共查询到19条相似文献,搜索用时 125 毫秒
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脂质氧化诱导的大豆蛋白质聚集机理的研究 总被引:2,自引:0,他引:2
利用脂肪氧合酶、亚油酸和大豆分离蛋白构建的模拟体系,研究了脂质氧化诱导的大豆蛋白质聚集的机理。结果表明,在制备大豆分离蛋白的模拟体系中同时添加亚油酸和脂肪氧合酶会使样品的蛋白质氧化值与表面疏水性增加,巯基与二硫键的含量下降,说明脂肪氧合酶催化的脂质氧化可使大豆蛋白结构发生明显的改变。SDS-PAGE电泳表明大豆蛋白7S和11S的各个亚基均参与了反应,尤其是7S部分反应更为明显。HPLC凝胶色谱和激光光散射分析进一步证实反应后的大豆蛋白(RSPI4和5)形成了相对高分子质量和颗粒粒径较大的聚集体。现有的实验证据表明,高度聚集蛋白质的形成可能是通过包括二硫键在内的共价变联,以及诸如氢键、盐桥,尤其是疏水相互作用等的非共价相互作用,形成较大的聚集体。由脂肪氧合酶诱导的蛋白质一脂质相互作用模拟实验的结果说明。脂质氧化对大豆蛋白具有明显的影响;在大豆分离蛋白加工的过程中,控制脂肪氧合酶的活力或脂质的含量是非常重要的。 相似文献
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《食品科学》2020,(6)
为探讨酸化速率对葡萄糖酸内酯诱导的大豆分离蛋白凝胶结构的影响,通过不同的保温温度制备大豆蛋白凝胶样品,将pH值、浊度、凝胶强度、保水性、频率扫描及微观结构作为测定指标,反映葡萄糖酸内酯酸化速率和大豆蛋白凝胶结构的变化情况。结果表明:随着保温温度的不断升高,葡萄糖酸内酯凝固剂的释放速率越来越快,大豆分离蛋白凝胶的pH值下降速率增大;蛋白浊度不断增加,表明蛋白聚集速率的增加,凝胶体系在越来越短的时间达到稳定状态,保温温度与蛋白凝胶的酸化速率呈正比。随着酸化速率的增加,大豆分离蛋白凝胶的凝胶强度和刚性不断提高;保水性在60℃时达到最大值;微观结构的测定结果显示,在60℃保温的大豆分离蛋白凝胶结构更均匀致密。综上,酸化速率显著影响大豆分离蛋白凝胶结构,60℃保温时的酸化速率形成最致密均匀的凝胶结构。 相似文献
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凝胶特性是鱼糜制品品质的决定性因素之一。鱼糜制品是典型的多相、多组分食品体系,蛋白、多糖、脂质等主要组分间的相互作用是鱼糜凝胶网络结构形成的基础,并最终决定产品品质。目前鱼糜混合体系中多组分间的作用机制及其对鱼糜复合凝胶品质的影响机制尚未明确,制约其加工技术以及理论的创新。本文基于鱼糜凝胶的形成机理以及影响因素,综述蛋白类、多糖类、脂质类、多酚等外源添加物对鱼糜热诱导凝胶特性的影响,总结鱼糜组分间的作用规律及其对凝胶特性的影响规律,为新型鱼糜制品开发和凝胶品质调控提供理论依据。 相似文献
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1大豆蛋白制品产业存在的问题当今,在欧美市场上,大豆食品种类增加到万余种。各种大豆食品随处可见,如大豆汉堡、大豆热狗、大豆蛋糕、大豆冰淇淋、大豆奶酪、大豆饮料、大豆奶、大豆烘烤食品等。中国在大豆蛋白制品的应用方面起步较晚,始于20世纪80年代初。中国生产的大豆蛋白(包括浓缩蛋白)90%以上为食用级的凝胶型产品,产品质量水平接近,即趋于同质化,这加剧了大豆蛋白厂之间的竞争。到目前为止,虽然国内大豆分离蛋白厂总的年设计生产能力达5万吨以上,但是国内大豆分离蛋白的生产工艺大同小异,产品品种单一,功能特性较差,质量较美国同类… 相似文献
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为了揭示百里香酚纳米复合诱导大豆蛋白自组装凝胶的途径及机制,该文研究了蛋白浓度、百里香酚添加量、反应初始pH值和反应终止pH值对大豆蛋白与百里香酚相互作用及其凝胶形成的影响。结果表明:四者协同调控大豆蛋白-百里香酚纳米复合物凝胶的形成,百里香酚荷载量的提高可降低大豆蛋白凝胶的临界蛋白浓度(75 mg/mL),反应结束后调节pH值至中性是凝胶形成的必要条件。在pH值为7.0条件下,百里香酚复合诱导大豆蛋白产生了明显的纤维化聚集,其颗粒平均粒径增加27.60%、光散射强度提高154.67%、Th T荧光强度提高93.78%,因此推测百里香酚复合主要通过诱导大豆蛋白纤维化聚集的产生继而诱导凝胶的形成。大豆蛋白-百里香酚纳米复合物凝胶在尿素和DTT溶液中的溶解度提高,因而推测维持凝胶网络的分子间相互作用力主要为氢键、疏水相互作用力和二硫键。研究结果为大豆蛋白冷致凝胶提供了新的技术解决方案,并为百里香酚的开发利用提供理论支撑。 相似文献
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《Food Reviews International》2013,29(3):323-351
Abstract The most important chemical reactions during the process of soybean protein foods are the intermolecular reactions among the residues exposed on the surface of the protein molecules through the denaturation process. In native soybean protein molecules, most amino acid residues responsible for the reactions—such as cysteine (‐SH), cystine (S‐S), and hydrophobic amino acid residues—are buried in the inside region of the molecule, inaccessible to water. These residues become reactable with each other through the exposure from the inside by heat denaturation during processing. The unique textures of soybean protein foods, such as tofu, kori‐tofu, yuba, and texturized products produced by extruder, etc., are the results of both the intermolecular interchange reaction between the exposed ‐SH and S‐S groups and the intermolecular hydrophobic reaction among the exposed hydrophobic amino acid residues. The exposure of amino acid residues is also important for the hydrolysis of soybean proteins by enzymes, through which soy sauce is produced, because the cleavage of the peptide bonds is carried out after binding between the active sites of the enzymes and the enzyme‐specific amino acid residues exposed through denaturation. These facts indicate the importance of the three‐dimensional structures of soybean protein molecules in the technology of soybean protein foods. Recently great progress has been made in the manufacturing techniques of soybean protein foods, such as soy milk, tofu, abura‐age, textured protein products, and soy sauce. The quality of soy milk and tofu was very much improved by controlling the action of the biologically active substances such as lipoxygenases and β‐glucosidases which are contained in soybeans and responsible for the production of off‐flavor. A new abura‐age, whose texture does not deteriorate during frozen storage or drying, was developed by using soybean protein isolate and oil as materials. A new type of textured protein product was also developed: a deep‐fat‐fried nugget with unique texture and flavor. This product is textured through a twin‐type extruder. For soy sauce manufacturing new biotechnology has been applied on the pilot‐plant scale. This is a system of continuous fermentation through bioreactors with the immobilized whole cells of microorganisms, by which the fermentation term is shortened strikingly. New and important discoveries were made on the nutrition of soybean proteins. According to recent experiments using human beings, the amino acid score of soybean proteins is 100 for persons more than 2 years old, indicating that the nutritive value of soybean proteins is equal to animal proteins. Further, it was elucidated that soybean proteins have cholesterol‐lowering action. A discussion is presented on the future of the soybean protein foods. 相似文献
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大豆蛋白源配料特性对素肉饼品质的影响 总被引:1,自引:0,他引:1
主要研究了大豆拉丝蛋白和大豆分离蛋白(Soy protein isolate,SPI)2种大豆蛋白源配料的功能特性对素肉饼品质的影响。研究表明,大豆拉丝蛋白的蛋白含量越高,素肉饼的品质越高,主要表现在口感韧性强、弹性高,更接近肉的纤维状质构和口感;而在素肉饼配方一定的情况下,大豆分离蛋白的凝胶值对素肉饼的品质影响呈现先提升再降低的趋势,凝胶值太高、太低都会降低素肉饼的质构和口感,但通过配方的调整优化,可以缓解凝胶值太高对素肉饼品质的影响,同时可以提高素肉饼的得率。配料选用70%蛋白含量的大豆拉丝蛋白和凝胶值在600~700 g范围内的大豆分离蛋白利于素肉饼形成且更接近肉的质构和口感。 相似文献
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Soybean lipoxygenase was inactivated to different degrees by dry heating of defatted soybean flour for 0, 5, 10, 15, 20 and 25 min and soy protein isolates were prepared thereof by isoelectric precipitation of the water extract of the defatted soybean flour. The fluorescence emission intensity at 420 nm of the chloroform–methanol extract of soy protein isolates, which was indicator of the existence of peroxidized lipid, varied in parallel with the lipoxygenase residual activity in defatted soybean flours. The dispersion of soy protein isolate showed an increasing turbidity with the increase of lipoxygenase residual activity in the starting defatted soybean flour, suggesting an elevated tendency to form insoluble aggregates during the preparation of soy protein isolate. Small deformation rheological test revealed that the gelling times were shorter for those soy protein isolates derived from low lipoxygenase activity defatted soybean flours than that of high lipoxygenase activity. Frequency sweep showed that G′ of soy protein isolate derived from low lipoxygenase defatted soybean flour was independent of oscillation frequency in contrast to that of derived from non dry-heated defatted soybean flour, the latter showed a marked frequency dependence. Large deformation test revealed that the gel hardness increased about 10 times after dry heating of defatted soybean flour for 20 min. As the increase of the lipoxygenase residual activity, the gel permeability increased markedly, suggesting that soy protein isolate from high lipoxygenase defatted soybean flour produced coarser textured gel, which corresponded well with the results of scanning electron microscopy. 相似文献
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ABSTRACT: The objective of this study was the detection and quantification of human IgE immunoreactive soybean proteins in commercially available soy ingredients and products. Optimum dilutions of primary antibody and antigens as well as detection sensitivity were determined for the implementation of a sandwich ELISA method using plasma from soy sensitive subjects (IgE ranging from 0.35 to 98.7 IU/mL). Human IgE immunoreactivity of commercial soybean ingredients showed that the plasma of subjects with strong allergic reaction to soybean presented proportionally higher immunoreactive response. Soy protein isolate and soy protein concentrate contained less immunoreactive proteins than soy flour and grits. As expected, a hypoallergenic soybean product presented the lowest IgE immunoreactivity. Hydrolyzed and fermented soy ingredients showed negligible human IgE immunoreactivity when proteins and peptides were < 20 kDa. The IgE immunoreactivity of soymilk samples ranged from 3.4 to 68.9 ng IgE/mg extracted protein. Tofu contained about 20-fold higher IgE immunoreactivity than soymilk products (median 171 ng IgE/mg extracted protein). Furthermore, soy cheese products presented twice the IgE immunoreactivity than tofu products (median 359 ng IgE/mg protein). Meat analogues presented considerably high extracted protein concentration (median 67.9 mg/g product). The findings of the current investigation demonstrate sandwich ELISA as a reliable immunochemical method with good repeatability, sensitivity, and low detection limit to quantify IgE immunoreactive proteins in soy ingredients and products. Quantitative measurement of specific IgE is likely to become an increasingly valuable tool for soybean industry to comply with food labeling for manufacturers, thus protecting soy-sensitive consumers. 相似文献
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为改善豆乳酸奶制品,分别从体系层面、颗粒层面和分子层面研究不同类型的乳蛋白——乳清分离蛋白(whey protein isolate,WPI)、乳浓缩蛋白(milk protein concentrate,MPC)和酪蛋白酸钠(sodium caseinate,NaCas)对豆乳凝胶特性的影响及机理。结果表明:WPI(≥20%)、40% NaCas的加入可以有效增强豆乳凝胶强度,其中WPI(≥20%)的作用最为显著。低替代比例的乳蛋白可以显著减小凝胶颗粒的粒径,而高比例的WPI会大幅度增大体系的凝胶颗粒。在微观结构方面,MPC的添加使得凝胶结构更为致密规则,NaCas的添加形成了细丝网状结构,而WPI的添加使得凝胶结构趋于不规则、致密。聚丙烯酰胺凝胶电泳及其光密度扫描结果显示,添加WPI(≤20%)可能会促进大豆7S蛋白的β亚基参与凝胶,而NaCas则会阻碍大豆11S蛋白碱性亚基的凝胶化。 相似文献