Polyphenol oxidase (PPO) from tomatoes was extracted and partially purified through  (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in solanum lycopersicum. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the ...

objective: polyphenol oxidase or ppo (ec 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. the objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of cysteine, ascorbic acid, citric acid, kojic acid and glycine at two different ph (6 and 7) in  hawthorn. me...

The solubilization of hydrocarbons by micelles formed of diblock and symmetric triblock copolymers in water are compared in the framework of a mean-field theory of solubilization. The block copolymers contain poly(ethylene oxide) as the hydrophilic block and poly(propylene oxide) as the hydrophobic block and are designated as EXPYEX or EWPZ (where E and P denote ethylene and propylene oxides an...

Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the qu...

We present a femtosecond broad-band fluorescence up-conversion study of the vibrational relaxation dynamics of two UV chromophores, 2,5-diphenyloxazole (PPO) and para-terphenyl (pTP), pumped with a large excess of vibrational energy (>2000 cm(-1)). The band narrowing of the transient fluorescence spectrum reflects a biphasic cooling process in a few hundreds of fs and a few ps. In the sub-ps re...

Abstract This paper presents an optimal and efficient design of low pass digital finite impulse response (FIR) filter using hybrid predator prey optimization (HPPO) technique. HPPO is an evolutionary algorithm that exhibits the features of basic PPO, hooke jeeves exploratory move and opposition based strategy that helps to design an optimal filter. Predator Prey Optimization is a global search ...

Plasma-etching is a powerful tool in the determination of the resistance of the sublayer of skinned asymmetric hollow fiber membranes of poly (2,6-dimethyl-1,4-phenylene oxide). Using a resistance model and data provided by etched hollow PPO fiber membranes it is possible to predict the ultimate selectivity of the total membrane for helium over nitrogen and oxygen over nitrogen. From this model...

Studies have shown that the lowest performing physicians in pay-for-performance (P4P) programs improved the most; however, it is unclear whether this would occur without the P4P program or be sustained. The objective of this study is to investigate the impact of P4P in a Preferred Provider Organization (PPO) on low performing physicians over a 4-year period. We used administrative claims data f...

Amphiphilic poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO)-based copolymers are thermoresponsive materials having aggregation properties in aqueous medium. As hydrosolubilizers of poorly water-soluble drugs and improved stability of sensitive agents, these materials have been investigated for improvement in solubility, stability, release and bioavailability of drugs. The goal of the prese...