共查询到19条相似文献,搜索用时 62 毫秒
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用乳清浓缩蛋白WPC80 为原料,在复合酶A 的作用下,研究乳清肽的制备工艺。复合酶A 的反应条件为[S]12g/100mL、温度50℃、[E]/[S]3%、pH9.0。选用截留分子质量10kD 的磺化聚砜膜,常温并在工作压差0.25MPa 下对水解液进行超滤处理后,选用树脂HZ00x 对水解液进行脱苦,得到的处理液无明显的苦涩味,只有轻微的蛋腥味,最后肽得率36.54%。产品中肽的分子质量分布以二、三和四肽为主,分别占峰面积的27.45%、34.88% 和26.65%。 相似文献
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乳清浓缩蛋白(WPC)相比β-乳球蛋白和乳清分离蛋白(WPI)成分更为复杂,其热聚合形成纤维聚合物的条件不同于β-乳球蛋白和WPI的形成条件.在pH值为1.8,90 ℃热处理10h的条件下,蛋白质量分数为3%的WPC可形成良好的纤维聚合物.通过测定表观度、乳化性和起泡性,比较乳清浓缩蛋白纤维聚合物与常规聚合物界面性质的差异,结果表明,纳米纤维聚合物具有较低的表观度,乳化性能和起泡性能有显著改善. 相似文献
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超滤浓缩乳清蛋白并分离乳糖的研究 总被引:1,自引:0,他引:1
采用管式超滤装置,选用切割分子量为20000的聚丙烯腈膜,对乳清进行了超滤浓缩试验。结果表明,降低乳清pH值可提高透液通量,把乳清调整至pH7.0,再离心除去不溶性钙盐,可获得最大透液透量。中性乳清经离心沉降后,在进口压力0.24MPa,温度45℃条件下浓缩180min,平均透液通量达到29.1kg/m2·h,蛋白质含量提高到2.85%,透过液中乳糖浓度变化不大。 相似文献
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为研究蛋白质-蛋白质相互作用对松仁蛋白(PKP)溶解度、结构和乳液性质的影响,以PKP和乳清浓缩蛋白(WPC)为研究对象,采用pH循环法制备PKP-WPC复合蛋白,利用SDS-PAGE、内源性荧光光谱、紫外-可见光谱、圆二色谱、荧光探针和ζ-电位等方法分析了复合蛋白结构特性和表面特性,再以PKP-WPC复合蛋白为原料,分别制备了油相体积分数为3%、10%和50%的乳液,并对制备的乳液性质进行了检测。结果表明:当WPC与PKP的质量比为1.0∶1.0,且体系pH值经历由7.0到12.0再回到7.0时的1次pH循环后,PKP的水溶性可从48.53%提高到92.43%。SDS-PAGE结果显示,PKP-WPC复合蛋白完整保留了PKP和WPC的亚基。内源性荧光光谱、紫外-可见光谱和圆二色谱结果表明,静电相互作用、疏水相互作用和氢键是驱动PKP和WPC相互作用的主要作用力,PKP与WPC相互作用使复合蛋白具有较高的结构韧性,抵抗酸诱导的构象折叠;WPC的加入改变了PKP的二级结构,α-螺旋、β-转角和无规卷曲结构的含量增加,而β-折叠结构相对含量降低。PKP-WPC复合蛋白具有较高的表面电荷(-34.74mV)来抵抗蛋白质的聚集。与由PKP制备的乳液相比,由PKP-WPC制备的乳液平均粒径和乳层析指数减小,ζ-电位绝对值增大,稳定性显著提高。乳液的性质因油相体积分数的不同而有较大的差异。油相体积分数为3%的复合乳液液滴小且分布均匀,稳定性好于油相体积分数为10%和50%的复合乳液。通过pH循环法,通过添加WPC,提高了PKP的溶解度,获得了稳定性较佳的PKP乳液,研究可为新型蛋白产品的研发提供理论基础,拓宽松仁蛋白在加工食品中的应用范围,推动PKP-WPC双蛋白乳液研究的发展。 相似文献
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婴幼儿时期是人一生中生长发育速度是快的阶段,因而也是对蛋白质等营养物质需要量最大的时期。如向婴幼儿食品中加入乳清浓缩制品,将对婴幼儿的快速生长及营养保健均有重要产本文着重分析乳清主要与婴幼儿的营养保健关系。 相似文献
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Microencapsulating Properties of Whey Protein Concentrate 75 总被引:3,自引:0,他引:3
ABSTRACT Emulsions containing various levels of soya oil dispersed in solutions of whey protein concentrate (WPC) 75 (5% w/v) were spray-dried to yield powders with oil contents ranging from 20% to 75% (w/w). The effect of homogenizing pressure and oil/protein ratio on oil globule size distributions and protein load of the emulsions and the microencapsulation efficiency (ME) and redispersion behavior of the powders were examined. Emulsion oil droplet size decreased with increasing homogenization pressure but was not affected by oil/protein ratio. Emulsion protein load and ME of the powders were negatively correlated with increasing oil/protein ratio. Powders with an oil/protein ratio < 0.75 were least susceptible to destabilization during spray-drying. 相似文献
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Gel strengths (work of penetration) of surimi (refined minced fish, MF) alone and in combination with egg white or whey protein concentrate were periodically measured by an annular pump during constant rate heating. Combination gels containing low percentages of MF were of a lesser strength than an additive relationship would have predicted. However, the strength of gels containing greater percentages of MF did relate to the gel strengths of the uncombined proteins. 相似文献
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The Spherosil-QMA ion exchange process was used to prepare whey protein concentrate (WPC) from cheese whey. The process recovered about 64% of the proteins from whey as a 63% protein WPC. The WPC contained about 20.8% lactose, glucose, and galactose. The WPC proteins ranged in solubility from about 32–42% as a function of pH 3–7 and appeared to have undergone substantial denaturation by HPLC but not by palyacrylamide gel electrophoresis. The gelation properties of WPC were compared with those of commercial and ultrafiltration WPCs as a function of pH 3–7.5 and 0.0–0.15M NaCl and CaCl2. The WPC did not function well as egg replacer in model cake and custard formulations. 相似文献
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Effects of Added Egg White or Whey Protein Concentrate on Thermal Transitions in Rigidity of Croaker Surimi 总被引:1,自引:0,他引:1
Rigidities of surimi [refined minced fish (MF)] sols, alone and in combination with egg white (EW) and whey protein concentrate (WPC) were measured during constant-rate heating by a nondestructive technique. Each of the protein types tested showed measureable changes due to variation of the heating rate or NaCl concentration of the sol. Rigidity and differential scanning calorimetric (DSC) thermograms for mixtures resembled composites of the individual protein source profiles, indicating that no major changes occurred in thermal gelling properties of the component proteins due to mixing. Maximum rigidity values indicated more favorable gelation of MF/WPC than MF/EW combinations. 相似文献
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目的:对易吸湿的蛋白/多糖类气凝胶进行疏水改性并对其性能进行评估。方法:对乳清分离蛋(whey protein isolate,WPI)-普鲁兰多糖(pullulan,PUL)复合气凝胶进行低温等离子体处理,使其羟基充分暴露后,使用硅烷偶联剂进行表面接枝处理,获得具有疏水性能的复合气凝胶,并研究其吸湿性、疏水疏油性、抗压性能、热失重、精油装载与缓释性能等。结果:甲基三甲氧基硅烷(methyltrimethoxysilane,MTMS)改性后复合气凝胶的平衡吸湿率为(9.67%±0.323%),十八烷基三甲氧基硅烷(octadecyltrimethoxysilane,OTMS)改性后复合气凝胶平衡吸湿率为(9.34%±0.276%),相比为改性前(11.41%±0.506%)均明显降低;改性前,复合气凝胶水接触角为(40.14°±2.16°),油接触角为(28.07°±2.43°);MTMS改性后水接触角为(82.10°±4.78°),油接触角为(56.14°±3.25°);OTMS改性后水接触角为(85.21°±4.61°),油接触角为(74.63°±3.08°);改性后疏水疏油性均有所提升,且OTMS改性处理效果更好。改性前复合气凝胶压缩模量(21.745±1.982)MPa,MTMS改性后(17.655±3.034)MPa,OTMS改性后(18.412±3.513)MPa。改性后抗压强度略有降低,但不影响正常使用。改性前复合气凝胶丁香精油的最大装载率为(254.26%±5.585%),MTMS疏水改性后丁香精油最大装载率(241.57%±5.214%),OTMS组则为(223.31%±4.436%)。丁香精油装载率有所下降但缓释性能均有所提升,且MTMS改性缓释效果更好。热稳定性方面均有所提升,且OTMS组热稳定性更好。结论:综上所述,硅烷接枝疏水改性处理可以显著提升复合气凝胶的疏水性并提高其亲油性。适用于油脂类活性物质的装载与缓释应用,拓宽了WPI-PUL复合气凝胶的应用领域。 相似文献
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The effect of pretreatment upon the composition and physicochemical and functional properties of whey, ultrafiltration (UF) retentate and freeze-dried and spray-dried whey protein concentrates (WPC) was investigated. Pretreatment was by cooling cheese whey to 0-5°C, adding calcium chloride, adjusting to pH 7.3, warming to 50°C, and removing the insoluble precipitate that formed by centrifugation or decantation. UF permeation flux rate of pretreated whey was about double that for control whey. Pretreated whey was essentially turbidity free, contained 85% less milkfat, 37% more calcium and 40% less phosphorus than whey. Pretreated whey WPC proteins were slightly more soluble at pH 3, but less functional for emulsification than whey WPC proteins. Neither whey WPC proteins nor pretreated whey WPC proteins was functional for foaming at 6% protein concentration. 相似文献
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Composite flours are extensively used in the bakery industry to develop designer food products, having specific nutritional
or functional properties. Though rich in carbohydrate, cassava flour has not been properly exploited for making bakery products,
mainly because of its low protein content contributing to poor dough characteristics. Induced malting using amylolytic enzymes
and pregelatinization through hydrothermal cooking were tried to modify the textural and functional attributes of cassava
flour, which was then blended with various cereal and legume additives as well as rice bran and used for making two baked
products such as muffins and biscuits. Whey protein concentrate (WPC) was added to fortify protein in all the formulations.
Pseudo-malted cassava flour-based muffins and biscuits had lower starch content (36–44% and 36.5–41.2%, respectively) than
similar products from unmalted cassava flour (39–46% and 43.75%, respectively). The crude protein content of the muffins and
biscuits from WPC fortified composite mixes ranged from 7.96% to 14.36% and 9.63% to 11.00%, respectively, which was significantly
higher than the native cassava flour (1.30%). Besides, the total dietary fiber could be enhanced to the extent of 1.54–3.10%
in muffins and 1.70–2.61% in biscuits, through fortification with cereal and/or legume flours or bran sources, which is also
considerable when compared to only 0.435% in native cassava flour. In vitro starch digestibility was the lowest for cassava
(unmalted)-/rice bran-based muffins (25.02 units) and cassava (unmalted)-/finger millet flour-based biscuits (36.08 units),
indicating the potential of these combinations for making therapeutic baked products for obese and diabetic people. Spread
ratio and spread factor were the least (9.27 and 60.99, respectively) for the biscuits made with unmalted cassava/finger millet
mixes, while use of Termamyl pseudo-malted cassava/finger millet raised the spread ratio to 11.11 and spread factor to 73.09. 相似文献
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The effects of protein concentration and heating conditions on the physical properties of whey protein isolate (WPI) (in 50 mM NaCl, pH 7) and egg white (pH 9) gels were examined. Egg white and WPI gels had similar values for shear stress at fracture (i.e., isostrength), while trends for shear strain at fracture were protein-type specific. The rigidity ratio (R0.3 ), ratio of the rigidity at fracture (Gf ) to the rigidity at 30% of fracture strain, measured departure from the stress-strain relationship of an ideal Hookean solid. All gels fit master curves of Gf vs R0.3 , which were described by a power law model of R0.3 =A(Gf )-°19, where "A" showed protein type-specific characteristics. 相似文献