Addition Of Tea Extract Research Articles

Tea extracts modulate fat accumulation and distribution and demonstrate anti‐inflammatory effects in C57BL/6 mice fed a high fat/Western diet

Tea may be effective in the prevention of obesity‐related chronic disease. We compared the effect of 3 teas including green (GT), black (BT) and oolong tea (OT) on body weight, fat distribution and inflammation. 120 C57BL/6 male mice were randomly assigned to 5 treatment groups: control diet (10% kcal from fat), high fat (HF)/Western diet (32% kcal from butter fat and corn oil), or a HF diet with GT, OT or BT extract (0.25% GT polyphenols) for 20 weeks. 3–6 mice per group were sacrificed every 4 weeks. Fat distribution was measured by magnetic resonance imaging (MRI) and fat pads were weighed. Gene expression of interleukin (IL)‐6, tumor necrosis factor (TNF) α and MCP‐1 was determined in liver, epididymal (E‐fat) and mesenteric fat (M‐fat) using qRT‐pCR. The addition of all 3 tea extracts significantly reduced the HFdiet‐induced increase in body weight, liver fat, M‐fat, and subcutaneous fat. GT and BT significantly decreased the amount of E‐fat and GT and OT significantly decreased perirenal fat. GT and BT significantly inhibited HFdiet‐induced MCP‐1 gene expression in the liver, and BT in both E‐fat and M‐fat. All 3 teas significantly reduced the HFdiet‐induced TNF α expression in E‐fat, but not in M‐fat. The addition of BT to the HFdiet led to significant inhibition of IL‐6 concentration in E‐fat. In summary the addition of tea extracts to an HFdiet differentially alleviated HFdiet‐induced fat accumulation and inflammation

Inhibition of Listeria monocytogenes ATCC 19115 on ham steak by tea bioactive compounds incorporated into chitosan-coated plastic films.

BackgroundThe consumer demands for better quality and safety of food products have given rise to the development and implementation of edible films. The use of antimicrobial films can be a promising tool for controlling L. monocytogenes on ready to eat products. The aim of this study was to develop effective antimicrobial films incorporating bioactive compounds from green and black teas into chitosan, for controlling L. monocytogenes ATCC 19115 on vacuum-packaged ham steak. The effectiveness of these antimicrobial films was evaluated at room temperature (20°C) for 10 days and at refrigerated temperature (4°C) for 8 weeks.ResultsThe HPLC results clearly show that relative concentrations of catechins and caffeine in green tea ranked EGCG>EGC>CAF>ECG>EC>C while in black tea extracts ranked CAF>EGCG>ECG>EGC>EC>C. The chitosan-coated plastic films incorporating green tea and black tea extracts shows specific markers identified by FTIR. Incorporating natural extracts into chitosan showed that the growth of L monocytogenes ATCC 19115 was inhibited. The efficacy of antimicrobial effect of tea extracts incorporated into chitosan-coated plastic film was dose dependent. However, chitosan-coated films without addition of tea extracts did not inhibit the growth of L. monocytogenes ATCC 19115. Chitosan-coated plastic films incorporating 4% Green tea extract was the most effective antimicrobial, reducing the initial counts from 3.2 to 2.65 log CFU/cm2 during room temperature storage and from 3.2 to 1–1.5 log CFU/cm2 during refrigerated storage.ConclusionsIncorporation of tea extracts into the chitosan-coated films considerably enhanced their effectiveness against L. monocytogenes ATCC 19115. 4% Green tea incorporated into chitosan-coated plastic film had a better antilisterial effect than 2% green tea or 2% and 4% black tea. Data from this study would provide new formulation options for developing antimicrobial packaging films using tea extracts to improve the microbiological safety and quality of ham steak during room and refrigerated storage.

Can tea extracts protect extra virgin olive oil from oxidation during microwave heating?

Olive oil is a key ingredient in worldwide cuisine. Microwave cooking is also increasingly used as a time-saving technology but it induces severe changes in the lipids, such as hydrolysis and oxidative reactions that lead to quality and nutritional losses. In this sense, the present work intends to verify the potential increased olive oil stability under microwave cooking induced by white and green tea aqueous extracts, rich in antioxidants. Quality parameters (free acidity, peroxide value, K232, K270 and ΔK), composition (fatty acids profile, tocopherols and total phenols content), antioxidant activity and oxidative stability were studied during different microwave heating exposure times (0, 1, 3, 5 and 10min). Until the first 3min of heating the tea extracts protect olive oil from the oxidative process. However, with higher heating periods the extracts were pro-oxidants, mainly green tea extracts. Globally, and independently from the addition of tea extracts, the olive oils suffered drastic changes in their quality and composition. PUFA content decreased with exposure time as well as antioxidant activity, total phenols and total vitamin E content, and oxidative stability, with higher losses in the olive oils with green tea extracts. Positive correlations were established between the quality parameters and the increasing heating time, and negative correlations with the composition and bioactive and stability indexes.

Sterilization and protection of protein in combinations of Camellia sinensis green tea extract and gamma irradiation

Sterilization of milk protein without heating is of great interest. Gamma irradiation is a very powerful method to decontaminated casein. Gamma-irradiation of proteins in aqueous media at doses higher than 5kGy is known to induce their aggregation (without oxygen) or degradation (in presence of oxygen). Camellia sinensis green tea extract addition before irradiation of caseins cow milk proteins was examined. It was found that the presence of C. sinensis green tea extract during irradiation in the presence of oxygen conditions prevented the protein aggregation even at doses higher than 10kGy, probably by scavenging oxygen radicals produced by irradiation. The protective role of C. sinensis green tea extract allowing the gamma-irradiation treatment of caseins cow milk proteins in solution, was asserted by sodium dodecyl-sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by high performance liquid chromatography inverse phase (RP-HPLC). The total viable microorganisms content evaluated by Plate Count Agar (PCA) incubation for 12h at 37°C, showed that caseins protein preparations gamma-irradiated remained sterile at a dose 2kGy in absence of C. sinensis green tea extract and at a dose lower than 2kGy in the presence of C. sinensis green tea extract.

녹차추출물 및 죽염처리에 의한 된장의 항돌연변이 및 in vitro 항암활성 증진효과

Antimutagenic and in vitro anticancer effects of doenjangs added with green tea extract and/or using bamboo salt were studied by Ames test using Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) TA100 and 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay on PC-3 and DU145 human prostate cancer cells, respectively. At the 1.25 ㎎/plate concentration, 1% green tea extract (GTE) added doenjang exhibited 85% antimutagenicity against aflatoxin B₁ (AFB₁), while the control doenjang revealed 63% antimutagenicity, showing increased antimutagenic effect by the addition of green tea extract during doenjang fermentation. GTE added doenjang also increased antimutagenic effect against MNNG. The inhibition rate of the control doenjang showed 34% at 0.625 ㎎/plate, while 1% and 2% GTE added doenjangs inhibited by 56% and 73% at the 0.625 and 1.25 ㎎/plate, respectively (p＜0.05). In MTT assay, GTE added doenjangs caused 70%~77% inhibition on the proliferation of PC-3 human prostate cancer cells at 0.5 ㎎/mL while the control doenjang exhibited 46% inhibition. However, 2% GTE added doenjang showed 91% inhibition at 1.0 ㎎/mL. The trend of the inhibition rate was similar in DU145 human prostate adenocarcinoma cells. When bamboo salt was used instead of natural sea salt, the antimutagenicity against MNNG and in vitro anticancer effect on the prostate cancer cells greatly increased. From these results, it can be concluded that green tea extract addition to doenjang and the use of bamboo salt during doenjang preparation increased the antimutagenic and in vitro anticancer activities of the doenjang and showed a synergistic effect.

In vitro Cytotoxicity of Epigallocatechin Gallate and Tea Extracts to Cancerous and Normal Cells from the Human Oral Cavity

This study compared the in vitro responses of malignant and normal cells from the human oral cavity to tea extracts and to its main polyphenolic component, (-)-epigallocatechin gallate (EGCG). The antiproliferative effects of tea polyphenolic extracts and EGCG were more pronounced towards immortalized, tumourigenic (CAL27, HSC-2, and HSG(1)) and non-tumourigenic (S-G) cells than towards normal (GN56 and HGF-1) fibroblasts and green tea was more toxic than black tea. As the addition of tea extract or EGCG to cell culture medium led to the formation of hydrogen peroxide (H(2)O(2)), the research then focused on EGCG as an inducer of oxidative stress, using CAL27, the cancerous cells most sensitive to EGCG, HSG(1), the cancerous cells least sensitive to EGCG, and GN56 cells. The toxicity of EGCG was decreased in the presence of catalase, an enzyme that degrades H(2)O(2), or of deferoxamine, a chelator of Fe(3+). Conversely, pretreatment of the cells with the glutathione depleters, 1-chloro-2,4-dinitrobenzene and 1,3-bis(2-chloroethyl)-N-nitrosourea, potentiated the toxicity of EGCG. A 4-hr exposure to EGCG lessened the intracellular level of reduced glutathione in the CAL27 and HSG(1) cells, but not in the GN56 fibroblasts. Whereas EGCG itself did not induce lipid peroxidation, Fe(2+)-induced lipid peroxidation was potentiated by EGCG. A 72-hr exposure to cytotoxic concentrations of EGCG induced significant cytoplasmic vacuolization in all cell types. The results presented herein are consistent with EGCG acting as a prooxidant, with the cancerous cells more sensitive to oxidative stress than the normal cells.

Tea extract as an inexpensive inducer of pectin lyase in Penicillium griseoroseum cultured on sucrose

Extracts of tea, coffee, cocoa, and yeast induced pectin lyase (PL) in Penicillium griseoroseum cultured in a mineral medium with sucrose as the carbon source. PL activity and fungal growth were similar in the treatments with 0.5% tea extract, the highest concentration tested, and 0.03% yeast extract. When tea extract was added singly to the culture medium, P. griseoroseum produced 59% and 17% of the PL activity and mycelial mass, respectively, obtained in a treatment with tea extract and sucrose. These results suggest that the production of the enzyme was not proportional to mycelial growth. No PL was produced in the medium with sucrose and without inducers. The small amounts of pectic substances present in the tea extract could not be responsible for PL induction. PL activity was detected after 12 h of growth in the medium containing sucrose and tea extract added at time zero, and after 48 h of growth when tea extract was added at times 12 and 24 h. Mycelial mass in all treatments was similar after 48 h of incubation. However, the addition of tea extract at time zero increased PL activity by 20–25%. Cyclic AMP at 5 and 10 mM in the culture medium induced 20 and 30%, respectively, of the PL activity obtained with 0.03% yeast extract, suggesting that PL induction brought about by either yeast extract or tea extract might involve the intracellular metabolism of cAMP.