In this study, the Alaska pollock protein isolate(APPI) was hydrolyzed by Neutrase for 20, 40, 80, 120, 160, 200, and 240 min. Hydrolysates with different molecular weights were produced and they were named as H1–H7....In this study, the Alaska pollock protein isolate(APPI) was hydrolyzed by Neutrase for 20, 40, 80, 120, 160, 200, and 240 min. Hydrolysates with different molecular weights were produced and they were named as H1–H7. Furthermore, the effects of hydrolysis on the average molecular weights, functional properties(solubility, oil-holding capacities, foaming activities, and emulsifying properties), and antioxidant activities(1, 1-diphenyl-2-picrylhydrazyl, superoxide, and hydroxyl free radical-scavenging activities) were determined. It was found that when the degree of hydrolysis(DH) increased, the average molecular weights of the hydrolysates decreased significantly. The functional properties of APPI were also significantly improved. The hydrolysates of APPI exhibited better solubility, emulsifying activities, and foaming activities. Hydrolysates with low molecular weights(<1 kDa) had better solubility, oil-holding capacities, and emulsifying activities, while hydrolysates with higher molecular weights(>1 kDa) had better foaming activities. In addition, the hydrolysates exhibited excellent antioxidant properties, while the inhibition values of 1, 1-diphenyl-2-picryl hydroxyl(DPPH), superoxide, and hydroxyl free radical-scavenging activities, were 85.22%, 53.56%, and 75.00% respectively, when the concentration of the hydrolysates was 5.0 mg mL^(-1). The lower the average molecular weight was, the higher was the antioxidant activity. These results indicated that hydrolysis with Neutrase is an effective method for improving the functional and antioxidant properties of APPI. The hydrolysates of APPI displayed great potentials to be used as natural antioxidants in protein-rich aqueous foods such as nutrient supplements and sports beverages.展开更多
Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilizati...Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilization/precipitation(ISP) processing; however, the functional properties of this process is limited by the large amount of water-insoluble proteins. In this study, we investigated the influence of high hydrostatic pressure(HHP) treatment on the solubility and structural changes of PPI. PPI obtained using ISP is treated with hydrostatic pressures of 200, 300, 400, and 500 MPa for up to 15 min, and the HHP-treated samples were observed to exhibit significantly improved solubilities. Further biochemical assays reveal that the continuous HHP treatments reduce the contents of free sulfhydryl groups and promote the formation of macromolecules with better water solubilities, which may induce the solubility improvements of the HHP-treated PPI. Our results indicate that HHP can be utilized to effectively prepare highly water-soluble Alaska pollock protein in food processing.展开更多
Fish skin collagen hydrolysates(FSCH) were prepared from walleye pollock(Theragra chalcogramma) using a mixture of enzymes,namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH ...Fish skin collagen hydrolysates(FSCH) were prepared from walleye pollock(Theragra chalcogramma) using a mixture of enzymes,namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1 000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems,including diphenylpicrylhy-drazyl radical(DPPH),superoxide anion radical,hydroxyl radical and hydrogen peroxide model,and compared with that of a native antioxidant,reduced glutathione(GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore,FSCH may have potential applications in the medicine and food industries.展开更多
This article will discuss a false dichotomy between two models,the modern art studio and the post-studio,which oppose the private and the public,the individual and the collective,hiding and the revealing.We will begin...This article will discuss a false dichotomy between two models,the modern art studio and the post-studio,which oppose the private and the public,the individual and the collective,hiding and the revealing.We will begin by analysing Daniel Buren’s position in his canonical text“Fonction de l’Atelier”and his practice,where the artist defines the foundations of post-studio work.As the text also describes a New York studio type that must be left behind,we will analyse Jackson Pollock’s and Andy Warhol’s workspaces through drawing reconstructions to demonstrate that these meet the defining characteristics of both models.It will be shown that the artists have used design strategies to retain certain aspects of studio culture while exploring others of the post-studio.This turning point reveals that the current belief about the obsolescence of the studio in a global era defined by communication,networking and mobility ignores its emerging post-studio qualities.This work aims to acknowledge this shift,obtaining a critical vision that will allow us to design contemporary workspaces avoiding stereotypical and reductionist approaches.展开更多
该研究选用0.2%腺嘌呤高蛋白饮食诱导的慢性肾衰竭小鼠模型,探究狭鳕鱼蛋白肽(protein peptides of pollock,THP)对慢性肾衰竭的改善作用。结果表明,口服400μg/mL THP可以有效缓解腺嘌呤诱导的慢性肾衰竭小鼠的肾脏损伤。THP可以改善...该研究选用0.2%腺嘌呤高蛋白饮食诱导的慢性肾衰竭小鼠模型,探究狭鳕鱼蛋白肽(protein peptides of pollock,THP)对慢性肾衰竭的改善作用。结果表明,口服400μg/mL THP可以有效缓解腺嘌呤诱导的慢性肾衰竭小鼠的肾脏损伤。THP可以改善小鼠的生长状态,促进小鼠饮食,增加小鼠体质量。通过对血清尿素氮和肌酐含量测定发现,THP显著降低尿素氮和肌酐含量(P<0.01),改善肾脏功能。THP还能明显减轻管腔扩张和肾间质炎性浸润的症状,下调促炎因子肿瘤坏死因子-α、白细胞介素-6、白细胞介素-1β和白细胞介素-18的mRNA相对水平;同时减轻肾脏细胞外基质过度生产和纤维化,下调人Ⅰ型胶原蛋白和纤维连接蛋白-1的mRNA相对水平。综上,THP能有效改善慢性肾衰竭小鼠的肾脏损伤状态,表明其具有保护肾脏的功效。展开更多
基金supported by grants from the China Postdoctoral Science Foundation to Dr.Chuyi Liu(No.2016M592251)
文摘In this study, the Alaska pollock protein isolate(APPI) was hydrolyzed by Neutrase for 20, 40, 80, 120, 160, 200, and 240 min. Hydrolysates with different molecular weights were produced and they were named as H1–H7. Furthermore, the effects of hydrolysis on the average molecular weights, functional properties(solubility, oil-holding capacities, foaming activities, and emulsifying properties), and antioxidant activities(1, 1-diphenyl-2-picrylhydrazyl, superoxide, and hydroxyl free radical-scavenging activities) were determined. It was found that when the degree of hydrolysis(DH) increased, the average molecular weights of the hydrolysates decreased significantly. The functional properties of APPI were also significantly improved. The hydrolysates of APPI exhibited better solubility, emulsifying activities, and foaming activities. Hydrolysates with low molecular weights(<1 kDa) had better solubility, oil-holding capacities, and emulsifying activities, while hydrolysates with higher molecular weights(>1 kDa) had better foaming activities. In addition, the hydrolysates exhibited excellent antioxidant properties, while the inhibition values of 1, 1-diphenyl-2-picryl hydroxyl(DPPH), superoxide, and hydroxyl free radical-scavenging activities, were 85.22%, 53.56%, and 75.00% respectively, when the concentration of the hydrolysates was 5.0 mg mL^(-1). The lower the average molecular weight was, the higher was the antioxidant activity. These results indicated that hydrolysis with Neutrase is an effective method for improving the functional and antioxidant properties of APPI. The hydrolysates of APPI displayed great potentials to be used as natural antioxidants in protein-rich aqueous foods such as nutrient supplements and sports beverages.
基金supported by grant from China Postdoctoral Science Foundation to Dr. Chuyi Liu (No. 2016 M592251)
文摘Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilization/precipitation(ISP) processing; however, the functional properties of this process is limited by the large amount of water-insoluble proteins. In this study, we investigated the influence of high hydrostatic pressure(HHP) treatment on the solubility and structural changes of PPI. PPI obtained using ISP is treated with hydrostatic pressures of 200, 300, 400, and 500 MPa for up to 15 min, and the HHP-treated samples were observed to exhibit significantly improved solubilities. Further biochemical assays reveal that the continuous HHP treatments reduce the contents of free sulfhydryl groups and promote the formation of macromolecules with better water solubilities, which may induce the solubility improvements of the HHP-treated PPI. Our results indicate that HHP can be utilized to effectively prepare highly water-soluble Alaska pollock protein in food processing.
基金supported by the High Technology Research and Development Program of China (No. 2006AA09Z438)the National Natural Science Foundation of China (No. 30871943).
文摘Fish skin collagen hydrolysates(FSCH) were prepared from walleye pollock(Theragra chalcogramma) using a mixture of enzymes,namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1 000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems,including diphenylpicrylhy-drazyl radical(DPPH),superoxide anion radical,hydroxyl radical and hydrogen peroxide model,and compared with that of a native antioxidant,reduced glutathione(GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore,FSCH may have potential applications in the medicine and food industries.
文摘This article will discuss a false dichotomy between two models,the modern art studio and the post-studio,which oppose the private and the public,the individual and the collective,hiding and the revealing.We will begin by analysing Daniel Buren’s position in his canonical text“Fonction de l’Atelier”and his practice,where the artist defines the foundations of post-studio work.As the text also describes a New York studio type that must be left behind,we will analyse Jackson Pollock’s and Andy Warhol’s workspaces through drawing reconstructions to demonstrate that these meet the defining characteristics of both models.It will be shown that the artists have used design strategies to retain certain aspects of studio culture while exploring others of the post-studio.This turning point reveals that the current belief about the obsolescence of the studio in a global era defined by communication,networking and mobility ignores its emerging post-studio qualities.This work aims to acknowledge this shift,obtaining a critical vision that will allow us to design contemporary workspaces avoiding stereotypical and reductionist approaches.
文摘该研究选用0.2%腺嘌呤高蛋白饮食诱导的慢性肾衰竭小鼠模型,探究狭鳕鱼蛋白肽(protein peptides of pollock,THP)对慢性肾衰竭的改善作用。结果表明,口服400μg/mL THP可以有效缓解腺嘌呤诱导的慢性肾衰竭小鼠的肾脏损伤。THP可以改善小鼠的生长状态,促进小鼠饮食,增加小鼠体质量。通过对血清尿素氮和肌酐含量测定发现,THP显著降低尿素氮和肌酐含量(P<0.01),改善肾脏功能。THP还能明显减轻管腔扩张和肾间质炎性浸润的症状,下调促炎因子肿瘤坏死因子-α、白细胞介素-6、白细胞介素-1β和白细胞介素-18的mRNA相对水平;同时减轻肾脏细胞外基质过度生产和纤维化,下调人Ⅰ型胶原蛋白和纤维连接蛋白-1的mRNA相对水平。综上,THP能有效改善慢性肾衰竭小鼠的肾脏损伤状态,表明其具有保护肾脏的功效。
