Properties and thermal stability of Pickering high internal phase emulsion prepared by TGase cross-linked collagen fibres

In this study, high internal phase emulsions (HIPEs) were prepared by algal oil and transglutaminase (TGase) cross-linked collagen fibres, and the properties and thermal stability (90 °C, 40 min) of HIPEs were also investigated. Under 1.0 wt % collagen fibres without TGase, the emulsion prepared by centrifugation could achieve an oil phase volume up to 60%, the non-centrifuged emulsion could only come up to 50% oil phase volume, however, with the addition of TGase, the HIPEs could be formed with 72% oil phase volume. The obtained HIPEs showed gel-like morphology. The droplets size of unheated HIPEs decreased as the TGase concentration increased, but the change was not significant when TGase was more than 20 U g⁻¹ collagen fibres. The droplets size of heated HIPEs increased, but it was almost the same as the unheated samples when TGase was more than 30 U g⁻¹ collagen fibres, suggesting good thermal stability.     

高稳定性蔗糖聚酯乳液的制备及其应用

为优化蔗糖聚酯的乳化工艺,提高其乳液的稳定性,采用转相乳化法,研究了复合乳化剂HLB值、用量、油水比例、乳化时间、乳化温度及搅拌速度对蔗糖聚酯乳化效果的影响,并对蔗糖聚酯乳液的稳定性和应用性进行了研究。结果表明,最佳的乳化条件为：复合乳化剂HLB值为9.8,用量为9%,乳化水油比例为2,乳化时间85 min,乳化温度30 ℃,剪切速率2000 r/min;该蔗糖聚酯乳液具有高稳定性和良好分散性,粒径分布均匀,长期放置不分层,且该蔗糖聚酯乳液能够有效降低织物表面摩擦因数,赋予织物良好的柔软效果,对织物色变影响较小。     

高内相Pickering乳液荷载生物活性物质的构建

目的 构建稳定荷载生物活性物质的高内相Pickering乳液。方法 通过简单的反溶剂纳米沉淀法制备玉米醇溶蛋白/果胶复合颗粒,再通过均质乳化技术,成功构建荷载姜黄素的高内相Pickering乳液,研究在不同pH条件下该乳液体系的储藏稳定性、外观、粒径和流变学特性。结果 该荷载姜黄素的高内相Pickering乳液（油相占比高达80%）能稳定储藏两个月以上不变质,乳液粒径较小,基本在100~200 μm之间,其流变学行为表明该乳液具有较好的粘弹性和凝胶特性,并且随着pH值的降低,胶体颗粒的三相接触角越接近90°,乳液的凝胶性越强,乳液越稳定。结论 本方法制备简单,操作方法,成功的构建了荷载姜黄素的高内相Pickering乳液,为高内相Pickering乳液在食品、药品和化妆品等领域的应用提供了一个方向。     

Construction of plant-based adipose tissue using high internal phase emulsions and emulsion gels

There is growing consumer demand for plant-based meat and seafood analogs due to ethical, environmental, and health concerns associated with the production of real meat and seafood. Meat and seafood analogs should mimic the desirable appearance, texture, and flavor of the real versions. In this study, we investigated the possibility of using advanced emulsion technologies to create plant-based adipose tissue. High internal phase emulsions (HIPEs) were formulated that consisted of concentrated dispersions of soybean protein-coated soybean oil droplets. The HIPEs contained 75% soybean oil and 0.25 to 3% soybean protein. At higher protein contents, the HIPEs mimicked the appearance of beef adipose tissue but were too soft at ambient temperature and did not melt upon heating. These problems could be partly overcome by using emulsion gels that consisted of soybean protein-coated soybean oil droplets dispersed in an agar hydrogel. The final composition of these emulsion gels was 60% soybean oil, 2% soybean protein, and 0.25 to 2% agar. The incorporation of the agar increased the hardness of the emulsion gels at ambient temperature and led to melting behavior. Nevertheless, the emulsion gels were still somewhat softer that real beef adipose tissue at ambient temperature and they melted at a higher temperature. These results show that concentrated emulsion gels containing cold-setting polysaccharides may be useful for mimicking the desirable physicochemical attributes of animal adipose tissue but further research is required to more accurately simulate their properties.     

乳滴粒径和皂皮皂苷浓度对高内相乳液凝胶及其模板油凝胶构建的影响

以天然皂皮皂苷为乳化剂,采用激光散射技术、动态流变学以及激光共聚焦显微技术探究了乳滴粒径皂皮皂苷质量分数对高内相乳液凝胶（HIPE-gels）及其模板制备的油凝胶流变特性和微结构的影响。结果表明： HIPE-gels和油凝胶均表现出剪切稀化特性,油滴间形成非共价物理交联的弹性凝胶结构;随粒径减小,乳滴堆积紧密,赋予HIPE-gels和油凝胶更强的凝胶网络结构和黏弹性;皂皮皂苷质量分数较低（≤1.5%）时,乳滴间的静电排斥作用对HIPE-gels的黏弹性和强度起主导作用,当皂皮皂苷质量分数较高（>1.5%）时,游离皂皮皂苷分子提高了HIPE-gels的凝胶强度,而油凝胶强度随乳滴粒径减小和皂皮皂苷质量分数的增加得到强化。     

脱脂芝麻粕稳定高内相乳液的制备及特性

分别以去皮和带皮脱脂芝麻粕为稳定剂制备了高内相乳液(HIPEs),研究了该乳液的基本性质,探讨了脱脂芝麻粕添加量、油相体积分数、体系pH以及离子浓度对HIPEs微观结构、粒径及流变性质的影响。结果表明:油相体积分数为0. 75时,去皮和带皮脱脂芝麻粕稳定HIPEs的最低添加量分别为5. 0%和3. 0%;去皮和带皮脱脂芝麻粕添加量为5. 0%时,其稳定HIPEs的最高油相体积分数分别为0. 75和0. 85;脱脂芝麻粕在中性pH以及添加适量NaCl下,制备的HIPEs更稳定。流变性质研究表明,HIPEs内部存在以弹性为主的凝胶网络结构,随着脱脂芝麻粕添加量的增大,HIPEs粒径逐渐减小且呈均匀分布,黏弹性能逐渐增大。     

共轭亚油酸多重乳状液的制备及稳定性研究

以多重乳状液相对体积为衡量标准,借助显微镜直接观察,探讨油水相质量比、亲油亲水乳化剂质量比、乳化剂的HLB值、乳化剂的含量等因素对共轭亚油酸多重乳状液体系稳定性的影响.结果表明,单一乳化剂体系中,以Tween80作亲水乳化剂制备的多重乳状液稳定性较好.当m(内水相):m(油相):m(外水相)=1:5:1.3,m(Span80):m(Tween80)=9,乳化剂的含量为9.7%时,多重乳液相对体积达到93%.复合乳化剂体系中,在第一相的HLB值为7.4,m(复合乳化剂):m(Tween80)=9,乳化剂质量分数为6.67%时,稳定性最好.     

Whey protein nanoparticles prepared with desolvation with ethanol: Characterization,thermal stability and interfacial behavior

Whey protein isolate (WPI) nanoparticles were prepared by diluting an alkaline solution of protein in ethanol at concentrations varying between 50 and 80%. The nanoparticles were then immediately diluted in buffer. While the nanoparticles were not stable at pH 7, they showed no changes in size when diluted at pH 3. When 75–80% ethanol was added during preparation, the size of the WPI nanoparticles ranged between 10 and 100 nm, with no change in size after dilution and storage at pH 3 for 96 h at 22 °C. When heating was applied, particle aggregation occurred, and large aggregates (>1 μm) were observed at temperatures > 60 °C. The particle size of the heat-induced aggregates could be reduced by homogenization. The nanoparticles prepared by desolvation showed interfacial pressure values similar to those of the corresponding protein solutions, indicating similar interfacial properties and the potential to be used to stabilize emulsions but as supramolecular aggregates of WPI.     

Preparation and stability of a protein stabilized orange oil-in-water emulsion

Flavours are an important category of additives which have been used extensively in many industries. Essential oils are highly concentrated flavors so they must be diluted before application in order to facilitate handling and to guarantee an equal distribution of flavor among the product. Most essential oils have low solubility in water due to their partial hydrophobic nature. The other alternative is to solubilize them in an organic solvent. These solvents are either expensive or prohibited for religion purposes. The most acceptable solution is to emulsify the essential oils in water, in the form of tiny particles to form essential oil-in-water emulsion. The present study was dedicated to apply a derivative of milk protein (sodium caseinate) to stabilize orange oil emulsions. The change in particle size and the rate of emulsion creaming was investigated at different caseinate concentrations and at different temperatures. The results obtained from this study revealed that sodium caseinate can be used, to a great extent, to stabilize orange oil emulsions. The average particle size of the emulsion was 0.29 μm and 0.40 μm as determined by the laser light diffraction instrument and the image analysis technique, respectively. The emulsion was stable for 100 days at 4°C for all caseinate concentrations (30%, 15% and 5% w/w on orange oil basis).     

乳清蛋白乳液界面性质及其物理稳定性和氧化稳定性的研究

以乳清蛋白与玉米油为原料,采用高压均质技术制备水包油型(O/W)乳液。探究乳清蛋白浓度(0.45%~3.60%)、离子强度(250 mmol/L Na Cl)对乳清蛋白乳液界面特性及其物理稳定性和氧化稳定性的影响。结果表明:随着乳清蛋白浓度的增加,乳液的粒径、乳析指数、过氧化值(POV)和丙二醛生成物(TBARS)都呈现降低的趋势,而乳液的界面蛋白浓度、电位随着蛋白浓度的增加而增加。乳液中加入250 mmol/L Na Cl能够增加乳液的粒径、乳析指数、界面蛋白含量、电位值、POV和TBARS值。上述结果表明乳液界面蛋白浓度增多,乳液的物理稳定性和氧化稳定性得到增强,而乳液中加入Na Cl后能够减弱乳液的物理稳定性和氧化稳定性。      

鱼皮明胶的制备、特性及应用

由于传统哺乳动物明胶带来的传染病问题以及穆斯林、犹太等特定消费者的需求,鱼明胶受到了很大的关注。本文叙述了鱼皮明胶的制备方法,并在分析其结构的基础上,论述了鱼皮明胶的胶凝特性、成膜性和感官特性,同时对鱼皮明胶在食品中的应用作了简单介绍。     

南瓜籽分离蛋白颗粒稳定的高内相皮克林乳液的 制备及应用研究

为了得到一种性能优异的天然来源的颗粒稳定剂,以南瓜籽为原料,采用碱溶酸沉法制备了南瓜籽分离蛋白（PSPI）,利用反溶剂法制备了南瓜籽分离蛋白颗粒（PSPI Ps),并以PSPI Ps为稳定剂制备了高内相皮克林乳液（HIPPEs）。考察了水相PSPI Ps质量分数、油相体积分数和水相pH对HIPPEs微观结构、粒径和流变性能的影响,并通过扫描电子显微镜以及激光共聚焦扫描显微镜对HIPPEs的界面结构进行了表征。另外,探究了HIPPEs的耐酸碱能力、常温储存稳定性、热稳定性和光稳定性。结果表明：制备的HIPPEs为O/W型微米级乳液;水相PSPI Ps质量分数在0.2%～2.0%范围时,随着PSPI Ps质量分数的增加,乳液液滴粒径显著减小,凝胶强度显著增加;油相体积分数在50%～84%范围时,随着油相体积分数的增加,乳液液滴粒径增加,而凝胶强度减小;水相pH在3～9范围时,随着水相pH的增加,乳液液滴粒径先增大后减小,凝胶强度先减小后增加;所制备的HIPPEs具有良好的耐酸碱能力、常温储存稳定性、热稳定性以及光照稳定性。综上,PSPI Ps是一种性能优异的高内向乳液稳定剂。     

环糊精稳定紫苏籽油Pickering乳液的制备及其稳定性

紫苏籽油具有很好的食用及保健功能,将其制成稳定的可涂抹乳液可增加其应用的多样性。本文利用β-环糊精的乳化特性,通过高速均质法将紫苏籽油制成Pickering乳液,观察乳液的微观结构、测定其粒度和Zeta电位,研究体系添加糖、盐、黄原胶以及pH值对乳液稳定性的影响,并对其黏度特性进行了初步测定。结果表明,紫苏籽油经β-环糊精乳化后可形成稳定的水包油型pickering乳液,油滴呈标准球形,粒径在数十纳米范围;外水相添加5%蔗糖或0.5%黄原胶可增加、添加食盐则降低乳液的黏度及稳定性,酸性条件不利于乳液的稳定;流变特性结果显示,环糊精稳定的紫苏籽油乳液为剪切变稀的假塑性流体,在25～80℃条件下乳液呈现类似奶油状特性。     

Formation and dynamic interfacial adsorption of glycinin/chitosan soluble complex at acidic pH: Relationship to mixed emulsion stability

The formation and interfacial adsorption of glycinin/chitosan (CS) soluble complex were investigated at acidic pH. The stability of the mixed emulsion stabilized by the complex was also evaluated at pH 4.5. Turbidimetric analysis, isothermal titration calorimetry (ITC) and dynamic light scattering were used to characterize the dynamic formation of the complex. The results showed that soluble complexes were formed mainly at pHs between 4.0 and 6.0, depending on CS/Glycinin mixing ratio. At pH 4.5, soluble complex was formed and saturated at mixing ratio = 0.1, showing a maximum size distribution at 164.2 nm. We found that the glycinin/CS soluble complex showed improved interfacial adsorption than glycinin at pH 4.5. In detail, dynamic interfacial adsorption data showed the coefficient of diffusion (K_diff), unfolding (K₁) and rearrangement (K₂) for soluble complex (K_diff, K₁ and K₂: 0.58 mNm⁻¹ s^−0.5, 2.23 E−4 s⁻¹ and 5.78 E−4 s⁻¹) were higher than those of the glycinin (K_diff, K₁ and K₂: 0.32 mNm⁻¹ s^−0.5, 1.72 E−4 s⁻¹ and 4.63 E−4 s⁻¹). The droplet size and confocal observation of the mixed emulsion fabricated with glycinin/CS soluble complex displayed improved stability at mixing ratios of 0.1 to/and 0.2, suggesting the synergistic effect of the two molecules. We concluded that interfacial and emulsifying properties of glycinin could be improved by formation of glycinin/CS soluble complex at acidic pH.     

大豆异黄酮对玉米淀粉老化的影响及体系水分迁移研究

花青素类化合物包括原花青素、花青素、花色苷等。其中,原花青素是一种聚多酚类化合物,花青素和花色苷均属黄酮类化合物。当在酸性介质中加热时,原花青素可产生花青素,花青素可通过糖苷键与糖相结合可产生花色苷。在深色谷物、浆果及蔬菜中,原花青素、花青素、花色苷广泛分布,均具有多种功效。淀粉价格低廉、来源丰富,具有多种功能特性,淀粉基食品的感官品质及营养价值主要由淀粉糊化性质、热力学性质、流变学性质、老化性质及消化性质等变化所决定。对于淀粉与其他化合物共存能够改善淀粉原本性质已有很多研究,但关于花青素类化合物对淀粉性质影响的概述较少。因此,本文综述了花青素类化合物提高淀粉的糊化温度,降低淀粉的糊化焓值,进而影响淀粉的热力学性质,同时降低淀粉的老化焓以及老化率,降低淀粉的消化速率等对淀粉糊化特性、热力学特性、流变学特性、老化特性和消化性质影响的最新研究进展,为利用花青素类化合物等改善淀粉基食品的加工性能、感官和营养品质提供指导。

     

大豆多糖对乳清分离蛋白—乳状液稳定性与流变特性的影响

本文研究了大豆多糖（SSPS）与乳清分离蛋白（WPI）乳状液静电组装,形成乳状液聚集体,考察了不同浓度的SSPS对WPI-乳状液稳定性与流变特性的影响,以期提高体系的粘弹性,形成高流变特性的食品体系。将不同浓度的大豆多糖与2%乳清分离蛋白乳状液（油相为20%）静电组装,分析乳状液的粒径,Zeta-电位,稳定性指数,流变性质和微观结构。结合剪切流变与微流变技术,深入研究了SSPS对乳清分离蛋白（WPI）乳状液流体特性与结构的影响。结果表明:随着SSPS浓度的增加,WPI乳状液的粒径在添加0.25%SSPS时达到峰值（3350±0.35）nm,而后随着SSPS浓度的增加而降低;Zeta-电位绝对值呈递减的趋势,表明SSPS与WPI间产生静电吸附作用;SSPS静电吸附提高WPI乳状液的稳定性;剪切流变结果表明,SSPS浓度为0.5%时,其粘度最大,并在剪切速率为95.8 s-1处其粘度是WPI乳状液粘度的10倍以上;微流变结果表明,0.5%SSPS-WPI乳状液的MSD曲线出现平台区,表明其弹性指数（EI）与宏观粘度指数（MVI）均显著提高达到最大值。微观结构结果表明,0.5%SSPS-WPI乳状液形成均一的乳状液聚集体。本研究将有助于理解大豆多糖与蛋白质乳状液的相互作用,同时为低脂高流变特性的食品（如蛋黄酱、调味汁、巧克力和植脂奶油等）生产提供理论指导。      

明胶微球的制备及其对多酚的吸附效果

采用乳化法制备明胶微球,利用显微镜和扫描电镜进行形态表征,研究了明胶微球对不同种类多酚的吸附及解吸附作用,考察了明胶微球的重复使用率。结果表明：在pH 3.5、35 ℃条件下吸附120 min时,明胶微球对表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）、安石榴苷和原花青素表现出良好的吸附作用,而对绿原酸吸附能力弱。用蒸馏水80 ℃处理120 min,微球上吸附的多酚可较好地解吸附。当微球多酚质量比为5∶1时,除绿原酸外,其他多酚的吸附率约54%～78%、单位明胶微球多酚吸附值约107～156 μg/mg、解吸率约60%～75%。明胶微球重复利用5 次后对EGCG的吸附率和解吸率仍然可达55%以上,但重复利用8 次后微球吸附性能急剧下降。因此,明胶微球在食品中多酚的去除和回收中具有潜在的应用价值。     

Characterisation and optimisation of physical and oxidative stability of structured lipid-based infant formula emulsion: Effects of emulsifiers and biopolymer thickeners

Response surface methodology (RSM) was applied to investigate the effects of lecithin (0–0.4 g/100 ml), monoacylglycerol (0–0.4 g/100 ml), locust bean gum (LBG; 0–0.1 g/100 ml), and carrageenan (0–0.02 g/100 ml) on the physical and oxidative properties of structured lipid-based infant formula emulsion containing dairy proteins, lactose, vitamins, minerals and other micronutrients. Particle size, optical stability, viscosity, relative content of docosahexaenoic acid, stearidonic acid and total oxidation value were assessed during 28-day storage. ANOVA results showed that the experimental data were satisfactorily fitted to second-order polynomial models by multiple linear regression. The contour plots illustrated that lecithin and monoacylglycerol played a dominant role in controlling the emulsion stability compared to LBG and carrageenan. Lecithin content significantly affected all the responses measured, particularly lipid oxidation. Increasing monoacylglycerol concentration led to an increase in particle size and emulsion viscosity. The optimal condition to achieve the highest stability was predicted to be 0.2, 0.4, 0.045, and 0.015 g/100 ml lecithin, monoacylglycerol, LBG and carrageenan, respectively. The verification data further demonstrated the suitability of the models explored by RSM. Overall, the findings obtained in this study have important implications for the successful incorporation of structured lipid into infant formula emulsion for better infant nutrition and health.     

羟（甲、乙、丙）基纤维素/明胶共混复合膜的制备和性能研究

以明胶为基体,甘油为增塑剂,羟甲基纤维素(HMC)、羟乙基纤维素(HEC)、羟丙基纤维素(HPC)分别为增强相,通过添加不同量的羟(甲、乙、丙)基纤维素,分别制备不同含量的羟(甲、乙、丙)基纤维素/明胶共混复合膜;采用扫描电子显微镜、智能电子拉力试验机、差示扫描量热仪和热缩试验仪对共混复合膜的表面形貌、力学性能和热稳定性进行表征。结果表明,随着共混复合膜中纤维素含量的增加,各复合膜的断裂伸长率和抗拉强度呈先提高后降低的趋势;达到最大抗拉强度时,各共混复合膜中羟基纤维素的含量分别为HMC 1%(38.4 MPa)、HEC 1%(35.3 MPa)、HPC 0.5%(32.1 MPa);各共混复合膜热稳定性均提高,而热缩率降低。添加羟基纤维素可增强共混复合膜的力学性能和热稳定性,但不同羟基纤维素作为增强相时,增强效果存在一定差距。