金鲳鱼肌原纤维蛋白乳液凝胶的制备及表征

本文以金鲳鱼肌原纤维蛋白作为乳化剂,以玉米油为油相制备乳液凝胶。利用SDS-PAGE、傅里叶红外光谱、电镜对金鲳鱼肌原纤维蛋白的结构进行表征;筛选优化制备金鲳鱼肌原纤维蛋白乳液凝胶的最佳蛋白浓度（C）、最佳油相比（φ）,采用激光共聚焦对乳液凝胶结构进行了表征;探究了pH和NaCl浓度对乳液凝胶稳定性影响。结果表明：金鲳鱼肌原纤蛋白具有典型的蛋白结构峰,β-折叠的含量最高,由椭圆颗粒聚集形成的纤维状结构,其蛋白浓度（C）为2.5%,油相比（φ）为0.68时制备出的乳液凝胶弹性模量G’最佳,平均粒径小。激光共聚焦结构显示,乳液凝胶的结构为W/O/W的多重乳液结构。乳液凝胶在pH酸性条件下不稳定,碱性环境下相对稳定,pH对乳液凝胶流变和粒径分布影响较大,NaCl的浓度改变对乳液凝胶的影响较小。综上,本文探究了金鲳鱼肌原纤维蛋白乳液凝胶的制备及表征,为金鲳鱼肌原纤维蛋白的开发利用提供了一定的技术参考。     

花生蛋白-果胶复合乳液凝胶的流变学特性和微观结构

研究不同油相及其添加量对转谷氨酰胺酶诱导制备的花生蛋白-果胶复合乳液凝胶质地特性的影响规律,同时通过流变学和微观结构特性研究探索乳液凝胶的形成机理。结果表明：花生蛋白-果胶复合乳液凝胶的凝胶强度显著高于水凝胶。凝胶外观和储能模量（G’）结果表明油滴与蛋白-果胶组成的凝胶基质相互作用,从而影响乳液凝胶的质地和凝胶强度。油相添加量的增加可以使乳液凝胶的力学性能增强,网络结构更稳定。花生蛋白-果胶复合乳液凝胶的G’值和硬度随油相添加量的增加而增大,说明分散的油滴作为活性填料与凝胶基质相互作用。花生蛋白-果胶复合乳液凝胶的微观结构结果表明,油相添加量60%（V/V）时24度棕榈油为油相的乳液凝胶网络结构更致密。研究结果为花生蛋白-果胶复合乳液凝胶在食品领域的开发利用提供思路。     

甘草酸纤维茶树精油乳液凝胶的制备及其结构表征

选取茶树精油为风味油相,利用甘草酸自组装纳米纤维作为结构单元构建风味精油乳液凝胶体系,研究甘草酸纤维质量分数、茶树精油质量分数、油相组成对精油乳液凝胶外观、微观结构、流变学特性的影响。结果表明：利用甘草酸的两亲性和纤维化自组装,能成功制备出乳滴粒度小（2.5 μm）且具有蜂窝状网络微结构的茶树精油乳液凝胶;流变学测试显示该乳液凝胶具有高凝胶强度,较高质量分数的甘草酸纤维（4%）及油含量（40%）构建的乳液凝胶体系流变黏弹性更强、更稳定;在混合油相中,油相组成（添加葵花籽油或中链脂肪酸甘油三酯）的改变可以显著影响乳液凝胶粒度,最终改善风味乳液凝胶外观及结构特征。     

不同质量比的火麻仁分离蛋白与黄原胶复合物对乳液凝胶稳定性的影响

对动态高压微射流处理后的火麻仁分离蛋白-黄原胶复合物进行研究,以复合物为乳化剂,亚麻籽油为油相,构建一种低油相（φ=0.26）乳液凝胶,并考察不同复配质量比的火麻仁分离蛋白/黄原胶对乳液凝胶冻融稳定性和贮藏稳定性的影响。结果表明,当火麻仁分离蛋白与黄原胶的复配质量比为1∶1 时,乳液凝胶具有良好的支撑性能、液滴分布形貌均匀、冻融黏弹性良好,并可明显抑制亚麻籽油在贮藏期间脂质过氧化氢、丙二醛、共轭二烯烃和共轭三烯的生成。     

油相结构化对大豆蛋白藻油纳米乳液氧化稳定性的影响

利用蜂蜡结构化藻油结合大豆分离蛋白-甜菊糖（soy protein isolate-stevioside,SPI-STE）复合体系的乳化特性,制备高稳态的藻油纳米乳液体系。藻油凝胶的微观结构观察、热性质测试以及流变学分析表明,当藻油中蜂蜡添加量达到4%(m/m)时,大量晶体组装成稳固的网络结构,从而构筑出稳定的油凝胶。进一步以SPI-STE为稳定剂制备藻油纳米乳液,研究了藻油结构化对纳米乳液形成及稳定性的影响。结果表明,油相中添加蜂蜡对纳米乳液的形成没有显著影响。随着藻油中蜂蜡质量分数的增大（0%～6%）,乳液的物理稳定性逐渐提高;但在高蜂蜡添加量（8%）下,刚性较强的凝胶网络破坏了油滴界面层,乳液稳定性变差。热促氧化及光促氧化结果显示,蜂蜡油相结构化明显提高了纳米乳液的氧化稳定性,其中油相中含有6%蜂蜡的样品延缓氧化的效果最明显。本研究可为食品工业构建高稳态的藻油纳米乳液载体及产品提供一定技术支持。     

基于大豆酶解聚集体制备Pickering乳液凝胶及环境稳定性分析

以大豆酶解聚集体（insoluble soy peptide aggregate,ISPA）制备Pickering乳液凝胶,在探索ISPA制备高油相乳液性质的基础上,对比分析模拟环境对乳液凝胶性质与稳定性的影响。结果表明：随着ISPA质量分数和油相体积分数增加,乳液粒径减小,凝胶强度增强,且以质量分数1.00%的ISPA和体积分数60%的油相制备的乳液展现出较强凝胶潜能;随后,将上述乳液凝胶置于不同NaCl浓度或酸性pH值下,发现乳液凝胶强度在高浓度NaCl或低pH值下仍有所增强,且经90 d常温贮藏或90 ℃加热60 min后粒径变化较小。综上,ISPA在新型Pickering稳定剂和食品配料开发中具有较大的加工应用潜能。     

肉桂油对蛋清蛋白/可得然胶凝胶理化特性及释放肉桂醛性能的影响

卤制工艺中风味组分的控制释放有望对卤制品品质的工业标准化程度进行调控。以蛋清蛋白和可得然胶为基质材料,以肉桂油为风味组分代表,水油两相均质后通过热诱导法制备乳液凝胶,探究肉桂油添加对乳液凝胶特性及释放肉桂醛性能的影响。结果表明,与大豆油乳液凝胶相比,肉桂油乳液凝胶颜色偏黄,微观结构更加致密,持水率、硬度、储能模量和损耗模量等参数显著增加,且当肉桂油质量分数为5%时凝胶性能最强。随着肉桂油添加量的增加,凝胶转变时间缩短,同时乳液凝胶的黏弹性减弱,亮度增加、黄度降低。红外光谱证实了肉桂油中的肉桂醛与蛋清蛋白发生了席夫碱反应,从而促进乳液凝胶的形成及凝胶性能的提升。在模拟卤制品加工环境下,肉桂油乳液凝胶对所含肉桂醛具有良好的控释效果:水相中肉桂醛的释放率随肉桂油添加量的增加而减小,当肉桂油质量分数从5%增加至11%时,乳液凝胶在水中煮制1h后,肉桂醛的累积释放率降低35.44%;与在水中煮制相比,调味料氯化钠、醋酸与乙醇可促进水相中肉桂醛的释放,且在醋酸中的累积释放率增幅最大(15.95%);但模拟卤制基质中的蛋白质和多糖会抑制肉桂醛的释放,累积释放率降低9.58%以上。乳液凝胶在模拟食品加工过程中能维持原有块状形貌,但在酸性条件下质地变硬、体积缩小、损失率最大,且凝胶结构破坏程度最严重,促进了肉桂醛的释放。因此,蛋清蛋白/可得然胶乳液凝胶的质地与释放性能可通过肉桂油的活性填充进行调控。研究结果旨在为食品工业中风味控释技术的开发提供理论参考。     

肉桂酸基油凝胶及其乳液的制备及理化性质表征

选择玉米油为溶剂,肉桂酸为凝胶剂制备油凝胶,探究其流变学、质构、持油性、热力学特性及凝胶剂晶体形态;以油凝胶为分散相,制备油凝胶乳液（O/W型）,分析其粒径、流变学、稳定性等物理性质。结果表明：肉桂酸临界成胶质量分数为4%,4?℃条件下存放的油凝胶持油性较常温条件下更好;肉桂酸质量分数越大的油凝胶硬度越大,热稳定性越好;肉桂酸在油凝胶中呈现随机分布的长纤维状聚集体;油相质量分数为10%～20%时,油相含量越低,其乳液粒径越小、黏度越低、物理稳定性越好。油凝胶在常温下稳定性较差,而油凝胶乳液在常温下能保持良好的稳定性,有益于其在食品工业领域的研发与应用。     

大豆蛋白稳定乳液油凝胶的制备及其在肉糜中的应用

以大豆蛋白为稳定剂,葵花籽油为油相,通过高速剪切乳化技术制备乳液油凝胶,研究载油量、大豆蛋白浓度和热处理时间对乳液油凝胶的影响,并将乳液油凝胶应用于肉糜中替代动物脂肪。结果表明：大豆蛋白颗粒可以承载体积分数达70%的油相,且在大豆蛋白浓度超过1%的条件下,能形成稳定的乳液油凝胶,其粒径随着大豆蛋白浓度的增加而略微变小。乳液油凝胶经80 ℃热处理后,粒径大小随加热时间基本不变,显示良好的热稳定性。流变分析表明乳液油凝胶的黏度随剪切速率升高而下降,不同加热时间下的储能模量均比损耗模量高,表明乳液形成了弹性的类凝胶网络,且加热处理45 min 的乳液油凝胶黏弹性最为突出。肉糜经高温蒸煮后,肉糜蒸煮得率随乳液油凝胶替代比例的升高而提高,当乳液油凝胶完全替代猪油脂时,油脂和水分的渗出率明显降低。     

不同油相比例对黑豆分离蛋白乳液凝胶特性的影响

对黑豆分离蛋白添加不同油相比例(大豆油10%~60%)后制备的乳液表观黏度及由葡萄糖酸内酯(GDL)、CaCl_2、谷氨酰胺转氨酶诱导的黑豆分离蛋白乳液凝胶特性的变化进行了研究。结果表明:随着油相比例的增加,油脂与蛋白质之间作用,使蛋白质分子之间连接更加紧密,表观黏度增大;随着油相比例的增加,由GDL、CaCl_2和谷氨酰胺转氨酶诱导的黑豆分离蛋白乳液形成完整的三维结构时间缩短,凝胶强度增大,持水性增大。     

Pickering石蜡乳状液的研制

研究了带正电荷的氢氧化镁铝微粒对液体石蜡／水体系的乳化与稳定作用。结果发现,氢氧化镁铝胶体可将液体石蜡／水体系乳化成O／W型石蜡乳状液。随液体石蜡体积分数和氢氧化镁铝加入量的增加,乳状液稳定性提高,黏度也随之增加,但乳状液液滴分别表现为增大和减小趋势。初始油水体积比例为3：1时,加入w（氢氧化镁铝）=0．25％,便可得到稳定性良好的石蜡乳液。     

EFFECTS OF OIL DROPLET AND AGAR CONCENTRATION ON GEL STRENGTH AND MICROSTRUCTURE OF O/W EMULSION GEL

The effects of oil droplet size and agar concentration on gel strength and microstructure of emulsion gels were investigated by compression test and cryoscanning electron microscope (Cryo-SEM). At all agar concentrations, the compressive stress values of emulsion gels were lower than those of the oil-free gels. Compressive stress and energy were significantly affected by oil droplet size and agar concentration, but compressive strain was not. SEM observation revealed that the overall volume of void spaces decreased and strand compactness increased with increasing agar concentration. Gels containing oil droplets had some void spaces between the gel network and the oil droplets. The strands of emulsion gels did not cover the oil globules completely, a phenomenon which was also observed for the gel with high agar concentration.     

Structural and rheology properties of pea protein isolate-stabilised emulsion gel: Effect of crosslinking with transglutaminase

The microstructures and characteristics (water holding capacity (WHC) and rheological properties) of pea protein isolate (PPI) emulsion gels produced via transglutaminase (TGase) with different oil-weight fractions (φ, 20%~50%) were studied in the present work. The results showed that the WHC and gel strength (storage modulus) of PPI emulsion gel were raised with increasing of φ. Simultaneously, the proteins entrapped within the network gradually increase due to the enzymatic treatment, which resulted in a tighter internal structure of emulsion gel. At high oil-weight fractions (e.g. 50%), the network of the emulsion was essentially a coarse chain of particulate, mainly forming a ‘close-knit’ oil droplet. Therefore, the gelation mechanism is related to the state of proteins in the system, which are divided into proteins adsorbed and unadsorbed on the interface. The results will be of significant assistance in comprehending the theories of the gelation process and the protein emulsion gels immobilisation by the enzyme.     

EFFECTS OF OIL DROPLETS ON PHYSICAL AND SENSORY PROPERTIES OF O/W EMULSION AGAR GEL

Effects of oil droplets in an agar gel matrix were investigated by mechanical analyses and sensory evaluation. The results for compressive and puncture properties were expressed in terms of relative values. All compressive properties; stress, strain and compressive energy of emulsion gels, as obtained by compression tests, decreased with both increases of oil droplet size and oil volume fraction. The stress, strain and energy of the emulsion gels obtained by puncture tests did not change with an increase in oil droplet size. Results of sensory evaluation showed that the sample containing small oil droplets was harder than that with large oil droplets. On the other hand, the large oil droplet sample was oilier than that with small oil droplets. The sensory evaluations for hardness and oiliness of emulsion gels did not exhibit significant relations to most of the properties of mechanical analyses.     

VISCOELASTIC PROPERTIES OF HEAT-SET WHEY PROTEIN EMULSION GELS

The viscoelastic properties of heat-set whey protein gels and whey protein-stabilized emulsion gels have been studied using the dynamic oscillatory rheometry technique. The storage modulus was monitored and analysed for pure protein gels and emulsion gels over a wide range of protein concentrations. The dependence of storage modulus on protein concentration is different for gels of low and high modulus. At low protein concentrations, the increase of storage modulus is much more sensitive to the increase of protein concentration. The protein-coated oil droplets behave as active filler particles and dramatically enhance the gel strength. The effect of the oil volume fraction on the rheology has been investigated for emulsion gels containing 11 vol. %, 20 vol. % and 45 vol. % Trisun oil. The formula of van der Poel fails to describe the experimental results. This is attributed to the strongly flocculated state of the emulsion system.     

Heat Gelation of Oil-in-Water Emulsions Stabilized by Whey Protein

The conditions under which a high volume fraction of oil can be trapped in whey protein gels were studied. Oil-in-water emulsions of whey protein and vegetable oil were subjected to heat treatment. Such emulsions, depending on their protein and oil content, on their pH and on the emulsification technique used, gelled or remained liquid. Homogenization was the major factor to achieve gelation and the firmness of heat-induced gels increased with increasing emulsion fineness and homogeneity. Emulsions with a high gelation capacity were characterized by a single droplet family of relatively narrow size distribution and a mean droplet diameter ranging from roughly 300–700 nanometers. The pH range suitable for gelation extended from 3.5–8.0.