Purification, kinetic parameters, and isoforms of polyphenol oxidase from “Xushu 22” sweet potato skin

2020 ◽  
Vol 44 (11) ◽  
Author(s):  
Fengmao Li
2019 ◽  
Vol 32 (2) ◽  
pp. 537-542
Author(s):  
SAMARA LOPES DE ALMEIDA ◽  
MARIA APARECIDA DOS SANTOS MORAIS ◽  
JOSÉ RICARDO TAVARES DE ALBUQUERQUE ◽  
AURÉLIO PAES BARROS JÚNIOR ◽  
ADRIANO DO NASCIMENTO SIMÕES ◽  
...  

ABSTRACT Enzyme assays are based on methodologies described in the literature. However, the enzyme kinetics must be adjusted to obtain more reliable results. This study aimed to adjust assays by testing different polyphenol oxidase (PPO) and peroxidase (POD) extract amounts and reaction times in sweet potato cultivars harvested at different times. Sweet potato cultivars Paraná, Mãe de Família, and ESAM1 were harvested at 120, 150, and 180 days after planting and minimally processed. A 0.25 g sample was used to determine PPO and POD activities immediately after minimal processing at each harvest. Extraction was performed in 1500 μL phosphate buffer (0.2 M, pH 6.0). The PPO assay was performed by adding 10-50 μL extract, 1490-1450 μL phosphate buffer (0.2 M, pH 6.0), and 1500 μL catechol (0.2 M). The POD assay was carried out by adding 10-50 μL extract to a reaction medium containing 1790-1750 μL phosphate buffer (0.2 M, pH 6), 100 μl guaiacol (5 g L-1), and 100 μL hydrogen peroxide (0.8 g L-1). In both cases, the evaluated reaction times were 1, 2, and 3 min. In the three cultivars, PPO and POD activities increased with the volume of extract and reaction time at all harvest times. The enzyme extract volume of 10 μL for 2 min promoted a continuous increase in PPO and POD enzyme activities in all studied cultivars and at all reaction times.


2014 ◽  
Vol 898 ◽  
pp. 153-156 ◽  
Author(s):  
Lu Gao ◽  
Li Chun Zhao ◽  
Ji Dong Duan ◽  
Yan Li Tao

The polyphenol oxidase (PPO) was extracted from fresh purple sweet potato (PSP) by phosphate buffer solution, and spectrophotometry method was applied in the experiment. The process of the reaction catalyzed by PPO with different substrate concentrations and the relationship between enzyme concentrations and PPO activity were mainly studied here. The result showed that the effect of enzyme concentration on PPO activity was stronger than that of substrate concentration on PPO activity.


Author(s):  
T.G. Belawa Yadnya ◽  
AA. A.S. Trisnadewi ◽  
I Ketut Sukada ◽  
I Gusti Lanang Oka

An experiment was carried out to determine the effect of fermented purple sweet potato (Ipomoea batatas L) skin in diets on feed and anthocyanin consumption, carcass characteristics antioxidant profile and meat texture of Bali duck.. Five  treatment diets were used in a completely randomized design (CRD) consisted of control diet A (diet without containing purple sweet potato skin), diet B containing 10% purple sweet potato skin, diet C containing 10% fermented purple sweet potato skin, diet D containing 20% purple sweet potato skin, diet E containing 20% fermented purple sweet potato skin.Each treatment consisted of four replications and each replicate had five ducks. The variables observed were feed and anthocyanin consumption,slaughter weight, carcass weight, carcass percentage, carcass physical composition,  meat antioxidant profile (capacity antioxidant (CA), malondialdehide (MDA), and superoxide dismutase (SOD). Experiment results showed that diets with fermented or unfermented purple sweet potatoin diets treatments B, C, D, and E increased the anthocyanin  consumption,  slaughter weight, carcass weight, carcass percentage and meat percentage of duck carcass but decreased  their fat and skin. Fermented purple sweet potato (Ipomoea batatas L) skin  in  C and E increased the antioxidant capacity(AC)  and superoxide dismutase (SOD) while  treatment B and  D were not significantly different (P>0.05) to the control group.  Malondialdehide (MDA) of the duck meat in treatment B,C, and D were significantly lower (P<0.05) compared to the control diet. Treatment E significantly  increased the perimesium and endomesium of meat texture , but its experiment was not significantly different to the control group. It was concluded that substitution of fermented purple sweet potato (Ipomoea batatas L) skin in diets could improve of feed and anthocyanin, carcass characteristics, antioxidant profile, and meat texture of bali duck.


2016 ◽  
Vol 63 (2) ◽  
pp. 86-92
Author(s):  
Kazunori Sasaki ◽  
Itaru Sotome ◽  
Hiroshi Okadome ◽  
Yumi Kai ◽  
Tomoyuki Oki ◽  
...  

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Chenfei Gao ◽  
Michael King ◽  
John Finley ◽  
Frank Greenway ◽  
Michael Keenan ◽  
...  

1992 ◽  
Vol 40 (12) ◽  
pp. 2369-2373 ◽  
Author(s):  
Euclides J. Lourenco ◽  
Valdir A. Neves ◽  
Maraiza A. Da Silva

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