加工条件对大黄鱼鱼肉抗氧化肽功能特性的影响

研究了不同加工条件下大黄鱼鱼肉抗氧化肽的溶解性、吸水性、持水性、吸油性、表观黏度、乳化能力、起泡性等功能特性。结果表明,大黄鱼鱼肉抗氧化肽的等电点处于pH 4.0左右,该pH值条件下,抗氧化肽的溶解性和乳化性表现为最低,而乳化稳定性、起泡性及泡沫稳定性最高。此外,大黄鱼抗氧化肽展现了良好的吸水性、吸油性和流动性,但持水性相对较差。大黄鱼鱼肉抗氧化肽可作为一种生产功能性食品的潜在添加剂。     

皮边角废料提取胶原蛋白的功能特性

采用单一酶和复合酶从皮边角废料中提取得到不同分子量分布范围的胶原蛋白及多肽样品 ,对这些样品的功能特性进行了测定。结果表明 :不同分子量分布的胶原蛋白和胶原多肽表现出不同的溶解性、吸水性、润湿性、吸油性、凝胶性、乳化性、起泡性和泡沫稳定性     

胶原蛋白多肽功能特性的研究

对胶原蛋白多肽的功能特性进行了测定,结果表明胶原蛋白多肽具有良好溶解性、吸水性、保水性、湿润性、吸油性和起泡性,一定的乳化性和较弱的凝胶性和泡沫稳定性。     

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。     

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.     

转谷氨酰胺酶聚合改性大豆分离蛋白的功能特性研究

研究了转谷氨酰胺酶(MTGase)聚合改性大豆分离蛋白的持水性、吸油性、溶解性、乳化性、发泡性及凝胶强度等功能特性。结果显示,与大豆分离蛋白相比,MTGase改性的大豆分离蛋白(MSPI)具有更高的凝胶性和乳化稳定性,但其溶解性、持水性、吸油性、起泡性与泡沫稳定性和乳化性明显减弱。     

南瓜籽分离蛋白功能性研究

以亚临界流体萃取南瓜籽油后的粕为原料,采用碱溶酸沉法制得南瓜籽分离蛋白,研究南瓜籽分离蛋白的溶解性、持水性、乳化性、起泡性、吸油性等功能特性。结果表明:南瓜籽分离蛋白的等电点为p H 5,在等电点时蛋白质功能特性较差,溶解性最小为4.25%,持水性仅为1.85 g/g,乳化性最弱,乳化性和乳化稳定性分别为52%、38%,起泡性和泡沫稳定性分别为5.77%、33.33%;在强酸和强碱环境中,南瓜籽分离蛋白功能特性较好,溶解性大,达到94.5%,最大持水性为6.33 g/g,最大乳化性和乳化稳定性分别为70%、94%,最大起泡性和泡沫稳定性分别为28.3%、93.33%,最大吸油性为2.33 g/g。     

苦杏仁蛋白的功能特性

采用稀盐溶液浸提及等电点盐析相结合的方法提取制备苦杏仁蛋白,研究pH值、NaCl浓度、蛋白质量浓度和温度等因素对苦杏仁蛋白功能特性(溶解性、持水性、吸油性、乳化性及乳化稳定性、起泡性及起泡稳定性)的影响。结果表明：在等电点pI附近时,苦杏仁蛋白的溶解性、持水性、乳化性及乳化稳定性、起泡性最差;在较低NaCl浓度范围内(0～0.8mol/L)提高NaCl浓度可促进蛋白溶解性、乳化性及乳化稳定性、起泡性及起泡稳定性的提高,而较高的NaCl浓度对蛋白功能特性提高具有抑制作用;当蛋白质量浓度达到一定水平时(3～4g/100mL),蛋白功能特性(乳化性及乳化稳定性、起泡性及起泡稳定性)提高趋于平缓;在适宜的温度范围内,提高温度可有效提高苦杏仁蛋白各项功能特性,但当温度继续上升,各项功能特性持续降低。     

温度和pH对山核桃蛋白功能性质的影响研究

以山核桃粕为原料,通过碱溶酸沉法提取山核桃蛋白,探讨温度和p H对其功能性质——溶解性、持水性、吸油性、乳化性及乳化稳定性、起泡性及泡沫稳定性的影响。结果表明:当p H为5.0时,山核桃蛋白在水中的溶解性最小,乳化性及乳化稳定性、起泡性及泡沫稳定性最差;当p H大于5.0时,山核桃蛋白的溶解性、乳化性及乳化稳定性、起泡性及泡沫稳定性随p H的增加而增加;当温度为50℃时,山核桃蛋白的持水性最大、吸油性最低;当温度高于50℃时,山核桃蛋白的持水性随温度升高而降低,而吸油性随温度升高而增加。     

鳕鱼皮胶原蛋白肽的功能特性及抗氧化活性

以鳕鱼皮胶原蛋白肽为实验材料,研究其吸水性、保水性、乳化性等功能特性,并且进行了体外抗氧化实验。结果表明鳕鱼皮胶原蛋白肽具有较好的吸水性、保水性、吸油性和起泡性,具有一定的乳化性和较弱的泡沫稳定性。体外抗氧化实验结果显示,鳕鱼皮胶原蛋白肽对DPPH自由基、羟自由基和超氧阴离子自由基均有一定的清除效果,且清除率与样品溶液的浓度存在剂量依赖关系;浓度为30mg/mL时,胶原蛋白肽对DPPH·、·OH和O2-·的抑制率分别可达到73.84%、85.76%、64.09%。分级后,分子量1ku以下的胶原蛋白肽对DPPH·和·OH的清除能力最强,30mg/mL时清除率达到84%和90.97%;分子量5ku以上的胶原蛋白肽对O2-·清除能力最强,30mg/mL时清除率达到74.02%。     

桃仁清蛋白与大豆分离蛋白功能特性比较研究

为提高桃仁清蛋白(PKA)在食品工业中的应用,将其与大豆分离蛋白(SPI)对照,研究了PKA的溶解性、持水性、持油性、起泡性及泡沫稳定性、乳化性及乳化稳定性和凝胶性等功能特性.结果表明:与SPI相比,PKA具有很好的溶解性、泡沫稳定性、乳化稳定性及较低的凝胶质量浓度,持油性略高于SPI,但起泡性、乳化性及持水性较差;PKA溶解性受溶解条件影响较小.PKA具有良好的功能性质,适合作为食品添加剂或配料.     

不同制备方法桑叶蛋白功能性质的比较

以广东桑大10为原料,采用水提法制备叶蛋白浓缩液,用加热法、酸沉法、酸热法、盐析法沉淀叶蛋白,分别得到蛋白样品RC、SC、SR、LC。对所得样品进行功能性质测定,与大豆分离蛋白对比,得出不同样品的功能特点。结果表明,异亮氨酸、赖氨酸分别为桑叶粉的第一、第二限制性氨基酸。不同沉淀方法对叶蛋白的功能性质有显著影响:LC的溶解性、起泡性、乳化性、吸油性最好,均优于SC、SR及RC;SR的持水性优于SC及RC,但乳化性、起泡性较差;RC、LC的胶凝性最好。与SPI相比,4个样品的吸油性均优于SPI,持水性、胶凝性则显著低于SPI(p0.05);LC的乳化稳定性(68.57%)及SC的起泡性(40%)最好,显著优于SPI(54.86%、37.67%),RC与SPI相当,SR最差,显著低于SPI(p0.05)。LC电镜扫描结果显示其具有典型的蜂巢结构。     

Enhancement of Functional Properties of Rice Bran Proteins by High Pressure Treatment and Their Correlation with Surface Hydrophobicity

Changes in functional properties of rice bran proteins as influenced by high-pressure (HP) treatment (100–500 MPa, 10 min) were studied. Properties evaluated were protein solubility, water absorption capacity, oil absorption capacity, foaming capacity, foam stability, emulsifying activity, emulsion stability, least gelation concentration, and surface hydrophobicity. HP treatment at 100 and 200 MPa significantly improved the solubility and oil absorption capacity, while water absorption and foaming capacities increased further reaching the maximum at 500 MPa. Compared with the untreated control sample, the emulsifying activity and foam stability of treated samples were significantly higher and least gelation concentration was lower, but none of them showed any specific trend with pressure level. Emulsion stability and surface hydrophobicity increased with the pressure level until 400 MPa and decreased slightly at 500 MPa. Pearson correlation coefficients clearly showed that surface hydrophobicity was positively correlated with water absorption capacity, foaming capacity, emulsifying activity index, and emulsion stability index, but negatively correlated with least gelation concentration. The pressure treated rice bran protein possessed good functional properties for use as a food ingredient in the formulations.     

绿豆萌发过程中绿豆蛋白的功能特性及其抗氧化性

本文以绿豆为材料,研究了其萌发过程中绿豆蛋白的功能特性(溶解性、持水性、持油性、乳化性、起泡性、乳化稳定性、起泡稳定性)及抗氧化性(DPPH自由基清除率、金属离子螯合率、超氧阴离子自由基清除率)的动态变化。结果表明,随着萌发时间的不断延长,绿豆蛋白的溶解性、持水性、持油性、乳化性、起泡性均呈现先增加后降低的趋势,乳化稳定性和起泡稳定性得以增强。其中,溶解性萌发24 h时达到最高,萌发96 h最低;萌发的绿豆蛋白持水性、持油性和乳化性相对于未萌发的分别提高了1.57倍、4.13倍和2.47倍;乳化稳定性、起泡性和起泡稳定性较未萌发的分别提高了43.8%、46.6%和61.3%。此外,萌发过程中的绿豆蛋白抗氧化性呈现先升高后下降的趋势,萌发促进了绿豆蛋白的抗氧化性。其中,DPPH自由基清除率和金属离子螯合率均在绿豆萌发36 h达到最大,较未萌发的分别提高了73.8%和31.0%;超氧阴离子自由基清除率萌发48 h达到最大,较未萌发的提高了81.7%。随着绿豆萌发时间的延长,绿豆蛋白的功能特性和抗氧化性呈现先升高后下降的趋势,萌发中期(24~48 h)达到最大。因此,萌发提升了绿豆蛋白的功能特性和抗氧化性,扩大了其在食品加工中的应用,提高了其利用价值。     

Effect of Partial Proteolysis and Succinylation on Functionality of Corn Germ Protein Isolate

Corn germ protein isolate (CGPI) was partially hydrolyzed with trypsin and pepsin and succinylated at three levels. Various functional and electrophoretic properties of the native and modified protein were determined. Water absorption and foaming properties of CGPI were Improved by partial hydrolysis with trypsin; emulsifying capacity and nitrogen solubility were reduced; oil absorption was increased only slightly. CGPI pepsin hydrolyzate has decreased oil absorption, nitrogen solubility and emulsifying capacity but improved foaming properties; water absorption was unchanged. Treatment of CGPI with succinic anhydride improved water and oil absorption, nitrogen solubility and foaming capacity but decreased emulsifying capacity; foam stability was unchanged. Succinylation retarded electropohoretic mobility while hydrolysis altered band intensities.     

Functional properties of 8S globulin fractions from 15 mung bean (Vigna radiata (L.) Wilczek) cultivars

The functional properties including solubility, water absorption capacity, oil absorption capacity, foaming properties and emulsifying properties of 8S globulin fractions from 15 mung bean cultivars were investigated in this study. In addition, the effects of pH on solubility, foaming properties and emulsifying properties were studied. The functional properties of the 8S globulin fractions varied significantly among the different mung bean varieties and exhibited better performance in solubility and emulsion stability compared with soya bean 7S protein. A negative correlation was found between water absorption capacity and oil absorption capacity. Remarkable differences in polypeptides constituents were observed in 8S globulin fractions, and the ratio of 11S/8S globulins has a positive effect on water absorption capacity while a negative effect on oil absorption capacity. As a function of pH, the emulsifying activity indexes of the 8S globulin fractions were found to be distinctly dependent on the solubility, while no significant correlation was found between the emulsifying stability and solubility, nor between the foaming properties and solubility. The foaming capacity showed a strong correlation with foam stability.     

限制性酶解结合大孔树脂吸附对葵花籽蛋白色泽及功能特性的影响

以低温脱脂葵花籽粕为原料提取葵花籽蛋白,对其分别进行大孔树脂吸附脱色和限制性酶解结合大孔树脂吸附脱色处理,对比不同处理的葵花籽蛋白白度值、绿原酸含量及功能特性(溶解性、乳化性、乳化稳定性、起泡性、泡沫稳定性、持油性、持水性和凝胶性)的差异。结果表明:限制性酶解10 min结合大孔树脂吸附脱色的葵花籽蛋白白度值(L^*)为86.3,绿原酸含量为0.16 mg/g,溶解性为77.60%,起泡性为20.87%,乳化性为3.44 m²/g,乳化稳定性为118.51 min,均显著优于葵花籽蛋白和大孔树脂吸附脱色葵花籽蛋白(P <0.05),持水性为1.94 mL/g,显著优于葵花籽蛋白,但与大孔树脂吸附脱色葵花籽蛋白相当,持油性和泡沫稳定性分别为4.40 mL/g和69.62%,显著低于葵花籽蛋白和大孔树脂吸附脱色葵花籽蛋白,限制性酶解10 min结合大孔树脂吸附脱色葵花籽蛋白展现出较好的凝胶性。研究表明,经限制性酶解结合大孔树脂吸附脱色后,葵花籽蛋白色泽显著改善,其溶解性、乳化性、起泡性、持水性和凝胶性均显著提高。     

桑叶蛋白的功能特性研究

采用超声波辅助提取结合盐酸沉析法提取桑叶蛋白,研究pH值、离子强度、蔗糖质量浓度和温度对桑叶蛋白功能特性的影响。结果表明：远离其等电点时,桑叶蛋白具有良好的持水性、溶解度、乳化性及乳化稳定性、起泡性;桑叶蛋白的持水性、溶解度和起泡性与NaCl浓度(0～1.0mol/L)呈正相关,而过高的离子强度(NaCl浓度高于0.6～0.8mol/L)会使桑叶蛋白的乳化性和乳化稳定性下降;蔗糖的加入会增加桑叶蛋白的持水性,但会降低其溶解度和起泡性,对桑叶蛋白的乳化性和乳化稳定性影响不大;桑叶蛋白的吸油性和起泡性与温度(4～80℃)呈正相关,持水性、溶解度、乳化性及乳化稳定性于60℃时最好。     

Functional properties of protein isolates,globulin and albumin extracted from Ginkgo biloba seeds

In this study, the functional properties of Ginkgo seed protein isolate (GPI), Ginkgo seed globulin protein (GGP) and Ginkgo seed albumin protein (GAP) extracted from Ginkgo biloba seeds were investigated. The protein contents of GPI, GGP and GAP were 91.0%, 93.4% and 87.8%, respectively in the samples in which the sugar, polyphenol and crude fibre were removed by the preparation procedure. For functional properties of Ginkgo seed proteins in the natural state, GAP showed the highest oil-absorption capacity (9.3 ml/g), foaming capacity (67.8%), emulsifying capacity (65.4%) and emulsion stability (90.6%); while GPI showed the highest water absorption capacity (1.93 ml/g), and GGP showed the highest foam stability (55.5%). The differences of the chemical components, surface hydrophobicity, disulphide bond (SS) and sulfhydryl group (SH) contents of GPI, GGP and GAP, which were correlated significantly with functional properties of Ginkgo seed proteins, were also investigated. The improved functional properties, such as water absorption capacity, solubility, foaming properties and emulsifying properties of Ginkgo seed proteins were observed in a pH range of 8.0–10.0 or sodium chloride concentration of 0.5–0.75 M.     

Solubility and functional properties of sesame seed proteins as influenced by pH and/or salt concentration

The protein content, solubility and functional properties of a total protein isolate prepared from sesame seeds (Kenana 1 cultivar) as a function of pH and/or NaCl concentration were investigated. The protein content of the seed was found to be 47.70%. The minimum protein solubility was at pH 5 and the maximum was at pH 3. The emulsifying capacity, activity and emulsion stability as well as foaming capacity and foam stability were greatly affected by pH levels and salt concentrations. Lower values were observed at acidic pH and high salt concentration. The protein isolate was highly viscous and dispersable at pH 9 with water holding capacity of 2.10 ml H₂O/g protein, oil holding capacity of 1.50 ml oil/g protein and bulk density of 0.71 gm/ml.