Results 231 to 240 of about 58,939 (280)

Effect of Polyphenol Oxidase on Deodorization

Bioscience, Biotechnology, and Biochemistry, 1997
A mixture of purified polyphenol oxidases (PPO), or acetone powders prepared from fruits and vegetables, and polyphenolic compounds (PPs) totally eliminated a methylmercaptan odor. 2-Methyl-thiochlorogenic acid was isolated from the reaction mixture of methylmercaptan and chlorogenic acid with burdock acetone powder.
O, Negishi, T, Ozawa
openaire   +2 more sources

Polyphenol Oxidase from Dominga Table Grape

Journal of Agricultural and Food Chemistry, 2005
Dominga grape polyphenol oxidase (PPO) was extracted using phase partitioning with Triton X-114. The enzyme was obtained in latent state and could be optimally activated by the presence of 0.2% sodium dodecyl sulfate (SDS) at pH 6.0. In the absence of SDS, the enzyme showed maximum activity at acid pH. The kinetic parameters of the enzyme at pH 3.0 and
Estrella, Núñez-Delicado, Marta, Serrano-Megías, Antonio José, Pérez-López, José Manuel, López-Nicolás   +3 more
openaire   +2 more sources

Properties of tobacco polyphenol oxidase

Archives of Biochemistry and Biophysics, 1959
Abstract The properties of partially purified tobacco leaf polyphenol oxidase have been studied. Evidence is presented to establish that the observed oxidations of catechol, caffeic acid, and chlorogenic acid were, in fact, catalyzed by polyphenol oxidase. Enzyme stability, activation, x-ray inactivation, inhibition, pH optima, substrate specificity,
openaire   +2 more sources

Polyphenol Oxidase from Allium sp.

Journal of Agricultural and Food Chemistry, 1997
Polyphenol oxidase (PPO) was isolated from Allium sp. PPO showed activity to catechol and dl-dopa (Km values were 25 mM for cathecol and 33 mM for dl-dopa;Vmax values were 666 EU/mL·min for cathecol and 166 EU/mL·min for dl-dopa). Catechol was the most suitable substrate for Allium sp. PPO (lowest Km value).
Tozlu, I, Arslan, O, Temur, A
openaire   +2 more sources

Characterization of polyphenol oxidase in coffee

Phytochemistry, 2000
Polyphenol oxidase (PPO) was characterized in partially purified extracts of leaves (PPO-L) and fruit endosperm (PPO-E) of coffee (Coffea arabica L.). PPO activity was higher in early developmental stages of both leaves and endosperm of fruits. Wounding or exposure of coffee leaves to methyl jasmonate increased PPO activity 1.5-4-fold.
P, Mazzafera, S P, Robinson
openaire   +2 more sources

Recombinant polyphenol oxidases for production of theaflavins from tea polyphenols

International Journal of Biological Macromolecules, 2019
Theaflavins (TFs) have attracted much attention due to their various bioactivities in black tea. This paper describes the first trial for enzymatic production of TFs by recombinant polyphenol oxidases (PPOs). PPO genes were cloned from nine species and expressed in E. coli.
Jun, Zeng, Gang, Du, Xue, Shao, Ke-Na, Feng, Ying, Zeng   +4 more
openaire   +2 more sources

New Spectrophotometric Assay for Polyphenol Oxidase Activity

Analytical Biochemistry, 1993
We describe a convenient and sensitive assay of polyphenol oxidase (PPO, EC 1.14.18.1) consisting of spectrophotometry at 300 nm based on the stoichiometric reaction of cysteine with o-quinones produced during the enzymatic oxidation of phenols. The adduct formed exhibited spectral properties different from those of the parent phenol.
Gauillard, Frederic, Forget, Florence, Nicolas, J.   +2 more
openaire   +3 more sources

Polyphenol Oxidase‐Like Nanozymes

Advanced Materials
Abstract Nanozymes are nanomaterials with enzyme‐like activities. Over the past decade, a steadily growing body of research on polyphenol oxidase‐like (PPO‐like) nanozymes, a subgroup of oxidase‐like nanozymes, has suggested their increasing prominence in nanozymology. Most importantly, PPO‐like nanozymes have developed a unique, well‐
Haolun Gu, Jingqi Li, Pengyu Dai, Tiedong Sun, Chunxia Chen, Zhong Guo, Kelong Fan   +6 more
openaire   +1 more source

Isoenzymes of banana polyphenol oxidase

Phytochemistry, 1975
Abstract Polyacrylamide-gel electrophoresis revealed 9 polyphenol oxidase (PPO) isoenzymes in the interior of banana pulp, 8 in the exterior pulp, and 10 in the peel. With the exception of the absence of one isoenzyme in the exterior pulp, the isoenzymes in the exterior and interior pulp had similar relative mobilities ( R m ).
M.W. Montgomery, V.C. Sgarbieri
openaire   +1 more source

Polyphenol Oxidase, Beyond Enzyme Browning

2018
Enzyme browning is a usual phenomenon that can be observed commonly in fruits and vegetables, which results in quality loss of the food including the change in color, taste, flavor, and nutritional value. This occurs when the phenolic compounds present in them react with polyphenol oxidase (type III copper enzyme).
E. Selvarajan, R. Veena, N. Manoj Kumar
openaire   +1 more source