Polyphenol oxidase (PPO) catalyses the browning reaction during fruit processing and storage. It is considered a threat to clean labels minimally processed products. Unwanted changes in fruits’ appearance quality represent cost industry. High pressure ultrasound, addition thermal treatment, are effective reducing PPO activity producing high-quality from different cultivars behaves differently w...

Red clover (Trifolium pratense) leaves contain high levels of polyphenol oxidase (PPO) activity and o-diphenol substrates. Wounding of leaves during harvest and ensiling results in browning of leaf tissues from activity of PPO on the o-diphenols. In association with browning, leaf proteins remain undegraded during ensiling, presumably due to PPO-generated o-quinone inhibition of leaf proteases....

Brownish colourations in Natural green table olives (non-treated with alkali) make this product less attractive to consumers than Spanish-style green table olives (treated with alkali), which develop a more appreciated bright golden-yellow colour. These colour differences were studied in relation to changes in the composition of chlorophyll and carotenoid pigments, as well as polyphenolic compo...

Food losses can occur during production, postharvest, and processing stages in the supply chain. With the onset of worldwide food shortages, interest in reducing postharvest losses in cassava has been increasing. In this research, the main goal was to evaluate biochemical changes and identify the metabolites involved in the deterioration of cassava roots. We found that high levels of ascorbic a...

Activity of the enzymes superoxide dismutase (SOD) and polyphenol oxidase (PPO) as well as Cu-Zn content have been monitored during the thirteen weeks growth of both Gordal and Manzanilla olive variety fruits. These metalloenzymes, with Cu and Zn in the prostetic group, are involved in controlling the redox balance in the chloroplast environment. The results indicated that, under similar phenol...

The effectiveness of pineapple juice in enzymatic browning inhibition was evaluated on the cut surface of banana slices. After storage of banana slices at 15 degrees C for 3 days, pineapple juice showed browning inhibition to a similar extent as 8 mM ascorbic acid but less than 4 mM sodium metabisulfite. Fractionation of pineapple juice by a solid-phase C18 cartridge revealed that the directly ...

The biochemical anti-herbivore defense of trembling aspen (Populus tremuloides Michx.) was investigated in a molecular analysis of polyphenol oxidase (PPO; EC 1.10.3.2). A PPO cDNA was isolated from a trembling aspen wounded leaf cDNA library and its nucleotide sequence determined. Southern analysis indicated the presence of two PPO genes in the trembling aspen genome. Expression of PPO was fou...

The activities of polyphenol oxidase (PPO) and peroxidase (POD) in hot pepper (Capsicum annuum L.) pericarp were evaluated using spectrophotometric method. The enzymes were extracted from the pepper pericarp 5 g with 20 mL of 0.1 M phosphate buffer solution pH 7. PPO and POD activities were determined using catechol and guaiacol as a substrate, respectively. The effects of the amounts of enzyme...

In the present study the effect of rare earth element Praseodymium (Pr) on flavonoids production and its biosynthesis key enzymes including Peroxidase (POD; EC 1.11.1.7), Polyphenol oxidase (PPO; EC 1.10.3.1) and Phenylanlanine ammonialyase (PAL; EC 4.3.1.5) in hairy roots of Scutellaria viscidula was investigated. After 7 days of suspension culture, activity of POD, PPO and PAL and total flavo...

portant for consumer acceptance (Moss, 1971; Miskelly, 1984, 1996), while low L* values indicate undesirable Polyphenol oxidase (PPO) causes darkening and discoloration of discoloration or darkening of noodles. wheat (Triticum aestivum L.) foods such as noodles. Consequently, a simple, nondestructive, quantitative assay for determining PPO on There is a need for a simple, quantitative assay for...