酪蛋白酸钠稳定的海藻油纳米乳液制备及表征

本文研究了酪蛋白酸钠稳定的平均粒径小于100 nm的海藻油乳液(O/W)的一般性质及环境因素对其稳定性的影响。采用微射流高压均质结合溶剂(乙酸乙酯)辅助蒸发法制备了海藻油含量1%的乳液(EAE-nano),用微射流高压均质法制备海藻油含量10%的乳液(AE-nano)作为对照。将AE-nano稀释10倍后与EAE-nano对比观察,AE-nano为乳白色,而EAE-nano呈半透明状。用动态光散射技术研究了EAE-nano的一般性质;以及加入0~500 mmol/L的Na Cl、在3.0~7.0的范围调节p H值、用沸水加热处理等环境因素对乳液物理稳定性的影响。在p H为7.0时,EAE-nano的平均粒径为76.8±0.5 nm,AE-nano的平均粒径为180.9±2.1 nm;EAE-nano比AE-nano对于Na Cl、p H值的变化、加热处理等环境压力有更好物理稳定性。用微射流高压均质结合溶剂辅助蒸发法制备的酪蛋白酸钠稳定的食品级乳液,在饮料的生产和疏水性生物活性物质的包封等应用方面显示出很高的潜在应用价值。     

大豆分离蛋白-甜菊糖苷复合稳定剂制备纳米乳液

为适应食品工业对食品配料天然绿色、营养健康的追求,采用大豆分离蛋白（soy protein isolate,SPI）-甜菊糖苷（steviol glycosides,STE）复合体系作为稳定剂制备纳米乳液,研究稳定剂组成、微射流参数、油相质量分数等对纳米乳液形成的影响,并对乳液稳定性及微结构进行表征。结果表明：油相质量分数为10%时,单独SPI（1%）制备的乳液粒度较大（d43为0.548 μm）,稳定性差。添加0.25%～1% STE时,乳液粒度分布更均匀,粒度变小;当STE质量分数为0.5%和1%时,乳液粒度小于200 nm,且具备较好的贮存稳定性（30 d）。添加2% STE会导致乳滴表面蛋白被完全取代,从而弱化乳液的长期稳定性。微射流压力、均质次数及STE质量分数的增加均可降低乳液粒度,但油相质量分数的增加可增加乳液粒度。进一步将纳米乳液进行冷冻干燥处理,可制得结构化良好且高油含量的油粉;相对于单独SPI稳定的结构化乳液,SPI-STE纳米乳液制得的油粉结构更为完整,表面黏性小。     

不同大分子乳化剂构建番茄红素纳米乳液的体外消化规律比较

通过体外模拟消化,研究以辛烯基琥珀酸酯化（octenyl succinic anhydride,OSA）变性淀粉、乳清分离蛋白（whey protein isolate,WPI）、酪蛋白酸钠（sodium caseinate,SC）为乳化剂构建的番茄红素纳米乳液的消化规律。结果表明,消化过程中纳米乳液的液滴大小、Zeta电位和微观结构取决于乳化剂类型,OSA变性淀粉和蛋白质类乳化剂构建的纳米乳液分别在肠和胃阶段发生水解,液滴聚集,乳液平均粒径增大,同时Zeta电位绝对值达到最小。经胃肠消化后3 种乳化剂构建的番茄红素纳米乳液游离脂肪酸释放率的大小排序为OSA变性淀粉（92.25%）＞SC（86.53%）＞WPI（79.88%）,高于对照组的48.7%,表明纳米乳液包埋体系能有效改善番茄红素的消化特性,且以OSA变性淀粉构建的纳米乳液表现出比蛋白质类乳化剂更高的番茄红素生物利用率,达到（25.60±3.08）%。     

载柚皮素的海藻酸钠/壳聚糖复合水凝胶

以海藻酸钠(SA)、羧甲基壳聚糖(CMCS)和柚皮素天然可降解的高聚物为原料,制备了复合水凝胶,对其微观形貌、力学性能、溶胀降解行为等进行表征与分析,为后续功能水凝胶材料的设计、制备和性能研究打下基础。     

锂皂石与海藻酸钠联合稳定ASA乳液的制备及其施胶性能研究

使用锂皂石与海藻酸钠联合稳定ASA乳液,研究了锂皂石与海藻酸钠的用量对ASA乳液稳定性和施胶性能的影响,探讨了固定锂皂石与海藻酸钠的用量下,硫酸铝用量、浆料pH值对ASA乳液施胶性能的影响,及乳液自身的水解稳定性。研究结果表明,海藻酸钠的加入有利于提高ASA乳液的稳定性和施胶性能,其用量0.3%时,施胶效果较好,加入0.5%的硫酸铝（对绝干浆）就使ASA乳液获得良好的施胶作用;在浆料pH值为5~9的范围内,ASA乳液均具有良好的施胶性能,在浆料pH值为6~6.5的范围内,ASA乳液施胶效果最佳。锂皂石与海藻酸钠联合稳定的ASA乳液放置120 min后,施胶效果仅降低16%,仍具有很好的水解稳定性。     

Characterization of Fish Myofibrillar Protein by Conjugation with Alginate Oligosaccharide Prepared Using Genetic Recombinant Alginate Lyase

ABSTRACT: The production of alginate lyase using genetically modified Escherichia coli was superior to the purification of alginate lyase from a culture medium of Pseudoalteromonas elyakovii regarding production efficiency. When alginate oligosaccharide (AO) prepared using genetic recombinant alginate lyase was introduced to fish myofibrillar proteins, the protein obtained high water solubility and improved thermal stability, similarly to AO prepared using wild-type lyase. Therefore, the use of genetic recombinant technology for the production of alginate lyase would be useful for the functional improvement of fish myofibrillar proteins by conjugation with AO.     

Nanoemulsions for Food Applications: Development and Characterization

The application of nanotechnology to food, medical and pharmaceutical industries has received great attention from the scientific community. Driven by the increasing consumers’ demand for healthier and safer food products and the need for edible systems able to encapsulate, protect, and release functional compounds, researchers are currently focusing their efforts in nanotechnology to address issues relevant to food and nutrition. Nanoemulsion technology is particularly suited for the fabrication of encapsulating systems for functional compounds as it prevents their degradation and improves their bioavailability. This review focuses on nanoemulsions and provides an overview of the production methods, materials used (solvents, emulsifiers, and functional ingredients) and of the current analytical techniques that can be used for the identification and characterization of nanoemulsions. Finally, nanotechnological applications in foods currently marketed are reported.     

Rheological Properties of Solutions and Emulsions Stabilized with Xanthan Gum and Propylene Glycol Alginate

The rheological effects of propylene glycol alginate (PGA) added to solutions and model emulsions containing xanthan gum (XG) were studied using controlled stress rheometry with concentrations appropriate for salad dressings. For samples with XG and XG + PGA blends, solutions and emulsions showed a Newtonian plateau at low shear stresses. The Newtonian plateau of a solution accurately predicted (r²= 1.00) the Newtonian plateau for an emulsion of equivalent gum concentration. Addition of PGA to constant levels of XG showed a more than additive increase in the Newtonian plateau viscosity for solutions and emulsions. For XG aqueous solutions, pseudoplasticity decreased upon addition of PGA. Storage and loss moduli increased with addition of PGA to XG for solutions and emulsions, although G’ for solutions of PGA alone were negligible.     

壳聚糖／海藻酸钠微胶囊固定化磷脂酶A1及其结构考察

对壳聚糖／海藻酸钠微胶囊固定化磷脂酶A1方法进行优化，利用红外光谱和电子扫描显微镜（SEM），对微胶囊结构进行考察。表明微胶囊具有规则的通孔结构，有很大的内表面积，可增加包埋酶的效率，提高磷脂酶与卵磷脂的接触界面面积和固定化酶的活力回收。     

茶多酚@沸石咪唑酯骨架材料/壳聚糖/海藻酸钠活性包装膜的制备及表征

本实验以海藻酸钠（sodium alginate,SA）和壳聚糖（chitosan,CS）为成膜基材,并以不同添加量（分别为0%（质量分数,后同）、1%、2.5%、5%）茶多酚（tea polyphenols,TP）@沸石咪唑酯骨架材料（zeolitic imidazolate framework-8,ZIF-8）纳米复合材料为功能性成分,通过层层组装的方式制备TP@ZIF-8/CS/SA复合膜。利用场发射扫描电子显微镜、热重分析仪、差示扫描量热仪、傅里叶红外光谱仪、质构仪、色差仪等对复合膜的形貌、组成进行表征。结果表明,TP@ZIF-8纳米复合材料添加量为5%时改变了CS/SA复合膜的颜色,并且影响了复合膜的微观形态,还增强了复合膜的热稳定性、阻隔性能和机械性能。此外,TP@ZIF-8纳米复合材料的加入使该复合膜表现出良好的抗氧化和抑菌效果。综上,本实验制备出一种具有抗菌和抗氧化的生物可降解活性包装膜,该活性包装膜在食品保鲜领域具有良好的应用前景。     

利用壳聚糖提高锂皂石稳定的ASA乳液的施胶性能

实验利用壳聚糖作为锂皂石稳定ASA乳液的胶体保护剂,研究了壳聚糖用量对锂皂石稳定的ASA乳液性质和施胶性能的影响,探讨了硫酸铝用量、浆料pH值对壳聚糖-锂皂石联合稳定的ASA乳液施胶性能的影响,并对乳液的水解稳定性进行了分析。结果表明,壳聚糖的加入使乳液的稳定性稍有降低,但有利于增加ASA乳液的施胶性能。加入硫酸铝促进ASA的施胶,且少量的硫酸铝就可使乳液获得良好的施胶性,在浆料pH值为5~9的范围内,乳液具有良好的施胶性能,并在浆料pH值为7时,施胶效果最佳,乳液放置120 min后,施胶效果仅降低10%,具有很好的水解稳定性。     

制备苹果酒酵母固定化载体ACA的研究

以苹果酒酵母固定化载体ACA的机械强度和通透性为指标,通过单因素试验观察了海藻酸钠浓度、氯化钙浓度、壳聚糖浓度、针头型号、固化时间和液化时间对制备固定化载体ACA的影响,并通过正交试验优化了载体ACA的制备工艺。试验结果表明,4个因素中海藻酸钠浓度(A)对载体ACA的机械强度和通透性有极显著影响,氯化钙浓度(B)对载体ACA的机械强度影响显著,壳聚糖浓度(C)对载体ACA的通透性影响显著,而交互作用(A×B)、液化时间(D)对载体ACA的机械强度和通透性影响均不显著。制备苹果酒酵母固定化载体ACA的最佳条件为:2.0%海藻酸钠溶液,2.0%CaCl2溶液,0.2%壳聚糖溶液,液化时间10min。     

天然和热处理大豆蛋白稳定乳液的性质研究

热处理(901、20℃)修饰的大豆分离蛋白用于制备水包油(O/W)乳液,并对天然和热处理蛋白乳液的粒径、微结构、絮凝率和分层稳定性进行表征。热处理蛋白的水力学半径随蛋白浓度和加热温度的增加而增加,证实了可溶性聚集体的产生。乳液粒径和分层稳定性受离子强度、聚集体粒径影响。低离子强度下(0 mmol/L),与天然蛋白相比,热处理蛋白乳液粒径较大,20 d放置后未发生分层。离子强度的增加(100mmol/L)导致天然蛋白乳液粒径明显增大;而热处理蛋白乳液则表现出较高耐盐性,体现在更小的粒径、絮凝率和分层指数。与90℃热处理相比1,20℃热处理减小了乳液液滴的粒径和絮凝。     

Development,Characterization, and Stability of O/W Pepper Nanoemulsions Produced by High-Pressure Homogenization

Interest in the utilization of bioactive plant compounds in foods has increased due to their biochemical activities (antioxidant, antimicrobial, etc.), and as alternatives in the reduction of the use of high concentrations of chemical substances. However, some of these additives are hydrophobic, thus being harder to disperse into the food matrix, which is generally water-based. A good alternative is the use of low concentrations of these compounds as nanoemulsions. The objective of the present study was to develop oil-in-water nanoemulsions containing “dedo-de-moça” pepper extract for food applications. Research in the development of these nanoemulsions was carried out using a high-speed homogenizer, followed by a high-pressure homogenizer. The influence of the following parameters was assessed: type and concentration of surfactants, hidrophilic-lipophilic balance, lipid/aqueous phase ratio, surfactant/oil ratio, pepper extract composition in nanoemulsion, and processing conditions. Nanoemulsions were evaluated by environmental (centrifugal and thermal) and storage stabilities, characterized by average droplet size and ζ-potential measurements, color, interfacial tension, atomic force, and cryo-scanning electron microscopy. Those with average droplet size between 132 ± 2.0 and 145 ± 1.0 nm were developed depending on working pressure and number of cycles; ζ-potential was around ? 36.71 ± 0.62 mV and the best nanoemulsion was stable to centrifugation and most of the thermal stresses. Droplets were characterized with cryo-scanning electron microscopy as being spherical, homogeneous, and stable, and remained stable when stored at 4 °C and room temperature for over 120 days. The pepper nanoemulsion, developed in the present study, has potential applications in the food industry.     

壳聚糖/酸枣仁黄酮复合膜的制备与表征

采用流延法制备含有不同比例酸枣仁黄酮提取液的壳聚糖复合膜,并测试复合膜的物理性能(厚度、密度及透明度)和机械性能(抗拉强度、断裂伸长率),通过傅里叶变换衰减全反射红外光谱(fourier transform attenuated total reflection infrared spectrometry,ATR-FTIR)、X-射线衍射(X-ray diffraction,XRD)和扫描电镜(scanning electron microscope,SEM)对其结构进行表征。结果表明,酸枣仁黄酮提取液的添加量对复合膜的拉伸强度、断裂伸长率和透明度均呈现逐渐减小的趋势。壳聚糖复合膜红外光谱显示在溶解制膜过程中壳聚糖分子的基本骨架未发生改变,X-射线衍射分析表明壳聚糖复合膜的晶体结构被破坏,SEM分析证实复合膜表明有酸枣仁总黄酮的聚集。     

以壳聚糖-海藻酸钠为壁材制备纸用微囊

采用天然高分子物质壳聚糖、海藻酸钠为壁材,无色染料油溶液为芯材,通过复合凝聚法制备纸用微囊.通过初步实验确定了主要影响因素,利用正交实验分析探讨了乳化、絮凝、固化过程中的最佳工艺条件.     

海藻酸钠/壳聚糖气凝胶对酸面团来源植物乳杆菌的包埋分析

以乳液为模板,利用层层自组装制备海藻酸钠/壳聚糖气凝胶对酸面团来源的植物乳杆菌T17进行包埋.结果表明:海藻酸钠/壳聚糖(ALC)和乳液模板海藻酸钠/壳聚糖气凝胶(EAC)对植物乳杆菌T17的有效载量分别为1.19×107 CFU/g和5.57×107CFU/g.红外光谱分析表明,海藻酸钠与壳聚糖之间通过静电相互作用实...     

纳米纤维素颗粒稳定的Pickering乳液的性能研究

以纤维素颗粒为乳化剂制备Pickering型乳液,研究纤维素颗粒浓度、油含量、纤维素颗粒大小对乳液粒径、电位、微结构和稳定性的影响。结果表明:随着纤维素浓度的增加,油滴表面吸附的纤维素颗粒越多,乳液粒径呈线性关系降低。随着水解时间的增加,纤维素与水的接触角增加,显示出较好的亲水湿润特性。纤维素颗粒粒径与其稳定的乳液颗粒之间存在粒度效应关系。当纤维素质量分数为0.9%,油添加量1%时水解10 h的纤维素制备得到的乳液颗粒较小,放置1周后没有发生分层现象,显示出较好的稳定性,说明利用纤维素可以构建稳定的乳液体系,实现对活性成分或药物成分的输送。