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1.
为了拓宽蚕豆蛋白在食品中的应用,解决传统工业方法制备的蚕豆蛋白溶解性差的问题,本文以传统的碱溶酸沉法提取的蚕豆蛋白为原料,采用限制性酶法对其进行增溶改性工艺优化,并对改性后的蚕豆蛋白的功能性质进行了研究。结果表明:风味蛋白酶是提高蚕豆蛋白溶解性的适宜用酶,酶解改性的最佳工艺条件为:料液比1∶14、酶加量(ES)0.1%、温度58℃、pH值7.5、酶解时间30 min,此条件下蚕豆蛋白的溶解性达到99.73%。改性后的蚕豆蛋白的溶解性、起泡性、乳化性及乳化稳定性在酸性和碱性条件下均显著提高,泡沫稳定性在碱性条件下显著提高,持水力在pH值为2~12的范围内显著下降。  相似文献   

2.
燕麦麸分离蛋白的酶解对其功能性质的影响   总被引:4,自引:3,他引:4  
为了改善燕麦蛋白的功能性质以扩大其在食品工业中的应用,该文以燕麦麸为原料制备了燕麦麸分离蛋白(OBPI),并利用胰蛋白酶对其进行水解,得到了3种不同水解度(4.1%、6.4%、8.3%)的酶解产物。SDS-PAGE分析结果表明OBPI中的主要蛋白成分是球蛋白,其经过胰蛋白酶处理后,球蛋白酸性亚基被部分水解而碱性亚基相对保持完整。胰蛋白酶水解显著改变了OBPI的功能性质。在所考察的水解度范围内,随着水解度的升高,酶解产物的溶解性、持水性、乳化活性及起泡能力等方面均逐渐增加;但持油性、乳化及泡沫稳定性有不同程度的降低。  相似文献   

3.
花生蛋白营养丰富,但因功能性质差,导致其在食品工业应用受限。低温等离子技术作为一种新兴的、非热、无危害技术,越来越受人关注,介质阻挡放电(dielectricbarrierdischarge,DBD)等离子体技术由于具有适应频率宽,可在较大空间内获得高密度非平衡等离子体,并且工艺简单、快速高效、节能环保,是近年来蛋白质改性研究的热点之一。采用介质阻挡低温等离子体对花生蛋白溶液进行改性处理,研究等离子体处理时间对花生蛋白结构及功能特性影响。试验结果表明:低温等离子处理能显著提高花生蛋白的溶解性、持水性,低温等离子处理时间为2min时,花生蛋白溶解性和持水性达最大,与未处理样品相比分别提高了24.8%和79.6%;同时,花生蛋白乳化性、乳化稳定性、起泡性、起泡稳定性和持油性也有不同程度的提高。借助十二烷基硫酸钠-聚丙烯酰胺电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PAGE)、傅里叶红外光谱(Fourier transform infrared,FTIR)、表面疏水性分析低温等离子对花生蛋白结构影响。分析结果表明,低温等离子处理并未改变花生蛋白的分子量分布;低温等离子处理后,β-折叠和无规则卷曲的含量增加,α-螺旋和β-转角的含量降低,蛋白的有序结构被破坏,结构由紧密变松散;花生蛋白表面疏水性显著提高。低温等离子处理是一种改善蛋白功能性质的有效方法。  相似文献   

4.
为研究酶解花椒籽蛋白制得的抗菌肽的溶解性、起泡性和乳化特性,通过不同p H、温度等因素对制备的抗菌肽进行处理并分析其加工特性。结果表明:抗菌肽在p H值≥6、30~50℃内均具有良好的溶解性(氮溶解指数NSI80%);抗菌肽在酸性、碱性条件下的起泡性均高于中性条件,在10min、p H值≥6时具有良好的泡沫稳定性(≥82%);在35~55℃温度范围内,抗菌肽具有一定的起泡性(起泡性≥40%),10min时能保持很好的稳定性(≥73%);抗菌肽的乳化能力随着肽浓度的增加而减小,稳定性随着浓度的增加而增大;在p H值4.0时,抗菌肽的乳化性和乳化稳定性最差,乳化性为2.44m2·g-1,乳化稳定性小于22min;抗菌肽的亲水亲油平衡值(HLB值)大于16.7,亲水性较强。本研究为花椒籽蛋白抗菌肽在食品领域的应用提供了理论依据。  相似文献   

5.
为探寻一种油料蛋白提取方法,该研究以双低冷榨菜籽饼为原料,碱性电解水为溶剂,通过单因素与响应面试验确定了碱性电解水提取冷榨菜籽饼分离蛋白(Alkaline electrolyzed water extracted Rapeseed Protein,ARP)的优化条件,并与相同条件下碱溶酸沉法提取菜籽分离蛋白(Ultrapure water extracted Rapeseed Protein,URP)的结果进行对比。结果表明: 提取工艺各环节因素对菜籽蛋白提取率影响的主次顺序分别为:碱性电解水pH值、温度、料液比、时间;提取优化工艺条件为温度45 ℃、碱性电解水pH值11.5、料液比1:10 g/mL和提取时间60 min,蛋白质提取率为59.34%。与相同条件下碱溶酸沉法相比,碱性电解水提取的菜籽分离蛋白游离巯基和二硫键含量高、表面疏水性强、粒径小、ζ电位绝对值大,同时其提取率、溶解性、持油性、乳化性和起泡性均显著得到改善(P<0.05);此外,ARP内源荧光光谱强度更高,二级结构更有序。由此可知,该研究结果为碱性电解水提取冷榨菜籽饼蛋白提供参考,不仅提高了提取率,而且最大程度地减少了对菜籽蛋白结构和功能特性的破坏。  相似文献   

6.
挤压稳定化处理对米糠各组分蛋白结构及功能性质的影响   总被引:4,自引:4,他引:0  
为了研究挤压稳定化处理对米糠各组分蛋白结构和功能性质的影响,选取龙粳31号大米米糠做为原料,采用双螺杆挤压技术对该原料进行稳定化处理。结果表明:米糠各组分蛋白在挤压处理后溶解性、起泡性和持油性显著降低(P?0.05),持水性、起泡稳定性和乳化稳定性升高,谷蛋白持水性提高的幅度最大,较挤压前提高了39%。米糠谷蛋白的乳化活性与其他两种组分蛋白差异显著,清蛋白和球蛋白较挤压前分别降低5%和10%,谷蛋白乳化活性增加,较挤压前增加8%。结构特性分析结果表明产生这种差异的主要原因不是分子间作用力,而是挤压后各组分蛋白发生重组,形成大的聚集体过程中二级结构的变化截然相反,米糠清蛋白α-螺旋、β-转角和无规则卷曲含量都有所降低,β-折叠含量增势明显提高。挤压后的米糠谷蛋白结构与白蛋白显示出不同的趋势,谷蛋白的二级结构在酰胺I带变化显著,α-螺旋、β-转角与无规则卷曲的含量有所提高,β-折叠的含量下降。结果可为米糠各组分蛋白的工业化制备及在各种食品配方中的应用提供理论支撑。  相似文献   

7.
为了进一步改善大豆分离蛋白的分散性及功能性质,该研究以大豆分离蛋白为原料,通过对天然大豆分离蛋白进行高压高剪切处理并联合冷冻干燥技术,制备大豆分离蛋白微粒,考察压力(60~100 MPa)对大豆分离蛋白微粒尺寸、功能性质及结构特性的影响,探究其构效关系。结果表明:随着压力逐渐增加,大豆分离蛋白平均粒径大幅度减小,粒径分布曲线向左侧移动,与天然大豆分离蛋白相比,在100 MPa时大豆分离蛋白粒径减小了1 631%,粒径曲线分布较宽。在60~100MPa压力范围内随着压力的增加。与天然大豆分离蛋白相比,大豆分离蛋白微粒的分散性指数(Protein Dispersibility Index, PDI)和功能性质均显著提高(P0.05),其中在100 MPa时大豆蛋白质的溶解性提高了172.98%,乳化活性和乳化稳定性分别增加了约28.71%和77.82%,持油性增加了约123.76%,起泡性随时间的变化其泡沫高度也均有所提高。由扫描电镜图可以观察到,未经过高压均质的大豆分离蛋白粒子呈聚集状态,球状的表面向内凹陷,经过高压均质联合冷冻干燥处理后的大豆分离蛋白微粒呈现网络结构。在高压和高剪切力的作用下,大豆分离蛋白微粒的疏水基团大量暴露,表面疏水性随之增加,静电斥力增加,α-螺旋和β-转角向β-折叠和无规则卷曲结构的转化是蛋白质的溶解性等功能性质提高的主要原因。溶解性等功能性质的提高有利于大豆分离蛋白更好的应用于食品加工行业,进一步为蛋白的理化性质及结构优化提供新思路。  相似文献   

8.
花生蛋白粉溶液流变学特性及功能性的研究   总被引:5,自引:1,他引:4  
用旋转粘度计对花生蛋白粉溶液的流变学特性进行了研究。探讨了不同花生蛋白浓度、pH、温度对其溶解性、粘度、起泡性、持水性的影响。实验结果表明,当pH在4.2~5.3范围内为其等电点,此时花生蛋白粉的溶解性、粘度、起泡性、持水性最低,在其两侧这些特性逐渐增强;随着温度升高花生蛋白粉的粘度、持水性下降,而起泡性增加;当温度超过70℃时,为花生蛋白溶液大幅度变性的临界温度,其溶解度显著下降,3%花生蛋白粉溶液的起泡性最高。花生蛋白粉的粘度随浓度增大而增大,为非牛顿型流体,具有剪切稀化现象  相似文献   

9.
为研究燕麦蛋白的理化性质,本研究采用碱提酸沉法提取燕麦蛋白,并分析不同pH值与温度对燕麦蛋白溶解性、ζ-电位和粒径分布的影响。结果表明,在等电点附近(pH值5.0),燕麦蛋白的表面电荷数最低,蛋白粒度较大,溶解性和乳化性较低。当pH值远离等电点时,燕麦蛋白的表面电荷增加,蛋白粒度逐渐减小,溶解度升高,乳化性也随之升高;随着温度升高(55~95℃),燕麦蛋白聚集体解离,粒度变小,溶解度增加,稳定性变好;温度进一步升高(121、130℃),燕麦蛋白重新聚集形成粒径较大的聚集体,溶解度降低,稳定性变差。本研究结果为燕麦蛋白资源的利用提供了重要的理论指导。  相似文献   

10.
葵花粕中分离蛋白的成分及特性   总被引:8,自引:0,他引:8  
该文以水酶法提取葵花籽油后的葵花粕为原料,通过盐提酸沉法提取其中的分离蛋白,并对其进行组分分析、氨基酸成分分析、电泳图谱分析和凝胶色谱分析,同时对其溶解性、吸水性、吸油性、乳化性和起泡性等功能特性进行研究。结果显示葵花籽分离蛋白的氨基酸组成与FAO必须氨基酸需要量模式相比赖氨酸含量较低,功能特性好于或接近大豆分离蛋白。葵花分离蛋白含有3个主要组分,其分子量分别为380×103,100×103和27×103,绿原酸与分离蛋白紧密结合。  相似文献   

11.
Some nutritional and functional properties of defatted wheat germ protein   总被引:24,自引:0,他引:24  
Defatted wheat germ protein (DWGP) was isolated by alkaline extraction at pH 9.5 and subsequent isoelectric precipitation at pH 4.0, and its nutritional and functional properties were studied. The results showed that the amino acid content of defatted wheat germ was as high as 26.793 g/100 g, and the contents of eight essential amino acids were all relatively high. The isoelectric point of DWGP was 4.0. When pH >6.0, the DWGP had high solubility with a nitrogen solubility index of 70%. The emulsifying activity and emulsifying stability of DWGP were similar to those of bovine serum albumin and a little higher than those of casein. DWGP had good foaming capacity, but its foaming stability (FS) was not very good. However, the FS of DWGP can be improved through physical, chemical, or enzymatic methods. Moreover, DWGP had excellent water retention (WR); especially at pH 8.0 and a temperature of 70 degrees C, the WR of DWGP was the highest at 229.4%. DWGP offers is a potential source of functional protein isolate for possible food applications.  相似文献   

12.
The objectives of this work were to investigate the nutritional and physicochemical characteristics as well as the functional properties of quinoa protein isolates (QPI) from different varieties, and to determine their potential use of such protein isolates in food products. Proteins were isolated by isoelectric precipitation at pH 5 from quinoa flour, and the QPI had a protein percentage of over 85%. The comparison of the flours and QPI electrophoretic profiles indicated that the extraction method allowed isolating practically all proteins of each variety. All the varieties analyzed had high lysine content, compared with cereals, and the essential amino acid content of Bolivian varieties was higher than varieties from Peru. The pH value affected the solubility and foaming capacity, and the magnitude of effects depended on the variety. Cluster analysis showed a strong influence of variety source and amino acid composition on protein physicochemical and functional properties; samples from Bolivia (cluster 2) were characterized as having the highest thermal stability, oil binding capacity, and water binding capacity at acid pH; samples from Peru (cluster 1) had the highest water binding capacity at basic pH and foaming capacity at pH 5. QPI presented a potential as an alternative vegetable protein for food application, in particular for vegetarian and vegan diets.  相似文献   

13.
Physicochemical and functional properties of buckwheat protein product   总被引:14,自引:0,他引:14  
This study was conducted to compare the physicochemical and functional properties of buckwheat protein product (BWP), soy protein isolate (SPI), and casein. BWP was prepared from buckwheat flour by the method including alkaline extraction and isoelectric precipitation. The amino acid composition of BWP was very similar to that of buckwheat flour. The protein solubility (PS) of BWP was much greater than that of SPI at all pH levels (pH 2-10) but lower than that of casein at pH 7-10. The isoelectric point of BWP was around pH 4. The higher aromatic hydrophobicities (ARH) of BWP, SPI, and casein were obtained at lower pH levels (pH 2-3). The emulsifying stability (ES) of BWP was lower than those of SPI and casein at high pH levels (pH 7-10). At all pH levels, BWP formed a thin emulsion. Regression analysis showed that the ARH of BWP was significantly associated with the ES. Although the water holding capacity of BWP was quite lower than that of SPI, its fat absorption capacity was slightly higher than those of SPI and casein. These results indicated that the physicochemical properties of BWP were different from those of SPI or casein. Thus, BWP is a potential source of functional protein for possible food application.  相似文献   

14.
This research optimized the extraction of different protein fractions from barley grains and assessed the physicochemical properties of the fractions obtained. Pearling was first used to remove the grain's outer layers (mainly bran and germ) so that the barley cytoplasmic proteins (albumin and globulin) would be enriched in the pearling flour (PF), while endosperm proteins (hordein and glutelin) would be enriched in the pearled grain flour (PGF). Salt, alcohol, and alkaline solutions were then used to extract different barley protein fractions from PF and PGF. The effects of extraction solvent type, pH, temperature, and extraction time on protein content and extraction efficiency were studied. Aqueous ethanol (55%, v/v) efficiently extracted barley hordein from PGF at 60°C, whereas pH 11.5 alkaline solution was the most efficient for extracting both cytoplasmic and endosperm proteins from barley PF and PGF at 23°C. Subunit molecular weight, amino acid composition, and the functional properties of each isolated barley protein fraction were investigated. Barley glutelin demonstrated superior oil‐binding property and emulsifying stability, whereas barley hordein exhibited good foaming capacity.  相似文献   

15.
不同干燥方法对栗粉的理化性质与功能特性的影响   总被引:7,自引:1,他引:7  
以毛板红板栗品种为原料,研究了4种不同干燥方法加工所得栗粉的理化与功能特性,结果表明自然干燥与热风干燥加工成的栗粉在理化和功能特性上差异较小,但自然干燥粉比热风干燥粉具有更好的起泡能力和泡沫稳定性;微波干燥粉比热风干燥有较多的淀粉发生糊化,表现在具有较低的峰粘度、崩解值和回复值,其吸水能力较热风干燥粉大,但起泡能力、泡沫稳定性和复水成泥后的一些质地特征值较热风干燥粉低。高温蒸后热风干燥粉的理化与功能特性与微波干燥粉类似,但有较高的崩解值和较低的回复值。从色泽来看,自然干燥和热风干燥粉比微波干燥和高温蒸后热风干燥的要白,而且有光泽。  相似文献   

16.
Solubility, foaming capacity/stability, water holding and fat absorption capacities, and emulsifying capacity/stability of a solubilized wheat protein isolate (SWPI) were compared with those of commercial protein, that is, sodium caseinate (NaCAS), dried egg white (DEW), nonfat dry milk (NFDM), and soy protein isolate (SPI). SWPI was highly soluble at pH 6.5-8.5. Foaming capacity of SWPI was superior to those of SPI, NFDM, and DEW, and its foaming stability was similar to those of the commercial proteins. Foaming properties of SWPI were greatly improved in the presence of 0.5% (w/v) CaCl(2). Water holding capacity of SWPI was greater than that of NaCAS, NFDM, and DEW, whereas its fat absorption capacity was comparable to that of SPI, NaCAS, and DEW. SWPI exhibited emulsifying properties similar to those of SPI. SWPI was incorporated at 5, 10, 15, or 20% into ice cream, chocolate chip cookies, banana nut muffins, and hamburger patties. Products containing <5% SWPI were acceptable to consumers.  相似文献   

17.
酶法预处理对花生蛋白提取效果的影响(简报)   总被引:1,自引:0,他引:1  
该文首次提出了以低温预榨花生饼为原料,经Viscozyme酶预处理后再碱溶酸沉提取蛋白质的新工艺,研究了酶处理条件对花生蛋白提取率的影响,通过中心组合试验设计和响应面分析优化的试验结果是:当花生饼浓度为15%,温度为45℃,酶用量1.26%,pH值为4.3,反应时间为134 min时,蛋白提取率为79.38%,而未用酶处理者蛋白提取率为58.35%,表明酶法预处理花生饼可以显著改善花生蛋白的提取效果。  相似文献   

18.
The major storage globulins (vicilins) of cowpea (Vigna unguiculata) and pea (Pisum sativum) seeds were purified by ammonium sulfate precipitation, and a semipurified cowpea protein isolate (CPI) was prepared by isoelectric precipitation. Some of the functional properties of these proteins, including solubility, foaming, and emulsifying capacities, were investigated and compared. The solubility of purified cowpea vicilin was reduced at pH 5.0, increasing markedly below and above this value. Pea vicilin exhibited poor solubility between pH 5.0 and pH 6.0, and CPI was little soluble in the pH range from 4.0 to 6.0. At neutral pH, the emulsifying activity indexes (EAI) of purified pea vicilin and CPI were 194 and 291 m(2)/g, respectively, which compare quite favorably to EAIs of 110 and 133 m(2)/g for casein and albumin, respectively. Remarkably, purified cowpea vicilin exhibited an EAI of 490 m(2)/g, indicating a very high emulsifying activity. Purified cowpea and pea vicilins exhibited lower foaming capacities and foam stablity indexes (FSI) than CPI. FSI values of 80 and 260 min were obtained for purified pea and cowpea vicilin, respectively, whereas a FSI value of 380 min was obtained for CPI. These results are discussed in terms of the possible utilization of purified vicilins or protein isolates from pea and cowpea in the food processing industry.  相似文献   

19.
The functional attributes of proteins withdrawn from different stages of a commercial ethanol fuel/distillers dried grains with solubles (DDGS) process that used a wheat feedstock were investigated. Specifically, protein coproducts were examined postliquefaction (PL), postdistillation (PD), and postdrying (DDGS) and related to those from the native wheat feedstock (WF). Water hydration, oil holding, foaming, and emulsifying properties of all materials were assessed. The WF and the PL coproduct showed similar water hydration capacities (WHCs), ranging between 80 and 110%, whereas WHCs for the PD and DDGS coproducts were significantly higher (ranging between 264 and 356%). WHC for all products was found to be independent over the pH range of 2.00–10.00. A similar trend was found for the oil holding capacities, for which both WF and PL materials showed lower values (≈120%) than both the PD (203%) and DDGS (171%) materials. Foam capacity and stability for the WF were found to be 32.8 and 61.4%, respectively, whereas no coproducts were foam forming. Emulsion stability decreased from ≈45% for the WF to <10% in all other materials. Findings indicated that initial changes to the protein's functional attributes occurred in the PL stage of ethanol/DDGS processing.  相似文献   

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