Immobilization and Characterization of Tannase and its Haze-removing

2009 ◽  
Vol 15 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Erzheng Su ◽  
Tao Xia ◽  
Liping Gao ◽  
Qianying Dai ◽  
Zhengzhu Zhang
Keyword(s):  
Kinetic Parameter ◽  
High Activity ◽  
Green Tea ◽  
Storage Stability ◽  
Residual Activity ◽  
Black Tea ◽  
Optimum Temperature ◽  
Oolong Tea ◽  
Optimum Ph

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ° C, decreasing 10 °C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10-4 mol/L. Fe2+ and Mn2+ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

scholarly journals The Properties of Immobilized Invertase Onto a New Support Material; Poly(Methacrylamide/Maleic Acid) Copolymeric Hydrogel

2018 ◽  
Vol 26 (2) ◽  
pp. 307-328 ◽  
Author(s):  
Hesna Nursevin Öztop ◽  
Fatma Banu Çatmaz ◽  
Dursun Saraydin
Keyword(s):  
Maleic Acid ◽  
Storage Stability ◽  
Maximum Velocity ◽  
Optimum Temperature ◽  
Michaelis Constant ◽  
Ph Values ◽  
Optimum Ph ◽  
And Storage ◽  
And Diffusion

Abstract Poly (methacrylamide / maleic acid) PM/MA and poly (methacrylamide) PM hydrogels were prepared aiming to be used as a support for invertase. Spectrophotometric, thermal analysis methods, swelling and diffusion experiments were used for the characterization of hydrogels. The swelling of PM/MA was higher than that of PM in water. The diffusion of water within the hydrogel was found to be non-Fickian. Invertase was immobilized onto PM and PM/MA (samples named PM-I and PM/MA-I respectively). The optimum pH values were found to be; 6.0, 5.0 and 5.5 for free invertase, PM-I and PM/MA-I respectively. The optimum temperature values were found to be 30 °C, 35 °C and 40 °C for free invertase, PM-I and PM/MA-I respectively. The Michaelis constant (Km) and maximum velocity of the enzymes (Vmax) were Km: 11,75 mM, Vmax: 1,95 μmol min−1 for free invertase, Km: 67,24 mM, Vmax: 60,6 μmol min−1 for PM-I and Km: 74,55 mM, Vmax: 18,12 μmol min−1 for PM/MA-I. PM/MA-I showed excellent thermal, operational and storage stability.

Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC

2015 ◽  
Vol 183 ◽  
pp. 30-35 ◽  
Author(s):  
Heyuan Jiang ◽  
Ulrich H. Engelhardt ◽  
Claudia Thräne ◽  
Beate Maiwald ◽  
Janina Stark
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Flavonol Glycosides ◽  
Oolong Tea

scholarly journals Comparative study of catechin levels from green tea, oolong tea and black tea product with various treatments

2021 ◽  
Vol 14 (1) ◽  
pp. 001-010
Author(s):  
Syamsu Nur ◽  
Andi Nur Aisyah ◽  
Alfat Fadri ◽  
Sharfianty ◽  
Amriani Sapra ◽  
...  
Keyword(s):  
Green Tea ◽  
Color Change ◽  
Black Tea ◽  
Processing Method ◽  
Uv Spectrophotometry ◽  
Uv Spectrum ◽  
Polyphenol Compounds ◽  
The Public ◽  
Chemical Reagents ◽  
Oolong Tea

Background: Tea is a refreshing drink that contains polyphenol compounds, namely catechins that are used for medicine and cosmetics. This study was to assess the content of catechin compounds in green tea, oolong and black tea products from Indonesia, China and Taiwan. Methods: Some tea products are brewed at varying temperatures (75±2; 85±2 and 95±20 C) and times (5; 10 and 15 minutes). Identification of catechin compounds was carried out using chemical reagents and UV spectrophotometry. The level of cathecin in tea products were analyzed by spectrophotometer at 280 nm wavelength. Results: The results obtained indicate that green tea, oolong tea and black tea contain epigallocatechin-3-gallate (EGCG) compounds according to the color change based on chemical reagents and for UV spectrum analysis which has λmax in the range 268-274 nm. The results of quantitative tests using UV-Vis spectrophotometry showed that the green tea samples gave the highest levels of catechins followed by oolong tea and black tea with brewing temperature at 95±20 °C. Conclusion: The catechin content of tea obtained from various products varies according to the type of processing method and the brewing temperature. Therefore, this study is expected to provide information related to catechin content to the public and researchers.

scholarly journals Characterization of Biosynthetic Enzymes for Ectoine as a Compatible Solute in a Moderately Halophilic Eubacterium, Halomonas elongata

1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Mass ◽  
Optimum Temperature ◽  
Sds Page ◽  
Halomonas Elongata ◽  
Optimum Ph

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.

Comparison of Antimutagenic Effect of Various Tea Extracts (Green, Oolong, Pouchong, and Black Tea)

1994 ◽  
Vol 57 (1) ◽  
pp. 54-58 ◽  
Author(s):  
GOW-CHIN YEN ◽  
HUI-YIN CHEN
Keyword(s):  
Salmonella Typhimurium ◽  
Green Tea ◽  
Aflatoxin B1 ◽  
Black Tea ◽  
Inhibitory Effect ◽  
Manufacturing Processes ◽  
Antimutagenic Effect ◽  
Oolong Tea ◽  
Tea Extract

The antimutagenic effects of various tea extracts prepared from nonfermented tea (green tea), semifermented tea (oolong tea and pouchong tea), and fermented tea (black tea) were investigated by Salmonella/microsome assay. No mutagenicity or toxicity in Salmonella typhimurium TA98 and TA100 was observed with any tea extract. The tea extracts markedly inhibited the mutagenicity of 2-amino-3-methylimidazo(4,5-f)quinoline, 3-amino-1,4-dimethyl-5H-pyridol(4,3-b)indole,2-amino-6-methyldipyrido(l,2-a:3′,2′-d)imidazole, benzo[a]pyrene, and aflatoxin B1 toward S. typhimurium TA98 and TA100 in the presence of S9 mixture, especially those of oolong and pouchong teas inhibited over 90% mutagenicity of these five mutagens at the dosage of 1 mg per plate. Among four tea extracts, black tea exhibited the weakest inhibitory effect on mutagenicity of these five mutagens. The mutagenicity of 4-nitroquinoline-N-oxide, a direct mutagen, was not inhibited by black and oolong tea extracts to S. typhimurium TA98 in the absence of S9 mixture but was increased by the tea extracts at the dose of 1 mg per plate to S. typhimurium TA100. As the antimutagenic effect of semifermented tea was stronger than nonfermented and fermented teas, some antimutagenic substances might be formed during manufacturing processes of tea.

The modulatory effect of infusions of green tea, oolong tea, and black tea on gut microbiota in high-fat-induced obese mice

2016 ◽  
Vol 7 (12) ◽  
pp. 4869-4879 ◽  
Author(s):  
Zhibin Liu ◽  
Zhichao Chen ◽  
Hongwen Guo ◽  
Dongping He ◽  
Huiru Zhao ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Green Tea ◽  
Black Tea ◽  
Tea Consumption ◽  
Obese Mice ◽  
High Fat ◽  
Oolong Tea

Tea consumption has been identified to have a gut microbiota modulatory effect, which may be related to its anti-obesity effect.

Study on the Optimum Condition for Immobilization and Properties of Laccase on Coordinated Chitosan-Cu2+

2013 ◽  
Vol 864-867 ◽  
pp. 1262-1265 ◽  
Author(s):  
Bo Yang ◽  
Xu Ming Wang
Keyword(s):  
Optimum Condition ◽  
Heat Resistance ◽  
High Activity ◽  
Storage Stability ◽  
Optimal Conditions ◽  
Immobilized Laccase ◽  
Complex Time ◽  
Optimum Ph ◽  
Polymeric Coordination ◽  
Optimum Ph And Temperature

Coordinated chitosan-Cu2+ as a carrier, the laccase was immobilized on it by polymeric coordination method. In this study, the optimal conditions for immobilization and properties of laccase were investigated. The optimal conditions for immobilization were: CuSO4 (0.05 mol/L), complex time (7 h), laccase concentration (250 U/mL), immobilization time (8 h). Under this condition, the activity of immobilized laccase can reach 820 U/g. In comparison with the free laccase, the optimum pH and temperature of immobilized laccase have a little change, while the heat resistance and pH stability were improved. After the immobilized laccase was stored in the refrigerator at 4 °C for 25 days, the activity of it remained 69.5 % of the original, it illustrates the immobilized laccase has a good storage stability. The laccase immobilized with chitosan-Cu2+ has high activity and has potential to use in industry as a biocatalyst.

scholarly journals Purification and characterization of endoglucanase Ss from Clostridium thermocellum

1991 ◽  
Vol 279 (1) ◽  
pp. 67-73 ◽  
Author(s):  
U Fauth ◽  
M P M Romaniec ◽  
T Kobayashi ◽  
A L Demain
Keyword(s):  
Clostridium Thermocellum ◽  
Hydrophobic Interaction Chromatography ◽  
Cellulolytic Enzymes ◽  
Crystalline Cellulose ◽  
Optimum Temperature ◽  
Purification And Characterization ◽  
Specific Antibodies ◽  
Optimum Ph ◽  
Exchange Adsorption

The extracellular cellulolytic enzymes of the thermophilic anaerobe Clostridium thermocellum occur as a protein complex or aggregate known as the cellulosome. By using a combination of ion-exchange, adsorption and hydrophobic-interaction chromatography, it was possible to isolate from extracellular broth a specific endoglucanase of interest without the use of denaturants. The endoglucanase was identified as the cellulosomal subunit Ss by the use of specific antibodies. The enzyme has an Mr of 83,000, an isoelectric point of 3.55, optimum pH of 6.6 and optimum temperature of 70 degrees C. It hydrolyses CM-cellulose and, at a higher rate, the cellodextrins, cellotetraose and cellopentaose, but does not hydrolyse a crystalline cellulose such as Avicel. Cellobiose and cellotriose are also immune to attack. It differs from endoglucanases previously isolated by others and a 76,000-Mr endoglucanase recently isolated in this laboratory.

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