Changes of fatty acid contents, lipoxygenase activities, and volatiles during black tea manufacture

Fatty acid composition in relation to lipolytic and lipoxygenase activities in tea leaf shoots, from different stages of the teamanufacturing process (i.e., withering, rolling, fermentation, and firing) was investigated in a series of black tea manufacturing experiments. More degradation of fatty acids and higher lipoxygenase activity were characteristics of tea leaves allowed to undergo the desiccatiodwithering process for longer periods of time. The oxidative breakdown of fatty acids was higher in the later part of the rolling process, while lipolytic activity was more prominent in the withering process as well as the earlier stage of rolling. A gradual decline of lipoxygenase activity as well as fatty acid content has been recorded during the fermentation and drying processes. Although the lipids and fatty acid degradation were directly related to the degree of withering, the volatile content of teas manufactured from hard withered leaves (lower moisture content) was unexpectedly lower than that in black teas from normal withered tea leaf shoots.

[1]  S. Ida,et al.  The Isolation of Multiple Forms and Product Specificity of Rice Lipoxygenase , 1983 .

[2]  Mridul Hazarika,et al.  Some studies on carotenoids and their degradation in black tea manufacture , 1983 .

[3]  R. Selvendran,et al.  Production of volatiles by degradation of lipids during manufacture of black tea , 1978 .

[4]  R. Seshadri,et al.  New hydrophobic lipid interactions in tea cream , 1988 .

[5]  R. Selvendran,et al.  Ultrastructural changes in tea leaves during ‘orthodox’ black tea manufacture , 1976 .

[6]  P. Schreier,et al.  Additional volatiles of black tea aroma , 1984 .

[7]  T. Takeo.  Production of linalol and geraniol by hydrolytic breakdown of bound forms in disrupted tea shoots , 1981 .

[8]  P. Tamuly,et al.  Lipid content and fatty acid composition of tea shoot and manufactured tea , 1991 .

[9]  R. Thomas,et al.  Characterization of Tannase Activity on Tea Extracts , 1985 .

[10]  T. Kajiwara,et al.  Interaction of Tea Catechins with Proteins: Formation of Protein Precipitate , 1984 .

[11]  Tadakazu Takeo,et al.  Comparison of black tea aromas of orthodox and CTC tea and of black teas made from different varieties , 1983 .

[12]  K. Surrey,et al.  Spectrophotometric Method for Determination of Lipoxidase Activity. , 1964, Plant physiology.

[13]  I. Safarik.  A spectrophotometric assay for lipase activity utilizing immobilized triacylglycerols. , 1991, Journal of biochemical and biophysical methods.

[14]  T. Shibamoto,et al.  Effects of moisture content on the Maillard browning model system upon microwave irradiation , 1991 .

[15]  R. Buttery,et al.  Chemical Changes in Flavor Components during Processing , 1985 .

[16]  H. Ashida,et al.  Autoxidizing Process Interaction of Linoleic Acid with Casein , 1987 .

[17]  P. Mahanta,et al.  Studies on fatty acid composition in tea Camellia sinensis , 1989 .

[18]  T. Hymowitz,et al.  Carotene and chlorophyll bleaching by soybeans with and without seed lipoxygenase-1 , 1982 .

[19]  C. Demandre,et al.  Linolenic acid biosynthesis via glycerolipid molecular species in pea and spinach leaves , 1988 .

[20]  D. Hildebrand,et al.  Effects of polyunsaturated free fatty acids and esterified linoleoyl derivatives on oxygen consumption and C6 aldehyde formation with soybean seed homogenates , 1991 .

[21]  T. Tsushida,et al.  Changes in lipoxygenase activity in relation to lipid degradation in plucked tea shoots , 1980 .

[22]  E. Frankel.  Review. Recent advances in lipid oxidation , 1991 .

[23]  M. Rouet-Mayer,et al.  Lipoxygenase isoenzymes of french bean pericarp: Separation, characterization and chlorophyll-bleaching activity , 1989 .

[24]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[25]  A. Hatanaka,et al.  Enzymic Oxygenative-cleavage Reaction of Linolenic Acid in Leaves — Chloroplastic Lipoxygenase and Fatty Acid Hydroperoxide Lyase in Tea Leaves , 1987 .

[26]  E. Mendoza,et al.  Purification and characterization of two lipoxygenase isoenzymes from cowpea [Vigna unguiculata (L.) Walp.] , 1982 .

[27]  K. Matsui,et al.  Fatty acid hydroperoxide cleaving enzyme, hydroperoxide lyase, from tea leaves , 1991 .

[28]  G. Bergström,et al.  Headspace volatiles of whole plants and macerated plant parts of Brassica and Sinapis , 1988 .

[29]  T. Swain,et al.  Plant Lipid Biochemistry , 1973 .

[30]  W. G. Duncombe,et al.  The colorimetric micro-determination of long-chain fatty acids. , 1963, The Biochemical journal.

[31]  Patrick J. Williams,et al.  New linalool derivatives in muscat of alexandria grapes and wines , 1980 .

[32]  Jyh-Ping Chen,et al.  Hydrolysis of Milk Fat with Lipase in Reversed Micelles , 1991 .

[33]  Tadakazu Takeo,et al.  Volatile and Non-volatile Forms of Aroma Compounds in Tea Leaves and Their Changes due to Injury , 1973 .

[34]  Pradip K. Mahanta,et al.  Relationship between process of withering and aroma characteristics of black tea , 1989 .

[35]  P. Roheim,et al.  A sensitive, inexpensive method for determining minute quantities of lipase activity. , 1989, Analytical Biochemistry.

[36]  M. Hazarika,et al.  Effect of Plucking Intervals on the Chemical Constituents of CTC Black Teas , 1986 .

[37]  John E. Thompson,et al.  Membrane deterioration during postharvest senescence of broccoli florets: modulation by temperature and controlled atmosphere storage , 1991 .

[38]  N. Tan,et al.  Acidimetric assay for phospholipase A using egg yolk suspension as substrate. , 1988, Analytical biochemistry.