Characterization of polyphenoloxidase from medlar fruits (Mespilus germanica L., Rosaceae)

Dinçer, Barbaros; Çolak, Ahmėt; Aydın, Neşe; Kadıoğlu, Asim; Güner, Saadettin

doi:10.1016/s0308-8146(01)00359-4

Cited by 108 publications

(95 citation statements)

References 42 publications

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“…It appears that crude PPO is sensitive to increases in temperature. Yomra apple PPO was almost inactivated 430 C in the presence of monophenol substrates, while diphenolic substrates were more activated 430 C. The optimal temperature values for PPO from persimmon fruits using 4-MCT, catechol and L-DOPA were 40 C, 20 C and 10 C, respectively 42 , 25 C from medlar with catechol as substrate 39 and 60 C from leaves of Cleome gynandra L. 47 . Polyphenol oxidase activities for Yomra apple were assayed using catechol, 4-MCT and L-DOPA as diphenolic substrates and L-tyrosine, HPPA as monophenolic substrates in this study.…”

Section: Resultsmentioning

confidence: 97%

“…The optimum pH for PPO enzyme varies in many fruits, but the maximum PPO activity in most plants is between 5.0 and 7.0 38 . However, the optimal pH value of PPO has been reported as 8.5 for catechol and 6.5 for 4-MCT and L-DOPA as substrates in medlar (Mespilus germanica L.) fruits 39 . Similar to our study, optimum pH for PPO enzyme has been reported to range from 5.5 to 7.5 for persimmon 42 and Jonagored apple 40 against 4-methyl catechol, catechol and DOPA.…”

Section: Resultsmentioning

confidence: 99%

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Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communisL.) from Turkey

Can

Dinçer²,

Şahin

et al. 2013

Journal of Enzyme Inhibition and Medicinal Chemistry

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In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phasehigh-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (K m , V max ), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. K m values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of K i were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communisL.) from Turkey

Can

Dinçer²,

Şahin

et al. 2013

Journal of Enzyme Inhibition and Medicinal Chemistry

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“…However, most fruits and vegetables are heat sensitive, and consequently, high-temperature treatments are inevitably accompanied by losses of texture, color, flavor, and nutritional quality. It has been reported that the optimum temperatures for PPO of peach (Dincer et al, 2002), grape (Dincer et al, 2002), banana (Unal, 2007), and lettuce (Gawlik-Dziki et al, 2008) are 20, 25, 30, and 35 °C, respectively.…”

Section: Response Surface Methodology (Rsm) and Experimental Designmentioning

confidence: 99%

Prevention of enzymatic browning of yacon flour by the combined use of anti-browning agents and the study of its chemical composition

Rodrigues¹,

Asquieri²,

Orsi³

2014

Food Sci. Technol (Campinas)

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“…The production of quinones has been shown to be enzymatic in nature, whilst the secondary oxidation is largely non-enzymatic. Quinones are highly reactive molecules that can polymerize, or react with amino acids and proteins to form brown, red, or even black pigments (Joslin and Pointing 1951;Zawistowski et al 1991;Martinez and Whitaker 1995;Solomon et al 1996;Karpeta 2001;Dincer et al 2002;Aydemir 2004;Fan et al 2005;Gawlik-Diziki et al 2008;Toivonen and Brummell 2008). Whilst the accumulation of these pigmented compounds is often referred to as browning, the most significant colour present in lettuce after seven days of storage is often red or pink (referred to as pinking) (Cantos et al 2001;Lewis 2001).…”

Section: Biochemistry Of Oxidative Discolourationmentioning

confidence: 99%

Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life

et al. 2017

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Lettuce discolouration is a key post-harvest trait. The major enzyme controlling oxidative discolouration has long been considered to be polyphenol oxidase (PPO) however, levels of PPO and subsequent development of discolouration symptoms have not always correlated. The predominance of a latent state of the enzyme in plant tissues combined with substrate activation and contemporaneous suicide inactivation mechanisms are considered as potential explanations for this phenomenon. Leaf tissue physical properties have been associated with subsequent discolouration and these may be influenced by variation in nutrient availability, especially excess nitrogen and head maturity at harvest. Mild calcium and irrigation stress has also been associated with a reduction in subsequent discolouration, although excess irrigation has been linked to increased discolouration potentially through leaf physical properties. These environmental factors, including high temperature and UV light intensities, often have impacts on levels of phenolic compounds linking the environmental responses to the biochemistry of the PPO pathway. Breeding strategies targeting the PAL and PPO pathway biochemistry and environmental response genes are discussed as a more cost-effective method of mitigating oxidative discolouration then either modified atmosphere packaging or post-harvest treatments, although current understanding of the biochemistry means that such programs are likely to be limited in nature and it is likely that they will need to be deployed alongside other methods for the foreseeable future.Keywords Lettuce Á Discolouration Á Biochemistry Á Environment Á Polyphenols Á Phenylpropanoid pathway Á Review The value of lettuceThe UK processed salad sector was valued at approximately £848 million in

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Characterization of polyphenoloxidase from medlar fruits (Mespilus germanica L., Rosaceae)

Cited by 108 publications

References 42 publications

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communisL.) from Turkey

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communisL.) from Turkey

Prevention of enzymatic browning of yacon flour by the combined use of anti-browning agents and the study of its chemical composition

Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life

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