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该文研究纳米粉碎对乳清浓缩蛋白(whey protein concentrate,WPC)及乳清浓缩蛋白微凝胶颗粒(whey protein concentrate micro-gel particles,WPM)粒径、分子量、游离巯基含量和内源性荧光光谱的影响,探究蛋白质多尺度结构的变化对WPM稳定乳液的微流变特性、贮藏稳定性和微观形貌的影响,以表征乳清浓缩蛋白界面性质的变化规律。研究结果表明:纳米粉碎预处理可以显著降低乳清浓缩蛋白的粒径并增强粒径分布的集中程度。纳米粉碎预处理后,蛋白质分子量并无明显差异,但是游离巯基含量明显减少,证明了大量分子内二硫键的形成;内源性荧光光谱结果显示WPC的最大吸收波长由333 nm红移至339 nm处,说明内埋的疏水性基团暴露,表面疏水性增强。经纳米粉碎和微粒化处理后,sWPM-8h乳液具有最强的黏性和弹性、较小的固液平衡值、最小的流动性指数和最高的贮藏稳定性。综上,纳米粉碎可以改善乳清浓缩蛋白的界面性质。 相似文献
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超高压对乳清分离蛋白结构和抗氧化活性的影响 总被引:1,自引:0,他引:1
为了研究超高压处理对乳清分离蛋白结构的影响,该研究对乳清分离蛋白进行了不同条件的超高压处理,之后测定表面疏水性、傅里叶变换红外光谱、自由巯基含量和内源荧光光谱分析乳清分离蛋白的结构变化。与未经处理的乳清分离蛋白相比,200 MPa及以上压力显著提高了乳清分离蛋白的表面疏水性,在400 MPa-30min时达到最大值。超高压处理使乳清分离蛋白的α-螺旋、β-折叠含量发生明显变化,证明了其对乳清分离蛋白二级结构的影响。超高压处理增加了蛋白自由巯基含量,在400 MPa-30 min时增加49%,并且超高压处理也引起了乳清分离蛋白内源荧光强度的显著变化。在所有的超高压处理条件中,400 MPa-30 min对乳清分离蛋白结构的影响最为显著,并显示出了最高的抗氧化活性。研究表明,超高压处理能显著改变乳清分离蛋白的二、三级结构,暴露出疏水基团等活性基团,从而对抗氧化活性产生影响。 相似文献
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用乳清浓缩蛋白WPC80 为原料,在复合酶A 的作用下,研究乳清肽的制备工艺。复合酶A 的反应条件为[S]12g/100mL、温度50℃、[E]/[S]3%、pH9.0。选用截留分子质量10kD 的磺化聚砜膜,常温并在工作压差0.25MPa 下对水解液进行超滤处理后,选用树脂HZ00x 对水解液进行脱苦,得到的处理液无明显的苦涩味,只有轻微的蛋腥味,最后肽得率36.54%。产品中肽的分子质量分布以二、三和四肽为主,分别占峰面积的27.45%、34.88% 和26.65%。 相似文献
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以乳清浓缩蛋白(whey protein concentrate,WPC)为原料,采用动态流变仪、光学微流变仪、圆二色谱仪、荧光分光光度计及扫描电镜探究WPC凝胶形成过程、分子间相互作用和微观结构,并研究热诱导温度(60、85 ℃)和pH值(2.0、4.5、7.0、9.0)对WPC凝胶性质和结构的影响机理。结果表明:pH值通过改变电荷密度影响WPC的凝胶结构;热诱导温度为85 ℃时,蛋白质分子展开更充分,α-螺旋结构含量较低,内源荧光的最大荧光强度波长处红移明显,形成的WPC凝胶具有更高的弹性模量和黏性模量;凝胶的弹性因子和宏观黏度指数较高,固液平衡值较低;相互作用力分析结果说明较高的热诱导温度能促进疏水相互作用、氢键与二硫键的形成,从而改善WPC凝胶的性质和结构。 相似文献
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研究了超高压(200、400、600 MPa)和加热处理(60、80、100℃)对菜籽蛋白溶解性、乳化性、起泡性、持水性、持油性和结构的影响。结果表明:碱性条件下,超高压处理可以提高溶解性,而加热处理会降低溶解性;超高压及加热处理对菜籽蛋白乳化稳定性影响无规律,但整体呈改善作用;超高压处理对菜籽蛋白的起泡性有促进作用,加热处理对泡沫稳定性有促进作用;与对照组相比,100℃加热处理的菜籽蛋白持水力提高了144. 67%,600 MPa处理的菜籽蛋白持油力提高了201. 81%; 100℃加热处理的菜籽蛋白二级结构变化最显著(P 0. 05)。研究认为,超高压和加热处理都能在一定程度上改善菜籽蛋白的功能性质。 相似文献
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High hydrostatic pressure modification of whey protein concentrate for improved functional properties 总被引:1,自引:0,他引:1
Whey protein concentrate (WPC) has many applications in the food industry. Previous research demonstrated that treatment of whey proteins with high hydrostatic pressure (HHP) can enhance solubility and foaming properties of whey proteins. The objective of this study was to use HHP to improve functional properties of fresh WPC, compared with functional properties of reconstituted commercial whey protein concentrate 35 (WPC 35) powder. Fluid whey was ultrafiltered to concentrate proteins and reconstituted to equivalent total solids (8.23%) as reconstituted commercial WPC 35 powder. Solutions of WPC were treated with 300 and 400 MPa (0- and 15-min holding time) and 600 MPa (0-min holding time) pressure. After HHP, the solubility of the WPC was determined at both pH 4.6 and 7.0 using UDY and BioRad protein assay methods. Overrun and foam stability were determined after protein dispersions were whipped for 15 min. The protein solubility was greater at pH 7.0 than at pH 4.6, but there were no significant differences at different HHP treatment conditions. The maintenance of protein solubility after HHP indicates that HHP-treated WPC might be appropriate for applications to food systems. Untreated WPC exhibited the smallest overrun percentage, whereas the largest percentage for overrun and foam stability was obtained for WPC treated at 300 MPa for 15 min. Additionally, HHP-WPC treated at 300 MPa for 15 min acquired larger overrun than commercial WPC 35. The HHP treatment of 300 MPa for 0 min did not improve foam stability of WPC. However, WPC treated at 300 or 400 MPa for 15 min and 600 MPa for 0 min exhibited significantly greater foam stability than commercial WPC 35. The HHP treatment was beneficial to enhance overrun and foam stability of WPC, showing promise for ice cream and whipping cream applications. 相似文献
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J.M. Chauhan 《Journal of dairy science》2010,93(4):1452-1458
The purpose of this study was to examine flavor binding of high hydrostatic pressure (HHP)-treated whey protein concentrate (WPC) in a real food system. Fresh Washington State University (WSU, Pullman) WPC, produced by ultrafiltration of separated Cheddar cheese whey, was treated at 300 MPa for 15 min. Commercial WPC 35 powder was reconstituted to equivalent total solids as WSU WPC (8.23%). Six batches of low-fat ice cream were produced: A) HHP-treated WSU WPC without diacetyl; B) and E) WSU WPC with 2 mg/L of diacetyl added before HHP; C) WSU WPC with 2 mg/L of diacetyl added after HHP; D) untreated WSU WPC with 2 mg/L of diacetyl; and F) untreated commercial WPC 35 with 2 mg/L of diacetyl. The solution of WSU WPC or commercial WPC 35 contributed 10% to the mix formulation. Ice creams were produced by using standard ice cream ingredients and processes. Low-fat ice creams containing HHP-treated WSU WPC and untreated WSU WPC were analyzed using headspace-solid phase microextraction-gas chromatography. Sensory evaluation by balanced reference duo-trio test was carried out using 50 untrained panelists in 2 sessions on 2 different days. The headspace-solid phase microextraction-gas chromatography analysis revealed that ice cream containing HHP-treated WSU WPC had almost 3 times the concentration of diacetyl compared with ice cream containing untreated WSU WPC at d 1 of storage. However, diacetyl was not detected in ice creams after 14 d of storage. Eighty percent of panelists were able to distinguish between low-fat ice creams containing untreated WSU WPC with and without diacetyl, confirming panelists’ ability to detect diacetyl. However, panelists were not able to distinguish between low-fat ice creams containing untreated and HHP-treated WSU WPC with diacetyl. These results show that WPC diacetyl-binding properties were not enhanced by 300-MPa HHP treatment for 15 min, indicating that HHP may not be suitable for such applications. 相似文献
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通过热处理和调节p H对乳清蛋白浓缩物80(Whey protein concentrate,WPC80)进行改性处理,并将改性后的WPC80添加至低脂稀奶油中,以改善其搅打性质。结果表明调节WPC80溶液的p H为3,在80℃下加热15min时具有最佳的溶解性和起泡性,相同p H条件下,不同的热处理时间会对溶解性和起泡性产生不同的影响;将热处理和p H改性后WPC80加入搅打稀奶油中,研究发现不同热处理时间,p H为5改性的WPC80可以显著提高搅打稀奶油的打发率(p<0.05),但是p H为7处理的WPC80使稀奶油的泡沫稳定性增加了154.67%~193.42%。因此可通过热处理和调节p H改性的WPC80来提高低脂稀奶油的搅打特性,且此操作方法简单易行。 相似文献
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Previous research demonstrated that application of high hydrostatic pressure (HHP), particularly at 300 MPa for 15 min, can enhance foaming properties of whey protein concentrate (WPC). The purpose of this research was to determine the practical impact of HHP-treated WPC on the body and texture of lowfat ice cream. Washington State University (WSU)-WPC was produced by ultrafiltration of fresh separated whey received from the WSU creamery. Commercial whey protein concentrate 35 (WPC 35) powder was reconstituted to equivalent total solids as WSU-WPC (8.23%). Three batches of lowfat ice cream mix were produced to contain WSU-WPC without HHP, WSU-WPC with HHP (300 MPa for 15 min), and WPC 35 without HHP. All lowfat ice cream mixes contained 10% WSU-WPC or WPC 35. Overrun and foam stability of ice cream mixes were determined after whipping for 15 min. Ice creams were produced using standard ice cream ingredients and processing. The hardness of ice creams was determined with a TA-XT2 texture analyzer. Sensory evaluation by balanced reference duo-trio test was carried out using 52 vol.nteers. The ice cream mix containing HHP-treated WSU-WPC exhibited the greatest overrun and foam stability, confirming the effect of HHP on foaming properties of whey proteins in a complex system. Ice cream containing HHP-treated WSU-WPC exhibited significantly greater hardness than ice cream produced with untreated WSU-WPC or WPC 35. Panelists were able to distinguish between ice cream containing HHP-treated WSU-WPC and ice cream containing untreated WPC 35. Improvements of overrun and foam stability were observed when HHP-treated whey protein was used at a concentration as low as 10% (wt/wt) in ice cream mix. The impact of HHP on the functional properties of whey proteins was more pronounced than the impact on sensory properties. 相似文献
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主要综述了国内外关于超高压处理对牛乳清蛋白水解及其产物功能特性影响的研究进展,并展望了超高压处理在酶法制备乳清蛋白生物活性肽方面的应用前景。 相似文献
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C.A. Padiernos 《Journal of dairy science》2009,92(7):3049-3056
Whey is the inevitable by-product of cheese production. Whey can be incorporated into a variety of foods, but little has been done to investigate its suitability in whipping cream. The objective of this work was to evaluate the foaming properties of selected low-fat whipping cream formulations containing whey protein concentrate (WPC) that did or did not undergo high hydrostatic pressure (HHP) treatment. Fresh whey was concentrated by ultrafiltration, pasteurized, and standardized to 8.23% total solids and treated with HHP at 300 MPa for 15 min. Viscosity, overrun, and foam stability were determined to assess foaming properties. Sensory evaluation was conducted with 57 panelists using a duo-trio difference test. The optimal whipping time for the selected formulations was 3 min. Whipping cream containing untreated WPC and HHP-treated WPC resulted in greater overrun and foam stability than the control whipping cream without WPC. Panelists distinguished a difference between whipping cream containing untreated WPC and whipping cream containing HHP-treated WPC. High hydrostatic pressure-treated WPC can improve the foaming properties of low-fat whipping cream, which may justify expansion of the use of whey in whipping cream and application of HHP technology in the dairy industry. 相似文献
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Nasir Mehmood Khan Tai‐Hua Mu Miao Zhang Jing‐Wang Chen 《International Journal of Food Science & Technology》2013,48(6):1260-1268
The influence of high hydrostatic pressure (HHP) treatment on the physicochemical and emulsifying properties of sweet potato protein (SPP) at various concentrations, e.g. 2%, 4% and 6% (w/v, SPP‐2, SPP‐4 and SPP‐6), was investigated. Significant differences in hydrophobicity, enthalpy of denaturation and solubility were observed (P < 0.05). Emulsifying activity indexes (EAI) of SPP‐2 and SPP‐6 increased at 400 MPa, whereas EAI of all SPP significantly decreased at 600 MPa (P < 0.05). Emulsion stability (ESI) was significantly decreased for SPP‐2 and SPP‐6, while increase in ESI was observed for SPP‐4 above 200 MPa (P < 0.05). SPP‐2 emulsions showed sharp decrease in apparent viscosity with pressure increase, while pseudo plastic flow behaviour was not changed for all of emulsions. Sporamins A and B were well‐adsorbed in pressurised emulsion without displacement. These results suggest that HHP treatment could be used to modify the physicochemical and emulsifying properties of SPP. 相似文献
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Jingwang Chen Taihua Mu Miao Zhang Dorothée Goffin 《International Journal of Food Science & Technology》2019,54(3):752-761
The effect of high hydrostatic pressure (HHP) treatment on the structure, physicochemical and functional properties of cumin protein isolate (CPI) was investigated. More aggregates, pores, irregular conformations and bigger particle size were observed for HHP-treated CPI. HHP resulted in an increase in α-helix, a decrease in β-strand and fluorescence intensity of CPI. Surface hydrophobicity (Ho) of CPI significantly increased after HHP treatment, from 343.35 for native CPI to 906.22 at 600 MPa (P < 0.05). HHP treatment at 200 MPa reduced zeta-potential and solubility of CPI, while had little effect at 400 and 600 MPa. Emulsifying activity and stability of CPI decreased after HHP treatment, of which droplet size of emulsions significantly increased (P < 0.05). HHP-treated CPI could form heat-induced gelation at lower temperature (68.5 °C) and improved storage modulus (G′) comparing to native one (80.6 °C), suggesting that CPI might be potential protein resources as gelation substitute in food system. 相似文献