Changes of polyphenol oxidase and peroxidase activities and pigment composition of some manufactured black teas (Camellia sinensis L.)

The specific activity of two principal enzymes, viz. polyphenol oxidase (PPO) and peroxidase (PO), responsible for formation of brown compounds known as theaflavins was studied in fermented or black teas. PPO and PO activities were assayed via a spectrophotometric method, while the theaflavin group...

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Bibliographic Details
Published in:	Journal of agricultural and food chemistry Vol. 41; no. 2; pp. 272 - 276
Main Authors:	Mahanta, Pradip K, Boruah, Santanu K, Boruah, Hemanta K, Kalita, Jatindra N
Format:	Journal Article
Language:	English
Published:	Washington, DC American Chemical Society 01-02-1993
Subjects:	ACTIVIDAD ENZIMATICA ACTIVITE ENZYMATIQUE Biological and medical sciences Camellia sinensis CATECHOL OXYDASE CATECOL OXIDASA Coffee, tea and other stimulative beverage industries FERMENTACION FERMENTATION Food industries Fundamental and applied biological sciences. Psychology PEROXIDASAS PEROXYDASE PIGMENT PIGMENTOS TECHNOLOGIE ALIMENTAIRE TECNOLOGIA DE LOS ALIMENTOS THE Tea Camellia sinensis Enzymatic activity Enzyme Dicotyledones Angiospermae Pigments Spermatophyta Processing parameter Peroxidase Phenol oxidase Theaceae
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Summary:	The specific activity of two principal enzymes, viz. polyphenol oxidase (PPO) and peroxidase (PO), responsible for formation of brown compounds known as theaflavins was studied in fermented or black teas. PPO and PO activities were assayed via a spectrophotometric method, while the theaflavin group of pigments was analyzed by high-performance liquid chromatography. Although the highest activities of both PPO and PO were observed on rolling, decrease of the former and increase of the latter are the result of mechanical injury, leading to the oxidative polymerization (enzymatic browning) of fermented black tea. Individual pigments were found to be characteristic in different clonal cultivars as well as in black teas manufactured under different conditions of withering and fermentation. The impact of technology on the development of a golden yellow color or on theaflavins production is discussed
Bibliography:	Q04 9501813 Q02 istex:344BA2075EE3A5F98E93E9FEA120522F3A9323E4 ark:/67375/TPS-WTW2XT1L-2 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23
ISSN:	0021-8561 1520-5118
DOI:	10.1021/jf00026a026