蛋清蛋白质凝胶质构特性的研究

蛋清蛋白质因具有良好的凝胶性能在肉制品、方便面等食品中有很好的应用,研究其凝胶质构特性可以为蛋清粉在这些食品中的应用提供重要的理论参考。本研究以蛋清粉为原料,通过旋转正交实验设计,研究蛋白质浓度、蛋清溶液的pH、加热温度、加热时间对凝胶形成的影响,采用物性仪对凝胶的质构特性如凝胶硬度和弹性进行了测定。结果表明,形成凝胶硬度最大的制备条件为:蛋白质浓度19%、蛋清溶液的pH5.5、温度85℃、加热时间55min;形成凝胶弹性最大的制备条件为:蛋白质浓度19%、蛋清溶液的pH6.0、温度78℃、加热时间40min。      

工艺条件对蛋清鲢鱼鱼糜凝胶特性的影响

为了提高鲢鱼糜品质及其附加值,采用质构分析法研究蛋清粉添加量、漂洗方式、加热方式及冻藏条件对蛋清鲢鱼鱼糜凝胶特性的影响。结果表明,蛋清粉添加量7.0%为宜;漂洗方式为先清水漂洗2次,再用1.0%NaCl漂洗1次,不宜用含有Ca~(2+)的漂洗液;二段式加热(水浴40℃加热60min—蒸汽85℃加热30 min)制备蛋清鲢鱼鱼糜凝胶较理想;蛋清鲢鱼鱼糜冻藏7d内凝胶劣化明显。通过最佳工艺条件,蛋清鲢鱼鱼糜凝胶特性显著改善。     

小麦淀粉凝胶质构特性研究

为了掌握不同小麦品种淀粉凝胶质构特性;陕西关中小麦品种和西澳面条用小麦品种的淀粉凝胶质构的异同;淀粉的直链淀粉含量、色度及粘度特性与淀粉凝胶质构特性的关系。以参加陕西省关中小麦品种区域试验的15个小麦品种(品系)、西澳8个面条用小麦品种(品系)为材料,研究了小麦品种淀粉凝胶质构特性及淀粉特性与凝胶质构特性的关系。结果表明:不同小麦品种淀粉凝胶质构特性不同,陕西关中小麦品种之间淀粉凝胶质构特性比西澳面条小麦品种之间差异大。直链淀粉含量与凝胶特性无明显关系;色度中L值与凝胶硬度呈显著正相关;粘度特性与淀粉凝胶质构特性显著相关。关中小麦品种小偃6号、小偃128、秦农068和西澳面条小麦品种具有相似的凝胶质构特性。     

卡拉胶凝胶质构特性的研究

研究了卡拉胶凝胶的质构特性。结果表明,影响卡拉胶凝胶硬度的主次因素依次为:〔K+〕、离子强度、〔Ca2+〕、卡拉胶浓度、pH、〔Mg2+〕;影响其弹性的因素依次为:〔K+〕、离子强度、卡拉胶浓度、〔Ca2+〕、pH、〔Mg2+〕。形成较好凝胶的条件为:卡拉胶浓度10～20mg/mL、pH5、离子强度0.3、〔K+〕0.05mol/L、〔Ca2+〕0.025～0.05mol/L。在肌原纤维蛋白中添加卡拉胶能明显增加凝胶的硬度、弹性和保水性。      

蛋清蛋白凝胶特性影响因素的研究

本实验对影响蛋清蛋白凝胶特性的内部因素和外部因素进行了研究。结果表明,蛋清蛋白的凝胶特性与静电作用、氢键、二硫键、蛋白质浓度、PH值、加热温度、加热时间等密切相关。因此,在应用蛋清蛋白凝胶特性的过程中要考虑这些因素。     

蛋清蛋白质凝胶化机理的研究进展

蛋清蛋白质以其优异的凝胶性能广泛应用于食品加工中,而加工中不同的诱导方式和条件使其形成凝胶的类型及性能均有较大差异,凝胶化机理也有所不同。本文主要从凝胶形成诱导方式及其条件出发,着重介绍热诱导和强碱诱导下蛋清蛋白质凝胶化机理的研究进展,以期为进一步丰富和完善蛋清蛋白质凝胶化机理理论体系的研究提供参考。      

蛋清蛋白质凝胶化机理的研究进展

蛋清蛋白质以其优异的凝胶性能广泛应用于食品加工中,而加工中不同的诱导方式和条件使其形成凝胶的类型及性能均有较大差异,凝胶化机理也有所不同。本文主要从凝胶形成诱导方式及其条件出发,着重介绍热诱导和强碱诱导下蛋清蛋白质凝胶化机理的研究进展,以期为进一步丰富和完善蛋清蛋白质凝胶化机理理论体系的研究提供参考。     

马铃薯蛋白与蛋清蛋白混合凝胶特性分析

以马铃薯蛋白(potato protein,PP)和蛋清蛋白(egg white protein,EWP)为原料制备热诱导混合凝胶,分析不同比例PP-EWP混合凝胶的质构、蛋白质二级结构、分子间作用力、游离巯基及流变性质的变化规律.结果 表明,随着PP含量的增加,混合凝胶的保水性由(73.5±0.71)％升高至(97....     

糖基化反应对蛋清蛋白质凝胶性的影响

为研究糖基化反应提高蛋清蛋白质凝胶性的机理,利用氨基酸分析仪、苯酚硫酸法、奥氏黏度计、静态激光散射仪对糖基化蛋清蛋白质氨基酸组成、总糖含量、特性黏度、粒径分布进行测定与分析。结果显示：糖基化反应可使蛋清蛋白质的凝胶强度和持水性分别提高91.7%和35.2%,且二者均在反应4d后达到最高值;糖基化处理5d后,蛋清蛋白质的赖氨酸含量相对降低28.42%,总糖含量增至2.18%;特性黏度随反应时间的延长增幅较小;糖基化蛋白粒径分布在0.1～50.0μm之间,糖基化2d内,粒径分布由小粒径峰向大粒径峰转变;糖基化2d后,粒径分布变化不明显。     

大豆分离蛋白凝胶制备和凝胶质构特性研究

本研究以大豆分离蛋白为原料，考察蛋白质浓度、pH值、加热温度、加热时间对凝胶形成的影响，采用物性仪对不同务件下制备的凝胶的质构特性进行研究，不同评价指标得出的结论不尽相同。通过正交实验得出形成凝胶硬度最大的制备条件为：蛋白浓度12％，pH值6．5，加热温度95℃，加热时间35min；形成凝胶脆性最大的制备凝胶争件为：蛋白浓度12％，pH值7．0，加热温度95℃，加热时间25min；形成凝胶弹性最好的制备凝胶务件为：蛋白浓度12％，pH值7．0，加热温度85℃，加热时间35min；形成凝胶粘附性最大的制备凝胶条件为：蛋白浓度12％，pH值7．0，加热温度95℃，加热时间35min。     

Structure and rheological properties of acid-induced egg white protein gels

This study compares the rheological properties of acid-induced gels prepared of industrial spray-dried egg white proteins (EWP) with the acid-induced gels prepared of ovalbumin (OA) and whey protein isolate (WPI). Also we aimed to form transparent gels of EWP by means of the cold-gelation process. We showed that it was not possible to prepare cold-set gels because ovotransferrin (OT), present in EWP, was found to interfere with fibril formation. Therefore, we developed a new purification method in which first OT was selectively denatured by a heating step, subsequently precipitated by acidification and removed by centrifugation. Finally, the supernatant was desalted by ultra filtration. This resulted in a preheated EWP preparation, which mainly contains OA (>80%). By removing OT using this new preheat procedure transparent gels were obtained after acid-induced gelation. Fracture properties of various EWP preparations were determined and compared with those of acid-induced gels of OA and WPI. Gels formed from different EWP preparations were weak (fracture stress 1–15 kPa, fracture strain 0.3–0.7), and the networks consisted of thin strands with hardly any additional disulphide bonds formed during the gelation step. In conclusion, the microstructure of the aggregates formed in the first step of the cold-gelation process and the amount of additional disulphide bonds formed during the second step appeared to be the determining factors contributing to the hardness and deformability of acid-induced gels of egg white proteins.     

棉籽球蛋白凝胶特性研究

该研究以棉籽球蛋白为原料,考察了棉籽球蛋白溶解度随pH的变化,并于中性条件下加热诱导棉籽球蛋白聚集形成凝胶。采用物性仪对不同条件下制备的凝胶质构特性进行研究。通过正交试验考察蛋白质浓度、pH、加热温度、加热时间对凝胶形成的影响,得出形成凝胶较为适宜的条件。     

Physicochemical and textural properties of heat-induced pea protein isolate gels

Chemical and thermal properties of pea protein isolates (laboratory prepared or native; PPIn and commercial; PPIc) and textural properties of heat-set gels obtained from pea protein isolates were compared with homologous soy protein isolates (laboratory prepared, or native; SPIn and commercial; SPIc). The protein banding pattern resulting from electrophoresis separation confirmed the presence of predominant storage proteins of pea and soy seeds in the respective protein products. PPIc and SPIc had lower nitrogen solubility than their native counterparts, likely due to their denaturated state which was further confirmed by the absence of distinct endotherms in these commercial materials compared to the laboratory prepared ones. Addition of NaCl at 1.0–2.0% (w/w) to PPIn and SPIn slurries increased thermal transition temperatures for both proteins.     

Comparative assessment of textural properties and microstructure of composite gels prepared from gelatine or gellan with maize starch and/or egg white

Single component gels (SCG) were formed from gelatine, gellan, maize starch or egg white, while binary composite gel (BCG) and ternary composite gel (TCG) were formed by mixing gelatine or gellan with maize starch and/or egg white. Each type of SCG exhibited distinct textural and microstructure characteristics. Gelatine‐SCG was the softest to hold but has the strongest and the most elastic network compared with other SCG. The effects of gelatine or gellan proportions on the textural properties of composite gels were investigated using mixture design experiments. Gelatine and gellan yielded composite gels that showed different textural behaviours and microstructure. All BCG and TCG blends showed antagonistic effects; the composite gels were softer and weaker as compared to the SCG. Gelatine‐BCG and TCG were comparatively stronger than those of gellan due to their different gelling mechanisms, in which the former had yielded a denser network structures as compared to the latter.     

Changes in the textural and flavor characteristics of egg white emulsion gels induced by lipid and thermal treatment

Egg white (EW) and peanut oil (PO), show good gel and flavor properties and were used to study the effects of lipid and heat treatment on the texture and flavor of emulsion gels. Good emulsification was obtained at low protein concentrations, and extremely high or low protein concentrations were essential for the formation of emulsion gel hardness, whereas the chewiness of emulsion gels with intermediate protein concentrations was sensitive to heat treatment. A new nonflowing proton (H⁺) from EW and lipid was integrated, and the water and lipids were closely bonded with other macromolecules in EW-PO emulsions. The bound and free water were combined with nonflowing water in emulsion gels due to heat treatment. 2-Methylbenzyl alcohol, octanoic acid ethyl ester, phenol and nicotinyl alcohol were the main flavor components of EW and PO, whereas 3,5-diethyl-2-methyl-pyrazine and 1-methyl-1H-pyrrole-2-carboxaldehyde were produced during the formation of the EW-PO emulsion. The formation of methylene-benzeneacetonitrile, 1H-pyrrole-2-carboxaldehyde, etc., in EW-PO emulsion gels were affected by the proportion of PO. Phthalic acid, benzaldehyde, 2,3-dihydro-benzofuran, 4-bromo-3-chloro-N-(4-methylthiobenzylydene)-benzenamine, 2-aminopyridine, hexanal, heptaethylene glycol monododecyl ether, isophytol and nicotinyl alcohol, etc., were formed in EW-PO emulsion gels. The main and differential flavors of EW-PO emulsions (or gels) may be attributed to EW and peanut oil, and the variation in flavor emitted from peanut oil and EW-PO gels was induced by heat treatment.     

巴氏杀菌鸡蛋清液磷酸化改性及性质研究

以巴氏杀菌鸡蛋清为原料,利用三聚磷酸钠(STP)对鸡蛋清液进行磷酸化改性。通过单因素和正交试验确定了磷酸化最佳工艺条件,即反应pH 7.5,STP添加量4%,反应温度40℃,反应时间4h,该条件下磷酸化程度为50.96mg/g,并利用低场核磁共振(LF-NMR)辅助观察了反应过程中蛋白质与水分的结合情况。结果表明,鸡蛋清液经过磷酸化改性后,其溶解性、持水性、起泡性、乳化性均得到了改善。     

蒸蛋的制作工艺优化及其质构特性研究

以蒸蛋为研究对象,通过单因素实验,以鸡蛋质量30 g为基准,考察了水的添加量、盐的添加量、蒸制时间对蒸蛋感官品质和质构特性的影响,并通过响应面法优化了蒸蛋的制作工艺,应用逐步回归的方法建立了蒸蛋质构特性与感官评分之间的线性回归模型。实验结果表明,当水的添加量为69.6 g,食盐的添加量为0.50 g,蒸制时间为9.9 min时,蒸蛋的品质最佳。水的添加量、食盐的添加量、蒸制时间对蒸蛋的硬度、弹性、粘聚性、弹性模量均有显著的影响。      

蛋清蛋白乳化香肠的加工工艺研究

以新鲜猪肉、蛋清蛋白为主要原料制作乳化香肠,主要研究了腌制时间、乳化搅拌时间和肉糜斩拌时间对乳化香肠品质的影响。通过感官评价、剪切力、系水力三个指标进行正交分析确定最佳加工工艺,实验结果表明,腌制时间、乳化搅拌和肉糜斩拌都对乳化香肠品质均有不同程度的影响,通过正交试验得到乳化香肠的最佳加工工艺条件为腌制时间4d、乳化搅拌时间5min,乳化肉糜斩拌时间5min,在此最佳加工工艺条件下,乳化香肠的品质较佳。     

酶解对蛋清蛋白液起泡性能和乳化性能的影响

利用碱性蛋白酶水解蛋清蛋白,主要研究了酶用量、底物浓度和酶解时间对蛋清蛋白液起泡性能和乳化性能的影响。实验结果表明,酶解条件对蛋清蛋白液的起泡性能和乳化性能有一定程度的影响,当碱性蛋白酶酶解温度为45~50℃,pH6~8.5时,其最佳酶解条件为酶用量4%,底物浓度3%,酶解时间6h。在此最佳酶解条件下获得的蛋清蛋白酶解液起泡性为27.65%,发泡能力178.26,泡沫稳定性60.33%,乳化容量37.86%,乳化稳定性127.23,乳化活性指数134.53,乳状液稳定指数1.83。