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Theafulvins, isolated from black tea, chromatograph as a hump on reversed phase column packings. When whole black-tea brews are similarly analysed other phenolic compounds appear as more or less resolved peaks ‘floating’ on this hump. Model solutions of isolated theafulvins containing individual pure compounds (flavanols, flavonols and caffeine) have been prepared and their chromatographic behaviour compared with that of the pure compound chromatographed alone. In the case of quercetin, epicatechin and epicatechin gallate, a statistically significant hyperchromic effect has been observed in which the peak area ‘floating’ on top of the theafulvin hump is larger than expected from the area obtained for the pure compound alone. There was little or no effect with catechin and caffeine, and rutin showed a weak and inconsistent response. The data are discussed by reference to the established literature on copigmentation but it is not possible to define the mechanism responsible for the hyperchromism at this stage.

The viscous behaviour of mixtures of deamidated gluten or soluble wheat protein (SWP) (7.5–13.5%, w/v) and sodium alginate (0.5–1.5%, w/v) in distilled water pH 6.5 were investigated. Mixtures of SWP and sodium alginate mixed under varying conditions indicated greater than expected viscosity values at higher biopolymer concentrations. Measurements made when the biopolymers were mixed at room temperature followed by heating at 60°C showed maximum viscosity at a ratio of 50 parts SWP to 50 parts sodium alginate. When the biopolymers were heated separately and then mixed, the maximum viscosity occurred at a ratio of 80 parts SWP to 20 parts sodium alginate. SWP spontaneously aggregated on hydration. Heating at 60°C caused fragmentation or disaggregation of the SWP leading to a reduction in viscosity and an increase in hydrophobicity ( Friedli, & Howell, (1996) Food Hydrocolloids , 10 , 255–261). Sodium alginate inhibited the breakdown of SWP aggregates at 60°C, when both polymers were mixed prior to heating, which was confirmed by phase contrast microscopy. Although the mixture did not appear to separate visually, microphase separation was evident by microscopy. The phase separation may be due to repulsion between the negatively charged sodium alginate and SWP which resulted in bicontinuous and more concentrated networks of the two polymers. The addition of SWP (1–8%) to a 1% (w/w) sodium alginate solution increased the gelation time from 30 to 90 min and resulted in soft opaque creamy gels with lower G ′ values.

A method has been developed which enables the easy and inexpensive preparation of gram quantities of (–)-epigallocatechin gallate from green tea ( Camellia sinensis ). A decaffeinated aqueous brew of commercial green tea is treated with caffeine (30 m m ). The precipitate is redissolved after decaffeination with chloroform and further purified by solvent partition with ethyl hexanoate and propyl acetate. Commercial leaf (25 g) yields 400 mg (–)-epigallocatechin gallate at better than 80% purity, as judged by reversed phase HPLC.

The present study was undertaken to evaluate the role of individual flavanols in the antimutagenic potential of green tea. Aqueous extracts of green tea were fractionated into four fractions, each of which was fully defined with respect to its content of (-)-epigallocatechin gallate, (-)-epicatechin gallate, (-)-epigallocatechin, (-)-epicatechin and gallic acid. The ability of each fraction to antagonize the mutagenicity of four model mutagens, namely N-nitrosopyrrolidine, benzo(a)pyrene, 2-aminoanthracene and Glu-P-1 (2-amino-6-methyldipyrido[1,2-a: 3,2-d]imidazole), was investigated in the Ames test. No correlation could be established between any of the flavanols and antimutagenic potential. Similarly, no correlation was evident between the flavanol content of each fraction and its ability to inhibit CYP1A, as exemplified by the O-dealkylations of methoxy- and ethoxy-resorufin. Furthermore, no relationship could be established between CYP2B activity, as exemplified by the O-depentylation of pentoxyresorufin and the antimutagenic potential of green tea. Using a modified Ames test procedure, the ability of each tea fraction to scavenge the metabolically generated reactive intermediates of the model mutagens was investigated, this being an additional mechanism of the antimutagenic potential of green tea. Generally, fractions with high flavanol content were more effective scavengers. It is concluded that the contribution of flavanols to the antimutagenic activity of green tea is, at best, limited. ©1997 SCI

Research involvement among registered dietitians (RDs) is important in advancing dietetics practice and ensuring high-quality and cost-effective health care. There are no standardized approaches to measuring levels of research involvement. The aim of the study was to develop a standardized measure of research involvement and test its validity and reliability among RDs. The Research Involvement Questionnaire (RIQ) was developed and underwent content validation, resulting in a content validity index of 0.92. A postal questionnaire survey of RDs was undertaken at two time points. RDs were purposively selected and, based on their number of publications and grants, were assigned by the authors to one of four levels of research involvement: evidence-based practice, collaborating on research, leading research, and leadership in research. Of 192 questionnaires mailed, 111 RDs (58%) returned the first RIQ, of whom 82 (74%) also returned the second RIQ. Total scores and scores for each level were higher for RDs with higher levels of research involvement (P

Black tea theafulvins, a fraction of thearubigins isolated from black tea aqueous infusions, potentiated the mutagenic activity of the mycotoxin aflatoxin B(1) in the Ames test, in the presence of a hepatic S9 activation system derived from Aroclor 1254-treated rats. In contrast, when the S9 activation system was replaced with isolated microsomes, theafulvins suppressed the mutagenicity of the mycotoxin. When microsomal metabolism was terminated after metabolic activation of the mycotoxin, incorporation of the theafulvins into the activation system reduced the mutagenic activity, whereas if it was added before termination of microsomal activity a potentiation of mutagenic response was observed. In in vitro studies, theafulvins inhibited epoxide hydrolase and glutathione S-transferase activities in a concentration-dependent manner. Finally, the mutagenicity of aflatoxin B(1) was much more pronounced in bacteria that were pre-exposed to theafulvins but from which they were subsequently washed off. It may be inferred from the above studies that the genotoxic synergy between aflatoxin B(1) and black tea theafulvins does not occur during the bioactivation of the carcinogen, but may partly be due to decreased deactivation of the reactive intermediate, aflatoxin B(1) 8,9-oxide, by conjugation with glutathione.

The rising concern with environmental issues has placed a spotlight on the tourism industry's relationship with the environment. Research in this area has tended to concentrate on the physical impacts of recreational activity and there has been little or no research on the different roles and responsibilities of the main tourism industry sectors. Meanwhile more case studies are emerging that catalogue examples of tourism changing the ambience of destinations, and of uncontrolled tourism development causing environmental damage. The emergence of new concepts such as ecotourism and sustainable tourism has also been the focus of much attention. The issues in the tourism and environment debate are huge and the whole debate is marked by many different perceptions and opinions. This paper discusses the role of international airlines in the tourism and environment debate and presents the case for their greater involvement.

1. Nine habitual tea-drinking volunteers were recruited and asked to follow a low-polyphenol and low-caffeine diet for 6 days and to provide daily 24-h urine samples. On day 4 of the experiment strong black tea brewed under standardized conditions was re-introduced to the volunteers' diet. 2. 1H-NMR and HPLC profiling of the urine samples indicated that consumption of black tea (6-10 mugs per day) was associated with a significant (p = 0.00017) increase in hippuric acid excretion relative to control, increasing from 153-512 to 742-1374 mg day(-1). The excretion of substantial amounts of hippuric acid has not previously been associated with black tea consumption. 3. For some volunteers, the quantity of benzoic acid processed exceeded the acceptable daily intake (ADI), but this is not considered to constitute any hazard. 4. A mass-balance analysis indicated that the necessary quantity of benzoic acid could not be obtained from the contents of gallic acid, flavanols, flavonol glycosides and theaflavins in black tea even if 100% transformation was obtained, suggesting that the thearubigins (the major and chemically ill-defined polyphenols of black tea) may be an important source.

Rats maintained on green, black or decaffeinated black tea (2.5%, w/v) as their sole drinking fluid displayed higher hepatic CN- insensitive palmitoyl CoA oxidase activity than controls; the extent of increase was similar with the three types of tea. Morphological examination of the liver using electron microscopy revealed an increase in the number of peroxisomes in the tea-treated animals. The same treatment of the animals with green and black tea resulted in a similar rise in hepatic microsomal lauric acid hydroxylation. Analysis by HPLC of the aqueous tea extracts employed in the current study showed that the total flavanol content of the green variety was much higher than the black varieties, and confirmed the absence of caffeine in the decaffeinated black tea. It may be concluded from the present studies that neither caffeine nor flavanoids are likely to be responsible for the proliferation of peroxisomes observed in rats treated with tea.