花生浓缩蛋白对鸡胸肉盐溶蛋白热诱导凝胶性能的影响

本文研究了花生浓缩蛋白对鸡胸肉盐溶蛋白热诱导凝胶性能的影响。对添加花生浓缩蛋白后的鸡胸肉盐溶蛋白热诱导凝胶的质构特性、动态流变特性以及热变特性进行测定并通过扫描电镜观察其微观结构。结果表明,添加花生浓缩蛋白后,鸡胸肉盐溶蛋白热诱导凝胶性能得以改善。当添加量为2.5%时,凝胶硬度及强度达到最大,最大值分别为52.5 g、93.02 g×cm;凝胶的储能模量G’显著提高(P0.05),其损耗角正切值tanδ明显降低(P0.05);凝胶的变性温度(Tmax)及变性焓(ΔH)显著提高(P0.05),当添加量为3.5%时,Tmax1、Tmax2、Tmax3和ΔH增至最大,分别为54.02℃、65.02℃、76.52℃、0.694 J/g;凝胶微观的三维网络结构更加紧密、有序,蛋白质交联度更高。因此,花生浓缩蛋白可以有效改善鸡胸肉盐溶蛋白热诱导凝胶硬度和强度、弹性、热稳定性以及微观结构等特性。     

牛肉盐溶蛋白质热诱导凝胶特性研究

实验以牛背最长肌为材料,采用L9（3^4）正交设计研究了MgCl2、NaCl和pH值对盐溶蛋白质热诱导凝胶特性的影响。研究表明,在0．01mol／LMgCh．0．6mol／LNaCl．pH值7．0条件下牛背最长肌盐溶蛋白质热诱导凝胶保水性最好,为92．25％,破断应力最高,为14．00kPa。NaCl浓度和pH值对凝胶保水性和凝胶强度均有显著影响（p〈0．01）。MgCl12仅对凝胶破断应力影响较大。凝胶的超微结构分析表明,保水性高的凝胶的网络结构比较致密,大量的微细孔洞均匀分布。保水性低的凝胶的网络结构中线条多呈束状、结构粗糙、不均匀。     

淀粉对鸡胸肉盐溶性蛋白乳化特性的影响

添加不同质量分数淀粉处理鸡胸肉盐溶性蛋白,研究淀粉含量对鸡胸肉蛋白质乳化特性的影响。结果表明：随着淀粉质量分数的增加,处理组淀粉蛋白乳化液的乳化活性和乳化稳定性均先上升后下降,乳化液中D10、D50和D90的粒径值逐渐降低,剪应力和黏度均为先下降后上升。此外,随着剪切速率的升高,不同处理组剪应力逐渐增加,而黏度均先下降随后趋于稳定。相关性分析结果表明：乳化液中淀粉质量分数与微粒D10的粒径（相关系数r＝－0.598）成极显著负相关（P＜0.01）,乳化活性与微粒D50的粒径（相关系数r＝0.549）、微粒D90的粒径（相关系数r＝0.558）均成显著正相关（P＜0.05）。这些结果说明适宜含量的淀粉添加至鸡胸肉盐溶性蛋白中,使得乳化液体系更稳定,形成的淀粉-蛋白质复合物会影响鸡胸肉蛋白质的加工特性。     

Gelation Properties and Morphology of Heat-induced Starch/Salt-soluble Protein Composites

ABSTRACT: The formation of starch (potato, corn, and rice) and ham salt-soluble protein (SSP) composite during heating was studied using thermal and rheological analysis. Measurements from differential scanning calorimetry showed that the peak temperature of starch/SSP composite was slightly lower than that of the corresponding starch. SSP exhibited an initial G' higher than zero and became a rigid structure as indicated by the decrease in tan δ after heating. The data of tan 8 δ illustrated that starch and protein transition proceeded independently. Scanning electron microscopy and light microscopy with the aid of histologic technique revealed the network and distribution of starch and protein in starch/SSP composite.     

竹笋膳食纤维对猪肉盐溶性蛋白热诱导凝胶特性的影响

通过提取猪肉盐溶性蛋白,添加不同比例（0%、1%、2%、3%、4%（猪肉盐溶性蛋白为100 g添加竹笋膳食纤维））的竹笋膳食纤维,应用质构仪、流变仪、低场核磁共振成像分析仪和扫描电镜测定分析竹笋膳食纤维-猪肉盐溶性蛋白形成的凝胶体系的凝胶强度、动态流变学特性、保水性、水分分布和微观结构,研究竹笋膳食纤维对凝胶体系的凝胶特性和保水性的影响。结果发现：添加竹笋膳食纤维显著增强凝胶体系的凝胶强度（P＜0.05）,当添加量为3%时,凝胶强度最高;随着竹笋膳食纤维添加量增加,猪肉盐溶性蛋白体系的储能模量（G’）和损失模量（G”）明显增加,凝胶体系的蒸煮损失和离心损失显著降低（P＜0.05）;低场核磁显示竹笋膳食纤维的添加显著提高了不易流动水的相对百分比并且降低了其弛豫时间T2（P＜0.05）;扫描电镜观察发现竹笋膳食纤维增加了凝胶体系的三维网络结构致密度和均一度。结果显示竹笋膳食纤维能够明显改善猪肉盐溶性蛋白的凝胶功能特性,在肉制品加工中有广阔的应用前景。     

Thermal Aggregation Properties of Duck Salt-Soluble Proteins at Selected pH Values

Thermal aggregation properties of duck breast and leg salt-soluble proteins (SSP) were studied at pH 5.50, 5.75 and 6.00. At pH 5.50, a major transition for breast was observed at 60.3°C and for leg at 41.8°C. At pH 5.75, major transitions at 44.6 and 43.2°C were obtained, respectively, for the breast and leg SSP. Three transitions at 46.0, 53.0 and 59.0°C were exhibited by breast SSP at pH 6.00, whereas only two major transitions at 47.4 and 54.0°C were identified in leg SSP. Changes in transition peak heights and shifts in transition temperatures as a result of pH changes indicated that, depending on fiber type, pH may enhance or suppress the aggregation behavior of specific constituents of the myosin/actomyosin complex, thereby altering the overall aggregation pattern of the protein preparation.     

木薯淀粉对猪肉盐溶蛋白凝胶特性的影响

研究了添加木薯淀粉对猪肉盐溶蛋白凝胶功能特性的影响。用质构仪、流变仪和离心法测定了凝胶质构、动态流变和保水性的变化,用低场核磁共振仪和扫描电镜分析了凝胶的水分状态和微观结构变化。结果表明,添加木薯淀粉不仅改善了猪肉盐溶蛋白凝胶的质构和保水性能,还改变了凝胶成型温度,单独盐溶蛋白凝胶储能模量在72℃时已达到最大值,添加木薯淀粉凝胶储能模量在80℃达到最大值;当木薯淀粉添加量为1.5%时,凝胶的硬度、弹性和保水性均达到最大,分别为379.02 g、0.85和85.16%,低场核磁共振分析表明添加1.5%木薯淀粉提高了凝胶的结合水和不易流动比例,从而提高了凝胶的保水性能,扫描电镜观察发现此时木薯淀粉主要通过填充效应贯穿在盐溶蛋白分子空隙之间,使凝胶更加紧密和有序。     

Gelation of Proteins from Washed Muscle of Threadfin Bream (Nemipterus japonicus) under Mild Acidic Conditions

Gelation of proteins of washed mince of threadfin bream was induced by the organic acids: acetic, lactic, tartaric, and citric. Washing of mince was essential for gelation. The strength of acetic acid-induced gel was affected by setting conditions and heat treatment. Gelation was associated with degradation of myosin heavy chain and appearance of a new protein band of about 160 kDa. Solubility studies of the gel in various solvents suggested structural changes. Gelation was also associated with oxidation of sulfhydryl groups. Salts negatively influenced gelation.     

磷酸盐对肌球蛋白热凝胶硬度、保水性和超微结构的影响

本文研究了焦磷酸钠(SPP)、三聚磷酸钠(TPP)和六偏磷酸钠(HMP)对肌球蛋白热诱导凝胶硬度、保水性和超微结构的影响。结果显示：SPP和TPP使凝胶硬度下降，HMP则相反：SPP和TPP可降低PM和提高SMp凝胶的保水性，而HMP可增大两者保水性；扫描电子显微镜观察凝胶超微结构发现，SPP、TPP使得蛋白凝胶网络中交联轴变长，孔洞直径变大，HMP的影响程度要小于前两者。     

Structural and Functional Properties of Caseinate and Whey Protein Isolate as Affected by Temperature and pH

The structural properties, i.e., active sulfhydryl (SH), flexibility and hydrophobicity, and functional properties, i.e., solubility, emulsion activity (EA), emulsion stability (ES), foam overrun (FO) and foam stability (FS), of commercial sodium caseinate (SC) and whey protein isolate (WPI) solutions were investigated at pH 6, 7 and 8 and at 25, 55 and 65°C. WPI contained a higher concentration of active SH and was more hydrophobic than SC. WPI provided comparable solubility and EA, lower FO, but higher FS than SC. Temperature and pH effects on the two proteins were somewhat inconsistent.     

鳙鱼宰后pH值和僵直指数的变化及其对盐溶蛋白凝胶特性的影响

以鳙鱼为材料,研究宰后冰藏期间pH值和僵直指数的变化及其对鳙鱼盐溶蛋白热诱导凝胶特性的影响。结果表明：宰后鳙鱼pH值迅速降低,宰后冰藏10h 时pH值由7.26降至6.51,冰藏48h后pH值开始上升。僵直指数从宰后冰藏19h开始增加,48h达到最大,最大僵直指数为72.1%。宰后冰藏1h的鳙鱼盐溶蛋白凝胶强度最低,随着僵直指数的增加,凝胶强度不断增大,僵直指数最大时,凝胶强度最大。当僵直指数开始下降,凝胶强度缓慢降低。     

Foaming Properties of Proteins as Affected by Concentration

Commercial sodium caseinate and whey protein isolate were evaluated at protein concentrations 0.25 to 16% with ovalbumin solutions as reference. Logarithmic models were developed to express the effect of protein concentration on foam expansion and serum drainage. The kinetics of gas release from milk protein-stabilized foams followed a three-phase pattern. Low foam collapse rates were observed in initial and final phases while rapid collapse occurred during the transition phase. No transition was observed for ovalbumin-stabilized foams. Globally, foam collapse rate increased with increasing protein concentration. Apparent viscosity of protein-stabilized foams increased with concentration to a maximum; beyond which, a reverse trend was observed. Maximum viscosities of milk protein foams were at concentrations & lt;0.5%, while ovalbumin foams showed maximum viscosity around 2% protein.     

Phosphates and Muscle Fiber Type Influence Thermal Transitions in Porcine Salt-Soluble Protein Aggregation

Salt-soluble proteins (SSP) were extracted from porcine Serratus ventralis (red), Vastus intermedius (red) and Longissimus dorsi (white) muscles and heated to examine dynamic changes and transitions in protein aggregation. At pH 6.0, red muscle SSP typically showed 1 or 2 transitions and white muscle SSP exhibited 3 transitions. Addition of ortho-, pyro-, tripoly- and hexametaphosphate up to 1% increased SSP transition temperatures and altered transition patterns; NaCl at comparable ionic strengths did not show this effect. SSP transitions were most affected by 0.15-0.25% tripolyphosphate and low pH (<6.0). Red and white SSP exhibited different thermal properties and responses to phosphate treatments. These findings indicate red and white muscle types should undergo different processing treatments for optimum quality meat products.     

猪肉盐溶性蛋白热诱导凝胶特性的研究

盐溶性蛋白是影响猪肉制品的保水性及凝胶特性的一类最主要蛋白质,其中对蛋白质热凝胶起决定作用的是肌球蛋白.本试验以猪肉为原料,首先通过单因素试验研究贮藏时间、离子强度、磷酸盐等因素的影响,再通过正交试验得出猪背最长肌(P1d)盐溶蛋白最合适的提取条件:MgCl2浓度0.01 mol/L、NaCl浓度0.5 mol/L、焦磷酸钠及多聚磷酸钠的比例均为0.4%.     

不同添加剂对鸡肉盐溶蛋白质热诱导凝胶性质的影响

采用质构分析法、动态流变分析法、差示扫描微量热法研究大豆分离蛋白、花生蛋白、卡拉胶对鸡胸肉和鸡腿肉盐溶蛋白热诱导凝胶性质的影响。试验结果表明:不同添加剂可在不同程度上改善鸡胸肉和鸡腿肉盐溶蛋白热诱导凝胶特性,其中卡拉胶添加效果最好。由动态流变学分析可知,鸡胸肉和鸡腿肉盐溶蛋白形成凝胶存在不同作用机理。热稳定性分析表明,鸡肉混合蛋白热诱导凝胶形成主要与肌球蛋白有关,肌动蛋白作用效果不明显。不同添加剂可增强鸡胸肉和鸡腿肉盐溶蛋白的变性温度和变性热,其中大豆分离蛋白添加效果最显著。     

血清蛋白质加热凝胶的形成

家畜血液中含有丰富的蛋白质。血液的主要成分——血清或血浆与卵白都有经加热可以形成凝胶的相同性质。食品中蛋白质凝胶的形成能力直接影响着食品的品质。通过对一定浓度的牛和猪的血清蛋白质加热形成凝胶强度的评价,分析了血清中主要蛋白质成分在凝胶形成过程中的作用及其机理。结果表明:牛血清的凝胶强度高于猪血清;牛血清中的白蛋白在血清加热凝胶形成过程中起着重要作用;通过加热血清蛋白,蛋白质分子间的二硫键交联形成凝胶;利用血清蛋白质经加热可以形成凝胶的性质将血清添加到食品中,不仅可以改善食品的品质,而且还可以提高食品中蛋白质的含量。     

Gelation of Egg White Proteins as Affected by Combined Heating and Freezing

Combined effects of preheating (60°C, 0 ～ 30 min) and freezing (– 10 or –20°C, 20 hr) on the gelation of dried egg white induced by reheating (80°C, 30 min) were examined in comparison with those of refrigerating (5°C, 20 hr). Refrigeration consistently induced harder gels, while freezing resulted in either harder or softer gels. Results of soluble protein content, turbidity, SDS-PAGE and gel filtration indicated that the unfolded and aggregated levels of ovotransferrin, caused by the cooperative effects of preheating and freezing or refrigerating, mainly determined the characteristics of gel properties.     

Heat-induced Gelation of Chicken Gizzard Myosin

Chicken gizzard myosin solution formed a gel when heated above 40°C. The rigidity of the gel was constant above 65°C. Maximum pH for gel formation was 5.9 at 0.6M and 5.7 at 0.15M KCl. Higher rigidity of the myosin gel was observed at low ionic strength than at high ionic strength. Rigidities of myosin at 0.6M KCl increased by (mg/mL)^2.5 and at 0.15M (mg/mL)^{1, 4} myosin concentration. The strength of gizzard myosin gels was comparable to that of myosin gels from chicken breast muscle under similar conditions.     

Physical Properties of Extruded Products as Affected by Cheese Whey

Corn, rice and potato flour were extruded with sweet whey solids (SWS) or whey protein concentrate (WPC) using low and high shear extrusion processing conditions. WPC added at product content of 25% had minimal effect on the texture of extruded products. Expansion and breaking strength were improved in some processes through changes in extrusion shear and moisture. Whey product incorporation resulted in reduced specific mechanical energy input to the process. Increasing whey product concentration beyond 25% reduced expansion and water absorption indices significantly, affecting textural hardness. Product quality characteristics were directly related to the whey product content.     

Protease-Induced Aggregation and Gelation of Whey Proteins

Aggregation and gelation of whey proteins induced by a specific protease from Bacillus licheniformis was revealed by turbidimetry, size exclusion chromatography, dynamic light scattering and rheology. The microstructure of the gel was examined by transmission electron microscopy. During incubation of 12% whey protein isolate solutions at 40°C and pH 7, the major whey proteins were partly hydrolyzed and the solution gradually became turbid due to formation of aggregates of increasing size. The viscosity of the hydrolysate simultaneously increased and eventually a gel formed. The gel had a particulate type of microstructure. We hypothesized that the aggregates forming the gel were held together by noncovalent interactions.