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大米谷蛋白易发生热聚集,离子强度对大米谷蛋白热聚集有明显影响,研究揭示Na Cl对大米谷蛋白的热聚集的影响规律及机制。当Na Cl浓度从0增加至0.15 mol·L-1时,热处理大米谷蛋白溶解度由13.78%降至12.49%,减小趋势不明显,浓度达到0.30 mol·L-1时,溶解度降至10.62%,并且出现了肉眼可见的浑浊。当NaCl浓度从0 mol·L-1增加至0.30 mol·L-1时,热处理大米谷蛋白的浊度由0.052显著增加至0.191,平均粒径由168 nm增至273 nm,并出现明显的聚集峰,Zeta电位由-14.4减小至-5.61,疏水性由329.16增加至535.80,谷蛋白荧光发射光谱发生微小蓝移,荧光强度增加。NaCl影响了谷蛋白分子的表面电荷和疏水性,当浓度大于0.15 mol·L-1时明显促进了大米谷蛋白分子热聚集。 相似文献
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Jian Guo Xiao‐Quan Yang Wei Gu De‐Bao Yuan Jin‐Mei Wang Na‐Na Wu 《International Journal of Food Science & Technology》2012,47(4):665-673
Poor solubility caused by thermal aggregation usually limits the utilisation of soy proteins in food industry. In this study, the anionic surfactant, sodium dodecyl sulphate (SDS), was found to be effective in suppressing thermal aggregation of glycinin which was the main composition of the insoluble aggregates of soy proteins. Turbidity, dynamic light scattering, surface tension, circular dichroism and fluorescence spectra analysis were used to reveal the mechanism for the inhibitory of thermal aggregation by SDS. Bound to SDS, the exposed hydrophobic groups on the protein molecules were covered by the ionic head groups of SDS. The approaching of the particles was unavailable in the presence of the strong electrostatic repulsive force. Therefore, the particles remained stable and disperse. Thermal aggregation was not effectively suppressed until the binding sites which interacted with SDS on the glycinin molecules were saturated. The strategy for improving the solubility of food protein was also discussed. 相似文献
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Abdellatif A Mohamed Patricia Rayas‐Duarte Sanghoon Kim 《Journal of the science of food and agriculture》2005,85(3):450-458
Lysozyme is being tested for use as a preservative in the food industry. The interaction between starch and lysozyme will help in recommending starch or starch fractions as carriers for lysozyme. The effect of starch fractions on the folding and unfolding of lysozyme was estimated by differential scanning calorimetry (DSC), kinetics and transmittance turbidometry. Lysozyme was unfolded (heated to 90 °C) and folded (cooled to 20 °C) five times in the presence of starch fractions. Starch was added at 1 and 2%. Overall, a trend of higher onset temperature (To) values occurred at 2% addition of all starch fractions except amylose. The increase in the number of cycles influenced the effect of starch on lysozyme denaturation. The percentage of lysozyme's ΔH values decreased as a new heating and cooling cycle was performed (ie 74.4% of the ΔH remained from the first cycle). The effect of amylose (AM) and amylopectin (AP) on the kinetics of lysozyme unfolding and folding was found to be different based on the assumption that the peak DSC temperature is the fastest step of the reaction. The unfolding showed higher activation energy (Ea) in the presence of both AM and AP, while the folding was not significantly changed. The turbidity of the solution containing lysozyme and potato starch showed transmittance in between that of lysozyme and starch. Stirring of the blend kept the transmittance unchanged while an increase in the transmittance was noticed when stirring ceased. Copyright © 2004 Society of Chemical Industry 相似文献
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蛋清蛋白质的热处理改性有助于提高其功能特性及生物有效利用率, 从而拓宽其在食品工业中作为配料的应用范围。热处理主要通过对蛋清蛋白质热聚集行为的影响, 从而影响其在食品体系中的应用, 而对蛋白质聚集行为的研究将有助于改善食品体系中蛋白质的功能性质。蛋清粉是许多食品加工中的重要原料, 也是很好的蛋白质体系, 是食品蛋白质热聚集行为和功能性构效关系的理想研究对象。对蛋清蛋白质聚集机制的研究将有助于功能性蛋制品的开发。因此, 本文主要对蛋清蛋白质热聚集行为的研究进行综述, 希望能为相关科研人员及企业提供一定的借鉴。 相似文献
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目的:考察溶菌酶酶解物的抑菌能力,为扩展溶菌酶的应用提供理论依据。方法:采用胃蛋白酶对溶菌酶进行酶解,得到溶菌酶酶解物(Lysozyme hydrolysate,LH);采用二倍稀释法检测LH对几种常见食品腐败菌的抑菌能力;以金黄色葡萄球菌为受试菌种,通过抑菌圈实验探讨LH的抑菌活性,并与溶菌酶和乳酸链球菌素作比较。结果:LH对几种常见阳性菌都有很强的抑制作用,其中对金黄色葡萄球菌的抑制作用最强;未经热处理时,LH的抑菌活性略低于溶菌酶,而高于乳酸链球菌素;经热处理后,LH的抑菌活性高于溶菌酶和乳酸链球菌素。菌酶酶解物有望被开发成一种天然的食品防腐剂。 相似文献
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Grzegorz Lesnierowski Jacek Kijowski & Renata Cegielska-Radziejewska 《International Journal of Food Science & Technology》2009,44(2):305-311
The aim of the study was to produce a lysozyme preparation with an increased content of enzyme polymeric forms using the ultrafiltration (UF) technique. The effect of selected parameters of the membrane process on the extent of enzyme modification was examined. The study showed that the membrane technique, developed for the production of lysozyme monomer, could also be used in the direct production of a preparation containing enzyme polymers. Under optimal conditions of the modification procedure, the obtained preparation contained 53.3% of lysozyme polymeric forms. The effectiveness of the antibacterial action of UF-modified lysozyme against selected strains of bacteria was determined. Its bacteriostatic activity depended on the applied modification conditions. Among lysozyme preparations modified by UF, the highest bacteriostatic activity against selected strains of bacteria was recorded in the preparation containing 53.3% polymeric forms. The modification procedure facilitates the extension of the antibacterial spectrum of lysozyme against Gram-negative bacteria ( Pseudomonas fluorescens ) . 相似文献
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郇延军 《食品与生物技术学报》1997,16(2)
研究了从新鲜蛋清中提取溶菌酶的方法。通过控制温度,调酸和加盐,可以使溶菌酶得到分离和纯化。采用超滤的方法将溶菌酶提取液浓缩及脱盐并进一步纯化。最后采用喷雾干燥的方法制成产品。产品活力可达11000u/mg. 相似文献
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溶菌酶活力的简易测定 总被引:14,自引:0,他引:14
对溶菌酶的测定方法进行了改进,简化了读数方法;对底物悬液进行了适当处理。本方法在酶活性为50~250U/mL范围内有良好的线性关系,反应底物无需用菌粉制成,读数只需记录第15s和第75s的OD450值。结果表明,该方法与常规方法相比较无显著差异(P<0.01)。 相似文献
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用苯甲酸钠、山犁酸钾、尼泊金酯、溶菌酶四种防腐剂处理酱油,以37℃恒温贮存7d、14d、21d时酱油菌落总数测定结果为基础进行防腐效果评价,天然防腐剂溶菌酶优于其他化学防腐剂。进一步研究溶菌酶与甘氨酸、EDTA二钠复配的防腐效果,通过正交试验确定最佳配方为溶菌酶0.05g/kg,甘氨酸0.3g/kg,EDTA二钠0.02g/kg,强于单一使用溶菌酶的防腐效果。 相似文献
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溶菌酶对草莓的保鲜效果 总被引:32,自引:2,他引:30
应用溶菌酶对草莓进行保鲜,结果表明,在20℃单独使用溶菌酶不如与甘氨酸复合使用效果;同时离子强度、pH值对结果有影响。最后得出最佳配比:溶菌酶0.07%,氯化钙0.5%,甘氨酸1.5% 相似文献
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目的 研究热处理和不同离子强度条件下汉麻蛋白的热聚集行为。方法 以汉麻籽为原料,考察在80、90、100℃热处理下,以及不同离子强度(0、0.2、0.4、0.6、0.8 mol/L NaCl溶液)下汉麻蛋白的ζ-电位、粒径、浊度、二级结构、凝胶电泳、巯基及二硫键等指标。结果 汉麻蛋白随着热处理温度的升高和离子强度的增大,ζ-电位绝对值降低、粒径增大、浊度增加;电泳图中在70 kDa处有聚集条带显示;红外光谱显示随着热处理温度升高,α-螺旋结构显著降低,β-折叠和无规则卷曲结构显著增大,β-转角的相对含量变化不大;随着离子强度增大,α-螺旋和β-转角结构显著降低,β-折叠结构增加,无规则卷曲变化不大;90℃热处理时游离巯基含量低于80℃和100℃,二硫键含量在80℃处理下最少;离子强度对汉麻蛋白总巯基影响不显著。结论 热处理温度的升高及离子强度增大对汉麻蛋白聚集行为具有促进作用,为汉麻蛋白热加工工艺优化和品质调控提供了理论基础。 相似文献