Research Database

Author: S.M. Abdeen and T.C. Mathew and H.M. Dashti and S. Asfar

Author: Mark E. Corey and William L. Kerr and Jake H. Mulligan and Vera Lavelli

In this study, apple products made with and without added green tea extract were freeze-dried and stored for up to 45 days at 30 °C in low and intermediate moisture environments (water activity, aw, 0.11, 0.22, 0.32, 0.57, and 0.75). Kinetic models were developed for the changes in color and decreases in contents of selected green tea and apple monomeric and polymeric flavanols and ascorbic acid. Moisture isotherms were developed for each product. At various moisture levels, the glass transition temperature (Tg) was measured by \{DSC\} and water mobility by 1H NMR. Chemical changes were related to Tg, aw, and water mobility in the products. Phytochemical degradation occurred more rapidly at higher moisture contents, except for caffeine which was stable. In the product containing apple with green tea, the content of monomeric flavan-3-ols decreased by 34% and 39% after 45 days of storage at aw of 0.56 and 0.75, respectively. Phytochemical degradation correlated with increasing aw, Tg, and water mobility. This study showed that, in general, storage at aw 0.75 most affected phytochemical stability and color.

 

 

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Author: Ramasamy Harikrishnan and Chellam Balasundaram and Moon-Soo Heo

Effect of diet enriched with green tea at 0, 0.01, 0.1 or 1.0% levels on immune responses such as non-specific humoral (lysozyme, antiprotease and complement) and cellular (myeloperoxidase content, production of reactive oxygen, and nitrogen species) and disease resistance on week 1, 2 or 4 in kelp grouper Epinephelus bruneus challenged with Vibrio carchariae(2.47 × 108 CFU ml−1) was quantified. At all doses green tea supplementation significantly enhanced the serum lysozyme activity from weeks 1 to 4. On the other hand, after week 2 the serum hemolytic complement activity, leucocyte myeloperoxidase content and reactive nitrogen species protection significantly increased in groups fed with 0.01 and 0.1% green tea supplementation diets. The serum antiprotease activity significantly increased in group fed with at 1.0% green tea from week 1 to 4. However, all diets except at 0.01% level resulted in a significant decrease in reactive oxygen species protection during the experimental period. Challenged groups fed with green tea enriched diet at 0.01 and 0.1% level had a higher relative percent survival than with 1.0% diet on week 1, 2 or 4. The results suggest that dietary administration of green tea supplementation at a concentration of 0.01 and 0.1% level positively enhances the non-specific humoral and cellular immune responses and disease resistance of kelp grouper E. bruneus to V. carchariae.

 

 

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Author: David Banji and Otilia J.F. Banji and Saidulu Abbagoni and Md. Sikinder Hayath and Srilatha Kambam and Vijaya Lakshmi Chiluka

Exposure to toxicants prenatally and postnatally could have deleterious consequences on the offspring. Postnatal exposure to valproate in mice pups is capable of inducing experimental autism resulting in neurobehavioral aberrations. Consumption of green tea has been associated with neuronal protection against the impact of toxicants. We investigated the role of green tea extract in reversing cardinal behavioral changes and aberrations in oxidative stress induced by valproate exposure. Young mice of both genders received a single dose of valproate (400 mg/kg subcutaneously) on postnatal day 14 followed by a daily dose of green tea extract (75 and 300 mg/kg) orally up to postnatal day 40. Mice pups were subjected to behavioral testing to assess motor co-ordination, nociceptive response, locomotion, anxiety, exploratory activity and cognition on various postnatal days up to postnatal day 40. At the end of behavioral testing, blood was withdrawn from the retro orbital plexus for the estimation of lipid peroxides. Animals were sacrificed on postnatal day 41 and whole brain was subjected to histopathological examination. Our studies revealed a significant improvement in behavioral assessments particularly with 300 mg/kg of green tea extract. Formation of markers of oxidative stress was reduced at both dose levels. Histological findings confirm the neuroprotective effect of green tea at a dose of 300 mg/kg. In conclusion it can be stated that green tea exerts neuronal cytoprotective action possibly due to anti-oxidant action and could be efficacious in the management of autism.

 

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Author: Sudathip Sae-tan and Kimberly A. Grove and Joshua D. Lambert

Green tea (Camellia sinensis, Theaceace) is the second most popular beverage in the world and has been extensively studied for its putative disease preventive effects. Green tea is characterized by the presence of a high concentrations of polyphenolic compounds known as catechins, with (−)-epigallocatechin-3-gallate (EGCG) being the most abundant and most well-studied. Metabolic syndrome (MetS) is a complex condition that is defined by the presence of elevated waist circumference, dysglycemia, elevated blood pressure, decrease serum high-density lipoprotein-associated cholesterol, and increased serum triglycerides. Studies in both in vitro and laboratory animal models have examined the preventive effects of green tea and EGCG against the symptoms of MetS. Overall, the results of these studies have been promising and demonstrate that green tea and EGCG have preventive effects in both genetic and dietary models of obesity, insulin resistance, hypertension, and hypercholesterolemia. Various mechanisms have been proposed based on these studies and include: modulation of dietary fat absorption and metabolism, increased glucose utilization, decreased de novo lipogenesis, enhanced vascular responsiveness, and antioxidative effects. In the present review, we discuss the current state of the science with regard to laboratory studies on green tea and MetS. We attempt to critically evaluate the available data and point out areas for future research. Although there is a considerable amount of data available, questions remain in terms of the primary mechanism(s) of action, the dose–response relationships involved, and the best way to translate the results to human intervention studies.

 

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Author: Kanokwan Jumtee and Hajime Komura and Takeshi Bamba and Eiichiro Fukusaki

The sensory quality ranking of Japanese green tea (Sen-cha) was evaluated and predicted using volatile profiling and multivariate data analyses. The volatile constituents were extracted from tea infusion using vacuum hydrodistillation and analyzed using GC/MS. A quality of green tea could be discriminated to a high or low grade regarding the volatile profile by partial least squares discriminant analysis (PLS–DA). A quality ranking predictive model was developed from the relationship between subjective attributes (sensory quality ranking) and objective attributes (volatile profile) using partial least squares projections to latent structures together with the preprocessing filtering technique, orthogonal signal correction (OSC). Several volatile compounds highly contributed to model prediction were identified as various odor-active compounds, including geraniol, indole, linalool, cis-jasmone, dihydroactinidiolide, 6-chloroindole, methyl jasmonate, coumarin, trans-geranylacetone, linalool oxides, 5,6-epoxy-β-ionone, phytol, and phenylethyl alcohol. The whole fingerprints of these volatile compounds could be possible markers for the overall quality evaluation of green tea beverage.

 

 

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Author: Raul Dominguez-Perles and Diego A. Moreno and Micaela Carvajal and Cristina Garcia-Viguera

Organic green tea, one of the most-consumed beverages worldwide, is rich in bioactive compounds (flavonols and flavanols) with healthy properties. Broccoli byproducts, consisting of leaves and stalks, are rich in bioactive compounds, including nitrogen–sulphur compounds (glucosinolates and isothiocyanates) and phenolics (chlorogenic and sinapic acid derivatives, and flavonoids), as well as essential nutrients (minerals and vitamins). They are of high interest as a source of health-promoting compounds, useful as ingredients for the development of functional foods. This work analyses minimally-processed broccoli byproducts as a source of bioactive ingredients to design novel beverages, using organic green tea as a food matrix. Green tea enriched with broccoli concentrates showed improved physical quality, phytochemical composition and antioxidant capacity. The functional quality of these novel beverages depends on the proportion of broccoli extracts added to the green tea. The results obtained in the present work should encourage the use of broccoli byproducts as ingredients in novel functional foods. Industrial relevance The industrial use of broccoli byproducts as an ingredient in the development of novel, functional foods may help to add value to the large amount of plant wastes generated in every cropping season, thus reducing their environmental impact. The objectives and aims of the EU producers, industry and stakeholders on the relationships between foods, nutrition and health, and therefore, the use of suitable ingredients from the agriculture to have impact on human health and the environment, with a sustainable use of natural resources are in agreement with this work, adding value to broccoli byproducts and encouraging the production of novel products and applications for nutritional and/or health claims under the EU Regulations (EC) No. 1924/2006 and 834/2007.

 

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Author: Benno F. Zimmermann and Maike Gleichenhagen

Green tea seems to have a positive impact on health due to the therein-found flavanols. The amounts of these substances depend on tea preparation. In this paper, the influence of steeping time (3–7 min) and temperature (70–100 °C) on the content of the main flavanols in green tea (epicatechin EC, epicatechin gallate ECg, epigallocatechin EGC, and epigallocatechin gallate EGCg) is presented. Furthermore, additives (phosphate buffers, ascorbic acid in different amounts, and citric acid) are used to investigate the influence of pH, antioxidative, and chelating agents, simulating the addition of lemon juice or pure vitamin C. The concentrations of flavanols in tea without additives are highest after 7 min of steeping at a constant 100 °C; the respective lowest and highest concentrations of the flavanols differ widely: 2.1-, 2.2-, 3.1-, and 3.6-fold for EC, EGC, EGCg, and ECg, respectively. The additives increase the flavanol concentrations up to 20%. pH emerges as the decisive factor for increasing concentrations, rather than the chemistry of the used additive.

 

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Author: Youngmok Kim and Kevin L. Goodner and Jong-Dae Park and Jeong Choi and Stephen T. Talcott

Monomeric flavonoids (flavan 3-ols or tea catechins) present in Camellia sinensis leaf are transformed to polymeric theaflavin and thearubigin by oxidation occurring during tea fermentation. The distinctive colour, decreased bitterness and astringency, and characteristic flavour are derived from the fermentation process giving fermented teas a marked distinction from non-fermented green tea. Even though teas are available in many different fermentation levels from green to black, the difference in phytochemicals and volatile compounds in teas with different degrees of fermentation has not been fully investigated yet within the same tea leaf. The objective of this study was to observe non-volatile phytochemicals including polyphenolic and volatile compounds changes by oxidation under strict processing control and to evaluate the degree of fermentation for the maximum antioxidant capacity with the same tea material. Harvested tea leaf was immediately processed to different degrees of oxidative fermentation (0%, 20%, 40%, 60%, and 80%). Tea infusions brewed with each processed tea leaf were analysed for polyphenolic profile, total soluble phenolics, antioxidant capacity, and volatile profile using LC–MS, HPLC, Folin–Ciocalteu assay, Oxygen Radical Absorbance Capacity (ORAC), and GC–MS analyses. The flavonoids in non-fermented green tea were significantly lessened during the oxidative fermentation process and the decreased monomeric flavonoids were transformed to polymeric theaflavin and thearubigin as the leaves were more processed. Total soluble phenolics and antioxidant capacity were significantly higher as tea leaves were less processed with a high correlation with individual polyphenolic changes. Volatile compounds present in tea leaf were analysed by GC–MS to observe changes due to processing and were utilised to create a model to differentiate fermentation based on volatile composition. Twenty-four compounds were used to build an initial model which was optimised to 16 compounds with complete separation of the groups using discriminant function analysis. The data suggested that fermentation diminished antioxidant capacity of tea and could result in lowering potential health benefits from flavonoids. This result should be considered for tea manufacturing and the development of functional foods desiring maximum potential health benefits from antioxidant flavonoids in tea.

 

 

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Author: Santosh K. Katiyar

Excessive exposure of the skin to solar ultraviolet (UV) radiation is one of the major factors for the development of skin cancers, including non-melanoma. For the last several centuries the consumption of dietary phytochemicals has been linked to numerous health benefits including the photoprotection of the skin. Green tea has been consumed as a popular beverage world-wide and skin photoprotection by green tea polyphenols (GTPs) has been widely investigated. In this article, we have discussed the recent investigations and mechanistic studies which define the potential efficacy of GTPs on the prevention of non-melanoma skin cancer. UV-induced DNA damage, particularly the formation of cyclobutane pyrimidine dimers, has been implicated in immunosuppression and initiation of skin cancer. Topical application or oral administration of green tea through drinking water of mice prevents UVB-induced skin tumor development, and this prevention is mediated, at least in part, through rapid repair of DNA. The DNA repair by GTPs is mediated through the induction of interleukin (IL)-12 which has been shown to have DNA repair ability. The new mechanistic investigations support and explain the anti-photocarcinogenic activity, in particular anti-non-melanoma skin cancer, of green tea and explain the benefits of green tea for human health.

 

 

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