超高压微射流均质对花生球蛋白性质的影响

以花生球蛋白为原料,超高压微射流均质为手段,研究不同均质压力(40～160MPa)对花生球蛋白微细结构和功能性质的影响.结果表明:花生球蛋白经超高压微射流均质后,粒径分布变窄,平均粒度变小,在均质压力为160MPa时达到最小;X一射线衍射(XRD)显示处理后花生球蛋白的微观晶体结构略有破坏;花生球蛋白的乳化性能在一定压力范围内随着超高压微射流均质压力的增大而提高;花生球蛋白经超高压微射流均质后表观黏度显著减小.流变模型由假塑性流体转变为趋近于牛顿流体.说明超高压微射流均质可改变花生球蛋白的微观结构.从而导致蛋白部分功能性质的改变.     

动态超高压微射流对蜡质玉米淀粉颗粒结构的影响

以蜡质玉米淀粉为研究对象,采用动态超高压微射流进行处理,研究不同压力(40-160 MPa)处理对淀粉颗粒结构的影响。结果表明:经动态超高压微射流均质后,淀粉颗粒表面会出现小孔和凹坑并破碎,并且随着压力的增大,被破坏程度会逐渐增大,当压力达到160 MPa时,会出现团聚现象;随着压力的增大,淀粉颗粒比表面积呈上升趋势;偏光显微镜分析得出淀粉颗粒的偏光十字随着处理压力的增大而逐渐减弱后消失;X射-线衍射分析得出蜡质玉米淀粉晶型为A型,结晶度随着压力的增大而减小。     

动态超高压微射流均质对大豆分离蛋白起泡性、凝胶性的影响

采用动态超高压微射流均质机对大豆分离蛋白进行处理,研究了不同的压力对大豆分离蛋白起泡性、凝胶性的影响.结果表明动态超高压微射流处理能使大豆分离蛋白的起泡性、凝胶性得到改善,随着均质压力的逐渐增加,都有不同程度的提高,100ml的6%大豆分离蛋白经高速分散搅打后,泡沫高度可以达到180ml,16%的大豆分离蛋白凝胶强度可以达到0.08355kg.     

高压微射流对长期贮藏大豆蛋白功能特性的影响

在常温密闭的贮藏条件下,大豆分离蛋白(SPI)功能特性随贮藏时间的延长而逐渐下降.高压微射流纳米均质可改善长期贮藏SPI的功能特性,结果显示:将SPI溶液在30、60、90和120MPa压力下,分别通过1次、2次和3次微射流均质后,可溶性蛋白含量随压力增加而增大,随均质次数增加而下降.SPI分别经过0、120、240和360 d贮藏后,可溶性蛋白含量随贮藏时间延长而下降,但通过120 MPa的2次微射流处理,SPI可溶性蛋白含量得到显著提高.在不同pH条件下,SPI的乳化活性也随贮藏时间延长而下降,经过微射流处理后乳化活性和乳化稳定性显著提高.SPI的起泡性随贮藏时间延长而下降,微射流处理后起泡性和起泡稳定性也显著提高.贮藏360dSPI的热凝胶弹性模量从处理前的563Pa上升到2527Pa.     

动态超高压微射流对卵清蛋白功能性质的影响

以6%的卵清蛋白溶液为原料,采用动态超高压微射流均质进行处理,研究不同处理压力对卵清蛋白功能性质(溶解性、持水性和凝胶性)的影响.结果表明:经动态超高压微射流均质处理后,卵清蛋白的溶解性随着压力的增加有明显的提高,在80MPa时达到最大;卵清蛋白的持水力由1.5 g/g增加到5.05 g/g,持水性明显提高;卵清蛋白的凝胶强度也有所提高,在160 MPa下凝胶硬度最强.     

动态超高压微射流对蜡质大米淀粉理化性质的影响

以蜡质大米淀粉为研究对象,采用动态超高压微射流进行处理,研究不同压力对蜡质大米淀粉理化性质(淀粉粒径、溶解度、膨胀度等)的影响.结果表明:动态超高压微射流处理后淀粉颗粒粒度减小,经过160MPa处理后,平均粒径为0.43μm;经过160MPa处理后,比表面积达1.271123m2/g;蜡质大米淀粉的溶解度和膨胀度随着处理压力的增大而显著增大.     

动态超高压均质对蛋清蛋自溶液的起泡性、成膜性的影响

采用动态超高压均质对80%蛋清蛋白溶液进行处理,研究不同的处理压力对蛋清蛋白起泡性、成膜性的影响.研究表明,蛋清蛋白溶液经过动态超高压均质处理之后,其颗粒大小明显减小,起泡性和成膜性均得到了改善.20mL的蛋清蛋白溶液经过160MPa处理后,泡沫高度可以达到47mL;蛋清蛋白膜的拉伸强度和拉伸率在100MPa时效果最好.     

微射流均质改善热压榨花生粕分离蛋白乳化特性的研究

以热压榨花生粕中提取的花生分离蛋白为原料,采用微射流高压均质进行改性处理,以乳化活性、乳化稳定性、粒度分布和离心乳析率为评价指标,系统研究了不同微射流均质压力对花生分离蛋白乳化特性的影响,并初步探讨了乳状液微观聚集状态和花生分离蛋白宏观乳化特性的相互关系.结果表明:随着均质压力增大,乳化活性和乳化稳定性均呈现先增大后减小趋势;乳化活性和乳化稳定性增大,相应乳状液粒径变小,离心乳析率下降;120MPa是改善花生分离蛋白乳化特性的优选条件.显微镜观察发现,宏观乳化特性改善时,体系微观聚集体减少,120MPa改性的花生分离蛋白制备的乳状液没有发生明显聚集.     

动态超高压微射流技术在玉米花粉多糖提取中的应用

研究动态超高压微射流(DHPM)处理对玉米花粉破壁效果和多糖得率的影响.在单因素实验的基础上,通过正交实验确定了微射流均质破壁花粉和热水提取多糖的最佳条件:均质压力120MPa,微射流处理一次,料液比1:20,提取温度70℃,提取时间2.5h,提取两次,在此条件下,玉米花粉粗多糖的得率最高可达7.545%.动态超高压微射流技术破壁花粉比干法粉碎破壁花粉提取的玉米花粉多糖得率更高,且破壁效果更显著.     

动态超高压微射流均质对半纤维素B理化性质的影响

以半纤维素B为研究对象,采用动态超高压微射流技术在不同压力(0～180MPa)下对半纤维素B进行处理,研究动态超高压微射流对半纤维素B理化性质的影响.结果表明:经动态超高压处理后,样品的平均粒径随着处理压力的增加呈先下降后上升的趋势,在140MPa时达到最低,为610.3nm;比表面积随处理压力的增加先上升后下降,在140MPa时达到最大,为0.65m2/g;随着压力的增大,半纤维素B的结合水的流动性变弱;半纤维素B溶液为假塑性流体,随着压力的增大,其表观黏度降低.     

高静压加工对新鲜蛋液微生物及品质的影响

研究在不同处理压力和时间条件下,高静压对新鲜全蛋液微生物(细菌总数、大肠菌群)、色泽、乳化特性(乳化活力、乳化稳定指数)及起泡特性(起泡性、泡沫稳定性)的影响。结果表明:200 MPa处理10 min,全蛋液微生物指标已符合国家标准;相比空白组,400 MPa处理10 min,全蛋液乳化活力及乳化稳定性显著增加,300 MPa处理20 min及400 MPa处理10 min全蛋液起泡性较好,而400 MPa处理10~15 min及500 MPa处理5~15 min可使全蛋液颜色更鲜亮。综上,适当的高静压处理可使全蛋液达到有效杀菌且改善其品质的目的。     

Enhancement of Functional Properties of Rice Bran Proteins by High Pressure Treatment and Their Correlation with Surface Hydrophobicity

Changes in functional properties of rice bran proteins as influenced by high-pressure (HP) treatment (100–500 MPa, 10 min) were studied. Properties evaluated were protein solubility, water absorption capacity, oil absorption capacity, foaming capacity, foam stability, emulsifying activity, emulsion stability, least gelation concentration, and surface hydrophobicity. HP treatment at 100 and 200 MPa significantly improved the solubility and oil absorption capacity, while water absorption and foaming capacities increased further reaching the maximum at 500 MPa. Compared with the untreated control sample, the emulsifying activity and foam stability of treated samples were significantly higher and least gelation concentration was lower, but none of them showed any specific trend with pressure level. Emulsion stability and surface hydrophobicity increased with the pressure level until 400 MPa and decreased slightly at 500 MPa. Pearson correlation coefficients clearly showed that surface hydrophobicity was positively correlated with water absorption capacity, foaming capacity, emulsifying activity index, and emulsion stability index, but negatively correlated with least gelation concentration. The pressure treated rice bran protein possessed good functional properties for use as a food ingredient in the formulations.     

超高压对鹰嘴豆分离蛋白功能性质的影响

研究了超高压(100-600 MPa)对鹰嘴豆分离蛋白功能性质的影响。结果表明:随着压力的增大和处理时间的延长,鹰嘴豆分离蛋白(CPI)的溶解性不同程度的下降,而表面疏水性、乳化性和起泡性都显著提高。当压力大于400 MPa(乳化性)、500 MPa(起泡性、表面疏水性),或者处理时间大于10 min时,反而导致功能性质的下降。     

水性聚氨酯机械发泡涂层的响应面法优化制备

为制备高透湿率和高强度的水性聚氨酯发泡涂层,采用响应面分析法对机械发泡工艺中成膜温度、发泡剂含量和发泡倍率3个参数进行优化。结果表明,回归得到的二次多项式模型显著且失拟项不显著,模型拟合性良好。各因素对透湿率影响顺序为：成膜温度>发泡倍率>发泡剂质量分数;对断裂强度影响顺序为：发泡倍率>成膜温度>发泡剂质量分数。以透湿率和断裂强度最大为原则,得到最优制备工艺条件：成膜温度120°C,发泡剂质量分数为 5.56 %,发泡倍率为 319.17%;在此条件下制备的水性聚氨酯涂层的实际透湿率为6088.71 g/(m2?24h),断裂强度为1.51 MPa,与模型理论预测值基本相符,表明优化模型有效可靠;以此作为超纤维合成革的发泡层制备水性超细纤维合成革,其透湿率达到 2070.24 g/(m2?24h),纵向、横向断裂强力分别为161.50、112.38 N。     

二段均质压力对黄油基搅打稀奶油品质的影响

该文在黄油基搅打稀奶油经高压均质、热处理后分别使用1.0~5.0 MPa压力进行二段均质处理,并以未经二段均质处理的产品为对照,比较经不同二段均质压力处理后产品稳定性及搅打品质的变化。实验发现,对照产品脂肪球粒度分布出现明显双峰现象,乳液稳定性差,搅打时间为372.00 s,起泡率仅193.70%,并且在光学显微镜下观察到大量絮凝的脂肪球簇;当二段均质压力在1.0~ 3.0 MPa范围内增大,产品脂肪球平均粒径减小,产品稳定性增强,搅打时间缩短,打发率上升,絮凝的脂肪球簇的数量明显减少;当二段均质压力达到3.0 MPa,产品粒度分布趋于稳定,搅打时间仅需306.50 s,起泡率达235.10%,光学显微镜下未观察到明显絮凝现象。相比对照组,经3.0 MPa压力处理后的产品稳定性更好,搅打成型时间由372.00 s缩短至306.50 s,起泡率由193.70%提高至235.10%,实验结果表明,在搅打稀奶油生产中使用3.0 MPa压力进行二段均质可有效阻止乳液脂肪球絮凝,提高产品的稳定性及搅打品质,可满足工业生产高品质搅打稀奶油的要求。     

Functional properties of whey proteins as affected by dynamic high-pressure treatment

An ultra high-pressure homogenizer was used to treat whey protein isolate solutions (3%, w/w). The treated solutions (up to 300 MPa) were characterised for both physico-chemical properties (particle size distribution, surface hydrophobicity and structural conformation) and functional properties (solubility, foaming stability and interfacial rheology). Dynamic high-pressure treatment did not affect the conformation of the proteins (determined by micro-calorimetry, size-exclusion chromatography and electrophoretic technique). This treatment dissociated large protein aggregates leading to unmasking of the buried hydrophobic groups without affecting protein solubility. Interactions may then occur between these groups that enhance the viscoelasticity of air-water interfaces (assessed by drop tensiometry) and improve foam stability (evaluated by sparging method). Dynamic high-pressure-treated whey proteins showed better foaming and stabilising properties.     

Effect of amidation on the foaming and physico-chemical properties of bovine serum albumin

Amidation of bovine serum albumin (BSA) was achieved by a water-soluble carbo-diimide, ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated reaction using ammonium chloride as the nucleophile. Partial and substantial amidation of 0.5% (w/v) BSA in 5.5 m ammonium chloride solution with 1 times 10-²mmol EDC over 120 min and 1 times 10^-1mmol EDC over 10 min respectively was achieved on a large scale using diafiltration for rapid termination of the reaction and purification. Residual ammonium chloride otherwise enhanced foaming properties. The amidated proteins were characterized by isoelectric focusing, electrophoresis and hydrophobicity and disulphide- and sulphydryl-group measurements. Compared with native BSA, partially amidated BSA (PA-BSA) produced enhanced foam expansion and foam stability values. This was attributed to minimal denaturation and to the presence of both acidic and basic components (pI range 5.25–7.50) within the single protein. In contrast, substantially amidated BSA (SA-BSA) (pI range 7–9.1) had similar foaming properties to those of the ultrafiltered BSA control which were slightly lower than those of native BSA. However SA-BSA interacted synergistically with native BSA producing enhanced foaming properties particularly at the 1:1 ratio through electrostatic interactions, conformational changes and increased hydrophobicity.     

Effect of dynamic high-pressure microfluidization on physicochemical,structural, and functional properties of oat protein isolate

Dynamic high-pressure microfluidization (DHPM) technology was used to treat oat protein isolate (OPI) to improve its functional properties and broaden its application in food processing. Results showed that the particle size of OPI was significantly reduced by 70.96%, and the absolute zeta potential increased by 33.51% at a DHPM pressure of 120 MPa. The major subunits of OPI were not degraded, but the secondary structures of OPI were altered with increasing α-helix, β-sheet, and β-turn structures and decreasing random coil after DHPM treatment. In addition, the significant increase in the surface hydrophobicity and free sulfhydryl content, as well as fluorescence quenching of OPI indicated the conformational expansion and rearrangement of OPI. Additionally, the changes in OPI structures affected its functional performance. DHPM treatment at 120 MPa significantly improved the solubility, water and oil holding properties, and emulsifying and foaming abilities of OPI. Therefore, DHPM treatment can improve the functional properties of OPI, which provides a new idea for expanding the application of OPI in food processing.     

高密度CO_2对全蛋液功能性质的影响

鸡蛋除具有很高的营养价值外,还有重要的功能特性如乳化性、起泡性和凝胶性等,文中研究了高密度CO2对全蛋液功能性质的影响。结果表明:全蛋液的功能性质随处理压力增加而增加,当处理压力大于15 MPa时,全蛋液的溶解性、起泡性、凝胶性及表面疏水性下降;全蛋液的乳化性在处理压力大于10 MPa时下降。全蛋液的功能性质随处理时间的延长而增加,当处理时间超过20 min时,全蛋液的溶解性、起泡性和表面疏水性下降;全蛋液的乳化性及凝胶性在处理时间超过25 min时下降。     

高静水压和热处理对荞麦蛋白功能性质的影响

高静水压（high hydrostatic pressure,HHP）处理技术作为一种新型的非热食品加工技术,在食品加工中具有对食物营养和感官品质破坏较小等多种优势。本实验通过HHP处理与传统热处理法（heat treatment,HT）处理荞麦蛋白（buckwheat protein,BWP）,并测定BWP溶解性、起泡性和乳化性等性质,此外通过BWP羰基含量、巯基含量和表面疏水性测定以及傅里叶变换红外光谱分析,研究不同加工处理方式对BWP功能性质的影响。结果表明：随着HHP处理压力的增加,BWP的羰基含量、表面疏水性显著升高（P＜0.05）,而巯基含量显著降低（P＜0.05）;在500 MPa、30 min时,BWP乳化性、起泡性均达到最大值（67.3 m2/g和91.5%）,较空白对照组（未经HHP处理）分别提高33.0%、16.1%,较HT处理组分别提高61.5%、52.8%。傅里叶变换红外光谱结果表明,HHP处理后BWP的α-螺旋和β-折叠相对含量减少,β-转角和无规卷曲相对含量增加。经相关性分析发现,BWP的溶解性、乳化性、起泡性、羰基含量与巯基含量之间均存在相关性。其中,BWP的乳化性与起泡性、表面疏水性呈极显著正相关（P＜0.01）,并且与巯基含量呈极显著负相关（P＜0.01）。综上,HHP处理可以改变BWP的功能性质。可为进一步研究BWP在功能食品的应用提供理论和实验依据。