mechanisms of hydrolysable tannin biodegradation has occurred since 1960. 

Tannase has also been detected in bacterial cultures (29), where its optimum activity was pH 5.5 with different strains isolated from decayed barks. 

Degradation of Gallotannins. Different investigations on tannase revealed that this enzyme was not equally efficient on all hydrolyzable tannins. This was particularly true for yeast, whose tannase was effective only on tannic... 

Table I. Microorganisms Producing Tannase (tannin-acyl hydrolase)...

Acetate buffer (20 mM - pH 5.0)equilibrated with the same buffer. The solution was passed through the column at a flow rate of 1 mL.mim with acetate buffer (20 mM -pH 5.0), followed by a linear gradient from 0-1M NaCI in the acetate buffer. The eluted fractions were collected in an automated fraction collector (Pharmacia Biotech) and the absorbance of the fractions was measured at 280 nm. The major peak fractions werethen assayed fortannaseactivity, and onlythefractions possessing tannase activity were pooled. 

Battesttn V, Macedo GA. Effects of temperature, pH and additives on the activity of tannase produced by Paecilomyces variottii. Electronic Journal of Biotechnology 2007 10 http //www.ejbiotechnology.cl/ content/voll0/issue2/full/9/index.html 6 (accesses 20.09.2012). 

Enzymes found in grapes include peroxidase, polyphenoloxidases, catalases, invertase, tannases, and pectic enzymes (2). Within this list, polyphenoloxidase has received considerable attention in grapes because of its detrimental effect on wine quality. 

Sabu, A., Pandey, A., Jaafar Daud, M. and Szakacs, G. (2005) Tamarind seed powder and palm kernel cake two novel agro residues for the production of tannase under solid state fermentation by Aspergillus niger ATCC 1 6620. Bioresource Technology 96(1 1), 1223-1228. 

Tannase. Immobilized tannase has been used to produce n-propylgallate from tannin and n-propanol in contact with a water-immiscible phase. The propyl gallate moves into the non-aqueous phase while the free gallic acid and sugar remain in the aqueous phase (48). 

Tannase Pentosanase Naringinase Brewing Milling Citrus... 

Work on tannase and other enzymes, further supports the premise that many previously unknown commercially feasible applications for enzymes exist if the eflFort is made to identify the need and seek a solution. While, at this time, there is insufficient data to determine whether the proportion of projects which were or will become commercially profitable, justifies the research investment, it seems likely with the continued inflation rate in Japan that this type of research, if not already uneconomical, will in the future be no more economically done in Japan than in the United States. 

Beverages Improve brewing process Clarification fruit juices Coffee, tea and cocoa proc. Protease, glucanase Pectinase, cellulase, amylase Pectinase, tannase... 

Hydrolysable Tannins These may be hydrolysed by acids or enzymes such as tannase. They are formed from several molecules of phenolic acids such as gallic and ellagic acids which are united by ester linkages to a central glucose residue. 

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