干热条件下大豆分离蛋白-壳寡糖美拉德反应及产物表征

对不同质量比的大豆分离蛋白（SPI）与壳寡糖（COS）在干热条件下的美拉德反应及产物性质进行系统性研究,以420 nm和290 nm下的吸光值、游离氨基酸、糠氨酸和5-羟甲基糠醛等的变化来监测美拉德反应的进程,并对美拉德反应产物的Zeta-电位、溶解性、乳化性、热性能、荧光强度等进行表征。结果表明:SPI与COS之间的美拉德反应程度随体系中COS比例的增大而增大;与SPI-COS混合物相比,SPI与COS的美拉德反应产物的Zeta-电位、溶解性、热稳定性均降低,SPI:COS为8:1时Zeta-电位最低达到?33.8 mV;SPI与COS之间的美拉德反应提高了SPI的乳化能力,其中SPI:COS为8:1时乳化活力最强,较SPI-COS混合物提高了509.3%,4:1时乳化稳定性最好,较混合物提高了183.3%。因此,SPI与COS之间的美拉德反应有效的提高了SPI的乳化性能,有望作为一种新型的乳化剂在食品领域广泛应用。     

湿热条件下大豆分离蛋白与葡萄糖、麦芽糖的美拉德反应

研究湿热条件下反应温度、反应时间及混合质量比对大豆分离蛋白（soybean protein isolate,SPI）与葡萄糖、麦芽糖之间美拉德反应的影响,并对所得美拉德反应产物的溶解性、乳化性、溶液pH值、电势、热性能、结构和分子质量的变化进行表征。结果表明,SPI与2?种还原糖发生美拉德反应的最适条件为按质量比4∶1混合后在80?℃条件下反应6?h。美拉德反应明显改善了SPI的溶解度,并且麦芽糖比葡萄糖对SPI的改性效果更佳;美拉德反应降低了SPI的乳化性,并对其ζ电势有一定影响,随着美拉德反应程度的增加,SPI的负电荷明显减少;美拉德反应会使SPI溶液的pH值降低;热稳定性分析表明美拉德反应降低了SPI的热稳定性;傅里叶变换红外光谱分析表明美拉德反应在SPI中引入了新的化学键;荧光分析表明美拉德反应增强了SPI的荧光强度;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定表明美拉德反应导致了大分子物质的形成。     

壳聚糖-木糖美拉德反应产物乳化性能的研究

本研究首先以壳聚糖与木糖为原料制备美拉德反应产物(MRPs),检测MRPs的粒径、电势及乳化性;并以MRPs为乳化剂制备大豆油乳液,以乳液稳定性为指标检测MRPs的乳化效果。分别研究了壳聚糖:木糖质量比、大豆油:MRPs体积比、乳化转速、乳化时间、乳化温度等因素对乳化效果的影响。结果表明,在p H为4.0、壳聚糖-木糖的质量比为1:1、100℃条件下反应3 h获得的MRPs,明显提高了壳聚糖的溶解性和乳化性(p0.05)。将得到的MRPs与大豆油进行混合乳化,当大豆油与MRPs按体积比1:5混合、20℃、10000 r/min高速分散乳化20min时得到的乳液稳定性效果最好。本研究有望为拓展壳聚糖-木糖MRPs在新型乳化剂开发中的应用提供参考,扩大其在食品领域的应用范围。     

PLA/MRPs乳液膜的制备及性能研究

以碱溶性半纤维素木聚糖和玉米醇溶蛋白合成的美拉德反应产物（MRPs）纳米颗粒水溶液为水相、聚乳酸/二氯甲烷溶液（PLA/DCM）为油相,通过乳液聚合法和模压成型工艺制备了PLA/MRPs乳液膜。分别利用傅里叶变换红外光谱仪、热重分析仪、扫描电子显微镜和紫外可见吸收光谱仪分析了PLA/MRPs复合材料的形貌结构和抗氧化性能,并对PLA/MRPs乳液膜的力学性能进行了探究。探讨了MRPs纳米颗粒水溶液的质量分数对PLA/MRPs乳液膜的抗氧化性能和力学性能的影响。结果表明,制得的PLA/MRPs复合材料具有水包油型结构,以质量分数0.50%MRPs制备的PLA/MRPs乳液膜在反应时间为30 h后,DPPH自由基清除率最大,为26.55%;而随着MRPs质量分数的增加,PLA/MRPs乳液膜的拉伸强度和断裂伸长率逐渐降低。     

湿热条件下低聚木糖-乳清分离蛋白的美拉德反应及产物乳化性与流变性研究

本文研究了湿热条件下不同混合质量比(1:1、1:2、1:3、1:4,W/W)对低聚木糖与乳清分离蛋白(WPI)美拉德反应及其产物的乳化性与流变性的影响。UV-Vis吸光度值,pH和粒径大小显著变化表明,该条件下成功制备了WPI和低聚木糖的美拉德反应产物 (MRPs)。数据显示,质量比为1:2的溶液体系美拉德反应程度最高;与未经过美拉德反应的体系相比,MRPs的平均粒径均减小而质量比为1:2的体系平均粒径最大;同时,美拉德反应提高了WPI的乳化活性和乳化稳定性,比例为1:2时MRPs具有最佳的乳化活性(38.63 m2/g)和乳化稳定性(65.23%);流变学测试表明糖基化修饰增强了WPI的凝胶性,比例为1:3时MRPs的储存模量提高最大,G''值高达约97,000 Pa (约WPI的7倍);在相同剪切速率下,MRPs溶液的表观粘度增加,而WPI的添加比例对体系粘度的影响占主导作用。上述研究表明,美拉德反应可改善WPI的乳化特性和凝胶特性。     

米糠多糖-乳清分离蛋白美拉德反应及其产物表征

目的：通过米糠多糖(rice bran polysaccharide,RBP)与乳清分离蛋白(whey protein isolate,WPI)非酶褐变反应,探究反应时间对美拉德反应的影响,开发一种新型乳化剂制备纳米乳液包埋脂溶性物质。方法：RBP与WPI在干热条件下反应不同的时间,以A_{294 nm}、褐变程度、色泽变化、游离氨基含量等的变化监控美拉德反应进程,对美拉德反应产物的分子质量、粒径、乳化活性、乳化稳定性、微观结构进行表征,并用美拉德反应产物制备大豆油纳米乳液。结果：A_{294 nm}、褐变程度、色泽变化及游离氨基含量的变化,表明混合体系发生了美拉德反应,且随反应时间的延长产物颜色变暗;美拉德反应产物分子质量为17 kDa;反应12 h时的产物粒径分布较为均匀;RBP接枝到WPI分子上显著提高了WPI的乳化活性和乳化稳定性(P<0.05);WPI-RBP(12 h)@纳米乳液比WPI@纳米乳液更稳定、粒径均匀,能抵抗酸性条件下和盐离子存在条件下对乳液的不利影响。结论：WPI与RBP间的美拉德反应有效改善了WPI的特性,可作为一种新型...     

酪蛋白与还原糖美拉德反应产物抗氧化性的研究

采用酪蛋白同还原糖（葡萄糖∶乳糖=1∶1）发生美拉德反应,研究其美拉德反应产物（MRPs）的抗氧化活性,测定了MRPs的还原力和对DPPH自由基的清除率。根据单因素及正交实验结果表明,酪蛋白与还原糖反应得到的美拉德反应产物的抗氧化活性同反应物浓度、反应温度、反应时间、反应起始pH存在一定的量效关系,并且确定酪蛋白浓度为3%、反应温度为100℃、反应时间为6h、反应起始pH10时是最佳美拉德反应模式,此时MRPs的抗氧化活性较强,DPPH·清除率可达72.87%。     

美拉德反应及其产物在食品改性中的应用研究进展

近年来,随着食品工业的发展,美拉德反应在食品加工中应用广泛。该文阐述美拉德反应的机理、美拉德反应产物（Maillard reaction products,MRPs）的制备方法、美拉德反应及其产物在食品改性中的应用,并对美拉德反应及其产物的研发提出了展望,以期为从事该方面研发工作的科技工作者提供新思路。     

美拉德反应产物的抗氧化性能研究

通过赖氨酸（甘氨酸）和木糖的美拉德反应可制备具有抗氧化活性的产物。研究了不同反应条件（如时间、pH和反应物摩尔比）对美拉德反应产物（Maillard Reaction Products，MRPs）的抗氧化性能的影响，并与常用食品抗氧化剂特丁基对苯二酚（TBHQ）进行了对比。     

大豆分离蛋白-壳聚糖美拉德反应 产物的制备条件优化

利用大豆分离蛋白（SPI）与壳聚糖（CS）建立美拉德反应体系,以DPPH自由基清除率、超氧阴离子自由基（O-2·）清除率、对细菌（大肠杆菌、金黄色葡萄球菌、沙门氏菌）的抑菌性作为检测指标,经单因素实验和正交实验优化分别具有高接枝度、强抗氧化性、强抑菌性的美拉德反应产物（MRPs）的适宜反应温度、相对湿度、反应时间以及SPI与CS质量比。结果表明：当反应温度80 ℃、相对湿度51.4%、反应时间5 h、SPI与CS质量比1∶ 1时,接枝度最高,为65.13％;当反应温度90 ℃、相对湿度51.4%、反应时间6 h、SPI与CS质量比1∶ 1.5时,MRPs对DPPH·清除率最高,为95.63%;当反应温度90 ℃、相对湿度61.0%、反应时间7 h、SPI与CS质量比1∶ 1.5时,MRPs对O-2·清除率最高,为91.93%;当反应温度100 ℃、相对湿度51.4%、反应时间6 h、SPI与CS质量比1∶ 1.5时,MRPs对大肠杆菌抑菌性最强;当反应温度100 ℃、相对湿度73.9%、反应时间7 h、SPI与CS质量比1∶ 2时,MRPs对金黄色葡萄球菌抑菌性最强;当反应温度100 ℃、相对湿度26.1%、反应时间3 h、SPI与CS质量比2∶ 1时,MRPs对沙门氏菌抑菌性最强。研究结果表明通过控制反应条件,可在一定范围内调节MRPs各个功能性质的强弱以满足不同的实际需要。     

高温短时干热法制备SPI-麦芽糊精糖基化产物及其乳化性的研究

采用高温(90,115和140℃)短时(2 h)干热法制备了大豆分离蛋白(SPI)-麦芽糊精(MD)糖基化产物。利用接枝度和SDS-PAGE研究了SPI与MD发生糖基化反应的程度。同时考察了SPI-MD糖基化产物稳定水包油乳液的性质,并探讨了盐离子和热处理对SPI-MD糖基化产物稳定乳液的储藏稳定性的影响。试验发现,提高反应温度能增大糖基化反应的接枝度,且pH 3.0时,与添加盐离子或经过热处理的SPI,SPI-MD糖基化产物(90℃)和SPI-MD糖基化产物(115℃)稳定乳液相比,添加盐离子或经过热处理的SPI-MD糖基化产物(140℃)的稳定的乳液具有较高的乳化稳定性和储藏稳定性。     

Improvement in emulsifying properties of soy protein isolate by conjugation with maltodextrin using high‐temperature,short‐time dry‐heating Maillard reaction

Soy protein isolate (SPI)–maltodextrin (MD) conjugates were synthesised using Maillard reaction under high‐temperature (90, 115 and 140 °C), short‐time (2 h) dry‐heating conditions. The loss of free amino groups in proteins and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) profile confirmed that SPI‐MD conjugates were formed and higher dry‐heated temperatures could increase the glycosylation degree. The emulsifying properties of SPI and SPI‐MD conjugates were evaluated in oil‐in‐water emulsions. The emulsions stabilised with SPI‐MD conjugates synthesised at 140 °C exhibited higher emulsifying stability and excellent storage stability against pH, ionic strength and thermal treatment compared with those synthesised at 90 °C, 115 °C and SPI stabilised emulsions. This might be due to a greater proportion of conjugated MD in SPI‐MD conjugates synthesised at 140 °C because of the higher glycosylation degree, and more conjugated MD on the droplet surface could provide steric effect and enhance the stability of the droplets in the emulsions.     

Ultrasound assisted vis-à-vis classical heating for the conjugation of whey protein isolate-gellan gum: Process optimization,structural characterization and physico-functional evaluation

In the present work, ultrasonic assisted synthesis and characterization of Maillard conjugates of whey protein isolate (WPI) and gellan gum (GG) was carried out and compared with the classical heating method. Conjugation was confirmed by FTIR, secondary structure, intrinsic fluorescence analysis, and degree of glycation (DG). The structural analysis revealed high protein unfolding by sonication confirming loss of α-helix content and exposing more amino groups to the conjugation reaction. Color change analysis confirmed that ultrasonication accelerated the initial stage of Maillard reaction but did not form the advanced Maillard reaction products. Ultrasonication gave higher DG in lesser time (17.22% in 60 min) than classical heating method (8.41% in 4 h). Physico-functional properties such as pH and thermal stability, emulsifying activity index, emulsion stability index, foaming capability and antioxidant activity of WPI-GG conjugates prepared by ultrasonic treatment were superior to classical heating method suggesting ultrasonication as a potentially alternative method for Maillard conjugation.Industrial relevanceImprovising supplementary protein functionality by conjugation with food grade polysaccharides like gellan gum through ultrasonication could make the process more controllable and economical. The undesired browning can be inhibited in ultrasonic assisted conjugate synthesis and hence the overall acceptance of the final product can be increased.     

Optimization of Maillard reaction products from casein-glucose using response surface methodology

Response surface methodology (RSM) was applied to optimize the processing parameters of casein-glucose Maillard reaction for improving the emulsifying ability and antioxidant activity. The effect of heating time, temperature and initial pH on Maillard reaction products (MRPs) was evaluated. Emulsifying ability and reducing power were taken as response values. An increase of temperature in range and initial pH were associated with an enhanced emulsifying ability and reducing power of the MRPs. Substrate concentration 20%, casein-glucose ratio 1:2, heating time 132.7 min, temperature 100.2 °C and initial pH 12.0 were optimum conditions for the improved emulsifying ability and antioxidant activity of the MRPs. The predicated results for optimum reaction conditions coincided well with experiments values.     

超声处理大豆分离蛋白与壳聚糖复合物对O/W型乳液稳定性的影响

为探究超声处理大豆分离蛋白-壳聚糖（soybean protein isolate-chitosan,SPI-CS）复合物对形成O/W型乳 液性质的影响,主要研究了复合物表面疏水性、乳化活性、乳化稳定性与油-水界面张力、乳液粒径、乳液稳定性 之间的关系。结果表明：未经超声处理的SPI-CS复合物表面疏水性、乳化活性、乳化稳定性和界面吸附性较低,形 成的O/W型乳液粒径相对较大,约100 μm,乳液Zeta电位较低,乳滴有发生聚集的倾向。乳液贮存7 d后乳层析指数 最高。经超声处理后SPI-CS复合物形成的乳状液性质发生明显变化,随着超声功率的增加,形成的O/W型乳液的稳 定性有所增加：超声功率为400 W时SPI-CS复合物形成的乳液最为稳定,乳层析指数最低;当超声功率超过400 W 时,乳液的光学显微镜观察显示其粒径有所增大,同时乳液的Zeta电位、乳化活性和乳化稳定性明显下降,界面张 力降低缓慢。超声处理暴露了蛋白质分子的内部结构,使部分结构展开、柔性增加,促进了其与壳聚糖之间的静电 相互作用,说明超声处理的大豆分离蛋白与壳聚糖形成的复合物影响了O/W型乳液的稳定性及相关性质。     

干法糖基化改性提高大豆分离蛋白的乳化性

在干热条件下,大豆分离蛋白与葡聚糖两种大分子通过Maillard反应进行共价键合,以共价物的乳化活性为指标,确定影响糖基化蛋白乳化活性的因素依次为:反应温度＞反应时间＞pH＞底物配比,最佳工艺条件为:反应温度70℃,反应时间24 h,糖-蛋白(2:1),pH 8.0.以共价物的乳化稳定性为指标,确定了影响糖基化蛋白乳化稳定性的因素依次为:底物配比＞反应时间＞反应温度＞pH.最佳工艺条件为:糖-蛋白(3:1),反应时间24 h,反应温度70℃,pH8.0.通过聚丙烯酰胺凝胶电泳验证了大豆分离蛋白与葡聚糖发生了接枝反应.     

The occurrence of a Maillard-type protein-polysaccharide reaction between β-lactoglobulin and chitosan

Reaction mixtures containing β-lactoglobulin and chitosan (1:4 weight ratio) were dry-heated at 40 °C and 79% relative humidity for 2 weeks. Absorbance measurements and SDS-PAGE analysis indicated the occurrence of the Maillard reaction and conjugate formation, respectively. Some β-lactoglobulin and chitosan properties were modified. For example, the emulsifying capacity at pH 4 and bactericidal activity against Escherichia coli of the Maillard reaction products (MRPs) increased with incubation period up to 2 days, after which these properties deteriorated. The latter was explained by MRPs degradation, which was confirmed by the increased appearance of degradation products in electrophoresis gels at longer incubation times. Data show that the Maillard reaction, under the studied conditions, can be successfully employed to generate MRPs from β-lactoglobulin and chitosan, which exhibit improved properties with respect to β–lactoglobulin alone.     

Improving Functional Properties of Soy Protein Hydrolysate by Conjugation with Curdlan

ABSTRACT:  Soy protein hydrolysate was conjugated with curdlan through the naturally occurring Maillard reaction to extend its application in food processing. The gel-forming and emulsifying properties of soy protein hydrolysates were significantly improved ( P < 0.05) by conjugation with curdlan. The soy protein hydrolysate–curdlan conjugate (SPHCC)–soy protein isolate (SPI) mixed gel had a much thicker network than the soy protein hydrolysate and SPI mixed gel judged from scanning electron microscopic images. The improvement of gelling properties of soy protein hydrolysate by curdlan-conjugate was attributed to both the decrease in the repulsive forces among soy protein hydrolysates and the increase in the solubility. The covalent binding of soy protein hydrolysates and curdlan also showed a profound effect on the antioxidative activity of the soy protein hydrolysates. The higher antioxidative activity of SPHCC was related to the peptide reductants produced from the Maillard reaction and the higher emulsifying property of SPHCC. The conjugates of soy protein hydrolysate and curdlan can be used as a functional food additive having excellent gel-forming, emulsifying properties and antioxidative activity.