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.     

功能性大豆浓缩蛋白的性能及应用研究

功能性大豆浓缩蛋白（ＦＳＰＣ）的乳化活性及乳化稳定性与大豆分离与蛋白相似，对固体脂肪的乳化能力超过分离蛋白，在乳化型碎肉制品中添加可使产品得率及质构超过添加分离蛋白的肉制品，作者认为ＦＳＰＣ的功能性质可能与蛋白分子形成可溶性聚集体有关。     

功能性大豆浓缩蛋白性能测定及其应用研究

实验研究功能性(物理和酶法改性)大豆浓缩蛋白(FSPC)的NSI值、乳化能力、凝胶性、持水性及吸油性等变化。结果表明,功能性大豆浓缩蛋白NSI值明显提高,大豆蛋白功能特性有不同程度提高和改善;FSPC应用试验,即乳化体凝胶强度试验表明,FSPCI(物理改性)大豆浓缩蛋白有较好凝胶、乳化、持油和持水性;而FSPC2(酶法改性)大豆浓缩蛋白有较好溶解、乳化性。     

Yield and Nutritive Value of Rapeseed Protein Concentrate

Rapeseed protein concentrate (RC) was prepared on a semi-pilot scale by a process involving 2% sodium hexametaphosphate. The nitrogen and total solids yields were 53 and 31%, respectively. The RC contained 77% protein, negligible amounts of glucosinolates, 14.2% ash, 3.4% phosphorous, and 1.26% phytic acid. The amino acid composition was similar to rapeseed flour. When fed to rats in diets at 5 and 10% protein levels, RC exhibited higher protein quality than the casein controls and no gross abnormalities were observed in all major organs. At the 20% dietary protein level, the difference in quality was not significant and rats fed RC had larger kidneys than those fed casein. This was attributed partly to the high phosphorous content of the diet. Mineral bioavailability was not affected by the phytic acid and phosphorous present in the RC.     

水相酶解法提油工艺对菜籽蛋白功能特性的影响

采用纤维素酶、果胶酶、Alcalase蛋白酶对油菜籽进行水相酶解法制取油脂和蛋白。对传统水剂法制油及水相酶解法提油工艺所得菜籽蛋白的功能特性进行了对比研究。研究表明：在实验条件下，工艺过程对菜籽蛋白的功能特性有一定的影响，表现为低度改性，所得菜籽蛋白溶解度显著提高，尤其是在菜籽蛋白等电区域。同时具有更好的起泡性、乳化性、持水性、吸油性，但泡沫稳定性和黏度比传统水剂法有所降低。这些功能特性的变化使之更有利于用做食品原料。     

Chemical Composition and Functional Properties of Acylated Low Phytate Rapeseed Protein Isolate

Protein isolates were prepared by isoelectric precipitation or dialysis of the first and second aqueous extracts of rapeseed flour which was unmodified or acylated by succinic or acetic anhydride. Acylation of the flour lowered the protein and phytic acid contents without significantly altering the amino acid composition of the isoelectrically precipitated protein isolates from the two extracts. The acylated protein isolates from the isoelectrically precipitated extracts had high nitrogen solubility, emulsifying and fat absorption properties. Isoelectrically precipitated and dialyzed acylated proteins did not differ in nitrogen solubility, but dialyzed unmodified protein isolates had nitrogen solubility which was considerably greater than that of isoelectrically precipitated proteins.     

花生粉,花生浓缩蛋白制备工艺及功能特性的研究

对花生蛋白，特别是花生浓缩蛋白的制备工艺进行了研究。对浓缩蛋白的三种制备方法进行了分析比较，并将产品的功能特性与大豆浓缩蛋白进行了对照。     

Effect of Whey Pretreatment on Composition and Functional Properties of Whey Protein Concentrate

The effect of pretreatment upon the composition and physicochemical and functional properties of whey, ultrafiltration (UF) retentate and freeze-dried and spray-dried whey protein concentrates (WPC) was investigated. Pretreatment was by cooling cheese whey to 0-5°C, adding calcium chloride, adjusting to pH 7.3, warming to 50°C, and removing the insoluble precipitate that formed by centrifugation or decantation. UF permeation flux rate of pretreated whey was about double that for control whey. Pretreated whey was essentially turbidity free, contained 85% less milkfat, 37% more calcium and 40% less phosphorus than whey. Pretreated whey WPC proteins were slightly more soluble at pH 3, but less functional for emulsification than whey WPC proteins. Neither whey WPC proteins nor pretreated whey WPC proteins was functional for foaming at 6% protein concentration.     

菜籽水解蛋白不同组分的体外功能性质研究

初步分析了水酶法工艺得到的菜籽水解蛋白的组成、体外抗氧化活性和抑制ACE活性,并用凝胶过滤色谱法分离水解蛋白得到不同组分,探讨了不同组分的体外抗氧化活性和抑制ACE活性与组分氨基酸组成、分子量分布的关系。结果表明,水解蛋白具有良好的体外功能性质,经Sephadex G-25分离后的9个峰中,峰2、峰4和峰5具有较好的体外功能性质,它们的分子量分布中90%以上低于1000,且含有较高量的疏水性氨基酸。     

高压均质对菜籽蛋白功能性质和酶解效果的影响

为了了解高压均质技术对菜籽蛋白的影响,采用不同压力(306、0、901、201、50 MPa)对菜籽蛋白溶液进行均质处理,并分析了处理前后菜籽蛋白功能性质和水解度的变化。结果表明:高压均质可提高菜籽蛋白的溶解度、乳化性、起泡性和泡沫稳定性等功能性质,且随着均质压力的升高其乳化性、起泡性和泡沫稳定性均增强;同时高压均质对蛋白质的氮溶指数、乳化稳定性也有显著的影响;此外,高压均质对菜籽蛋白的酶解也起到了促进作用,且随着压力的增大作用效果越明显。     

豇豆蛋白功能特性及其在食品工业中应用

该文介绍豇豆蛋白的提取、氨基酸组成、功能性质及其在食品工业中应用。     

不同工艺制备的大豆浓缩蛋白功能特性的比较

分别采用醇法、酸法和超滤的方法制备大豆浓缩蛋白,比较3种方法制备的浓缩蛋白在功能性质上的区别。结果表明:超滤法生产的浓缩蛋白其蛋白质含量、风味色泽、溶解性、起泡性、乳化性及乳化稳定性均较突出,而泡沫稳定性则最差。     

Composition and Properties of Spherosil-QMA Whey Protein Concentrate

The Spherosil-QMA ion exchange process was used to prepare whey protein concentrate (WPC) from cheese whey. The process recovered about 64% of the proteins from whey as a 63% protein WPC. The WPC contained about 20.8% lactose, glucose, and galactose. The WPC proteins ranged in solubility from about 32–42% as a function of pH 3–7 and appeared to have undergone substantial denaturation by HPLC but not by palyacrylamide gel electrophoresis. The gelation properties of WPC were compared with those of commercial and ultrafiltration WPCs as a function of pH 3–7.5 and 0.0–0.15M NaCl and CaCl₂. The WPC did not function well as egg replacer in model cake and custard formulations.     

Whey Protein Concentrate Fortified Baked Goods from Cassava-Based Composite Flours: Nutritional and Functional Properties

Composite flours are extensively used in the bakery industry to develop designer food products, having specific nutritional or functional properties. Though rich in carbohydrate, cassava flour has not been properly exploited for making bakery products, mainly because of its low protein content contributing to poor dough characteristics. Induced malting using amylolytic enzymes and pregelatinization through hydrothermal cooking were tried to modify the textural and functional attributes of cassava flour, which was then blended with various cereal and legume additives as well as rice bran and used for making two baked products such as muffins and biscuits. Whey protein concentrate (WPC) was added to fortify protein in all the formulations. Pseudo-malted cassava flour-based muffins and biscuits had lower starch content (36–44% and 36.5–41.2%, respectively) than similar products from unmalted cassava flour (39–46% and 43.75%, respectively). The crude protein content of the muffins and biscuits from WPC fortified composite mixes ranged from 7.96% to 14.36% and 9.63% to 11.00%, respectively, which was significantly higher than the native cassava flour (1.30%). Besides, the total dietary fiber could be enhanced to the extent of 1.54–3.10% in muffins and 1.70–2.61% in biscuits, through fortification with cereal and/or legume flours or bran sources, which is also considerable when compared to only 0.435% in native cassava flour. In vitro starch digestibility was the lowest for cassava (unmalted)-/rice bran-based muffins (25.02 units) and cassava (unmalted)-/finger millet flour-based biscuits (36.08 units), indicating the potential of these combinations for making therapeutic baked products for obese and diabetic people. Spread ratio and spread factor were the least (9.27 and 60.99, respectively) for the biscuits made with unmalted cassava/finger millet mixes, while use of Termamyl pseudo-malted cassava/finger millet raised the spread ratio to 11.11 and spread factor to 73.09.     

Modification of the Sodium Hexametaphosphate Extraction-Precipitation Technique of Rapeseed Protein Concentrate Preparation

A previously reported method of preparing rapeseed protein concentrate (RC) involving 2% sodium hexametaphosphate (SHMP) was modified to reduce SHMP lost in the effluent, to produce a product with higher protein, lower phosphorous content and improved color close to that of rapeseed flour and promine D. Addition of 0.25% Na₂S₂O₅ to the 0.25% SHMP extractant improved color but had little effect on flavor. Except for nitrogen solubility, whippaachieved the first two objectives. Double washing of precipitate with 50% alcohol or precipitation in 15 or 30% alcohol yielded RC with color close to that of rapeseed flour and promine D. Addition of 0.25% Na₂S₂O₅ to the 0.25% SHMP extractant improved color but had little effect on flavor. Except for nitrogen solubility, whippability and viscosity, the functional properties and chemical scores of the improved RC's were similar to the control RC (2% SHMP).     

Effects of Liquid Whey Protein Concentrate on Functional and Sensorial Properties of Set Yogurts and Fresh Cheese

The production and incorporation of liquid whey protein concentrates (LWPCs) in fresh cheese and set yogurt is proposed as a solution for immediate reutilization of whey produced by small- and medium-scale dairy plants avoiding expensive processing steps (e.g., evaporation and drying) for the recovery of this by-product. Accordingly, the incorporation of LWPCs in such products was performed in order to compare the functional and sensorial properties of modified products with the conventional ones. The use of LWPC in fresh cheese increased water-holding capacity as well as product stability during storage. Fresh cheese hardness, chewiness, and gumminess decreased during storage in a more pronounced way in products with LWPC. The fat content influences significantly all the physicochemical properties tested in set yogurts. Incorporating LWPC in set yogurts does not produce appreciable differences in the visual properties when considering products with medium-fat content, but these differences become significant for full-fat yogurts. Adhesiveness and springiness were not significantly affected with storage time or by the amount of LWPC incorporated for medium-fat yogurts. Higher values of hardness and gumminess were obtained for full-fat yogurts, but these parameters decreased with LWPC incorporation. Syneresis was reduced using LWPC but increased with storage time. During storage, viscosity differences between LWPC incorporated yogurts and the conventional ones were only maintained in the case of creamy yogurts. The sensory panel detected differences between conventional and modified products in the case of fresh cheeses but no significative differences were detected between yogurts. LWPCs can be a good alternative to conventional dry products used in fresh cheese and set yogurt manufacture since their utilization reduces milk consumption and allows for the increase in total solids content. Additionally, their incorporation in milk originates end products with attractive physicochemical and sensorial characteristics at lower production costs.     

米糠浓缩蛋白的提取及功能性评价

对米糠蛋白的碱法提取新工艺进行研究 ,获得最佳工艺条件。试验结果表明 :采用该工艺不仅蛋白提取率达 93 7% ,而且所得米糠浓缩蛋白的白度较通常碱法工艺提高 1倍 ,其功能特性接近美国宝利来大豆分离蛋白     

葵花籽油蜡糊蜡精制的研究

The new basic technology of extractiog protein from rice bran was studied,obtaining optimum technology conditions. The results of the experiments showed that extraction ratio of protein was 93.7%, rice bran protein concentrate was twice as white as that made with traditional basic technology, and its functional properties was near to the soybean protein separate made by Protein Technologist International.     

蛋白氧化及对肉制品品质和功能性的影响

肉蛋白氧化及功能性和品质变化目前已经引起国内外关注。本文从氨基酸残基侧链的改变、羰基衍生物的产生、蛋白质聚合物的形成三方面阐述了肉中蛋白氧化的机理,同时对氧化给肉蛋白品质和功能性带来的影响进行了概括性论述。