scholarly journals Insight of Polyphenol Oxidase Enzyme Inhibition and Total Polyphenol Recovery from Cocoa Beans

Antioxidants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 458 ◽  
Author(s):  
Said Toro-Uribe ◽  
Jhair Godoy-Chivatá ◽  
Arley René Villamizar-Jaimes ◽  
María de Jesús Perea-Flores ◽  
Luis J. López-Giraldo
Keyword(s):  
Heat Treatment ◽  
Polyphenol Oxidase ◽  
Morphological Changes ◽  
Safe Procedure ◽  
Total Polyphenol ◽  
Chemical Inhibitors ◽  
Oxidase Enzyme ◽  
New Equation ◽  
Full Factorial ◽  
Microscopy Images

A full factorial design (ascorbic acid/l-cysteine inhibitors, temperature, and time as factors) study was conducted to enhance inhibition of polyphenol oxidase (PPO) activity without decreasing cocoa polyphenol concentrations. The data obtained were modelled through a new equation, represented by Γ, which correlates both high polyphenol content with reduced specific PPO activity. At optimized values (70 mM inhibitory solution at 96 °C for 6.4 min, Γ = 11.6), 93.3% PPO inhibition and total polyphenol of 94.9 mg GAE/g were obtained. In addition, microscopy images confirmed the cell morphological changes measured as the fractal dimension and explained the possible cell lysis and denaturation as a result of heat treatment and chemical inhibitors. Results also showed that PPO enzyme was most suitable (higher vmax/Km ratio) for catechol, with a reduction in its affinity of 13.7-fold after the inhibition heat treatment. Overall, this work proposed a suitable and food-safe procedure for obtaining enriched polyphenol extract with low enzyme activity.

The role of polyphenol oxidase and peroxidase in the browning of water caltrop pericarp during heat treatment

2011 ◽  
Vol 127 (2) ◽  
pp. 523-527 ◽  
Author(s):  
Jhih-Ying Ciou ◽  
Hsin-Hung Lin ◽  
Po-Yuan Chiang ◽  
Chiun-C. Wang ◽  
Albert Linton Charles
Keyword(s):  
Heat Treatment ◽  
Polyphenol Oxidase

Heat Treatment Map of Al2Ca-added AlSi11MnMg Pressure-Cast Alloy Plotted by Full Factorial Design of Experiment and Analysis of Variance

2019 ◽  
Vol 61 (7-8) ◽  
pp. 511-516
Author(s):  
Gil-Yong Yeom ◽  
G. Eisaabadi B. ◽  
Shae K. Kim ◽  
Soong-Keun Hyun ◽  
Kyeong Suk Sim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Factorial Design ◽  
Analysis Of Variance ◽  
Design Of Experiment ◽  
Cast Alloy ◽  
Full Factorial Design ◽  
Full Factorial

scholarly journals Bioactive Compounds and Antioxidant Activity of Cauliflower According to Heat Treatment Method (P06-074-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Eun-Sun Hwang
Keyword(s):  
Heat Treatment ◽  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Science Research ◽  
Total Flavonoid ◽  
Total Phenolic ◽  
Cooking Methods ◽  
Cruciferous Vegetables ◽  
Total Polyphenol ◽  
Health Promoting

Abstract Objectives Cauliflower is one of the cruciferous vegetables and contains various physiologically active substances such as glucosinolates, polyphenols, and flavonoids. Unlike ordinary vegetables, cruciferous vegetables are often consumed by cooking through heat treatment. The purpose of this study was to investigate the effects of different heating procedures, in particular steaming and boiling, on glucosinolate, total polyphenol, and total flavonoid concentrations in cauliflower. In addition, antioxidant activity was compared between fresh uncooked, steamed, and boiled cauliflower, which are the main methods of preparing cauliflower before consumption. Methods Glucosinolates in uncooked, steamed, and boiled cauliflower were subjected to high-pressure liquid chromatography. Total phenolic and total flavonoid content and antioxidant activities in cauliflower extracted in both water and 80% ethanol were determined. Results Eight glucosinolate peaks were detected in cauliflower representing glucoiberin, progoitrin, glucoraphanin, sinigrin, gluconapin, glucoiberverin, glucobrassicin, and gluconasturtiin. Boiling cauliflower significantly decreased the glucosinolate, total polyphenol, and total flavonoid concentrations compared to those of uncooked or steamed cauliflower. The results clearly indicated that health-promoting compounds in cauliflower are significantly affected by different cooking methods, showing that uncooked > steamed > boiled. The amounts of total polyphenols and total flavonoids contained within uncooked cauliflower extracted by 80% ethanol were higher than those in the steamed and boiled extracts. The highest antioxidant activity was observed in uncooked cauliflower extracted in 80% ethanol compared to that of water extracts at the same concentration. Steamed and boiled cauliflower extracts showed lower antioxidant activity. Conclusions Based on these results, fresh uncooked cauliflower is optimal in terms of the content of health-promoting compounds and antioxidant activity. It may be desirable to use steaming rather than boiling to minimize the loss of glucosinolates when storing, pretreating, processing, and cooking cruciferous vegetables. Funding Sources This research was supported by the Basic Science Research Program through the National Research Foundation of Korea.

Polyphenol Oxidase Enzymes in the Sap and Skin of Mango Fruit

1993 ◽  
Vol 20 (1) ◽  
pp. 99 ◽  
Author(s):  
SP Robinson ◽  
BR Loveys ◽  
EK Chacko
Keyword(s):  
Heat Treatment ◽  
Polyphenol Oxidase ◽  
Catechol Oxidase ◽  
Hexadecyltrimethylammonium Bromide ◽  
Temperature Optimum ◽  
Mango Fruit ◽  
Salicylhydroxamic Acid

Severe sapburn occurs in mango fruit of the cultivar Kensington when sap contacts the fruit, resulting in browning and then blackening of the skin. Both the sap and skin of mango fruit contained considerable polyphenol oxidase (PPO) activity. The sap enzyme was not activated by SDS, was inhibited by hexadecyltrimethylammonium bromide, and was active with both para- and ortho-diphenol substrates. The skin enzyme was activated by SDS, was inhibited by salicylhydroxamic acid and polyvinylpyrrolidone, and was active only with ortho-diphenol substrates. These properties suggest that the sap PPO is a laccase-type enzyme (EC 1.10.3.2) whereas the skin contains the more common catechol oxidase-type PPO (EC 1.10.3.1). The skin enzyme had a temperature optimum at 30�C but the sap enzyme had maximum PPO activity at 75�C. Both enzymes were relatively thermostable, requiring more than 15 min at 80�C for 50% loss of activity. It is concluded that browning of mango skin induced by the sap is predominantly catalysed by PPO in the skin and that this is unlikely to be prevented by heat treatment of the fruit.

Retention of mutant α1-antitrypsin Z in endoplasmic reticulum is associated with an autophagic response

2000 ◽  
Vol 279 (5) ◽  
pp. G961-G974 ◽  
Author(s):  
Jeffrey H. Teckman ◽  
David H. Perlmutter
Keyword(s):  
Endoplasmic Reticulum ◽  
Morphological Changes ◽  
Human Fibroblasts ◽  
Secretory Protein ◽  
Organ Injury ◽  
Morphological Alterations ◽  
Intracellular Degradation ◽  
Er Retention ◽  
Chemical Inhibitors ◽  
At Deficiency

Although there is evidence for specific subcellular morphological alterations in response to accumulation of misfolded proteins in the endoplasmic reticulum (ER), it is not clear whether these morphological changes are stereotypical or if they depend on the specific misfolded protein retained. This issue may be particularly important for mutant secretory protein α1-antitrypsin (α1AT) Z because retention of this mutant protein in the ER can cause severe target organ injury, the chronic hepatitis/hepatocellular carcinoma associated with α1AT deficiency. Here we examined the morphological changes that occur in human fibroblasts engineered for expression and ER retention of mutant α1ATZ and in human liver from three α1AT-deficient patients. In addition to marked expansion and dilatation of ER, there was an intense autophagic response. Mutant α1ATZ molecules were detected in autophagosomes by immune electron microscopy, and intracellular degradation of α1ATZ was partially reduced by chemical inhibitors of autophagy. In contrast to mutant CFTRΔF508, expression of mutant α1ATZ in heterologous cells did not result in the formation of aggresomes. These results show that ER retention of mutant α1ATZ is associated with a marked autophagic response and raise the possibility that autophagy represents a mechanism by which liver of α1AT-deficient patients attempts to protect itself from injury and carcinogenesis.

scholarly journals Sodium iron EDTA and ascorbic acid, but not polyphenol oxidase treatment, counteract the strong inhibitory effect of polyphenols from brown sorghum on the absorption of fortification iron in young women

2013 ◽  
Vol 111 (3) ◽  
pp. 481-489 ◽  
Author(s):  
Colin I. Cercamondi ◽  
Ines M. Egli ◽  
Christophe Zeder ◽  
Richard F. Hurrell
Keyword(s):  
Ascorbic Acid ◽  
Polyphenol Oxidase ◽  
Young Women ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Fe Isotopes ◽  
Absorption Studies ◽  
Oxidase Enzyme ◽  
Strong Inhibitory Effect

In addition to phytate, polyphenols (PP) might contribute to low Fe bioavailability from sorghum-based foods. To investigate the inhibitory effects of sorghum PP on Fe absorption and the potential enhancing effects of ascorbic acid (AA), NaFeEDTA and the PP oxidase enzyme laccase, we carried out three Fe absorption studies in fifty young women consuming dephytinised Fe-fortified test meals based on white and brown sorghum varieties with different PP concentrations. Fe absorption was measured as the incorporation of stable Fe isotopes into erythrocytes. In study 1, Fe absorption from meals with 17 mg PP (8·5 %) was higher than that from meals with 73 mg PP (3·2 %) and 167 mg PP (2·7 %;P< 0·001). Fe absorption from meals containing 73 and 167 mg PP did not differ (P= 0·9). In study 2, Fe absorption from NaFeEDTA-fortified meals (167 mg PP) was higher than that from the same meals fortified with FeSO4(4·6v.2·7 %;P< 0·001), but still it was lower than that from FeSO4-fortified meals with 17 mg PP (10·7 %;P< 0·001). In study 3, laccase treatment decreased the levels of PP from 167 to 42 mg, but it did not improve absorption compared with that from meals with 167 mg PP (4·8v.4·6 %;P= 0·4), whereas adding AA increased absorption to 13·6 % (P< 0·001). These findings suggest that PP from brown sorghum contribute to low Fe bioavailability from sorghum foods and that AA and, to a lesser extent, NaFeEDTA, but not laccase, have the potential to overcome the inhibitory effect of PP and improve Fe absorption from sorghum foods.

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