Kanauchi_2024_Methods.Mol.Biol_2851_87

Tannin, which is an astringent taste in the mouth, is a polyphenol compound contained in some plants. Tannin causes denaturation of proteins of the tongue or oral mucosa. Tannase, a hydrolase that cleaves carboxylic ester bonds specifically, is used in many industrial fields. Some tannase (tannin acyl hydrolase, EC3.1.1.20) is used widely to prevent or reduce creaming of some foods and beverages. Because some tannins are formed of insoluble salts combined with protein, they reduce creaming such as the white hazing of iced tea. Moreover, they can clarify beverages such as fruit juices during wine and beer production. Tannase is produced by microorganisms under conditions with tannic acid present, mainly from plants. Tannase characteristics differ according to its microorganism of origin. Therefore, it is important to study the microbes used as lactic acid bacteria (LAB), evaluate new methods of tannase assay, and apply them in food or other industries. In this chapter, assay of tannase in LAB is demonstrated using methyl gallate as substrate, with color development by rhodanine and potassium hydroxide solution, using a spectrophotometer. Actual data of high tannase-producing LAB, Lactobacillus plantarum, and enzyme characteristics in optimum conditions are presented in this chapter.