Evaluation of Gingerbread Cookies Supplemented with Sunflower Protein Concentrate

The protein content, baking characteristics, physical characteristics, and sensory characteristics of gingerbread cookies supplemented with sunflower protein concentrate were examined. Protein content increased from 7.2% to 15.9% as the substitution level increased from 0% to 30%. Supplementation resulted in higher moisture loss during baking and more compact inner structure of the cookies. Although the texture of supplemented cookies was slightly crispier and harder, evaluation showed that sensory characteristics were not significantly affected by the addition of sunflower protein concentrate.     

Preparation and Properties of Acid-Modified Sunflower Protein Isolate

Sunflower protein isolate (SFPI), 1–10% w/v dispersion, was heated in HC1 (0.025–0.1M) at 90°C. Extents of deamidation and peptide bond hydrolysis were a function of both acid and protein concentration. SDS gel electrophoresis indicated that acid modification of SFPI induced cleavage of a major protein component of molecular weight about 66,000 daltons into two smaller components. Acid modification decreased the isoelectric point of the protein and resulted in a marked increase in solubility at near neutral pH values. Acid-modified SFPI, soluble at pH 7, was successfully incorporated into a model infant formula. Acid modification also improved foam expansion and foam stability properties of SFPI.     

响应面优化转谷氨酰胺酶改性大豆分离蛋白工艺

为获得适于添加到冷饮食品中的大豆分离蛋白,利用转谷氨酰胺酶(TG)对其进行改性,提高其乳化性。采用响应面试验设计,以酶添加量、酶解时间、酶解温度为试验因素,以乳化活力指数为响应值,建立数学模型,对酶解条件进行优化。结果表明,最佳酶解条件为TG酶的添加量0.93×10-4g、温度46℃、时间1.2h。在此条件下,乳化活力指数的预测值为1.9623m2/g,验证实验所得乳化活力指数为1.9658m2/g。所得回归模型拟合情况良好,达到设计要求,本实验得到的改性大豆分离蛋白的乳化性显著高于未改性的大豆分离蛋白。     

Physicochemical Properties of 2S Albumins and the Corresponding Protein Isolate from Sunflower (Helianthus annuus)

ABSTRACT: Sunflower albumins (SFAs) are a diverse group of proteins present in sunflower isolates, with a sedimentation coefficient of approximately 2S. This research presents a detailed study of the influence of pH on the structure and solubility of SFAs. The effect of temperature on the structure of SFAs was also studied. Furthermore, the solubility of a sunflower isolate (SI) was studied and discussed in terms of its main protein components (SFAs and helianthinin). The native structure of SFAs revealed to be very stable against pH changes (pH 3.0 to 9.0) and heat treatment (>100 °C), and their solubility was only marginally affected by pH and ionic strength. The solubility of the sunflower isolate as a function of pH seems to be dominated by that of helianthinin: SI ( I = 30 m M ) showed a U-shaped solubility curve with a minimum between pH 4.0 and pH 6.0.     

Preparation of Functional Soybean Protein Isolate

Soybean protein isolate(SPI) is a high purity soybean protein product.Its protein content is over 90%.A popular processing method is alkali dissolution and acid precipitation.This method can produce various functional SPIs by changing the temperature,pH,types of alkali and acid,and by different pretreatment and post transformation treatment.The properties addressed in this paper would open a big market for the appli cation of SPI.     

大米蛋白乳化性质研究

本文研究了大米分离蛋白(RPI)、酶法大米分离蛋白(E-RPI)、谷蛋白等在不同pH和Na2SO3存在条件下的乳化性能及其表现特点，并与大豆分离蛋白(SPI)的乳化性能进行了比较，结果表明，增加大米蛋白溶解性的措施均有利于改善大米蛋白的乳化性能。谷蛋白一旦溶解其乳化能力与大豆蛋白相当。RPI、E-RPI经Na2SO3处理后，乳化性能明显提高，说明通过解除大米蛋白分子中亚基的聚合，可以改善大米蛋白的物化功能性。     

功能性大豆分离蛋白的制备

大豆分离蛋白是一种高纯度的大豆蛋白制品,蛋白质含量在９０％以上。目前,国内外生产大豆分离蛋白主要以碱酸沉法为主。它可以控制和改变工艺流程中的温度,ＰＨ酸碱种类,前期处理和后期调整等手段生产功能特性各异的大豆分离蛋白。     

马铃薯分离蛋白的提取工艺

采用盐溶碱提酸沉法制备马铃薯分离蛋白,并对马铃薯分离蛋白提取条件和功能特性进行研究。十二烷基硫酸钠- 聚丙烯酰胺电泳结果表明,马铃薯分离蛋白的亚基相对分子质量较广,其中分子质量低于21.0kD 的亚基较多。马铃薯分离蛋白的最佳提取工艺为料水比1:10(g/mL)、温度40℃、pH8.0、NaCl 浓度0.4mol/L。     

芋艿分离蛋白质的流变特性

以芋艿分离蛋白为材料,研究了不同pH值环境条件下芋艿分离蛋白的流变特性、紫外和荧光光谱。结果表明：pH值环境对芋艿蛋白的变性及聚集有明显的影响。在pH值接近芋艿蛋白的等电点时,芋艿分离蛋白因聚集导致其表观黏度较高,滞后现象明显,胶凝点温度（Tgel）及凝胶储能模量（G’）较高;当pH值升高至8.0时（大于芋艿蛋白的等电点）,芋艿分离蛋白解聚集,构象展开,表观黏度较低,滞后现象减弱,Tgel及凝胶G’降低。随溶液pH值的升高,频率扫描曲线G’与损耗模量（G”）的交点逐渐向高频方向移动并最终消失。在pH 7.0时,芋艿分离蛋白的紫外吸收峰位于284 nm波长处;其荧光光谱最大激发波长为289.7 nm,最大发射波长为330.3 nm。     

Thermorheological Characteristics of Soybean Protein Isolate

ABSTRACT: Small amplitude oscillation shear measurement was used to study gel rigidity of commercial soy protein isolate (SPI) dispersions during isothermal and non-isothermal heating. Temperature sweep data (20°C to 90°C atheating rate of 1°C/min) of SPI dispersions demonstrated that elastic modulus (G) predominates over viscous component (G') for all concentrations studied. The gelation kinetics of SPI was evaluated by a non-isothermal technique as a function of elastic modulus (G). During experiments, it was observed that a critical concentration of 10% was required to form a true SPI gel. Thermorheological data of 10% and 15% SPI dispersions were adequately fitted by 2nd-order reaction kinetics. The reaction order of gelation was initially calculated by multiple regression technique correlating dG'/dt, G'and temperature, which finally was verified by linear regression of kinetic equation at selected order. Isothermal data of 15% SPI was also followed by 2nd-order reaction kinetics. The activation energy during the isothermal technique was significantly higher than non-isothermal gelation of SPI at same concentration level. Gel strength of the non-isothermally heated SPI sample (15% to 20%) was compared with isothermally heated (90°C for 30 min) one. Higher protein concentration (20%) and isothermal heating exhibited significantly higher gel rigidity while the difference between the 2 processes was insignificant at 15% concentration at a similar condition.     

Use of Sunflower Protein in Sausages

Beef sausages were prepared in which the normal wheat gluten was replaced with sunflower flour, sunflower protein isolate and soy protein isolate. Sausages prepared with sunflower flour produced a more stable sausage emulsion, were equally acceptable to a sensory panel and not inferior in any cooking parameter when compared to the sausages prepared with gluten and soy protein isolate. Sausages prepared with sunflower protein isolate were the least acceptable due to a dark coloration.     

葵花蛋白的分离及特性研究

通过盐提酸沉法提取葵花籽中的分离蛋白,通过盐溶盐析法分离其主要蛋白成分11S球蛋白,对葵花分离蛋白和其主要成分葵花11S球蛋白的溶解性、吸水性、吸油性、乳化性和起泡性进行研究并与大豆分离蛋白进行比较,发现葵花分离蛋白其功能特性都好于或接近大豆分离蛋白.葵花分离蛋白凝胶层析有5个峰,3个主峰的分子量分别380000、100000和27000,最大的主峰和葵花11S球蛋白吻合.对葵花分离蛋白和11S球蛋白进行电泳分析,发现11S球蛋白含有10条主带,是葵花分离蛋白主要成分.     

花生分离蛋白磷酸化改性研究

采用响应面优化法对花生分离蛋白进行磷酸化改性,以氮溶解指数(NSI)为指标得出花生分离蛋白磷酸化改性的最佳条件为三聚磷酸钠添加量7.77%、花生分离蛋白质量分数6.38%、反应温度44.85℃、反应体系pH8.24、反应时间5.68h。得到的花生改性蛋白NSI 最大值为77.74%。改性后,花生分离蛋白的吸油性、吸水性、持水性、乳化性、乳化稳定性、泡沫稳定性都有不同程度的提高。     

Enrichment of Genistein in Soy Protein Concentrate with b-glucosidase

Genistein has been reported to have the most potent anticarcinogenic effect among isoflavones. Conversion of genistin in the glucoside form to genistein in the aglucone form by a b-glucosidase enzyme hydrolytic activity during soy protein concentrate (SPC) preparation was evaluated. The optimum conditions for the conversion of genistin to genistein were pH 5.0, 50 °C incubation temperature, 2 units of enzyme/g of soy flour, 1 h incubation period, and 1:10 (w/v) defatted soy flour to water ratio. Under these conditions, 1.214 mg/g genistein were obtained in SPC and is significantly (p < 0.05) higher than the genistein content in SPC prepared under similar conditions without enzyme addition (0.845 mg/g).     

大豆分离蛋白膜的DSC分析

采用差示扫描量热法(DSC),研究不同相对湿度(RH)条件下,大豆分离蛋白(SPI)膜的热特性以及谷氨酰胺转移酶(TGase)改性对热特性的影响。对于SPI膜,无论是对照膜还是TGase改性膜,蛋白膜的热稳定性随着RH的增高而下降。TGase改性改变了SPI膜吸热峰出现的位置与数量。在同一RH条件下,TGase改性膜更易失去水分。TGase改性使SPI膜的耐热特性基本未变。     

大豆分离蛋白成膜工艺优化

本文以大豆分离蛋白(SPI)为成膜基质,研究了单宁、可溶性淀粉、微波、超声及干热处理对SPI膜性能的影响,并优化了SPI成膜工艺,结果表明:单宁与可溶性淀粉可极显著(P<0.01)降低膜的透光率、水溶性、氧气及水蒸气透过性,可溶性淀粉可极显著(P<0.01)提高膜的抗拉伸强度;微波与超声处理可极显著(P<0.01)降低...     

紫苏分离蛋白功能性研究

为了开发紫苏蛋白在食品工业中的应用,以大豆分离蛋白为对照,研究紫苏分离蛋白的功能特性。结果表明：紫苏分离蛋白的溶解性与大豆分离蛋白的溶解性随pH值变化的趋势基本一致,但在等电点时紫苏分离蛋白的溶解性高于大豆分离蛋白。在pH7.0时,紫苏分离蛋白的持水性、起泡性及泡沫稳定性、乳化性和凝胶性均不及大豆分离蛋白。但紫苏分离蛋白的吸油性仅稍小于大豆分离蛋白,此外,在紫苏分离蛋白的蛋白质质量浓度为3g/100mL以后,其乳化稳定性与大豆分离蛋白的乳化稳定性基本相当。紫苏分离蛋白在食品加工中作为一种蛋白质强化剂具有一定潜力。     

超声和Alcalase 酶复合处理水解大豆分离蛋白工艺研究

以大豆分离蛋白为底物,通过单因素试验和正交试验,确定超声和Alcalase 酶复合处理对大豆分离蛋白水解的最佳条件。结果表明,最佳水解条件为大豆分离蛋白质量分数5.0%、超声处理时间30min、加酶量5.0%、酶解pH8.0、酶解温度55℃、酶解时间4.0h,在此条件下,大豆分离蛋白水解度为12.21%。     

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。     

Ultrastructural Analysis of a Soybean Protein Isolate

Various fixation techniques were employed in an effort to prepare a dry protein isolate from soybeans for analysis using transmission electron microscopy. A number of fixation schemes proved successful, and different properties of the material were brought out by the various treatments. Comparisons of electron micrographs of the isolate fixed and extracted in different ways yielded an effective means for determining the distribution of fat and protein in the sample and the effect of moisture on that distribution. Analysis of the isolate demonstrated the occluding effect of dry protein for fat located in walls of the protein shells of the isolate.