罗非鱼-豆粕共沉淀蛋白的提取工艺及蛋白组成分析

以罗非鱼肉和脱脂豆粕为原料,采用p H调节法制备罗非鱼-大豆共沉淀蛋白（Co-p）,探讨溶解p H、不同质量比混合的原料、溶解时间对可溶性蛋白得率的影响及沉淀p H对蛋白沉淀得率的影响。结果表明,p H调节法回收罗非鱼-豆粕共沉淀蛋白的最佳酸溶p H2.0、3.0,碱溶p H11.0、12.0,原料比1∶1,溶解时间30 min;SDS-PAGE分析显示,可溶性共沉淀蛋白条带深/浅（极端p H2.0蛋白降解）,表明可溶性蛋白含量高/低,从分子量分布范围可知,共沉淀蛋白主要由肌球蛋白重链、7 S抗原蛋白的三个亚基、肌动蛋白、肌球蛋白轻链、11 S抗原蛋白的两个亚基和小分子水溶性蛋白组成,表示可溶性共沉淀蛋白组成齐全;酸/碱可溶性共沉淀蛋白最佳沉淀p H为4.5,在此条件下,溶解、沉淀过程的蛋白得率分别为88.05%⁹4.70%。经冷冻干燥得到共沉淀蛋白粉即Co-p（1∶1）,其蛋白含量高于85%,脂肪含量在0.84%左右,灰分含量低于4.17%;可用p H调节法回收罗非鱼-豆粕共沉淀蛋白。      

罗非鱼蛋白-大豆蛋白共沉淀物的乳化性

为研究罗非鱼蛋白-大豆蛋白共沉淀物的乳化性,以罗非鱼肉和脱脂豆粕为原料,按照不同质量比(1∶0、1∶1、2∶1、3∶1、0∶1)混合,采用碱溶酸沉法制备鱼分离蛋白(FPI)、罗非鱼蛋白-大豆蛋白共沉淀物(Co-p)和大豆分离蛋白(SPI),并探讨了p H、盐浓度、多糖对其乳化活性(EAI)和乳化稳定性(ESI)的影响。结果表明:FPI、Co-p(1∶1)、Co-p(2∶1)、Co-p(3∶1)和SPI的得率分别为62.21%、39.10%、29.58%、18.45%、32.10%(P0.05);p H 3.0时,FPI、Co-p和SPI的乳化活性依次减小,而p H 4.0~10.0时,Co-p(2∶1)和Co-p(3∶1)的乳化活性最好(P0.05);在0%~0.4%Na Cl体系中,Co-p的乳化活性明显强于FPI或SPI;p H 3.0~7.0时,添加0.2%~0.3%的瓜尔豆胶和黄原胶能显著提高蛋白乳化体系的EAI值(P0.05),且Co-p的乳化性较FPI或SPI有明显提高。比较而言,罗非鱼蛋白-大豆蛋白共沉淀物较FPI或SPI有更好的乳化性。     

脱脂豆粕中大豆分离蛋白提取工艺的研究

介绍了大豆分离蛋白的生产工艺,以脱脂豆粕为原料,经过碱提、分离残渣、酸沉、分离蛋白、再干燥得到产品。其中,对从脱脂豆粕中碱提过程进行了重点研究,通过单因素和正交试验,确定了碱提的最佳条件:NaOH溶液质量浓度为1.0g/L,温度为50℃,时间为40min。     

罗非鱼-大豆共沉淀蛋白乳液稳定二十二碳六烯酸藻油的研究

为探究共沉淀蛋白乳液稳定二十二碳六烯酸(docosahexenoic acid, DHA)藻油的可行性,该研究以罗非鱼分离蛋白(tilapia protein isolate, TPI)、3种罗非鱼-大豆共沉淀蛋白(tilapia-soy protein co-precipitates, TSPC_2∶1、TSPC_1∶1和TSPC_1∶2)和大豆分离蛋白(soy protein isolate, SPI)为乳化剂,高压均质制备TPI、TSPC和SPI-DHA藻油乳液,比较5种乳液的物理稳定性和氧化稳定性。结果表明,与TPI乳液比较,随着原料中大豆比例的增加,TSPC-DHA藻油乳液的平均粒径和乳析指数减小(P<0.05),Zeta电位绝对值增大(P<0.05),乳液的物理稳定性增强。与SPI乳液比较,贮藏过程中TSPC-DHA藻油乳液的过氧化值和硫代巴比妥酸反应物值明显较小(P<0.05),乳液的氧化稳定性明显改善。TSPC_1∶1和TSPC_1∶2乳液在4℃贮藏28...     

两种方法提取的亚麻籽蛋白持水性、持油性、溶解性和氨基酸组成比较

以亚麻籽饼粕为原料,分别采用双酶复合法和碱溶酸沉法提取亚麻籽蛋白,测定并比较两种亚麻籽蛋白的持水性、持油性、溶解性及氨基酸组成。结果表明：碱溶酸沉法提取的亚麻籽蛋白的持水性在pH 6~7、40~80 ℃下优于双酶复合法;双酶复合法提取的亚麻籽蛋白的持油性在pH 4~8下优于碱溶酸沉法,但碱溶酸沉法提取的亚麻籽蛋白的持油性在40~100 ℃下优于双酶复合法;双酶复合法提取的亚麻籽蛋白的溶解性在pH 2~9（pH 3和pH 7除外）、20~60 ℃、NaCl浓度 0.3~15 mol/L下优于碱溶酸沉法;亚麻籽蛋白氨基酸种类丰富,谷氨酸含量最高,双酶复合法和碱溶酸沉法提取的亚麻籽蛋白的谷氨酸含量分别为10.793%和10.615%,两种方法氨基酸总和差异较小。     

美藤果蛋白的提取工艺及氨基酸组成分析

以美藤果蛋白提取率为考察指标,在单因素实验的基础上,采用正交实验优化了碱溶酸沉法制备美藤果蛋白的工艺条件,并分析了美藤果蛋白的氨基酸组成。结果表明,美藤果蛋白的最优提取工艺条件为∶料液比1∶30,碱提时间2 h,碱提温度70℃,碱提pH 9.0。在最优条件下,美藤果蛋白提取率为83.91%。美藤果蛋白的氨基酸组成种类齐全,必需氨基酸含量较高,是一类较优质的植物蛋白质资源。     

罗非鱼头蛋白质的提取及性质研究

以罗非鱼头为原料,采用加热浸提、酶法水解、酸/碱溶解-等电点沉淀法提取鱼蛋白,冷冻干燥得到4种鱼蛋白粉,分别记为热提鱼蛋白(HFP)、酶解鱼蛋白(EFP)、酸溶鱼蛋白(AFP)和碱溶鱼蛋白(ALFP),并探讨了4种鱼蛋白的营养特性、溶解性和乳化性。结果表明:ALFP和AFP的蛋白含量分别为89.97%和85.87%,必需氨基酸占总氨基酸的比例达到49.72%和48.63%,而脂肪和灰分含量以及白度值均低于HFP和EFP,且差异显著(P<0.05)。溶解性和乳化性的研究显示,EFP和HFP在pH 2.0～10.0内溶解度均高于93%,但体系的乳化活性和稳定性较差;而AFP和ALFP的溶解度随pH值的变化非常明显,在pH 4.0～6.0内,体系的溶解性和乳化性极差,而在pH值低于4.0或高于6.0时,溶解度大大增强,乳化活性和乳化稳定性随之提高,且乳化活性和稳定性明显高于HFP和EFP。酸/碱溶解-等电点沉淀法可用于制备营养价值高,乳化特性相对较好的鱼分离蛋白。     

菜籽粕中清蛋白的超声辅助提取及氨基酸组成研究

以脱脂菜籽粕为原料,在单因素试验基础上采用响应面分析方法优化菜籽清蛋白的超声辅助提取工艺,研究液料比、提取时间、超声温度、超声功率对菜籽清蛋白提取率的影响;并对得到的产品进行氨基酸组成分析。结果表明,最佳的工艺条件为液料比18 m L/g,提取时间62 min,超声温度42℃,超声功率80 W,且最优条件下实际提取率为8.53%;氨基酸分析结果显示,菜籽清蛋白中氨基酸种类齐全,必需氨基酸组成均衡,符合FAO/WHO推荐模式,是一类优质的植物蛋白资源。     

利用豆粕提取组织蛋白的试验研究

本试验采用SDP-45小型单螺杆膨化机，对用豆粕提取组织蛋白进行了试验研究，经试验证明，采用的工艺路线是可行的，并对机筒温度、螺杆转速、物料的含水率对产品组织化质量的影响进行了分析，找出了最佳参数组合。     

啤酒糟中醇溶蛋白的提取及氨基酸组成分析

以啤酒酿造过程中,过滤后得到的啤酒糟为原料,采用响应面法对啤酒糟中醇溶蛋白提取进行优化,并对提取后醇溶蛋白的氨基酸组成进行分析.结果显示,啤酒糟中醇溶蛋白的最佳提取工艺条件为乙醇体积分数为64％,液料比为4.5:1(mL/g),超声辅助提取时间为27 min,3个提取条件对醇溶蛋白提取率影响大小顺序为:乙醇体积分数>液...     

蚕蛹蛋白精制及其氨基酸成分分析

以缫丝后蚕蛹为原料,对蚕蛹蛋白进行提取工艺优化,并测定提取后蚕蛹蛋白的氨基酸含量及分子量分布。实验结果表明蚕蛹蛋白提取最佳工艺为:固液比1∶3、提取次数3次、pH3.0,此工艺下蛋白提取率为53.0%;通过氨基酸分析发现提取前后蚕蛹蛋白氨基酸组成未发现明显变化,说明该提取方法并不会造成蚕蛹蛋白氨基酸组成的改变,并且该提取方法制得的蚕蛹蛋白不仅氨基酸种类丰富且各氨基酸配比合理,分子量分布范围从500～100000u,可进一步应用于制药、食品及化妆品等领域。      

The amino acid composition,solubility and emulsifying properties of sweet potato protein

A protein was purified from the high-protein type sweet potato variety 55-2 available in China. The amino acid composition, solubility and emulsifying properties of the sweet potato protein (SPP) were studied. The SPP was rich in aspartic acid (18.5%) and glutamic acid (9.30%) while essential acid amino acids made up approximately 40.7% of the SPP. The SPP was highly soluble in distilled water over a wide range of pH. However, solubility of the SPP in 1.0 M NaCl and 1.0 M CaCl₂ solutions was low especially at pH below the pI of the SPP. The SPP in CaCl₂ demonstrated emulsifying activity index (EAI) and emulsion stability index (ESI) many folds higher than those in distilled water and NaCl solution (P < 0.05).     

Blood amino acids and milk composition from cows fed soybean meal, fish meal, or both

Twelve multiparous Holstein cows at 48 +/- 8 d in milk were used in a 4 x 4 Latin square with 21-d periods to determine the effect on feed intake, milk yield, milk composition, and blood amino acids when soybean meal was replaced with fish meal. Fish meal substituted for soybean meal on an isonitrogenous basis at 0, 25, 50, and 100% of supplemental protein. Total mixed diets were (dry matter basis) 25% corn silage, 25% alfalfa hay, and 50% concentrate mix. Intake of dry matter (27.9, 27.8, 26.1, and 25.8 kg/d for diets 1 to 4, respectively) was similar for all diets. Milk yield (37.5, 37.8, 37.2, and 37.7 kg/d) was not affected by diets. Milk protein percentages (3.23, 3.24, 3.31, and 3.35) increased with 100% fish meal supplementation and tended to be higher, with 50% fish meal supplementation compared with 100% soybean meal diet. Milk fat percentages (3.18, 2.99, 3.04, and 2.87) and yields were lower with the 100% fish meal than with the 100% soybean meal diet. Molar proportions of ruminal volatile fatty acids and ammonia were not greatly affected by diet. Fish meal supplementation slightly improved Met status, as shown when blood amino acid data were evaluated. Both extraction efficiency and transfer efficiency of amino acids from the blood by the mammary gland indicated that Met, Lys, and Phe were the most limiting amino acids in all diets. Replacing as much as 50 or 100% of dietary soybean meal with fish meal may improve the amino acid balance and increase the protein content in milk; however, feeding 100% fish meal will likely decrease milk fat percentages.     

苎麻籽油脂肪酸组成及其粕氨基酸组成分析

用气相色谱法对苎麻籽油脂肪酸组成进行了分析,同时用氨基酸全自动分析仪对苎麻粕进行分析,为苎麻籽的开发利用提供基础数据。结果表明,苎麻籽油中不饱和脂肪酸含量90%以上,多不饱和脂肪酸含量79%以上,亚油酸含量尤为丰富,达77.40%~78.84%;苎麻粕含17种氨基酸,总含量为209.02~278.46 mg/g,其中7种必需氨基酸占总氨基酸的32.06%~33.17%。     

豆粕质量及其鉴定

分析了豆粕中的抗营养因子以及涉及到豆粕品质的各种营养素，并分析了尿酶活性和蛋白KOH溶解度在检测豆粕加热不足和加热过度中不同的灵敏性，阐明了适度加工的豆粕所应具有的品质特征。     

Walnuts (Juglans regia L): proximate composition,protein solubility,protein amino acid composition and protein in vitro digestibility

Walnuts contained 16.66% protein and 66.90% lipids on a dry weight basis. Non‐protein nitrogen values ranged from 6.24 to 8.45% of the total nitrogen when the trichloroacetic acid concentration was varied within the range 0.25–1.0 M . Albumin, globulin, prolamin and glutelin respectively accounted for 6.81, 17.57, 5.33 and 70.11% of the total walnut proteins. Walnut proteins were minimally soluble at pH 4.0. The majority of total walnut protein polypeptides had estimated molecular weights in the range 12 000–67 000. The Stokes radius of the major protein in walnuts (glutelin fraction) was 66.44 ± 1.39 Å. Lysine was the first limiting essential amino acid in total walnut proteins as well as in the globulin and glutelin fractions. Leucine and methionine plus cysteine were the second limiting essential amino acids respectively for the prolamin and albumin fractions. Hydrophobic and acidic amino acids dominated the amino acid composition in all protein fractions. Native and heat‐denatured walnut glutelins were easily hydrolysed by trypsin, chymotrypsin and pepsin in vitro. © 2000 Society of Chemical Industry     

超声波对牡丹籽粕蛋白质碱提取工艺及氨基酸组成的影响

以脱脂牡丹籽粕为原料,通过单因素实验和正交实验考察超声波对牡丹籽粕蛋白质碱提取工艺条件的影响。结果表明:常规碱提取的最佳工艺条件为料液比1:15(g:mL)、溶液pH值11、提取温度55℃、提取时间100 min,在该条件下蛋白质的提取率为81.49%;超声辅助碱提取的最佳工艺条件为料液比1:10(g:mL)、溶液pH值11、超声功率180 W、超声温度55℃、超声时间100 min,在该条件下蛋白质的提取率达87.34%。与常规碱提取相比,超声辅助碱提取的提取率提高了7.17%,碱液消耗降低了33.33%。同时,超声辅助碱提取的牡丹籽粕蛋白的各种氨基酸含量均高于常规碱提取的牡丹籽粕蛋白,氨基酸总含量达95.049 mg/100 g,纯度提高14.49%。     

超声辅助提取豆粕植酸及其抗氧化性质研究

植酸具有多种生物功能,可作为功能性食品的添加剂或药品原料起到防治多种疾病(如糖尿病、肠炎、癌症、骨质疏松、帕金森症等)的效果。豆粕中植酸含量较高,但不同提取方法对植酸的提取量影响较大。本研究采用单因素和响应面优化试验,比较了浸提法和超声辅助提取法提取豆粕植酸的差异,探究了豆粕植酸最佳提取工艺,最后对植酸提取物的抗氧化性质进行表征。结果表明:豆粕植酸最优提取工艺为pH 3、温度60℃、料液比1:12、超声时间10 min及超声功率240 W,豆粕中植酸提取量为1.14%,豆粕植酸中植酸提取率为95.61%;超声辅助提取法较浸提法提取率提升了22.45%;植酸纯度提升18.71%,达到91.86%。所提取植酸浓度为1.0 g/L时,DPPH自由基清除率为43.61%,·OH清除率为77.09%,Fe2+还原力为1.56,具有高抗氧化活性。因此,超声辅助提取豆粕植酸效率高,提取物抗氧化能力强,为植酸提取及利用提供了理论依据。     

Immunoreactivity reduction of soybean meal by fermentation,effect on amino acid composition and antigenicity of commercial soy products

Food allergy has become a public health problem that continues to challenge both the consumer and the food industry. The objectives of this study were to evaluate the reduction of immunoreactivity by natural and induced fermentation of soybean meal (SBM) with Lactobacillus plantarum, Bifidobacterium lactis, Saccharomyces cereviseae, and to assess the effect on amino acid concentration. Immunoreactivity of commercially available fermented soybean products and ingredients was also evaluated. ELISA and western blot were used to measure IgE immunoreactivity using plasma from soy sensitive individuals. Commercial soy products included tempeh, miso and yogurt. Fermented SBM showed reduced immunoreactivity to human plasma, particularly if proteins were <20 kDa. S. cereviseae and naturally fermented SBM showed the highest reduction in IgE immunoreactivity, up to 89% and 88%, respectively, against human pooled plasma. When SBM was subjected to fermentation with different microorganisms, most of the total amino acids increased significantly (p < 0.05) and only few of them suffered a decrease depending on the type of fermentation. All commercial soy containing products tested showed very low immunoreactivity. Thus, fermentation can decrease soy immunoreactivity and can be optimized to develop nutritious hypoallergenic soy products. However, the clinical relevance of these findings needs to be determined by human challenge studies.