高压均质处理对不同浓度肌原纤维蛋白水悬液理化特性及蛋白结构的影响

以鸡肉中的肌原纤维蛋白(Myofibrillar proteins,MP)为对象,研究103 MPa压力条件下高压均质(High pressure homogenization,HPH)对不同浓度(5、10、15 mg/mL)MP水悬液理化性质和蛋白结构的影响。结果表明:HPH可以显著提高不同浓度MP在水中的溶解性(P<0.05),改善MP水悬液的分散性、流变性等理化特性,破坏蛋白结构。随着MP浓度增加,MP水悬液溶解度下降、稳定性变差(P<0.05);高浓度的MP在HPH处理过程中可能会发生蛋白聚集,导致水悬液中蛋白粒径增大,表观粘度变大,流动性降低;MP水悬液二、三级结构改变,表面疏水性降低,巯基含量上升,α-螺旋增加,β-折叠下降,从而影响其溶解性;其中5 mg/mL的MP水悬液经过HPH处理后溶解性较好,溶解度达到88.39%,在4 ℃条件下放置9 d后仍然能保持79.08%的溶解度。本研究为食品行业中肉蛋白的深加工提供了参考依据。     

高压均质协同高酰基结冷胶对青椒蛋蔬液流变特性及稳定性的影响

研究高压均质（high pressure homogenization,HPH）协同高酰基结冷胶（high acyl gellan gum,HA）处理对青椒蛋蔬液（liquid egg with green pepper juice,LEGP）稳定系数、持水力、流变特性、粒径及电位的影响,进而探讨HPH协同HA对LEGP流变特性及稳定性的影响。结果表明：HPH处理可以明显提高LEGP的稳定系数、持水力、屈服应力、表观黏度和ζ-电位绝对值,并减小体系粒径,说明HPH处理可以有效提高LEGP体系稳定性。与HPH相比,HPH协同HA处理可以进一步提高LEGP的稳定系数、持水力、屈服应力、表观黏度和ζ-电位绝对值,使体系粒径进一步减小且分布更均匀,表明HPH协同HA处理可以更好地提高LEGP体系稳定性;其中,均质压力为150 MPa时,LEGP的稳定系数和持水力达到最大。流变实验结果表明HPH处理或HPH协同HA处理样品的流变模型均符合Herschel-Buckley模型,且其流体为带屈服值的假塑性流体,其中,HPH协同HA处理均质压力为150 MPa时,LEGP的屈服应力、表观黏度和弹性模量最高,流体的假塑性最强,体系粒径最小,ζ-电位绝对值最大,LEGP表现出最高的稳定性。     

高压均质技术提高烟用料液稳定性

  目的  为改善烟用料液的均一性,避免分层、沉淀产生,运用高压均质技术提高料液的稳定性。  方法  通过选取不同的均质压力、均质次数探讨高压均质对料液稳定系数、离心沉淀率、颗粒粒径、烟草提取物粘度及颗粒沉降速率的影响。  结果  :（1）随着均质压力的升高,料液的稳定系数先增加后下降,离心沉淀率减小后又增大,均质压力120 MPa时料液稳定性较好;（2）随着均质次数的增加,料液的稳定系数增加,离心沉淀率下降后上升,根据回归分析的结果,均质次数7次时料液稳定性较好;（3）增大均质压力至150 MPa,料液颗粒粒径显著减小（均质前:1.02 μm;均质后:0.4 μm,P < 0.01）,增加均质次数对料液颗粒粒径无显著影响;（4）均质次数较均质压力对料液烟草提取物粘度的影响更为显著;（5）增加均质压力至120 MPa,颗粒在料液中的沉降速率减小约45%（均质前:1.98 μm/s;均质后1.07 μm/s,P < 0.05）。  结论  高压均质技术可有效提高烟用料液均一、稳定性。      

超微粉碎处理对核桃蛋白结构及功能性质的影响

以核桃蛋白为原料,探究超微粉碎对核桃蛋白结构和功能性质的影响。通过对核桃蛋白进行不同频率的超微粉碎处理,得到8种不同粒径的核桃蛋白。采用扫描电子显微镜（scanning electron microscope,SEM）和傅里叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR）研究核桃蛋白结构,并考察超微粉碎对核桃蛋白巯基含量、溶解性、持水性、持油性、起泡性、乳化性等功能性质的影响。研究结果显示,超微粉碎处理后,随着频率降低,核桃蛋白的粒径整体呈减小趋势,核桃蛋白的粒径最小达到10.65 μm,比表面积最大为354.2 m2/kg。SEM结果显示经超微粉碎后的核桃蛋白颗粒更细小、更分散,比表面积更大。FTIR研究结果显示,经超微粉碎后的核桃蛋白β-折叠结构比例降低,β-转角结构比例增加。随着超微粉碎频率的减小,游离巯基含量整体呈先增加后降低趋势,35 Hz上超微粉碎处理得到的游离巯基含量最高,为30.01 μmol/g;溶解性整体呈先增加后降低趋势;泡沫稳定性、持水性和持油性整体呈下降趋势,与原料相比,15 Hz上超微粉碎处理得到的蛋白持水性下降了59.95%,持油性下降了44.84%;起泡性和乳化稳定性整体呈增加趋势,15 Hz上超微粉碎处理得到的蛋白起泡性为原料的1.92倍,乳化稳定性为原料的1.4倍。因此,超微粉碎处理对核桃蛋白的结构和功能性质有重要影响。     

高压均质对大豆分离蛋白功能性质的影响

为了了解高压均质技术对大豆分离蛋白（SPI）功能性质的影响,采用不同的均质压力、均质次数和料液比对大豆分离蛋白溶液进行了高压均质处理,并分析处理前后SPI功能性质的变化.结果表明：高压均质可在一定程度上提高SPI的溶解性、乳化活性及其稳定性和起泡性及泡沫稳定性.均质压力在0～70 MPa的范围内升高时,SPI的溶解性、乳化稳定性、起泡性和泡沫稳定性得到了相应的改善,而乳化活性在压力为40 MPa时达到最高;均质次数由1次向3次增加时,SPI的乳化稳定性、起泡性及泡沫稳定性得到了提高,而溶解性和乳化活性则降低;均质物料料液比在1∶16～1∶8 （g∶mL）的范围内逐步增大时,SPI的各项功能性质均有不同程度的提高,并在料液比为1∶8时达到了最高值.     

低钠条件下超声处理对鸡肉肌原纤维蛋白乳液稳定性的影响

低钠条件下肌原纤维蛋白（myofibrillar protein,MP）作为乳化剂制备的乳液稳定性差,本实验采用高强度超声波（high intensity ultrasound,HIU）（频率20 kHz、功率450 W）对低钠条件下（0.15 mol/L NaCl）MP进行不同时间（0、3、6、9、12 min）处理,测定处理后MP乳液乳化活性指数（emulsifying activity index,EAI）、乳液稳定性指数（emulsion stability index,ESI）、Turbiscan稳定性指数（turbiscan stability index,TSI）和平均粒径等,并进行微观结构观察和流变性分析等,研究低钠条件下超声处理对鸡肉MP乳化特性及其乳液稳定性和流变性能的影响。结果表明：与对照组相比,随着超声处理时间延长,MP的EAI和ESI显著增加（P＜0.05）,MP制备乳液的TSI和粒径随着超声处理时间的延长明显减小,且乳液液滴分布均匀,乳液Zeta-电位的绝对值显著增加（P＜0.05）。乳液的流变学特性分析结果表明超声波明显提高了MP乳液的黏弹性。MP乳液的油-水界面张力分析结果显示超声处理有效增强了MP的移动性,使界面张力迅速降低,同时超声处理显著增加了MP乳液吸附蛋白相对含量（P＜0.05）,这表明超声处理MP有助于稳定乳液。通过冷场扫描电子显微镜观察进一步证实了超声处理12 min MP制备的乳液液滴体积最小。综上,超声波能够有效提高低钠条件下MP的乳液稳定性,本实验可为超声处理在减盐乳化型肉制品中的应用提供理论参考。     

高压均质对胡萝卜汁物化特性及类胡萝卜素含量的影响

为研究高压均质(HPH)对胡萝卜汁物化特性和类胡萝卜素含量的影响,在不同均质压力(20,60,100,150 MPa和180 MPa),均质次数(1,2次和3次)和进料温度(25,50℃和70℃)的条件下处理胡萝卜汁并用激光粒度分析仪、Zeta电位仪、浊度仪和流变仪分别测定和计算胡萝卜汁粒径分布、Zeta电位、悬浮稳定性和流变特性(流体类型、黏度曲线和黏弹性),以此评估HPH处理参数对胡萝卜汁物化特性的影响。应用高效液相色谱法测定胡萝卜汁中类胡萝卜素的含量。结果表明:随着均质压力的升高(20～180 MPa)和均质次数的增加(1～3次),粒径分布峰向左移动,20 MPa均质处理与未均质相比,D_(50)减小52.41%,D[4,3]减小41.46%,D[3,2]减小49.48%。180 MPa均质处理与20 MPa相比,D50减小87.21%,D[4,3]减小82.9%,D[3,2]减小84.49%,HPH处理可减小胡萝卜汁中颗粒粒径并提高胡萝卜汁的悬浮稳定性。经流变学数据分析,胡萝卜汁属于假塑性流体(0n1),流变曲线符合Herschel-Bulkley模型,且胡萝卜汁具有凝胶特性(G′G″)。随着均质压力的升高(20～180 MPa)和均质次数的增加(1～3次),胡萝卜汁表观黏度降低,G′和G″均减小。HPH不降低胡萝卜汁中类胡萝卜素含量,甚至促进类胡萝卜素从植物组织释放至胡萝卜汁中。在进料温度25℃,均质次数3次,均质压力60MPa时β-胡萝卜素和α-胡萝卜素含量最高,分别为44.86μg/mL和22.39μg/mL。     

蒸谷米糠蛋白功能特性研究

研究在不同温度和不同pH值条件下,酶解提取的蒸谷米糠蛋白（PRBP）溶解性、乳化性和泡沫性,并和大豆分离蛋白（SPI）做比较。结果发现：在不同温度下,蒸谷米糠蛋白的溶解性、乳化性、泡沫性随温度增加,先升高后下降。而乳化稳定性和泡沫稳定性一直下降;在不同pH值下,蒸谷米糠蛋白的溶解性、乳化性、泡沫性与泡沫稳定性随pH值增加,先降低、后升高,而乳化稳定性先升高后降低;大豆分离蛋白的乳化性和泡沫性好于蒸谷米糠蛋白。     

超声波对不同盐浓度下肌原纤维蛋白溶解性的影响

应用超声波处理(频率20 kHz,功率450 W,超声波强度30 W/cm²,时间0、3、6和9 min)不同NaCl浓度(0.2、0.4、0.6 mol/L)下鸡胸肉肌原纤维蛋白(myofibrillar protein,MP),分析MP的溶解度、浊度、粒径、电位及二级结构,研究超声波处理对MP溶解特性的影响。结果显示:随着超声波处理时间的增加,不同NaCl浓度下的MP溶解度显著上升(P<0.05),电位绝对值显著增大(P<0.05),而浊度和粒径显著下降(P<0.05);超声波处理能够促进二级结构由螺旋向折叠等转化,有助于MP溶解性的增加。结果表明,超声波处理破坏MP有序结构,降低MP聚集程度,减小MP粒径大小,同时增加蛋白之间静电相互作用,使MP体系均匀分散。因此,超声波处理部分改善了降盐水平下MP的溶解性,为超声波技术在低盐鸡肉制品的应用提供理论依据。     

高压均质处理对豌豆淀粉流变特性及多尺度结构的影响

以豌豆淀粉(pea starch,PS)为原料,分别在0、20、40、60、80、100 MPa条件下高压均质(high-pressure homogenization,HPH)处理3次,每次约30 min,探究HPH处理对PS凝胶流变特性及淀粉多尺度结构的影响。结果表明,随着均质压力的增加,PS黏度、触变性先增加后减小;频率扫描结果显示,HPH处理后PS凝胶的储能模量G’、损耗模量G”明显升高,40 MPa处理后PS凝胶黏性和弹性最好;PS凝胶的G’、G”曲线在70～75℃区间内出现拐点。HPH处理使PS的颗粒形貌、晶体结构及短程有序结构等多尺度结构均发生变化。其中,HPH处理后PS颗粒表面出现裂缝、塌陷及坑洞,其粒径分布发生变化;通过X射线衍射、傅里叶变换红外光谱分析发现,与原PS相比,100 MPa处理后PS非结晶区比例增加,且HPH处理使PS的在1 047、1 022 cm^-1处吸收峰峰面积的比值升高,短程有序结构数量增多;¹H核磁共振图谱表明PS中α-1,4糖苷键、α-1,6糖苷键均受到破坏,PS的分支度降低。本研究为HPH在淀粉流...     

Conformational changes induced by high-pressure homogenization inhibit myosin filament formation in low ionic strength solutions

Myofibrillar proteins (MPs) of chicken breast are generally insoluble in water. We have developed a new method whereby MPs are solubilized in water by applying high-pressure homogenization (HPH) thus potentially enabling greater utilization of meat in various products. To clarify the mechanism of solubilization of MPs by HPH, we investigated their conformation, solubility and filament forming behavior in low ionic strength solutions induced by 15,000 psi HPH (103 MPa). HPH induces unfolding of MPs which subsequently exposes sulfhydryl and hydrophobic groups to the surface. Our findings, determined by circular dichroism, ATR-FTIR, SDS-PAGE and LC-ESI-MS/MS analysis suggest that HPH leads to unraveling of helical structures and to formation of myosin oligomers through disulfide bond. Due to intermolecular electrostatic repulsion and physical barrier of disulfide bonds in the rod induced by HPH, we suggest that the altered myosin conformation in MPs inhibits filament formation, thus contributing to high solubility of MPs in water.     

Potential of high pressure homogenization to solubilize chicken breast myofibrillar proteins in water

Myofibrillar proteins (MPs) of chicken breast were generally insoluble in water. The potential of high-pressure homogenization (HPH) to solubilize chicken breast MPs in water was tested. The effects of 0 psi (0.1 MPa), 10,000 psi (69 MPa), 15,000 psi (103 MPa) and 20,000 psi (138 MPa) for two passes HPH on solubility, protein profile, particle property, flow property and microstructure of MPs in water were investigated. HPH at 15,000 psi (103 MPa) could induce the suspension of MPs with small particle size species (sub-filament, oligomers or monomer structure) and high absolute zeta potential, thus enhancing the solubility, flow ability and stability without individual protein degradation. Reduction of particle size and strengthening of intermolecular electrostatic repulsion appeared to be the main reasons in solubilizing MPs in water treated with HPH.Industrial relevanceThe qualitative characteristics of meat products are closely related to the solubility of meat proteins. Myofibrillar proteins (MPs), as major part of total muscle proteins, are generally considered to be insoluble in water. The results showed that high-pressure homogenization has potential application for solubilizing MPs in water to develop new meat-based products in the food industry.     

Properties of starch nanoparticle obtained by ultrasonication and high pressure homogenization for developing carotenoids-enriched powder and Pickering nanoemulsion

The effect of ultrasound (US) and high pressure homogenization (HPH) on starch nanoparticles and their ability to stabilize Pickering nanoemulsion of carotenoids and bioactives-enriched olive oil was evaluated. The carotenoids used in nanoemulsion were extracted from the peel of passion fruit (Passiflora edulis). As the US treatment time increased, mean particle size decreased from microsize to 340 nm and subsequent HPH treatment of this suspension caused further decrease in particles size (<60 nm). US and HPH treatments increased swelling and solubility and also the gelatinization and melting temperatures of the starch nanoparticles. The Pickering nanoemulsion was rich in carotenoids and total phenolic content and exhibited high antioxidant activity, which had protective effect on its stability. The carotenoids-enriched nanoemulsion was found to be stable to heat and freeze-thaw treatments. The developed nanoemulsion showed better oxidative stability as well as physical stability during storage at 6 °C and 25 °C.     

Using high-pressure homogenization as a potential method to pretreat soybean protein isolate: Effect on conformation changes and rheological properties of its acid-induced gel

This study evaluated the conformational changes and rheological properties of acid-induced gels of insoluble soybean protein isolate (SPI) pretreated with high-pressure homogenization (HPH) under different pressure and cycles. Results showed that HPH pretreatment destroyed the spatial structure of the insoluble SPI, significantly decreased the particle size of the SPI dispersion, and increased the SH content. Through the characterization of its acid-induced gelation product, the best ability to withstand small strains (< 3%) of gel was found in a single HPH cycle under 100 MPa. The SPI gels with a relatively compact structure transformed from strain stiffening to strain softening with the strain increased, and it provided satisfactory stability to withstand large-amplitude oscillatory shear in three-time HPH cycles under 100 MPa. Meanwhile, SPI gels exhibited a more chaos spatial topology network after HPH pretreatment through fractal analysis, and the gels eventually exhibited “soft gel” and shear-thinning behavior with HPH pretreatment. This provides an evidence for the beneficial effect of HPH on the structural homogenization and subsequent gel formation stability of protein gels, and explores its potential applications in the food industry.     

Effects of high‐pressure homogenisation on structural and functional properties of mussel (Mytilus edulis) protein isolate

In this study, the effects of high‐pressure homogenisation (HPH) treatment on structural and functional properties of mussel protein isolate (MPI) were investigated. HPH treatment did not modify the protein profiles of MPI, but caused changes in secondary, tertiary and quaternary structure. HPH treatment improved functional properties of MPI such as solubility, foaming ability, emulsifying activity and stability. This preliminary study demonstrated the potential of HPH technology to process MPI due to improving its functional properties.     

Effect of high pressure processing on gastrointestinal fate of carotenoids in mango juice: Insights obtained from macroscopic to microscopic scales

High hydrostatic pressure (HHP) and high-pressure homogenization (HPH) were applied to mango juice to explore their effects on gastric retention rate (G-CRR), bioaccessibility (BAC) of total and individual carotenoids, and the corresponding mechanisms from macroscopic to microscopic scales. Compared to the control, both HHP and HPH at 50 MPa had no significant effect on BAC and G-CRR, whereas HPH at 100 MPa significantly increased BAC by 44.33% and G-CRR by 11.84%. Further HHP treatments (particularly at 400 MPa) on the 100 MPa-HPH-pretreated samples significantly increased BAC by 71.37% and G-CRR by 24.24%. Violaxanthins/esters were less stable than carotenes in the stomach, resulting in lower bioaccessibility of violaxanthins/esters. G-CRR and BAC were negatively correlated with the viscosity and particle size of juice, whereas they were positively correlated with the solubility/dispersibility of carotenoids. In addition, pectin-carotenoid interactions may also be an important factor affecting the digestive fate of carotenoids in juice.Industrial relevanceHigh pressure processing (High hydrostatic pressure, HHP, and high pressure homogenization, HPH) is a non-thermal technique and its effect on the bioaccessibility of carotenoids in fruits and vegetables have attracted attention from researchers. Our research found that HPH and HHP combined treatment could decrease the particle size of mango juice, and increase the viscosity and turbidity as well as the bioaccessibility of carotenoids therein. This technology can be used to preserve the physical stability of mango juice and improve the nutritional value.     

高压均质对NFC水蜜桃浊汁稳定性及品质的影响

本文采用高压均质技术,探究了均质压力（20~40 MPa）及次数（1~2次）对NFC水蜜桃浊汁的混浊度、离心沉淀率、粒径、Zeta电位等稳定性指标和pH、TSS、总酸、固酸比、还原糖、色泽、总酚、V_C等品质指标的影响。结果表明:高压均质（30~40 MPa/1、20~40 MPa/2）可有效提高NFC水蜜桃浊汁的稳定性,离心沉淀率较未处理组下降13.49%~24.22%,平均颗粒粒径由1853.67 nm降至501.10~665.27 nm,绝对Zeta电位值显著提高（P<0.05）。随着均质压力及次数的增加,浊汁中可溶性果胶含量上升,而残存果胶甲基酯酶活力逐渐降低。高压均质后,浊汁色泽显著改善,L*值升高,褐变指数BI值下降（P<0.05）;30 MPa/1下,品质保持最佳,总酚、V_C含量较未处理组显著提高（P<0.05）,而pH、TSS、总酸和固酸比无变化（P>0.05）;随着均质次数增加,pH、TSS、总酚和V_C含量显著降低（P<0.05）,品质下降。高压均质处理可有效提高NFC水蜜桃浊汁稳定性、抑制褐变,并提高总酚、V_C等营养物质含量。     

Impact of high-pressure homogenization pretreatment on recovery of curcumin from turmeric by different combinations of extraction and drying methods

This study reports the effect of different extraction and drying techniques in the recovery of curcumin, where the impact of the pre-treatment step on turmeric rhizome using high-pressure homogenization (HPH) was evaluated. Soxhlet extraction (SE) and ultrasound-assisted extraction (UAE) followed by drying (oven drying, vacuum drying, and freeze drying) were applied to HPH-treated and control (non-HPH) samples. The HPH treatment condition of 100 MPa for 10 cycles demonstrated the lowest particle sizes in the turmeric suspensions and the highest curcumin content in the aqueous supernatant. It was also found that HPH treatment increased the release of curcumin from the freeze-dried turmeric extracts obtained from SE (+76.2%) and UAE (+57.5%). Besides, freeze drying was the best drying method demonstrating higher antioxidant activity of extracts than other thermal drying methods. The total phenolic content was increased by about 65.5% upon HPH treatment on turmeric extract obtained from UAE followed by vacuum drying.     

Comparison of polysaccharide degradations by dynamic high-pressure homogenization

The mechanical degradation of polysaccharides was investigated using dynamic high and ultra-high-pressure homogenization (HPH). The objectives were to reduce the molar mass of polymer chains, and simultaneously, the apparent and intrinsic viscosity of polysaccharides in solution. The influence of homogenization pressure (up to 200 MPa) and cycles was compared on polysaccharides with different physical and structure properties: namely, guar gum, hydroxyethylcellulose (HEC), sodium carboxymethylcellulose (Na-CMC), sodium alginate (Na-alginate) and gum arabic. HPH was applied on semi-dilute solutions. The apparent changes in molar mass, gyration radius and intrinsic viscosity were deduced from size exclusion chromatography coupled on-line with multi-angle laser light scattering, differential viscometer detector and differential refractive index detector (SEC/MALS/DV/DRI), while the evolution of the critical overlap concentration (C^∗) was obtained by viscosimetry. A method based on a succession of homogenization cycles and polymer pre-concentration steps was developed to determine the minimum molar mass achieved at constant pressure. Molar mass, and intrinsic viscosity were shown to fall simultaneously while logically C^∗ increased during HPH for all polysaccharides, except gum arabic, probably because of its globular and branched structure. This highlights that the differences of polysaccharide structures and conformation (linear, branched…) exhibit a stronger impact on HPH treatments than polymer charge or molar mass. Finally, via an empirical approach linking the decrease of both molar masses and viscosities, we have evidenced a specific scaling exponent that should characterize the flexibility of the treated polymer (i.e. its ability to be degraded by HPH).