超滤在生产浓缩乳蛋白类产品中的应用

超滤技术是一种先进的膜分离技术,其作为一种分离和浓缩的工具已经被广泛应用于乳品工业。本文对超滤技术进行了概述,综述了其在生产乳蛋白浓缩物及浓缩乳清蛋白产品中的研究及应用现状,同时对如何通过超滤过程中条件的选择以提高膜过滤性能进行了阐述,并且对该领域的未来发展趋势做了展望。     

蛋白质氧化对乳清分离蛋白功能性质的影响

为了进一步研究蛋白质氧化对乳清分离蛋白(WPI)功能性质及流变学性质的影响,试验采用两种不同浓度的氧化系统H2O2(1 mmoL/L~20 mmoL/L)和FeCl3浓度(0.1 mmoL/L~2 mmoL/L)对WPI分别氧化1 h、3 h、5 h,测定其性质。结果表明:20 mmoL/L的H2O2氧化WPI 5 h,其乳化活性下降了50%以上;1 mmoL/L FeCl3氧化WPI 3 h,其凝胶硬度降低了94.5%;20 mmoL/L H2O2与1mmoL/L FeCl3氧化WPI 3 h,其弹性从0.976下降到0.713和0.721,分别降低了26.9%和26.1%;当H2O2浓度20 mmoL/L时,弹性模量从8154 Pa降到5399 Pa,复合模量从10890 Pa降到6653 Pa,分别降低了33.79%和38.91%;当FeCl3浓度为1 mmoL/L时,弹性模量从8154 Pa降到4935 Pa,复合模量从10890 Pa降到6049 Pa,分别降低了39.47%和44.45%。长时间高浓度的氧化条件使得蛋白质的空间结构受到严重影响,WPI的功能性质及凝胶质地发生较大的变化。因此,在实际生产中应尽可能地控制蛋白氧化的发生,减少其因为氧化所带来的营养损失或者降低其应用价值。     

限制性酶解乳清蛋白功能性质研究

探究乳清蛋白在碱性蛋白酶限制性水解下功能性质变化。以乳清蛋白的溶解性,乳化性、乳化稳定性,起泡性、起泡稳定性为考察指标,确定乳清蛋白的等电点及分析不同水解度下乳清蛋白功能性质在p H调控下的变化。结果表明:乳清蛋白的等电点为4.8。乳清蛋白进行限制性酶解后功能性质有了很大提高,其中溶解性在DH14、p H10下达到最大值,较原蛋白提高了14.55%;起泡性在DH14、p H4下达到最大值,较原蛋白提高了107.5%;起泡稳定性在DH4、p H4下达到最大值,比原蛋白提高了8.66%;乳化性在DH14、p H12下达到最大值,比原蛋白提高了56.1%;乳化稳定性DH4、p H12下达到最大值,比原蛋白提高了50.42%。      

蛋白含量对牦牛乳清蛋白浓缩物功能特性的影响

通过不同截留分子质量的再生纤维素膜过滤纯化牦牛原乳清液和牦牛甜乳清液,分别制取牦牛原乳清蛋白浓缩物（native whey protein concentrate,NWPC）和牦牛甜乳清蛋白浓缩物（sweet whey protein concentrate,SWPC）,研究蛋白含量不同的乳清蛋白浓缩物（whey protein concentrate,WPC）主要成分（乳糖含量、pH值和总蛋白质含量）和功能特性（溶解性、持水性、持油性、起泡性、乳化性及热稳定性）的特征。结果表明：10 000 Da再生纤维素膜透析得到的牦牛WPC中总蛋白含量达到80%以上,不含乳糖,功能特性（溶解性、持水性、持油性、起泡性、乳化性及热稳定性）均显著高于经3 500 Da卷式膜、5 000 Da再生纤维素膜透析得牦牛WPC,WPC蛋白含量越高,其功能特性越好;不同蛋白含量的牦牛SWPC起泡能力、泡沫稳定性、乳化活性和乳化稳定性均显著（P＜0.05）高于牦牛NWPC。牦牛乳WPC最不稳定温度为85 ℃,高于荷斯坦牛乳WPC的80 ℃,热处理会适当改善牦牛WPC的起泡性能、乳化性能和热稳定性。通过膜牦牛处理获取的高蛋白含量的WPC,功能特性较好,应用广泛,对解决牦牛乳清资源的利用问题、保护环境、提高企业的经济效益起到关键性作用。     

乳蛋白包覆纳米磷酸三钙的表面性质和机理研究

研究了酪蛋白(SC)和乳清分离蛋白(WPI)包覆在纳米磷酸三钙(TCP)颗粒表面的过程和作用机理。Zeta电位的测试表明SC和WPI包覆在TCP表面,使得TCP纳米颗粒表面所带负电荷增加。被不同种类的乳蛋白包覆的TCP悬浮颗粒在溶液中的稳定性都得到了提高,其中被WPI包覆的TCP颗粒的水相再分散液的稳定性得到了最为明显的改善,虽然实验结果也表明SC对TCP的包覆更容易发生。研究乳蛋白的不同组分在TCP表面的包覆过程发现,SC中αsCN上的Ser-P在对TCP颗粒表面的包裹过程中更有优势。WPI中的β-Lg对TCP的包覆会比α-La容易发生。作者还讨论了乳蛋白包覆在TCP颗粒表面的作用机理,认为乳蛋白对TCP的包覆过程和效果与两种乳蛋白和TCP颗粒的结构和表面性质有关。     

食品蛋白质的功能性质（一）——乳清蛋白与酪蛋白

乳清蛋白和酪蛋白磷酸肽是极好的营养强化剂,其添加于食品中有利于人体健康.本文介绍了乳清蛋白和酪蛋白磷酸肽的功能特性及其在食品中的应用.由于其具有多种保健功能,在食品行业中其应用前景十分广泛.     

扁杏仁分离蛋白与水解蛋白功能性质的比较研究

对扁杏仁水解蛋白与分离蛋白功能性质进行了比较研究,水解蛋白的溶解性、吸水性和吸油性均优于分离蛋白。分离蛋白的起泡性优于水解蛋白,但水解蛋白的泡沫稳定性较好。NaCl及蔗糖对水解蛋白和分离蛋白的乳化能力均有影响,在0.2mol/L的NaCl体系,水解蛋白和分离蛋白的乳化能力最强,分别达到37.04、47.44m/g。蔗糖浓度达到0.4g/L时,水解蛋白和分离蛋白的乳化能力最强,分别为16.74、23.02m/g,分离蛋白的乳化稳定性稍高于水解蛋白。     

扁杏仁分离蛋白与水解蛋白功能性质的比较研究

对扁杏仁水解蛋白与分离蛋白功能性质进行了比较研究,水解蛋白的溶解性、吸水性和吸油性均优于分离蛋白。分离蛋白的起泡性优于水解蛋白,但水解蛋白的泡沫稳定性较好。NaCl及蔗糖对水解蛋白和分离蛋白的乳化能力均有影响,在0.2mol/L的NaCl体系,水解蛋白和分离蛋白的乳化能力最强,分别达到37.04、47.44m/g。蔗糖浓度达到0.4g/L时,水解蛋白和分离蛋白的乳化能力最强,分别为16.74、23.02m/g,分离蛋白的乳化稳定性稍高于水解蛋白。      

黑米蛋白的功能与结构性质

以黑米为原料,通过碱提酸沉法提取黑米蛋白,并与大豆分离蛋白进行对比,研究该蛋白的功能与结构性质。研究结果表明,黑米蛋白与大豆分离蛋白的功能性质具有显著的差异,具体表现为:黑米蛋白的乳化稳定性与持油性高于大豆分离蛋白,而黑米蛋白的溶解性、乳化性、起泡性、起泡稳定性与持水性均低于大豆分离蛋白。此外,黑米蛋白的变性温度为87.35℃。采用红外光谱法对黑米蛋白特征官能团进行测定,得出羰基、氨基及羧基等特征官能团。二级结构测定结果表明黑米蛋白中α-螺旋含量为5.15%,β-折叠含量为40.65%,β-转角含量为21.70%,无规则卷曲含量为32.40%。     

全谷物的功能特性评价

随着经济发展和国民健康保健意识逐渐增强,健康已成为人们生活的主题。全谷物对人体具有增强饱腹感、清除自由基、预防疾病等多种保健功能。本文叙述了全谷物对人体健康的功效,分析了全谷物发展的制约条件并展望了其发展前景。     

全谷物的功能特性评价

随着经济发展和国民健康保健意识逐渐增强,健康已成为人们生活的主题。全谷物对人体具有增强饱腹感、清除自由基、预防疾病等多种保健功能。本文叙述了全谷物对人体健康的功效,分析了全谷物发展的制约条件并展望了其发展前景。      

Preparation and rheological properties of a dairy dessert based on whey protein/potato starch

Gels were prepared by heating different mixtures of whey protein concentrates (WPC) potatoes and ι-carrageenan. The influence of these ingredients on the strength of the obtained gels was investigated. The rheological properties of these gels were also measured during cooling from 90 to 10 °C at variable frequencies and strains. Analysis of variance showed a highly significant (P<0.0001) relationship between the concentrations of the different ingredients and the gel strength. The storage modulus (G^′) was generally higher than the loss modulus (G″) at different temperatures. Generally, the log (G^′) and log (G″) increased with the increase in the applied frequency, which suggested a weak gel entanglement network. Desserts were also prepared using 4% WPC and 3% potato starch (PS), 0.1% ι-carrageenan, 10% sucrose, 3% milk fat and 3% cocoa powder, by heating at 100, 110 or 120 °C for 30 min, packaged hot and stored for 28 days at room temperature (20 ± 5 °C). Samples of fresh and stored desserts were taken at 0, 7, 14, 21, 28 days of storage and their gel strengths were measured. Also, the effect of heat treatment during preparation on G^′, G″ and phase angle (δ) of the different desserts was followed. The effects of the heating time and temperature on the gel strength and rheological properties were relatively small.     

On protein functional properties and the methods of their control. Part I. On the concept of protein functional properties

In the present review the functional properties of proteins (PFP) are discussed from the standpoint of ihe classification of protein processing techniques suggested by the authors. The PFP conception is clarified on the bases of model systems. The results of the studies developed at the USSR Academy of Sciences Institute of Organoelement Compounds are used for discussion.     

Evaluation of high protein oat forage for dairy cattle

Spear, a high protein oat variety, was evaluated during 2 consecutive yr for yields of forage dry matter and for feeding value as a silage to heifers, steers, and lactating cows. In yr 1 and 2, Spear yielded 7% and 13% less forage dry matter per hectare than Burnett, a comparative oat variety. Crude protein contents in silages were similar for varieties both years. In yr 1, Holstein heifers fed high protein and medium protein oat silages gained the same amount of weight but less weight than heifers fed alfalfa-brome hay. In a total collection digestion trial with six lactating cows, digestibilities of Spear were less than Burnett oat silage or alfalfa-brome hay. In yr 2, Spear and Burnett silages were fed ad libitum without a concentrate mixture to seven Holstein heifers each. Average daily gains were higher with Spear than Burnett. Apparent digestibilities as determined with steers tended to be less for Spear than Burnett. Dry matter intakes, milk yield, and composition were similar in a switchback lactation trial with ten cows fed spear or Burnett in oat silage supplemented with a concentrate at 1 kg per 3 kg milk produced.     

仿母乳奶油粉的营养功能特性和婴儿配方奶粉干法生产

按母乳脂肪酸组成将玉米油、豆油、茶油、棕榈油进行调配，使亚油酸等不饱和脂肪酸接近母乳脂肪；添加婴儿成长发育需要的DHA(二十二碳六烯酸)、AA酸(花生四烯酸)后利用微胶囊技术，采用乳糖(或D90脱盐乳清粉)或糊精、酪蛋白等壁材，经过乳化、均质、喷雾造粒干燥生产婴儿配方奶粉专用仿母乳奶油粉。结果表明，仿母乳奶油粉与牛奶粉和其他营养组分均匀混合(干法)生产婴儿配方奶粉，营养成分及性能与母乳接近，弥补了牛奶粉营养成分的某些不足。仿母乳奶油粉油脂富含亚油酸，赋予了产品更好的流动、乳化和溶解性。     

Evaluation of functional properties of offal proteins

Evaluation of functional properties of beef heart and lip tissue proteins was based on the data obtained in the following determinations: protein extractability, fat emulsifying capacity, emulsion stability, gel forming ability, and water holding capacity after heat treatment. Beef skeletal muscles were used as the control. It was found that extractability of proteins of the raw materials was low as well as their ability to stabilize emulsions was on a low level. Proteins soluble at high ionic strength (fraction HIS) of beef heart and lip tissue emulsified 80.7 ml and 68.9 ml of oil/100 mg of protein, respectively, as compared to 106.6 ml in the control group. Analogically, protein soluble at low ionic strength (fraction LIS) emulsified 77.9 ml, 61.2 ml and 100.4 ml of oil, respectively. Emulsion stability of offal proteins appeared to be dependent on ionic strength. Generally at higher concentrations of salt their ability to stabilize emulsions was better as well as their water holding capacity increased. Their gelation properties as compared to control were also low. In each case, the functionality of cardiac proteins proved to be better than that of beef lip tissue.     

蛋白组分对米蛋白功能性质影响的研究

以不同配比米蛋白组分的样品为试材,比较各样品的功能性质变化,明确各蛋白组分对蛋白产品品质影响的差异,为今后进行分子设计和重组生产米蛋白产品提供理论支撑。通过各蛋白样品的溶解性,乳化特性,起泡特性,持水性/持油性等功能性质研究,结果表明,米糠浓缩蛋白的溶解性比大米浓缩蛋白高200%左右;米糠蛋白各功能性质显著优于大米蛋白,但大米蛋白的起泡稳定性比米糠蛋白提高近20%。米蛋白中的清蛋白提高产品的溶解性、持水性/持油性,降低起泡稳定性;醇溶蛋白提高产品的乳化特性;谷蛋白提高产品的起泡稳定性。蛋白产品的功能性质与蛋白组分的组成密切相关。     

核桃蛋白的分离纯化及功能性质的研究

对传统的碱溶酸沉法制备核桃蛋白的工艺进行了改进,以提高核桃蛋白的纯度.同时,对影响核桃蛋白功能性质的主要因素进行了分析.研究结果表明,通过对碱溶分离的上层清液加1%α-淀粉酶酶解,对酸沉分离的沉淀于40 ℃下水洗2次,核桃蛋白纯度可达93.5%;当pH为5时,核桃蛋白的溶解性、持水性、起泡性和乳化性最弱;温度为50 ℃时,核桃蛋白吸油性最差;温度为40 ℃时,核桃蛋白黏度最高.     

大米蛋白功能性研究进展

大米蛋白是一种高营养、低过敏性优质植物蛋白源,具有很高开发价值和良好应用前景。该文介绍大米蛋白的结构、组成,并对目前国内外有关大米蛋白功能性质研究进行综述。