棉籽分离蛋白功能性质的研究

考察了棉籽各分离蛋白,包括清蛋白、球蛋白、醇溶谷蛋白及谷蛋白在棉籽蛋白中所占的比例,研究了各蛋白的功能性质,包括吸水性、吸油性、乳化性和乳化稳定性、起泡性与泡沫稳定性以及各蛋白的抗氧化活性。结果表明,谷蛋白为棉籽蛋白中的主要分离蛋白,棉籽清蛋白具有较高的吸水性、乳化性、乳化稳定性以及起泡性,吸油性相对较差,适用性相对较好,但在棉籽蛋白中含量较少,而谷蛋白的吸水性、乳化性、起泡性很差,具有一定的吸油性,适用性较差,但在棉籽蛋白中含量丰富,在抗氧化活性方面,各分离蛋白的抗氧化活性能力都较差,需要进行改性处理。     

物理改性对棉籽分离蛋白功能特性影响

采用水浴加热、超声波和微波辐射三种方法对棉籽分离蛋白进行改性处理,研究不同方法对蛋白的溶解性、持水性、吸油性、乳化性、乳化稳定性和起泡性等影响。实验结果表明,不同处理方法对棉籽分离蛋白功能特性均有一定改善,其中加热方法对蛋白起泡性影响较大,提高53.2%;微波辐射方法对蛋白溶解性、持水性、吸油性、乳化性有明显改善,分别提高5.0%、70.3%、6.5%、35.8%;超声波方法对蛋白乳化稳定性及起泡稳定性有一定改善,乳化稳定性提高51.6%;三种方法以微波辐射改性方法效果最优。     

红小豆分离蛋白功能特性研究

研究红小豆分离蛋白的溶解性、吸水性、吸油性、乳化性和乳化稳定性、起泡性和起泡稳定性,并与大豆分离蛋白进行对比。结果表明:红小豆分离蛋白在较低的pH值下具有更好的溶解性,吸油性、乳化性和起泡性与大豆分离蛋白相当,但比大豆分离蛋白具有更好的乳化稳定性和起泡稳定性。     

两种溶剂萃取棉籽油和棉籽粕的质量比较

利用正己烷和异丙醇作溶剂,分别萃取棉籽仁得到棉籽油和棉籽粕.对棉籽油的理化指标进行测定,结果表明两种不同溶剂萃取得到的棉籽油在理化指标上存在一定的差异.分析所得棉籽粕的蛋白含量和功能特性,结果表明正己烷萃取的棉籽粕中粗蛋白含量和水溶性蛋白含量均低于异丙醇萃取的棉籽粕;正己烷萃取的棉籽粕吸油性、泡沫稳定性小于异丙醇萃取的棉籽粕,但是吸水性、乳化性、乳化稳定性和起泡性却高于异丙醇萃取的棉籽粕.分析游离棉酚含量时,发现异丙醇萃取的棉籽油中游离棉酚(FGP)含量高于正己烷萃取的棉籽油.用异丙醇萃取的棉籽粕中FGP含量在国家标准规定的安全使用限量范围内,用作饲料时不需再增加脱毒工艺.     

固态发酵菜籽肽功能特性研究

研究固态发酵制备菜籽多肽的功能特性,同时与菜籽蛋白功能特性进行比较。结果表明,发酵菜籽肽具有良好溶解性,在pH2.0～12.0 范围内,保持较高的氮溶解指数(NSI ＞ 85%),而菜籽蛋白在pH8.0 以下会凝聚沉淀;在20～80℃温度范围内,菜籽蛋白的吸水力和吸油力变化不大,而发酵菜籽肽的吸水力和吸油力则随着温度的升高而降低;在2～5g/100mL 质量浓度范围内,菜籽肽的乳化性优于菜籽蛋白;发酵菜籽肽也具有良好的起泡性和泡沫稳定性,但是不具有凝胶性;另外,在0～500μg/mL 质量浓度范围内,菜籽肽对DPPH 自由基的清除能力与其质量浓度成线性相关(R2=0.9912),IC50 为328μg/mL。     

大鲵皮胶原蛋白肽理化性质和功能特性研究

高温高压辅助提取大鲵皮胶原蛋白肽,并研究大鲵皮胶原蛋白肽的的主要的理化性质,如:水分、灰分、透射比、氨基酸组成和氮溶解指数等以及功能特性,如:吸水性、保水性、湿润性、吸油性、乳化性与乳化稳定性、起泡性与泡沫稳定性和凝胶性等。结果表明大鲵皮胶原蛋白肽的理化指标高于轻工业标准,含有7种人体必需氨基酸,并且具有良好的氮溶解指数、吸水性、保水性、湿润性、吸油性、相对较弱的乳化性和乳化稳定性、起泡性泡沫稳定性,低浓度下无胶凝现象,因此可直接用于食品生产中。     

伽马射线辐照对红豆分离蛋白功能性质的影响

以红豆分离蛋白作为原料,采用伽马射线辐照处理,考察不同剂量(1、3、5、7、10k Gy)辐照处理条件对红豆蛋白功能性质的影响。对红豆蛋白吸水性、吸油性、溶解性、乳化性和乳化稳定性、起泡性和起泡稳定性进行测量,结果表明,在低剂量辐照处理时,红豆蛋白的蛋白质分子结构展开,疏水基团暴露,各种功能性质均有所改善,但随着辐照剂量进一步增加,红豆蛋白分子发生聚集,使吸水性、溶解性、乳化性、起泡性有所下降,但吸油性、乳化稳定性和起泡稳定性仍呈现上升趋势。不同剂量的辐照处理使红豆蛋白质结构发生不同程度的改变,进而影响其功能性质。     

干茶叶蛋白和新鲜茶叶蛋白性质研究

分别用碱法从新鲜茶叶和干茶叶中提取出茶叶蛋白,对两种蛋白的溶解性、分子量、氨基酸成分、吸水性、吸油性、乳化性、乳化稳定性、起泡性、凝胶性等功能性质进行了研究.结果表明,干茶叶蛋白的吸油性、凝胶性和乳化性比新鲜茶叶蛋白好,而溶解性、吸水性、乳化稳定性、起泡性和起泡稳定性不如新鲜茶叶蛋白.对两种茶叶蛋白的分子量分布和氨基酸成分也做了研究.     

双低油菜籽浓缩蛋白的制备及其功能特性的研究

通过响应曲面法，确定以含水乙醇洗涤法制备双低菜籽浓缩蛋白的最佳工艺参数为：选用浓度为70％的乙醇做溶剂，控制液固比为8．85：1，在60℃温度搅拌下，洗涤次数为6次，洗涤时间为20min／次。该工艺条件下制备的菜籽浓缩蛋白，其色浅味淡，无溶剂残留。蛋白质含量可达62．48％，其中硫甙能够完全脱除，植酸含量下降了60％。研究并对菜籽浓缩蛋白的溶解性、吸水性、吸油性、乳化性和起泡性等功能特性及功能特性的改善进行了研究。     

小粒黑大豆蛋白质功能特性研究

以收集于黄土高原的8种小粒黑大豆为实验材料,4种小粒黄大豆为对照,采用碱溶酸沉法提取蛋白质,对其蛋白质的功能特性进行分析。结果表明,8种小粒黑大豆蛋白的氮溶解指数、吸水性、吸油性、乳化能力及乳化稳定性、起泡能力、凝胶强度在51. 72%～62. 07%、2. 29～2. 95 g/g、1. 52～1. 70 g/g、54. 40%～88. 60%、83. 35%～97. 16%、75. 70%～95. 80%、154. 59～203. 66 g之间。小粒黑大豆蛋白的氮溶解指数和吸油性显著低于小粒黄大豆;盐池黑豆、定边小黑豆和靖边王渠子黑豆的蛋白质吸水性显著高于小粒黄大豆;乳化能力及乳化稳定性均优于小粒黄大豆,起泡性和泡沫稳定性差于粒小粒黄大豆;除子洲小黑豆、横山老黑豆和偏关小黑豆外,小粒黑大豆蛋白的凝胶强度显著高于小粒黄大豆。不同品种间小粒黑大豆蛋白质的氮溶解指数、吸水性、吸油性、乳化稳定性、起泡能力及凝胶强度有显著差异。     

Functional Properties of Guar Proteins

Water and fat absorption, emulsification capacity (E.C.), foaming capacity (F.C.), and foam stability (F.S.) of guar meal and protein isolate have been determined and compared with those of soybean meal and isolate. Guar meal had lower water absorption capacity, similar fat absorption capacity and greater F.S. and E.C. than soybean meal. Guar protein isolate (GPI) had lower water absorption capacity but higher fat absorption capacity than soy protein isolate (SPI). The foaming capacity and emulsification capacity were similar at all pH's except around pH 4. However the foam stability of GPI was greater than that of SPI.     

Preparation and Functional Properties of Linseed Protein Products Containing Differing Levels of Mucilage

The functionality of two high-mucilage protein concentrates (HMPC) prepared from linseed and linseed expeller cake by extracting and coprecipitating the mucilage with protein was compared with those of a low-mucilage flour (LMF), a protein concentrate (LMPC), and a protein isolate (LMPI) in simple systems. The HMPC samples had better water absorption and emulsifying properties, higher foaming capacity, but lower nitrogen solubility, oil absorption, and foam stability than LMF and LMPC. They also registered higher values of viscosity and emulsification characteristics than LMPI.     

Chemical composition,functional properties,and bioactivities of rapeseed protein isolates

In order to utilize rapeseed protein from oil industry waste for food applications, rapeseeds were pretreated to remove the oil using hexane. Two protein isolates were prepared, one by precipitation at controlled pH and the other by ultrafiltration. The precipitated and ultrafiltered protein isolates, respectively, contained 70.8% and 98.7% protein. The ultrafiltered protein isolate had a better emulsification capacity than had whole egg. The ultrafiltered protein isolate had a protein solubility of 52.5–97.2% in the range pH 3–9, whilst the maximum protein solubility of the precipitated protein isolate was 26.4% in the pH range 7–9. There were no significant differences between the precipitated and ultrafiltered protein isolates regarding their angiotensin converting enzyme inhibition are their bile acid-binding capacity. Their bile acid-binding capacity and angiotensin converting enzyme inhibition capacities were lower than of those de-oiled soybean. They showed stronger DPPH radical-scavenging activity than did de-oiled soybean.     

Foaming properties of oilseed proteins

Oilseeds are important sources of edible proteins. Their varieties varied in oil and protein content; sesame and rapeseeds had the highest oil content, but soybean and glandless cottonseeds had the highest protein content. Foaming properties of oilseed proteins are important for the domestic market to be used in the preparation of various food products. Whole rapeseed had the highest foam capacity followed by soybean, sunflower, safflower, glandless cottonseed, peanut and finally sesame. The extraction of lipids from oilseeds caused a significant improvement in their foam capacity and foam stability. High positive correlation was found between soluble proteins and foam capacity of oilseeds. The foam capacity was high at pH 7, and decreased below it reaching a minimum at pH 4. The foam stability also varied with pH; being maximum at the isoelectric point and minimum at pH 7. The foam capacity of oilseed protein isolates decreased with the prolongation of heating time at 100 °C.     

棉籽蛋白资源开发研究进展

我国棉花资源丰富,棉花加工的副产物——棉籽经脱壳提油后的棉籽粕中蛋白质含量高达40%~50%。棉籽蛋白是一种营养价值高、品质良好的植物蛋白资源。介绍了棉籽蛋白的营养价值以及脱酚棉籽蛋白粉、棉籽浓缩蛋白、棉籽分离蛋白等产品的制备工艺及产品的溶解性、持水性、持油性、乳化性与乳化稳定性、起泡性与泡沫稳定性等功能特性的研究进展,并对棉籽蛋白产品目前在食品、饲料、发酵等领域的应用情况进行了论述。     

Functional Properties of Chinese Rapeseed Protein Isolates

A membrane-based protein isolation process developed in our laboratory produced two protein isolates from CH₃OH/NH₃/H₂O-hexane-extracted Chinese rapeseed meal. Both contained ～99% protein (NX6.25), and they were essentially free of glucosinolates or their breakdown products (<2,2 μmol/g). Their functional properties were evaluated and compared with a commercial soybean protein isolate. The precipitated isolate gave high values for all properties except nitrogen solubility index (NSI) while the soluble isolate showed excellent NSI and fat absorption but poor emulsification characteristics. They both had good foaming properties. The two Chinese rapeseed protein isolates complemented each other and were comparable to soybean protein isolate in most functions.     

Functionality of Flours, Protein Fractions and Isolates from Field Peas and Faba Bean

Field pca and faba bean proteins are rich sources of lysine, and air classification of the pin milled flours essentially doubled the protein contents in the protein fractions. The proteins in these flours and protein fractions were highly soluble at acid pH and exhibited only a narrow range of insolubility at pH 4–5. Water holding and oil absorption capacities increased in proportion to protein contents of the flour, protein fraction, and isolate of each legume, including soybean flour and isolate, but oil emulsification properties were uniformly high among all products. The protein fractions exhibited excellent whipp-ability and foam stability compared to soybean controls, and their promising functional properties suggested potential applications in meat emulsions, beverages and bakery products.     

CERTAIN FUNCTIONAL PROPERTIES OF SUNFLOWER MEAL PRODUCTS

Certain functional properties including water absorption, fat absorption, emulsification, whippability and foam stability were determined on the sunflower flour, protein concentrates and isolate. The results were also compared to those obtained on soy products. Data on water and fat absorption studies suggest that soy products are more hydrophilic in nature while sunflower material exhibited greater lipophilic properties than the soy products. Emulsification tests showed that sunflower flour was superior to all other soy and sunflower products. In general, whipping properties of soy and sunflower isolates were similar, while less whippability was observed for the soy flour and protein concentrates. Whipped foams produced by soy and sunflower protein isolates and sunflower flour were more stable than soy flour, soy and sunflower protein concentrates.     

酰化和酶水解对菜籽蛋白功能性质和抗氧化活性的影响

研究乙酰化和丁二酰化对菜籽蛋白功能性质和抗氧化活性的影响,以及碱性蛋白酶水解对酰化菜籽蛋白功能性质和抗氧化活性的影响。结果表明,乙酰化和丁二酰化能明显提高菜籽蛋白的水溶性、吸油性和乳化性,但对乳化稳定性和起泡性影响不大,泡沫稳定性略有增加;酰化反应还能提高菜籽蛋白对DPPH自由基的清除率;酶水解酰化菜籽蛋白能显著提高水溶性,同时提高乙酰化菜籽蛋白对DPPH自由基的清除率。