The color and polyphenol oxidase (PPO) activity of fresh-cut Golden delicious apples were evaluated throughout cold storage under modified atmospheres. The shelf life of cut apples was extended to several weeks, especially when an initial atmosphere of 90.5% N(2) + 7% CO(2) + 2.5% O(2) and plastic pouches of 30 cm(3)/cm(2) x bar x 24 h were used. Under these conditions, a maximum 62% PPO activi...

Proximal Policy Optimization (PPO) is an important reinforcement learning method, which has achieved great success in sequential decision-making problems. However, PPO faces the issue of sample inefficiency, due to cannot make use off-policy data. In this paper, we propose Off-Policy method (Off-Policy PPO) that improves efficiency by utilizing Specifically, first a clipped surrogate objective ...

The effect of modifying polyphenol oxidase (PPO) and peroxidase (POX) activity during the extraction of virgin olive oil has been assessed in terms of its influence on the phenolic profile of the oil produced. These enzymes were modified by adding exogenous enzyme or specific inhibitors during the milling and subsequent kneading step, studying the effect on specific phenolic compounds in the oi...

Despite a slight drop in enrollment and a dramatic shift in the landscape of the rural Medicare Advantage (MA) market in early 2010, MA plans have experienced modest growth in enrollment in rural areas over the last two quarters of 2010. The majority of the growth is concentrated in preferred provider organization (PPO) plans, counteracting a decline in private fee-for-service (PFFS) plan enrol...

Calluses from seasonal mature shoots of Taxus globosa Schltdl. were subcultured in new medium containing 1 mg l -1 NAA, 0.5 mg l -1 2, 4-D, 0.025 mg l -1 BA. Calluses growing for 30 and 40 days in a medium added with 0.1-5.0 mg l -1 of chlorocholine chloride (CCC) were harvested for determination of taxol, phenolic compounds, and for polyphenol oxidase (PPO) activity. The results showed that by...

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 phase behavior of two types of poly(ethylene oxide)/poly(propylene oxide) (PEO/PPO) copolymers in aqueous solutions was studied by light scattering, viscometry, and infrared spectroscopy. Both the reverse poloxamer (Pluronic 10R5) and the star type poloxamine (Tetronic 90R4) have practically the same PEO/PPO ratio with their hydrophobic blocks (PPO) located in the outer part. The temperatur...

Polyphenol oxidase (PPO) (monophenol, o-diphenol: oxygen oxidoreductase; EC 1.14.18.1) is a binuclear copper-cluster-containing monooxygenase ubiquitously present in biological systems (1, 2). PPO may be distinguished from the related oxidase laccase [p-diphenol:oxygen oxidoreductase; EC 1.10.3.2] by its substrate specificity and the type and number of catalytic coppers. PPO catalyzes the oxida...

A set of diphenyl ether herbicides [1] was examined with Comparative Molecular Field Analysis (CoMFA) using standard steric and electrostatic ®elds and alternative frontier orbitals as 3-D ®elds to explain observed Protoporphyrinogen oxidase (PPO) enzyme inhibition. Signi®cant CoMFA models were obtained utilizing standard CoMFA and the LUMO ®eld both together and separately. These ®ndings suppo...