APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Cong Wang,Shaoyi Jia,Yongchao Zhang,Yao Nian,Yan Wang,You Han,Yong Liu,Haitao Ren,Songhai Wu,Kexin Yao,Xu Han
SO 4 − and OH radicals are important oxidative species that play important roles in the oxidation of organic contaminants by peroxomonosulfate (PMS)/persulfate (PS) and Co 3 O 4 under acidic conditions. However, the facet effect of Co 3 O 4 on the catalytic oxidation of phenol by PS under alkaline conditions has not been investigated yet. In this study, we synthesized three Co 3 O 4 nanoparticles with different facets [rod (110), cube (100) and octahedra (111)]. The Co 3 O 4 rods show the highest catalytic reactivity in the oxidation of phenol by PS, followed by Co 3 O 4 cubes and Co 3 O 4 octahedra. Quenching experiments and EPR analysis rule out contributions of SO 4 − , OH, O 2 − and 1 O 2 to phenol oxidation and suggest that H-abstraction from phenol to phenoxyl radicals is an important pathway in all Co 3 O 4 -PS systems. The analysis of total organic carbon (TOC) and solid characterizations reveal that more than 96.6 % phenol has been transformed into polyphenols, instead of being mineralized into smaller organic molecules or CO 2 in the rod-PS-phenol system. The DFT (density functional theory) calculations further confirm that PS is more readily activated via a non-radical pathway on the Co 3 O 4 (110) plane with appropriate Co(II)-Co(II) distances, and the activated O O bonds then abstract H atoms from phenol molecules with the production of phenoxyl radicals, as well as SO 4 − and OH radicals. The produced phenoxyl radicals then link together to form dimers, trimers, oligomers and eventually insoluble polymers. This study not only enriches our understanding on the facet effect of different Co 3 O 4 in the oxidation of phenol, but also gives new insight into turning phenolic wastes into polyphenol "treasures".
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Kaibo Yu,Lei Zhou,Yuefang Sun,Zicong Zeng,Huiwen Chen,Junping Liu,Liqiang Zou,Wei Liu
Enzymatic browning control of cloudy fruit juice with natural substances has received much attention for improving its nutritional and commercial value. This study explored the anti-browning potential of Rosa roxburghii in apple juice. The anti-browning effects and mechanisms were evaluated by serial measurements of appearance, browning index, polyphenol oxidase (PPO) activity, UPLC-QE-Orbitrap-MS identification, inhibition kinetics and molecular docking. The results showed that Rosa roxburghii juice (0.25%-1.25% w/w) could effectively inhibit browning and PPO activity of apple juice. Ascorbic acid (1.67 g/100 g) as a reducing agent was a main anti-browning factor. Furthermore, seven phenolic compounds in Rosa roxburghii were screened as PPO inhibitors. Representative phenolic inhibitors induced mixed or competitive inhibition of PPO, mainly driven by hydrophobic forces and hydrogen bonds. This work demonstrates that Rosa roxburghii is a promising natural anti-browning ingredient to control the browning of cloudy apple juice due to abundant ascorbic acid and PPO inhibitors.
研究领域:
食品科学
·
植物化学
✓ 已验证
DOI
PubMed
高影响因子
Frontiers in Plant Science
·
2023
·
IF 5.6
Shengnan Zhai,Hang Liu,Xianchun Xia,Haosheng Li,Xinyou Cao,Zhonghu He,Wujun Ma,Cheng Liu,Jianmin Song,Aifeng Liu,Jingjuan Zhang,Jianjun Liu
Polyphenol oxidase (PPO) activity is a major cause of the undesirable brown color of wheat-based products. Ppo1 , a major gene for PPO activity, was cloned based on sequence homology in previous studies; however, its function and regulation mechanism remain unclear. In this study, the function and genetic regulation of Ppo1 were analyzed using RNA interference (RNAi) and Targeting Induced Local Lesions IN Genomes (TILLING) technology, and superior mutants were identified. Compared with the control, the level of Ppo1 transcript in RNAi transgenic lines was drastically decreased by 15.5%–60.9% during grain development, and PPO activity was significantly reduced by 12.9%–20.4%, confirming the role of Ppo1 in PPO activity. Thirty-two Ppo1 mutants were identified in the ethyl methanesulfonate (EMS)-mutagenized population, including eight missense mutations, 16 synonymous mutations, and eight intron mutations. The expression of Ppo1 was reduced significantly by 6.7%–37.1% and 10.1%–54.4% in mutants M092141 (G311S) and M091098 (G299R), respectively, in which PPO activity was decreased by 29.7% and 28.8%, respectively, indicating that mutation sites of two mutants have important effects on PPO1 function. Sequence and structure analysis revealed that the two sites were highly conserved among 74 plant species, where the frequency of glycine was 94.6% and 100%, respectively, and adjacent to the entrance of the hydrophobic pocket of the active site. The M092141 and M091098 mutants can be used as important germplasms to develop wheat cultivars with low grain PPO activity. This study provided important insights into the molecular mechanism of Ppo1 and the genetic improvement of wheat PPO activity.
研究领域:
植物学
·
遗传学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2016
·
IF 2.624
Lei Zhou,Wei Liu,Zhiqiang Xiong,Liqiang Zou,Junping Liu,Junzhen Zhong,Jun Chen
Polyphenoloxidase (PPO) plays an important role in the browning of vegetables, fruits and edible fungi. The effects of ultrasound, malic acid, and their combination on the activity and conformation of mushroom ( Agaricus bisporus ) PPO were studied. The activity of PPO decreased gradually with the increasing of malic acid concentrations (5–60 mM). Neither medium concentrations (10, 20, 30 mM) malic acid nor individual ultrasound (25 kHz, 55.48 W/cm 2 ) treatment could remarkably inactivate PPO. However, the inactivation during their combination was more significant than the sum of ultrasound inactivation and malic acid inactivation. The inactivation kinetics of PPO followed a first-order kinetics under the combination of ultrasound and malic acid. The conformation of combination treated PPO was changed, which was reflected in the decrease of α-helix, increase of β-sheet contents and disruption of the tertiary structure. Results of molecular microstructure showed that ultrasound broke large molecular groups of PPO into small ones. Moreover, combined treatment disrupted the microstructure of PPO and molecules were connected together.
研究领域:
食品科学
·
生物化学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Yang Zhao,Ze-Hua Huang,Hui-Ming Zhou,Ke-Xue Zhu,Xiao-Na Guo,Wei Peng
The role of polyphenol oxidase (PPO) in the browning of fresh wet noodle sheets (FWNS) was discussed. To release the chemical formation mechanism of the dark spots formed on FWNS, the reconstituted FWNS and PPO-catechol reaction systems were prepared. Different from the overall color change of FWNS, almost all the melanins in dark spots were indirect products of PPO catalysis. The PPO catalytic dehydrogenation was an essential step for the formation of dark spots, but once the phenol dehydrogenation products were formed, the dark spots could still form through a further polymerization process, even though the PPO was completely deactivated. The optimum pH for the phenolic dehydrogenation in FWNS was about 7, and the alkaline condition was advantageous to the progress of the polymerization. Comprehensively, the maximum amount of dark spots was formed at about pH 9.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Jinghao Li,Jie Liu,Gengsheng Xiao,Lu Li,Yujuan Xu,Yuanshan Yu,Zhanhong Liang,Sai Xu,Lina Cheng
The synergistic effect of the initial state of the enzyme and pressure level on the denaturation of PPO has not been clear yet, but it significantly affects the application of high hydrostatic pressure (HHP) in the enzyme-containing food processing. Solid (S-) and low/high concentration liquid (LL-/HL-) polyphenol oxidase (PPO) was used as the study object, and the microscopic conformation, molecular morphology and macroscopic activity of PPO under HHP treatments (100–400 MPa, 25 °C/30 min) were investigated by spectroscopic techniques. The results show that the initial state has a significant effect on the activity, structure, active force and substrate channel of PPO under pressure. The effec can be ranked as follows: physical state > concentration > pressure, S-PPO > LL-PPO > HL-PPO. High concentration has a weakening effect on the pressure denaturation of the PPO solution. Under high pressure, the α-helix and concentration factors play a crucial role in stabilizing the structure.
研究领域:
食品科学
·
酶学
✓ 已验证
DOI
PubMed
高影响因子
Vietnam Journal of Chemistry
·
2023
·Vol. 61
·期 2
·204-209
·
IF 0.9
Nguyen Van Vinh Ha,Nguyen Thi Thu Ha,Ong Ngoc Khanh,Dinh Truc Phuong,Ho Thanh Nhat,Nguyen Thanh Tung
Herein we reported a method for copper pivalate mediated, directed functionalization of ortho C−H bonds in (2-methylthio)aniline benzamides. Diaryl disulfides were used for thiolation, while successful phenoxylation was obtained with phenol as the coupling agent. Our report marks a rare example for flexible transformation of benzamide C(sp 2 )−H bonds into the corresponding unsymmetrical diaryl ethers and thioethers.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2017
·
IF 4.529
Zhenna Zhang,Juan Wang,Xueying Zhang,Qingli Shi,Le Xin,Hongfei Fu,Yunyang Wang
This paper is focused on the effects of radio frequency (RF) heating on the relative activity of polyphenol oxidase (PPO), weight loss, texture, color, and microstructure of potatoes. The results showed that pure mushroom PPO was almost completely inactivated at 80 °C by RF heating. The relative activity of potato PPO reduced to less than 10% with increasing temperature (25–85 °C). Enzyme extract showed the lowest PPO relative activity at 85 °C after RF treatment, followed by the potato cuboids and mashed potato, about 0.19 ± 0.017%, 3.24 ± 0.19%, and 3.54 ± 0.04%, respectively. Circular dichroism analysis indicated that RF heating changed the secondary structure of PPO, as α-helix content decreased. Both electrode gap and temperature had significant effect ( P < .05) on weight loss, color, and texture of the potato cuboids. Microstructure analysis showed the changes of potato cell and starch during RF heating.
研究领域:
食品科学
·
食品工程
·
生物物理学
·
酶学
·
农产品加工
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Ran Yang,Jun Cai,Hu Yang
Zero-valent aluminum (ZVAl) is a promising reductant because of its relatively low redox potential , which can efficiently activate molecular oxygen to generate reactive oxygen species . However, its long-term performance is limited by the intrinsic dense oxide layer and the passivation effect of the accumulative Al-(hydr)oxide on its surface during the reaction. In this study, four clay minerals with different compositions were mixed with ZVAl by ball milling to obtain four composites of ZVAl and clay (ZVAl-Clay), which were used to degrade a high concentration of 4-chlorophenol (4-CP) under ambient conditions. The oxidation efficiencies of different ZVAl-Clays were strongly relevant to Fe contained in the clay minerals. The Fe-free ZVAl-Clay presented poor oxidation performance, whereas the reaction efficiencies of those ZVAl composites with Fe-bearing clays exhibited varying degrees of improvement. In comparison with the original ZVAl, the highest oxidation rate increased by 23 times, the maximum increased OH production was approximately 8 times, and the corresponding mineralization efficiency improved by 38.7%. However, the levels of improved oxidation performance of various ZVAl-Clays were not positively correlated with their actual total Fe contents, and their degradation efficiencies might also be affected by other physical and/or chemical properties of different clays. The synergistic mechanism revealed by various characterizations was that electron transfer might occur from ZVAl to the structural Fe(III) of the clay through the basal plane or edge of clays triggered by ball milling. Thus, the partially produced Fe(II) on the clay surface promoted the Fenton-like reaction to decompose H 2 O 2 into OH for efficient oxidation of 4-CP. In short, the ZVAl composites with Fe-bearing clays deserved further exploration as potential materials for efficient degradation of organic matters in wastewater samples.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Yanyue Liu,Yisheng Sun,Mengting Ye,Liqin Zhu,Lili Zhang,Shuhua Zhu
Nitroxyl (HNO) has attracted much attention due to its unique biological activity. To investigate the preservation effect of HNO on fruits, a nitroxyl liposome based on 1-nitrosocyclohexyl acetate was prepared and characterized by infrared spectroscopy and transmission electron microscopy. The optimal preparation conditions were explored, and then HNO liposomes were prepared under the optimal conditions to study the effect of HNO liposomes on postharvest quality of tomatoes. The tomato fruits were treated with different concentrations (0, 5, 10, 15 and 20 μmol L -1 ) of HNO liposomes and stored at room temperature. The results indicated that treatment with HNO liposomes can more effectively delay the browning and slow down the decrease in lightness of tomatoes. Additionally, HNO liposomes can reduce the activity of PPO and POD, inhibit the increase of MDA and total phenol content. These results suggest that treatment with HNO liposomes can effectively preserve the quality of tomatoes.
研究领域:
植物学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Yang Zhao,Ze-Hua Huang,Hui-Ming Zhou,Ke-Xue Zhu,Xiao-Na Guo,Wei Peng
Hexose oxidase was a feasible prevention for the dark spots in the fresh wet noodle sheets (FWNS). The chemical mechanism that hexose oxidase recucing the melanins of dark spots was discussed basis on the UPLC-TOF-MS analysis of the polyphenol oxidase (PPO)-catechol system. In the process of PPO browning, hexose oxidase catalyzed the oxidation of o -benzoquinone derivatives and their oligomers, hindering the formation of melanins. Hexose oxidase was efficient in FWNS with low ash content when water addition was 24%~44% or pH range was 4 ~ 7.5. Hexose oxidase could inhubit dark spots in the presence of 10 metal ions. The recommended addition amount was 40 ~ 60 ppm, by which the dark spots could be compolitely inhibited. Hexose oxidase was also suitable for wholewheat and oat FWNS, Δ L 6d of wholewheat and oat FWNS were reduced by 4 and 7.98, respectively.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food and Bioprocess Technology
·
2019
·Vol. 12
·期 11
·1907-1916
·
IF 3.032
Zhou Lei,Liao Tao,Liu Junping,Zou Liqiang,Liu Chengmei,Liu Wei
The activity of polyphenoloxidase (PPO) treated by acidic pH and mild thermal processing was found to be closely related to the conformational changes. Weakly acidic environment (pH 4.0–6.0) resulted in reversible inhibition of activity and slight changes in the conformation, and refolding of PPO was observed after readjusting pH to 6.8. At pH lower than 4.0, PPO activity was strongly inhibited with great unfolding in conformation and all changes were irreversible. Acidic environment increased the susceptibility of PPO to thermal treatment, and greater changes in activity and conformation of PPO were observed under the combined treatment of acidic pH and mild thermal treatment. Besides, the inactivation of PPO induced by thermal treatment followed a biphasic kinetic model, and acidic pH increased the inactivation rate of labile and stable PPO. The combination of acidic pH and mild thermal processing expected to avoid the nutritional loss and sensory damage in fruits and vegetables caused by severe acid or temperature.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）