反相微乳法与碱法、酶法制备的茶蛋白功能性质比较研究

本文以绿茶茶渣为原料,采用新兴的反相微乳法提取制备茶渣蛋白,以开发利用茶渣蛋白为目标,对茶渣蛋白的功能特性展开研究,并与碱溶酸沉法、酶法茶蛋白功能性质比较分析。对CTAB-Tween80反相微乳提取制备的茶渣蛋白的功能性质进行研究,结果表明:茶渣蛋白在p H4.0时溶解度最低,溶解度随p H的增加呈现先降低后升高的趋势,其吸油性为2.54 g/g,持水力为1.78 g/g,乳化性为60.27%、乳化稳定性为84.56%,发泡性为68.69%、泡沫稳定性为59.30%。表明反相微乳法制备的茶渣蛋白除了在吸油性、持水力及泡沫稳定性方面与碱溶酸沉法和酶法稍有差异外,乳化性、乳化稳定性及发泡性等均优于碱溶酸沉法和酶法,因而反相微乳法可较好的保持茶渣蛋白的功能特性。     

不同提取方式对红花籽粕蛋白提取率及其功能特性的影响

通过盐提、碱提、碱溶酸沉和超声波辅助法得到红花籽粕蛋白,测定提取液中蛋白质提取率、多肽及游离氨基酸含量,比较蛋白的乳化性及乳化稳定性、起泡性及起泡稳定性。实验表明:超声波辅助碱溶酸沉法得到的蛋白提取液中蛋白质含量和提取率为最高,达到51.49 mg/mL和26.53%,蛋白质中多肽含量最高,达到6.56 mg/mL;碱法中游离氨基酸含量最高,达到2.14 mg/mL;不同提取方式对红花籽粕蛋白功能特性有影响;红花籽粕蛋白乳化性和乳化稳定性与大豆蛋白类似,当pH7.5时趋于稳定上升,均大于20%,且盐溶法蛋白乳化性最好,超声波辅助法最差;当pH5时红花籽粕蛋白起泡性和起泡稳定性优于大豆蛋白,均超过30%。     

丝瓜籽蛋白的功能特性研究

测定了丝瓜籽蛋白的相对分子质量,研究了丝瓜籽蛋白的保水性、吸油性、溶解度、起泡性及泡沫稳定性、乳化性及乳化稳定性等功能特性。室温下,p H 6时,比较了丝瓜籽蛋白与大豆蛋白的功能特性。结果表明:丝瓜籽蛋白的吸油性、溶解度、起泡性及泡沫稳定性较好,但其保水性、乳化性及乳化稳定性较差。     

胃蛋白酶水解大米蛋白的研究

采用胃蛋白酶对大米蛋白进行水解以改善其功能性质。结果表明,酶添加量7U/g(以蛋白质干基计)、pH1.5、时间5h、温度30℃时,胃蛋白酶对大米蛋白溶解性有较好的改善作用。水解后大米蛋白的乳化稳定性与乳化性分别为33.28min、0.456,高于大豆蛋白和鸡蛋清蛋白;起泡性和起泡稳定性比未经过任何处理的大米蛋白分别提高了25.0%、82.4%;持水性和持油性为2.80、3.30g/g,是未经处理的大米蛋白的2.09、2.92 倍。     

梨小豆蛋白功能特性及消化特性的研究

以梨小豆为原料,采用碱提酸沉法提取其蛋白质,探究pH、温度、离子强度对梨小豆蛋白功能特性(溶解性、乳化性、乳化稳定性、起泡性、起泡稳定性)的影响,并通过体外模拟消化实验研究其消化特性。结果表明:pH、温度和离子强度对梨小豆蛋白功能特性均有一定影响,在pH5的碱性条件、较低的温度和NaCl浓度环境下均能提高梨小豆蛋白的功能特性,且当加工条件分别处于pH为10,温度为40℃,NaCl浓度为0.4%时,梨小豆蛋白具有较佳的溶解特性、乳化特性和起泡特性;与其他谷类蛋白相比,梨小豆蛋白的溶解性(85.59%)高于芸豆蛋白和绿豆蛋白,乳化性(15.88 mL/g)高于其他谷类蛋白,乳化稳定性(76.24%)高于大豆蛋白和荞麦蛋白,起泡性(73.67%)高于绿豆蛋白和荞麦蛋白,起泡稳定性(83.48%)高于大豆蛋白,与芸豆蛋白接近;在胃液和肠液消化作用下,梨小豆蛋白含量均呈现下降趋势,而游离氨基含量呈现上升趋势且较消化之前分别提高了1.73倍和1.03倍。这说明梨小豆蛋白具有极佳的加工特性和消化特性。     

茶渣碱提取物中的蛋白质性质分析

茶渣的蛋白质含量较高，可通过碱提法高效获得，然而该法获得的茶渣蛋白质可能与多酚、糖类物质等发生反应，影响其在食品工业中的应用。本研究测定绿茶渣蛋白质提取物的理化性质与生理活性，对碱提法获得的茶渣蛋白质进行分析。采用酶法改进茶渣蛋白质的乳化性、起泡性、抗氧化性。结果表明，提取物中蛋白质含量为52％，其等电点(pI)为3.6，可主要分为3个组分。茶渣蛋白质的溶解度、分散性、起泡性和乳化性与溶液pH值呈正相关性。当茶渣蛋白质质量浓度为80 mg/mL时，对嗜冷菌和假单胞菌的抑菌率分别为98%和93%。经胃蛋白酶处理后，茶渣蛋白质的起泡性为58.3 mL/g，约是未处理样品的2倍。乳化性为100.0 mL/g，约是未处理样品的4倍，抗氧化性变化较小。经碳水化合物复合酶ViscozymeCL 处理后，茶渣蛋白质的起泡性提至52.4 mL/g，乳化性降至12.0 mL/g，抗氧化性提升约0.5倍。试验证明茶渣蛋白质提取物及其酶解产物具有较好的功能性质和开发新型功能性食品的应用潜力。     

牡丹籽蛋白功能特性的研究

研究了牡丹籽蛋白的功能特性,为食品以及饲料行业更好的利用牡丹籽蛋白提供参考。研究结果表明温度为30℃时,牡丹籽蛋白的保水性最好,为3.51 g/g;温度为50℃时,牡丹籽蛋白的吸油性最好,为2.82 g/g;蛋白质量浓度为10 mg/mL时,乳化性和乳化稳定性最好,乳化性为20.1 m~2/g,乳化稳定性为294min;pH为8时,牡丹籽蛋白的乳化性最好,为23.11 m~2/g,pH为7时,蛋白的乳化稳定性最好,为289 min。蛋白质量浓度为70 mg/mL时,牡丹籽蛋白起泡性为61%,pH为7时,起泡性为53%。     

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。     

改性大豆蛋白在植脂奶油中的应用

研究了改性大豆蛋白的乳化性、乳化稳定性、起泡性,以及其替代进口酪朊酸钠应用于植脂奶油对其搅打时间、起泡率、保形性、变粗程度、入口即化感、光泽度、细腻度、油腻感的影响,研究表明,改性大豆蛋白的乳化性、乳化稳定性、起池陛介于进口酪朊蛋白和国产酪朊蛋白问,优于国产大豆分离蛋白;改性大豆蛋白替代进口酪朊酸钠50％应用于植脂奶油产品品质良好。     

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。     

Composition and functional properties of hemp seed protein isolates from various hemp cultivars

Hemp seed protein isolates (HPI) were extracted from seven commercial hemp cultivars, a Cornell breeding line, and a commercial hemp heart product, and their composition and functional properties were investigated. HPI contained different ratios of edestin, vicilin, and albumin proteins, which affected protein solubility and functionality. Higher protein solubility was associated with cultivars that contained more vicilin and albumin, which influenced the subsequent functional properties of HPI. Significant differences in water holding capacity (0.83–1.05 g water/g protein isolate), oil holding capacity (1.28–1.81 g oil/g protein isolate), foam capacity (52.9%–84.9%), and foam stability (68.1%–89.4%) were observed across HPI. The Cornell hemp breeding line exhibited the highest protein solubility at pH 7.0 and was uniquely capable of forming an emulsion. The relationship identified between hemp seed protein composition and functionality, in conjunction with the demonstration of an on-going hemp breeding line, suggest that continued, targeted development of hemp cultivars can improve its seed protein functional properties for ingredient utilization in plant-based foods.     

不同功率超声波对芸豆蛋白理化和功能性质的影响

研究超声波处理对芸豆蛋白(KBP)理化和功能性质的影响.分别探讨了不同超声波功率对芸豆蛋白的紫外光谱、荧光光谱等理化性质及溶解度、吸油性、起泡性能和乳化性能等功能性质的影响.结果表明,超声波处理对芸豆蛋白的紫外光谱和荧光光谱有明显的影响;芸豆蛋白的溶解度随超声波功率增加而逐渐提高,芸豆蛋白400 W时的起泡性和起泡稳定性、500 W时的乳化性和乳化稳定性和200 W时的吸油性最高.说明适宜的超声波功率水平能够改善芸豆蛋白的理化性质和功能性质.     

大豆分离蛋白的磷酸化改性研究

采用三聚磷酸钠 (STMP)对大豆分离蛋白 (SPI)进行磷酸化改性。研究了不同改性程度下SPI功能特性的变化。结果表明 :磷酸化SPI等电点由 pH 4 4 1移至pH 3 86,溶解性、乳化能力和持水性也有明显提高     

Physicochemical and Functional Properties of Tea Protein

Tea protein has received much attention due to its potential health functions. This article studied the molecular weight, foaming capacity, foam stability, emulsifying capacity, emulsion stability, and oil absorption of tea protein prepared from tea residue by alkali extraction. The results showed that tea protein contained two components with different molecular weights (1.26 × 10⁶ ± 1.3 × 10⁴ and 2.4 × 10⁴ ± 1.1 × 10³). The content of the lower molecular component in tea protein was higher than the higher molecular one. When the concentration of tea protein was 4 mg/mL, its sparkling ability was satisfied, while the foaming capacity and foam stability was the best, respectively, at the conditions of pH 9 and 7. The emulsifying capacity was 62 ± 2% as well as 99 ± 1% of emulsion stability, and oil absorption was 170 ± 7%.     

茶叶籽粕蛋白功能特性研究

以大豆分离蛋白为对照,研究碱法和酶法提取茶叶籽粕蛋白的功能特性。结果表明：酶法提取茶叶籽粕蛋白的溶解性、吸油性、乳化能力和乳化稳定性、起泡性、凝胶脆度优于碱法提取茶叶籽粕蛋白,而后者的吸水性、泡沫稳定性则优于前者,两者所形成蛋白凝胶的黏性和硬度相当。碱法和酶法提取的茶叶籽粕蛋白的乳化能力和乳化稳定性稍优于大豆分离蛋白,但起泡性和泡沫稳定性则不及大豆分离蛋白,溶解性与大豆分离蛋白相当,它们形成凝胶的最低质量分数分别为13%和15%,凝胶的黏性和硬度低于大豆分离蛋白。pH值、蛋白质量分数、NaCl浓度等因素对茶叶籽粕蛋白功能特性均有不同程度的影响。     

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。     

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.     

Physico-Chemical Properties of the Flour, Protein Concentrate, and Protein Isolate of the Cupuassu (Theobroma grandiflorum Schum) Seed

ABSTRACT:  Defatted flour, protein concentrate, and protein isolate obtained from Amazonian cupuassu seeds were evaluated for their solubility properties, water and oil retention capacity, foam formation and stability, gelling properties, emulsifying ability, and emulsion stability. The protein contents of defatted flour, the concentrate, and the isolate were 27.65%, 31.18%, and 64.29%, respectively. As expected, the protein isolate exhibited higher solubility than the protein concentrate, achieving more than 90% solubility at pH 8.0. The flour and the protein concentrate, however, showed excellent water and oil retention capacities. High emulsifying capacity at pH 7.0 was also observed for all 3 products: 987 mL oil/g, 977 mL oil/g, and 1380 mL oil/g for the flour, protein concentrate, and protein isolate, respectively. Gelling properties were not exhibited by any of the products, but all of them exhibited good utilization potential, not only to enrich other foods but also to enhance relevant functional properties.