Tetralobulate glandular trichomes are present on the foliage of many solanaceous species. Resistance of many of these species to insects is conditioned by the ability of trichomes to rupture upon contact and to rapidly polymerize their contents, resulting in entrapment of insects in hardened trichome exudate. In the wild potato, Solanum berthaultii, polymerization of trichome exudate is initiat...

Abstract Polyphenol oxidase (PPO) is an enzyme associated with the browning process that can occur from mechanical injury and postharvest storage. Thus, its inactivation to inhibit this of great interest food industry. Recently a nonthermal technology, high frequency ultrasound (100–1 MHz), has found usage in aspect. In work, application high-frequency (378 kHz, 583 1144 1175 kHz) low (20 treat...

The aim of this study was to evaluate the impact ultrasound (US) at different frequencies (20, 370, and 583 kHz) power levels (35 48 W) on residual activity (RA) peroxidase (POD) polyphenol oxidase (PPO) in strawberry puree. Total anthocyanin content (TAC), total phenolic (TPC), ferric ion reducing antioxidant (FRAP) trolox equivalent capacity (TEAC) were also assessed. Results compared with un...

Polyphenol oxidase (PPO) is a necessary medium for converting catechins into theaflavins in tea. This study aimed to provide an efficient and cost-effective method the purpose of developing tea beverage rich four main (TFs) by optimizing key factors affecting enzymatic oxidation reaction produce TFs. Autumn green (AT) soup was mixed with pear PPO crude enzyme solution then reacted different tim...

Reactive oxygen species (ROS) play an active role in plant defense. Polyphenol oxidase (PPO) and peroxidase (POD) participate the synthesis of phytoalexins. The comparative activities ROS, including hydrogen peroxide (H2O2), superoxide anions (O2−), hydroxyl radicals (·OH), against fungal pathogen Colletotrichum gloeosporioides from papaya fruit were evaluated. effects ROS on PPO POD inoculated...

Polyphenol oxidase (PPO) plays a key role in the postharvest pericarp browning of litchi fruit, but its underlying mechanism remains unclear. In this study, we cloned the litchi PPO gene (LcPPO, JF926153), and described its expression patterns. The LcPPO cDNA sequence was 2120 bps in length with an open reading frame (ORF) of 1800 bps. The ORF encoded a polypeptide with 599 amino acid residues,...

The effects of rice bran extract (RBE) on browning in potato, banana and apple slices compared with distilled water (DW) were investigated by measuring the changes of color values. Potato slice treated with RBE had lower browning value than that treated with DW during storage 9 to 12 hrs (p≤0.05). The browning values of potato treated with RBE and DW stored for 12 hrs were 4.72 and 7.64, respec...

Field bean (Dolichos lablab) contains a single isoform of PPO (polyphenol oxidase)--a type III copper protein that catalyses the o-hydroxylation of monophenols and oxidation of o-diphenols using molecular oxygen--and is a homotetramer with a molecular mass of 120 kDa. The enzyme is activated manyfold either in the presence of the anionic detergent SDS below its critical micellar concentration o...

Bruce's Sport is a mutant grapevine (Vitis vinifera L.) with green and white variegated fruit derived from the Sultana variety. The white regions of tissue have decreased polyphenol oxidase (PPO) activity resulting in a reduced capacity for browning. Active PPO from Sultana grapes was purified and had an apparent molecular weight of 40,000 on sodium dodecyl sulfate-polyacrylamide gel electropho...