改性处理对豌豆蛋白结构和功能特性的影响

以豌豆蛋白为原料,研究了挤压处理、磷酸化处理、挤压协同磷酸化处理三种改性处理方法对豌豆蛋白二硫键含量、二级结构含量、亚基组成,以及表面疏水性、溶解性、持水性及持油性、乳化活性及乳化稳定性的影响.结果表明,不同改性处理条件下豌豆蛋白结构及功能特性均发生变化,与挤压处理和磷酸化处理相比,挤压协同磷酸化处理对豌豆蛋白理化性质影响最为明显.与未改性豌豆蛋白相比,挤压协同磷酸化处理的豌豆蛋白二硫键含量增加了26.25％;二级结构中β-折叠含量增加了15.06％,β-转角含量减少了9.85％;亚基组成中豆球蛋白A和豆球蛋白B含量减少;表面疏水性提高了101.95％.挤压协同磷酸化处理后的豌豆蛋白溶解性、持油性、乳化活性及乳化稳定性显著高于未改性豌豆蛋白(P<0.05),而单一的挤压处理、磷酸化处理对豌豆蛋白这些功能性的改善效果不如挤压协同磷酸化处理,特别是挤压处理后豌豆蛋白溶解性减小.     

超高压处理对大米蛋白功能特性及结构的影响

以不同压力(200、400、600 MPa)对大米进行超高压处理。研究了超高压处理对大米中谷蛋白功能特性以及清蛋白、球蛋白和谷蛋白结构的影响。结果表明:超高压处理后大米蛋白的功能特性和二级结构均发生变化,不同压力影响效果不同。200 MPa时蛋白质的溶解性、持水性和乳化性提高,持油性降低;400 MPa时持水性和乳化性降低,持油性提高,溶解性升高不明显;600 MPa时溶解性、持水性、持油性和乳化性均降低。超高压处理后清蛋白、球蛋白和谷蛋白的二级结构发生改变,β-折叠结构含量降低,无序结构增多。相关性分析结果表明压力、功能特性和二级结构三者之间存在相关性。     

pH值碱性偏移结合热处理对米糠蛋白结构和功能性质的影响

研究pH值碱性偏移（pH 11）结合热处理（50、60 ℃）对米糠蛋白结构和功能性质的影响。结果表明,pH值碱性偏移促使米糠蛋白二级结构由有序向无序转化,pH值碱性偏移结合热处理使得米糠蛋白二级结构呈现折叠-去折叠-复折叠的复杂变化,并伴随巯基氧化。pH值碱性偏移促使米糠蛋白展开,随着处理时间的延长,米糠蛋白重新聚集,热处理会加剧聚集程度。pH值碱性偏移使得米糠蛋白持水性、起泡性、泡沫稳定性、乳化性和乳化稳定性显著下降,仅持油性显著改善;随着处理时间的延长,米糠蛋白持水性、起泡性、乳化性和乳化稳定性逐渐上升,其中乳化性上升幅度最大。pH值碱性偏移结合热处理可显著改善米糠蛋白的持水性、起泡性、泡沫稳定性和乳化稳定性,同时也会降低米糠蛋白的持油性和乳化性。     

研磨对豌豆分离蛋白应用特性的影响

为改善豌豆分离蛋白应用特性,扩大其在食品工业的应用.该文采用研磨干法处理豌豆分离蛋白,研究其持水性、持油性、泡沫特性、乳化性能、凝胶性能等应用特性变化;并根据研磨后豌豆分离蛋白结构特征,分析研磨对应用特性的影响机理.结果表明:研磨对豌豆分离蛋白形态结构及亲水性基团产生了显著影响,进而影响了豌豆分离蛋白应用特性.研磨时间...     

超声波处理对豌豆分离蛋白功能特性的影响

以豌豆分离蛋白为原料,采用不同强度的超声波处理,研究超声波处理对豌豆分离蛋白溶解性、起泡性、乳化性、持水性、吸油性等功能特性的影响。结果表明,一定强度的超声波处理范围内,豌豆分离蛋白的溶解度、乳化性和乳化稳定性均随着超声波强度的提高而增大,当超声波强度超过69.36 W/cm~2时,豌豆分离蛋白的溶解度逐渐趋于平稳;豌豆分离蛋白的乳化性和乳化稳定性的变化在超声波强度分别为75.68 W/cm~2和59.28 W/cm~2后趋于稳定。豌豆分离蛋白的起泡性、泡沫稳定性、持水性和吸油性随着超声波强度的增大呈现先上升后下降的趋势,在超声波强度为69.36 W/cm~2时,起泡性和泡沫稳定性达到最高,持水性和吸油性则在超声波强度分别为75.68、49.35 W/cm~2时达到最高。上述分析表明,适度强度的超声波处理可改善豌豆分离蛋白的功能特性。     

脱壳处理对火麻蛋白提取、功能特性和消化性的影响

以火麻仁粕和未脱壳火麻籽粕为原料,研究了脱壳处理对火麻蛋白回收率、色泽、溶解度、持水性、持油性、乳化性及乳化稳定性、起泡性及起泡稳定性和消化性的影响.结果表明:从脱壳处理后的火麻仁粕中提取的火麻仁蛋白在蛋白质回收率(83.90％ ±0.69％)、蛋白质质量分数(88.56％ ±0.65％)和色泽上都显著(P<0.05)...     

动态高压微射流环境中豌豆白蛋白-绿原酸复合物的相互作用

通过对豌豆白蛋白以及豌豆白蛋白-绿原酸复合物粒度、Zeta电位、荧光光谱、红外光谱与疏水性、溶解性、乳化特性等指标的测定，探究动态高压微射流不同处理压力对豌豆白蛋白和复合物结构与功能特性的影响，以及二元体系中绿原酸对豌豆白蛋白影响的机制和效果。结果表明，豌豆白蛋白经过动态高压微射流处理后，粒径与Zeta电位值均呈先降低后增加趋势；改性后的豌豆白蛋白微观结构、二级结构与三级结构均发生变化；剪切力等作用的小粒径豌豆白蛋白溶解性显著提高了42.37%，可达到0.84 mg/mL(P<0.05)，乳化特性也得到一定增强。动态高压微射流处理加工豌豆白蛋白-绿原酸复合物体系中，绿原酸改变了豌豆白蛋白色氨酸的微环境，使白蛋白结构发生显著变化。绿原酸使豌豆白蛋白表面疏水性显著增加（P<0.05），溶解性显著降低（P<0.05），并将豌豆白蛋白乳化活性提高。本研究阐释了动态高压微射流和绿原酸对豌豆白蛋白的影响作用，为豌豆白蛋白改性提供思路，为高值化蛋白产品的开发提供一定理论基础。     

乳化大豆油与乳化猪油对肌原纤维蛋白/面筋蛋白凝胶的影响

为了改善蛋白凝胶的品质,研究不同比例的乳化大豆油与乳化猪油对肌原纤维蛋白/面筋蛋白凝胶的弹性、硬度、咀嚼性、持水性、可冻结水、非可冻结水、分子间作用力、蛋白二级结构的影响。结果表明：与对照组（未添加脂肪的凝胶）相比,随着乳化大豆油与乳化猪油添加量（5%-20%）的增加,肌原纤维蛋白/面筋蛋白凝胶的硬度、咀嚼性、弹性、胶粘性以及持水性均显著上升（p＜0.05）;可冻结水含量逐渐增加、非可冻结水含量逐渐降低;凝胶的疏水相互作用、氢键、二硫键作用逐渐增强,离子键作用逐渐减弱;蛋白二级结构由α-螺旋逐渐转化为β-折叠和β-转角。     

膳食纤维对低盐鸡胸肉糜凝胶特性的影响

研究燕麦、豌豆、苹果膳食纤维的理化特性差异及其对低盐(含质量分数1%NaCl)鸡胸肉糜凝胶特性的影响。结果表明：3种膳食纤维的持水性、膨胀性由大到小的顺序依次为：豌豆膳食纤维>苹果膳食纤维>燕麦膳食纤维;3种膳食纤维添加均可显著改善低盐鸡胸肉糜的蒸煮得率、硬度和咀嚼性(P<0.05),其中,豌豆、苹果膳食纤维的改善效果优于燕麦膳食纤维;3种膳食纤维均能提高肉糜的储能模量(G’),缩短自由水的横向弛豫时间(T₂₂),增加凝胶内部弱结合水(P_2b)、不易流动水的相对含量(P₂₁),并促进形成紧凑、密实的凝胶三维网络结构;豌豆膳食纤维显著增加蛋白质二级结构中β-折叠的相对含量(P<0.05),而苹果膳食纤维和燕麦膳食纤维均显著增加β-转角的相对含量(P<0.05)。综上所述,燕麦、豌豆、苹果膳食纤维能通过改变肉糜体系的流变学特性、水分流动性及分布状态、微观结构及蛋白质的二级结构,从而显著改善低盐鸡胸肉糜凝胶的持水性和质构特性。     

超声处理对杜仲籽仁蛋白结构及理化特性的影响

旨在为杜仲籽仁蛋白的开发与应用提供参考,以杜仲籽仁粕为原料,采用碱溶酸沉法提取蛋白,采用500 W、35 kHz超声波对杜仲籽仁蛋白处理不同的时间(0、10、20、30 min和40 min),探究超声处理对杜仲籽仁蛋白微观结构、理化特性（粒径、Zeta-电位、内源荧光光谱、溶解性、持水性、持油性、起泡性、起泡稳定性、乳化性、乳化稳定性）的影响。结果表明：超声处理可改变杜仲籽仁蛋白的微观结构、粒径、Zeta-电位和荧光强度;超声处理20 min时,杜仲籽仁蛋白溶解度达到7535%;超声处理10 min时,杜仲籽仁蛋白乳化性最大,达到72.12 m2/g;超声处理40 min时,杜仲籽仁蛋白持水性、持油性、起泡性和起泡稳定性最大,分别达到4.32 g/g、3.46 g/g、23.12%和21.12%。综上,超声处理可改善杜仲籽仁蛋白的持水性、持油性、起泡性、乳化性等功能特性。     

谷氨酰胺转氨酶对高水分豌豆蛋白挤出物结构及消化特性的影响

本实验以豌豆蛋白为原料,利用双螺杆挤出机制备挤出物,探究高水分挤出过程中添加不同比例的谷氨酰胺转氨酶（transglutaminase,TG）对挤出物结构及消化特性的影响。通过质构分析、组织化度分析和扫描电子显微镜观察等方法表征挤出物的宏观结构和微观结构。通过测定流变特性、蛋白质溶解度以及消化特性评价挤出物的结构性能及营养价值。结果表明,添加适量TG(0.25%～1.00%)促进了豌豆蛋白分子间交联,形成致密的网络结构,提高了挤出物的消化率,促进游离氨基酸释放。然而添加过量TG(2.00%)则对挤出物纤维的形成以及消化特性起到抑制作用。TG添加量为1.00%时,制备的豌豆蛋白高水分挤出物组织化程度与营养价值较好。综上,高水分挤压-TG法联用加工工艺能够有效改善植物蛋白肉的结构及消化特性。     

海藻酸钠添加对大豆浓缩蛋白植物肉特性的影响

以大豆浓缩蛋白为原料，添加不同比例海藻酸钠并改变模头温度，利用双螺杆高水分挤压技术制备植物肉。通过组织化度、咀嚼度、颜色、扫描电子显微镜等指标表征植物肉的宏观结构和微观结构。通过比机械能、蒸煮特性、吸水率评价植物肉的结构性能。结果表明，海藻酸钠的添加可以提高植物肉的组织化度，增强咀嚼性。并且在模头温度为150 ℃时，所有挤压样品具有较好的组织化特性。比机械能和吸水率表明，海藻酸钠增强了蛋白质-蛋白质、蛋白质-水之间的相互作用，得到的植物肉持水性升高。扫描电子显微镜表明，过量的海藻酸钠会使产品形成致密的层状而非纤维状结构。因此，海藻酸钠添加量为6%时，通过高水分挤压技术可制备组织化程度高，蒸煮效果较好的大豆浓缩蛋白挤压植物肉产品。     

挤压对谷物蛋白的微观结构和功能特性影响的研究进展

谷物蛋白是丰富的蛋白质资源之一,谷物挤压加工在新型食品创制中得到大量应用。研究谷物蛋白在挤压过程中的微观结构和功能特性的影响机理,对促进谷物蛋白类产品加工的创新开发具有重要意义。本文分析挤压对谷物蛋白的微观结构的影响,综述了谷物蛋白在挤压过程中,一级结构不发生变化;二级结构未被完全破坏,构象之间存在相互转化;三级结构发生改变;进而导致四级结构发生变化,使蛋白质变性。谷物蛋白质微观结构的改变致其功能特性发生变化,具体表现在溶解性降低,乳化性提高,降低乳化稳定性,起泡性提高,蛋白质的消化率得到显著提高。这些功能特性的改变也为谷物蛋白在食品以及生物材料领域创造了良好条件。     

Physical and technofunctional properties of yellow pea flour and bread crumb mixtures processed with low moisture extrusion cooking

The potential utilization of yellow pea flour and bread crumb blends was investigated to generate nutritionally-dense extruded products with superior physical and/or technofunctional properties. Yellow pea flour mixed with bread crumb at different ratios were processed using low-moisture twin-screw extrusion cooking conditions to examine the effect of blending ratios and feed moisture contents on physical (that is, radial expansion index, extrudate density, microstructure, texture, and color) and technofunctional (that is, emulsifying capacity, emulsifying stability, water solubility [WS], water binding capacity [WBC], oil binding capacity [OBC], and pasting) properties of the final products. Compared to the two feed materials alone, samples produced with yellow pea flour and bread crumb blends showed lower hardness and higher crispiness. Moisture content (12% to 18%) was found to significantly affect physical and technofunctional properties. With an increase in feed moisture content from 12% to 18%, the WBC of the extrudates increased while the WS decreased. Extrudates produced with higher feed moisture content, and higher yellow pea flour content had higher setback viscosity. Among all formulas and feed moisture contents studied, extrudates produced with 50% yellow pea flour and 50% bread crumb at 12% feed moisture content had the highest radial expansion and bigger cells with thinner cell walls. This study has shown that incorporation of yellow pea flour and bread crumb in extrusion cooking process could be used to develop nutritionally-dense foods with improved physical and technofunctional properties.     

挤压和酶解挤压对豌豆粉淀粉体外消化率、蛋白质结构和流变特性的影响

目的:研究挤压和酶解挤压处理对豌豆粉理化性质的影响.方法:采用挤压和酶解挤压的方法改性豌豆粉,利用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱、快速黏度分析仪、流变仪分析原料、挤出物和酶解物3种样品的结构变化,并测定体外淀粉消化特性.结果:挤压处理能部分破坏豌豆的结构,表现为相对结晶度下降,I1045cm-1/I1...     

Effect of the extrusion process on allergen reduction and the texture change of soybean protein isolate-corn and soybean flour-corn mixtures

Soy protein and corn meal are widely used as main ingredients in the cereal and snack industries. We studied the effect of extrusion processing on the immunoreactivity of proteins in soy protein isolate-corn meal (SPI-corn) blends and soy flour-corn meal (SF-corn) blends using a full-factorial design with two levels of temperature, moisture, and screw speed (SS). The changes in protein solubility, protein secondary structure and physical properties, such as the expansion ratio, specific volume, water hydration capacity (WHC), texture, and color, were also studied. The western blotting results illustrated that extrusion processing decreased the immunoreactivity of proteins in SPI-corn and SF-corn blends and eliminated certain allergenic proteins in SF-corn extrudates. The enzyme-linked immunosorbent assay (ELISA) results indicated that different extrusion conditions decreased the immunoreactivities of SPI-corn and SF-corn blends in the ranges of 53%–68% and 80%–86%, respectively, compared with the raw material. The protein solubility decreased after extrusion by >58.7% for SPI-corn extrudates and by 66.3% for SF-corn extrudates compared with the initial materials and decreased significantly for both SPI-corn and SF-corn extrudates with the increase in extrusion temperature (P < 0.05). The α-helix structure decreased and β-strand structure increased after extrusion for both SPI-corn and SF-corn blends. Higher moisture significantly decreased the expansion ratio, specific volume and WHC of SPI-corn and SF-corn extrudates, as well as increased the energy required to cut the samples. Thus, the effect of extrusion on allergenic proteins using the human plasma of subjects allergic to soybean and corn showed that moisture had a clear effect on their reduction. Product treated with low moisture (20%), regardless of the starting material used, was the most effective based on the reduction of allergenic proteins.     

Effect of high moisture extrusion cooking on protein–protein interactions of pea (Pisum sativum L.) protein isolates

This study focuses on protein alterations in fibrous meat substitutes produced by high moisture extrusion cooking of pea protein isolates. Three commercially available pea protein isolates and their respective extrudates were evaluated regarding their amino acid composition, molecular weight distribution and protein–protein interactions. Extrusion had no effect on the degree of hydrolysis and amino acid composition indicating that the thermal and mechanical energy during extrusion did not cause the formation of peptide bonds or the degradation of amino acids due to Maillard reactions. Decrease of protein solubilised from extrudates in a buffered solution containing urea indicated that the structural integrity of extrudates could be attributed mainly to covalent disulphide bonding and, to a smaller extent, to non‐covalent interactions. Additionally, the disappearance of legumin bands in extrudates as determined by electrophoresis could be explained by its participation in a macromolecular network that was aggregated and cross‐linked via disulphide bonds. This study contributes to a better understanding of the way the proteins interact during extrusion of pea protein isolates.     

Assessment of color development due to twin-screw extrusion of rice-glucose-lysine blend using image analysis

An image analysis method was developed to determine the color change of rice-glucose-lysine blend during extrusion. The color of extrudates was analysed and compared by using different extrusion conditions. Extrusion process variables included moisture content, screw speed, barrel temperature, and screw geometry. The influence of specific mechanical energy input (SME) and product temperature on the color of extrudates was significant. The color parameters were related to product temperature and SME by a 4th degree polynomial. Product temperature and color were modeled and tested using rice-glucose-lysine blend at various screw configurations and extrusion conditions with reasonable accuracy. Validations of product temperature and color models were done using different screw geometries and other processing variables with reasonable accuracy. Extrusion tests indicated that the developed predictive models can be of use for extrusion processing. The results also showed that the image analysis method developed provides an objective and efficient approach for assessing the color development of extrudates.     

脱脂花生粉特性对其挤压产品结构的影响

以低温脱脂花生粉为原料,采用DSE-25型双螺杆挤压实验室工作站,在花生粉高水分挤压组织化工艺优化的基础上,研究了原料特性(粒度、pH值和油脂含量)对挤压组织化产品结构的影响规律。结果表明,原料特性对脱脂花生粉挤压组织化产品的质量和结构有明显影响。粒径在0.2~0.3mm范围内的原料,其挤压产品既可保持适当的硬度和咀嚼度,又有较好的组织化结构,其微观结构细致,气腔小且分布均匀。原料的pH值对产品的流变学性质和微观结构影响较大;在花生蛋白等电点附近(pH值4.5),挤压产品的硬度和咀嚼度最高,具有较致密的组织结构;在接近中性时,组织化度最高;偏碱性条件不利于产品组织化结构的形成。随原料中油脂含量的增加,挤压产品的硬度、咀嚼度和剪切力均明显下降,扭矩显著降低;综合挤压产品的感官质量和质构分析结果,认为原料中油脂含量在3%~6%范围内,有利于挤压产品组织结构的改善和感官质量的提高。