本研究目的在于通过调整浸烫参数的方式减少淘汰蛋鸡在屠宰加工中的损失。以饲养日龄为400 d的淘汰蛋鸡作为研究对象,探究不同浸烫方式对其羽毛去除效果及皮下肌肉过熟程度的影响。分别设置三种温度和时间的浸烫组合:65℃-3 min(高温浸...本研究目的在于通过调整浸烫参数的方式减少淘汰蛋鸡在屠宰加工中的损失。以饲养日龄为400 d的淘汰蛋鸡作为研究对象,探究不同浸烫方式对其羽毛去除效果及皮下肌肉过熟程度的影响。分别设置三种温度和时间的浸烫组合:65℃-3 min(高温浸烫,High Temperature Scald,HS)、60℃-4 min 20 s(中温慢烫,Middle Temperature Slow Scald,MSS)、58℃-4 min 20 s(低温慢烫,Low Temperature Slow Scald,LSS),并以未经浸烫的淘汰蛋鸡作为对照组。通过测定浸烫后去羽力(Feather Retention Force,FRF)及计数残留羽毛数量表征浸烫脱毛效果。通过测定肉色、测量过熟区域深度、DSC扫描、拉曼光谱扫描表征不同浸烫处理对皮下肌肉过熟程度。浸烫后淘汰蛋鸡HS组与LSS组羽毛去除效果无显著差异,MSS组去羽力与残留羽毛数量显著低于另外两处理组(P<0.05),两种残留羽毛计数结果显示采用长时间浸烫能够使毛根数量减少。浸烫后鸡胸肉L*值显著高于对照组(P<0.05),其中HS组L*值比LSS、MSS组分别显著高出5.33与4.75(P<0.05)。沿肌纤维方向切割鸡胸肉发现截面出现明显分层(白色肉与正常肉),HS组白色肉厚度相比LSS组与MSS显著增加。DSC结果显示虽然三种浸烫处理均会使淘汰蛋鸡胸肉肌球蛋白变性,但是HS组胸肉中肌浆蛋白或胶原蛋白以及肌动蛋白的变性程度均高于其他两处理组。蛋白质二级结构相对含量显示HS组胸肉蛋白质变性程度最高。综合羽毛去除效果结果与胸肉过熟结果,得到淘汰蛋鸡最适浸烫参数为:60℃-4 min 20 s。本研究在抑制浸烫中皮下肌肉过熟程度的同时提升了浸烫脱毛效果,为企业屠宰淘汰蛋鸡提供技术参考。展开更多
A single molecule theory for protein dynamics has been developed since 2012. It consists of the concepts of conformational Gibbs free energy function (CGF) and single molecule thermodynamic hypothesis (STH) that claim...A single molecule theory for protein dynamics has been developed since 2012. It consists of the concepts of conformational Gibbs free energy function (CGF) and single molecule thermodynamic hypothesis (STH) that claims that all stable conformations are (local or global) minimizers of CGF. These are enough to give a unified explanations and mechanisms to many aspects of protein dynamics such as protein folding;allostery;denaturation;and intrinsically disordered proteins. Formulas of CGF in water environment had been derived via quantum statistics. Applications of them to soluble proteins are: docking Gibbs free energy difference formula and a practical way to search better docking site;single molecule binding affinity;predicting and explaining why structures of a monomeric globular protein looks like a globule and is tightly packed with a hydrophobic core;a representation of the hydrophobic effect;and a wholistic view to structures of water soluble proteins.展开更多
The characterization of microbial communities of different depth sediment samples was examined by a culture-independent method and compared with physicochemical parameters, those are organic matter （OM）, total nitro...The characterization of microbial communities of different depth sediment samples was examined by a culture-independent method and compared with physicochemical parameters, those are organic matter （OM）, total nitrogen （TN）, total phosphorus （TP）, pH and redox potential （Eh）. Total genomic DNA was extracted from samples derived from different depths. After they were amplified with the GC-341 f/907r primer sets of partial bacterial 16S rRNA genes, the products were separated by denaturing gradient gel electrophoresis （DGGE）. The profile of DGGE fingerprints of different depth sediment samples revealed that the community structure remained relatively stable along the entire 45 cm sediment core, however, principal-component analysis of DGGE patterns revealed that at greater sediment depths, successional shifts in community structure were evident. The principle coordinates analysis suggested that the bacterial communities along the sediment core could be separated into two groups, which were located 0-20 cm and 21-45 cm, respectively. The sequencing dominant bands demonstrated that the major phylogenetic groups identified by DGGE belonged to Bacillus, Bacterium, Brevibacillus, Exiguobacterium, γ-Proteobacterium, Acinetobacter sp. and some uncultured or unidentified bacteria. The results indicated the existence of highly diverse bacterial community in the lake sediment core.展开更多
Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especi...Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especially when proteins are used as drug molecules or vaccines. It is preferred to add pharmaceutical excipients in protein formulations to avoid denaturation and thereby stabilize them. The present study aimed at using bile salts(BSs), a group of well-known drug delivery systems, for stabilization of proteins.Bovine serum albumin(BSA) was taken as the model protein, whose association with two BSs, namely sodium cholate(Na C) and sodium deoxycholate(Na DC), was studied. Denaturation studies on the preformed BSA-BS systems were carried out under chemical and physical denaturation conditions. Urea was used as the chemical denaturant and BSA-BS systems were subjected to various temperature conditions to understand the thermal(physical) denaturation. With the denaturation conditions prescribed here,the data obtained is informative on the association of BSA-BS systems to be hydrophobic and this effect of hydrophobicity plays an important role in stabilizing the serum albumin in its native state under both chemical and thermal denaturation.展开更多
The denaturational behaviour of bovine β-lactoglobulin B has been studied in solutions containing guanidine hydrochloride by differential scanning calorimetry. The experiments have shown that complete peaks of cold d...The denaturational behaviour of bovine β-lactoglobulin B has been studied in solutions containing guanidine hydrochloride by differential scanning calorimetry. The experiments have shown that complete peaks of cold denaturation can be recorded also in high concentration of protein solutions. The cold denaturation and the renaturation of the protein are reproducible, but the thermal denaturation is irreversible. The activation energy of thermal denaturation calculated is about 285 kJ/mol.展开更多
文摘本研究目的在于通过调整浸烫参数的方式减少淘汰蛋鸡在屠宰加工中的损失。以饲养日龄为400 d的淘汰蛋鸡作为研究对象,探究不同浸烫方式对其羽毛去除效果及皮下肌肉过熟程度的影响。分别设置三种温度和时间的浸烫组合:65℃-3 min(高温浸烫,High Temperature Scald,HS)、60℃-4 min 20 s(中温慢烫,Middle Temperature Slow Scald,MSS)、58℃-4 min 20 s(低温慢烫,Low Temperature Slow Scald,LSS),并以未经浸烫的淘汰蛋鸡作为对照组。通过测定浸烫后去羽力(Feather Retention Force,FRF)及计数残留羽毛数量表征浸烫脱毛效果。通过测定肉色、测量过熟区域深度、DSC扫描、拉曼光谱扫描表征不同浸烫处理对皮下肌肉过熟程度。浸烫后淘汰蛋鸡HS组与LSS组羽毛去除效果无显著差异,MSS组去羽力与残留羽毛数量显著低于另外两处理组(P<0.05),两种残留羽毛计数结果显示采用长时间浸烫能够使毛根数量减少。浸烫后鸡胸肉L*值显著高于对照组(P<0.05),其中HS组L*值比LSS、MSS组分别显著高出5.33与4.75(P<0.05)。沿肌纤维方向切割鸡胸肉发现截面出现明显分层(白色肉与正常肉),HS组白色肉厚度相比LSS组与MSS显著增加。DSC结果显示虽然三种浸烫处理均会使淘汰蛋鸡胸肉肌球蛋白变性,但是HS组胸肉中肌浆蛋白或胶原蛋白以及肌动蛋白的变性程度均高于其他两处理组。蛋白质二级结构相对含量显示HS组胸肉蛋白质变性程度最高。综合羽毛去除效果结果与胸肉过熟结果,得到淘汰蛋鸡最适浸烫参数为:60℃-4 min 20 s。本研究在抑制浸烫中皮下肌肉过熟程度的同时提升了浸烫脱毛效果,为企业屠宰淘汰蛋鸡提供技术参考。
文摘A single molecule theory for protein dynamics has been developed since 2012. It consists of the concepts of conformational Gibbs free energy function (CGF) and single molecule thermodynamic hypothesis (STH) that claims that all stable conformations are (local or global) minimizers of CGF. These are enough to give a unified explanations and mechanisms to many aspects of protein dynamics such as protein folding;allostery;denaturation;and intrinsically disordered proteins. Formulas of CGF in water environment had been derived via quantum statistics. Applications of them to soluble proteins are: docking Gibbs free energy difference formula and a practical way to search better docking site;single molecule binding affinity;predicting and explaining why structures of a monomeric globular protein looks like a globule and is tightly packed with a hydrophobic core;a representation of the hydrophobic effect;and a wholistic view to structures of water soluble proteins.
基金This work was supported by the National Basic Research Program （973） of China （No. 2002CB412307） the Hi-Tech Research and Development Program （863） of China （No. 2002AA601011） the National Natural Science Foundation of China （No. 40371102）.
文摘The characterization of microbial communities of different depth sediment samples was examined by a culture-independent method and compared with physicochemical parameters, those are organic matter （OM）, total nitrogen （TN）, total phosphorus （TP）, pH and redox potential （Eh）. Total genomic DNA was extracted from samples derived from different depths. After they were amplified with the GC-341 f/907r primer sets of partial bacterial 16S rRNA genes, the products were separated by denaturing gradient gel electrophoresis （DGGE）. The profile of DGGE fingerprints of different depth sediment samples revealed that the community structure remained relatively stable along the entire 45 cm sediment core, however, principal-component analysis of DGGE patterns revealed that at greater sediment depths, successional shifts in community structure were evident. The principle coordinates analysis suggested that the bacterial communities along the sediment core could be separated into two groups, which were located 0-20 cm and 21-45 cm, respectively. The sequencing dominant bands demonstrated that the major phylogenetic groups identified by DGGE belonged to Bacillus, Bacterium, Brevibacillus, Exiguobacterium, γ-Proteobacterium, Acinetobacter sp. and some uncultured or unidentified bacteria. The results indicated the existence of highly diverse bacterial community in the lake sediment core.
基金DSTSERB,India(SB/FT/CS-032/2012),for the financial support
文摘Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especially when proteins are used as drug molecules or vaccines. It is preferred to add pharmaceutical excipients in protein formulations to avoid denaturation and thereby stabilize them. The present study aimed at using bile salts(BSs), a group of well-known drug delivery systems, for stabilization of proteins.Bovine serum albumin(BSA) was taken as the model protein, whose association with two BSs, namely sodium cholate(Na C) and sodium deoxycholate(Na DC), was studied. Denaturation studies on the preformed BSA-BS systems were carried out under chemical and physical denaturation conditions. Urea was used as the chemical denaturant and BSA-BS systems were subjected to various temperature conditions to understand the thermal(physical) denaturation. With the denaturation conditions prescribed here,the data obtained is informative on the association of BSA-BS systems to be hydrophobic and this effect of hydrophobicity plays an important role in stabilizing the serum albumin in its native state under both chemical and thermal denaturation.
基金This project was supported by the National Natural Science Foundation of China
文摘The denaturational behaviour of bovine β-lactoglobulin B has been studied in solutions containing guanidine hydrochloride by differential scanning calorimetry. The experiments have shown that complete peaks of cold denaturation can be recorded also in high concentration of protein solutions. The cold denaturation and the renaturation of the protein are reproducible, but the thermal denaturation is irreversible. The activation energy of thermal denaturation calculated is about 285 kJ/mol.
