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蛋白质是构成生命的物质基础,在人体的新陈代谢和内环境平衡中发挥着重要的作用。天然来源的蛋白质或经某种方法提取的蛋白质的某些功能特性不能满足实际加工的要求,需对其进行改性。超声波因具有独特的物理化学效应而被广泛应用于蛋白质等大分子的提取和改性研究中。本文综述了超声波的物理、化学效应,归纳了超声波对生物酶以及蛋白质结构与功能特性影响的研究进展,并简要总结了超声波协同其它方法对蛋白质的改性研究,为深刻揭示超声波对蛋白质的改性机理以及进一步拓宽超声波在蛋白质改性领域的应用提供一定的参考依据。 相似文献
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采用超声波改性、谷氨酰胺转氨酶改性、超声波-谷氨酰胺转氨酶复合改性3 种方法对猪肌原纤维蛋白进行改性处理,以凝胶的强度、硬度、弹性、持水性、化学作用力、白度等为评价指标研究改性处理对猪肌原纤维蛋白凝胶特性的影响,以蛋白质二级结构、差示扫描量热、紫外吸收光谱表征改性处理对肌原纤维蛋白结构的影响。结果表明:超声波-谷氨酰胺转氨酶复合改性效果最明显,与对照组相比,其巯基含量降低、持水性增加、白度增加、疏水相互作用力增加,凝胶强度、硬度、弹性分别是对照组的3.57、3.65、1.15 倍。蛋白质结构分析结果表明,超声波-谷氨酰胺转氨酶复合改性后蛋白质热变性温度升高,α-螺旋相对含量下降,β-折叠、β-转角相对含量升高,紫外吸光度增加。改性后蛋白质结构向有利于提高肌原纤维蛋白凝胶特性方向转变。本研究结果为实现肌原纤维蛋白的综合利用提供了理论依据。 相似文献
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不同改性方法对蛋白质溶解性的影响研究进展 总被引:3,自引:1,他引:3
溶解性是蛋白质主要的功能特性之一,更重要的是,溶解性是蛋白质生理功能特性及其他加工功能特性的前提和基础。通过对蛋白质溶解性的物理、生物酶及化学改性3大类改性方法进行了分类论述,分析了不同改性方法对蛋白质溶解性的影响。其中,物理方法介绍了微波、超声波及热处理等方法;生物酶方法介绍了木瓜、碱性及胰蛋白酶等处理方法;化学方法介绍了不同活性基团的改性方法。分别对各种改性过程中蛋白质的结构变化和蛋白质溶解性提高的机理进行了初步探讨。通过物理、生物酶和化学等方法等来引起分子结构的微变化,可使人们获得各种符合预期的性能优良的蛋白产品。 相似文献
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《酿酒科技》2016,(5)
为提高酒糟中蛋白质的提取率,研究了超声波预处理对双酶法提取蛋白质的影响。以蛋白质提取率为指标,筛选适宜酒糟蛋白质提取的酶解方案,通过响应面设计考察超声波预处理对蛋白质提取率的影响并优化预处理参数。结果表明,单种酶辅助提取时,添加纤维素酶的蛋白质提取率高于木聚糖酶。与单种酶辅助提取相比,纤维素酶和木聚糖酶2种酶同步添加的双酶法提取效果最好。双酶同步提取蛋白质的适宜条件为:纤维素酶和木聚糖酶的添加质量分数分别是3%和4%,酶提取时间4.5 h,该条件下蛋白质提取率为30.25%。响应面优化后的超声波预处理条件为:料液比1∶17、超声波时间38 min和超声波功率480 W,超声波预处理后的蛋白质提取率升至43.37%。超声波预处理能有效提高酒糟蛋白质的酶法提取率。 相似文献
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主要研究了含水量在5.0%至35.0%范围内7个梯度水平下的黔江肾豆的各项物理特性,以期为黔江肾豆的实际生产加工、后续的开发研究及其他研究分析提供所需的籽粒物理性质数据参考。主要研究测定不同含水量下黔江肾豆的各项物理性质,包括:粒径、圆球度、体积、表面积、千粒重、容重、真实密度、孔隙率、休止角、静摩擦系数等。结果表明,除圆球度外,各项物理性质受水分含量影响均显著。随着含水量的增加,容重值降低;摩擦系数随含水量增加而增大,同时又与接触表面性质相关,木质横纹>木质直纹>钢>铝;其他各物理特性值均升高。 相似文献
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以普冰9946小麦为对照,研究西农黑大穗挤压膨化过程中加工温度、物料含水量、喂料速度变化对挤压膨化的扭矩、4区压力、5区压力、单位机械能耗、产品比容、径向膨化率、脆度、硬度的影响。结果表明,在试验范围内,温度为T1时,西农黑大穗产品比容、径向膨化率高,单位机械能耗高;温度为T3时,产品脆度高、硬度低,膨化率低。含水量为20%时,产品物理特性相对较好;含水量为22.5%时,单位机械能耗较低。喂料速度为20 g/min时,产品物理特性较好,单位机械能耗较高。加工过程中,西农黑大穗的扭矩、压力均高于对照,单位机械能耗和产品物理特性与对照差异极显著(P0.01)。 相似文献
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Coconut is a widely used fruit with soft flesh used for eating and its husk used as natural fiber. Husking is an important process in coconut processing and coir manufacturing which should be done with minimum effort. In an attempt to optimize the effort and productivity relationship, the physical and mechanical properties of local varieties of Indian coconuts are investigated. A sample of 70 coconuts are taken from coconut palms in Kerala, India, and divided into two groups of 35 each, dry and green coconuts. Its physical properties (size, weight, husk thickness, moisture content, and shell diameter) and mechanical properties (husk-separating force and shell-breaking force) are measured and the relationship between them is investigated. The results show that high dependence of mechanical properties exists on the physical properties of the coconut. 相似文献
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M.L. Vignolles C. Lopez M.N. Madec J.J. Ehrhardt P. Schuck R. Jeantet 《Journal of dairy science》2009,92(1):58-70
Changes in fat properties were studied before, during, and after the drying process (including during storage) to determine the consequences on powder physical properties. Several methods were combined to characterize changes in fat structure and thermal properties as well as the physical properties of powders. Emulsion droplet size and droplet aggregation depended on the homogenizing pressures and were also affected by spray atomization. Aggregation was usually greater after spray atomization, resulting in greater viscosities. These processes did not have the same consequences on the stability of fat in the powders. The quantification of free fat is a pertinent indicator of fat instability in the powders. Confocal laser scanning microscopy permitted the characterization of the structure of fat in situ in the powders. Powders from unhomogenized emulsions showed greater free fat content. Surface fat was always overrepresented, regardless of the composition and process parameters. Differential scanning calorimetry melting experiments showed that fat was partially crystallized in situ in the powders stored at 20°C, and that it was unstable on a molecular scale. Thermal profiles were also related to the supramolecular structure of fat in the powder particle matrix. Powder physical properties depended on both composition and process conditions. The free fat content seemed to have a greater influence than surface fat on powder physical properties, except for wettability. This study clearly showed that an understanding of fat behavior is essential for controlling and improving the physical properties of fat-filled dairy powders and their overall quality. 相似文献
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桑蚕丝/氨纶包缠丝性能与弹性织物质量的关系分析 总被引:2,自引:0,他引:2
分析了单包缠丝与双包缠丝的结构、基本物理性能及其对织物质量的影响。试验结果表明,双包缠丝的氨纶芯丝被桑蚕丝覆盖较好,各项物理性能指标较均匀,丝线较稳定,采用双包缠丝为原料,对提高弹性织物的质量有着重要的作用。 相似文献
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The objective of this study was to prepare the edible composite films using high-amylose corn starch (HACS) and corn zein and to determine their physical properties. HACS was gelatinized using the specially designed high-pressure container. HACS film containing 20 g sorbitol/100 g as a plasticizer had suitable physical properties. The HACS film coated with corn zein containing 20 g oleic acid/100 g had moderate physical properties and barrier properties. 相似文献