【作者】 张利；

【导师】 赵国华； 阚建全； 周才琼；

【作者基本信息】 西南农业大学 ， 农产品加工及贮藏工程， 2003， 硕士

【摘要】 本实验以卵清蛋白粉（OVA）、马铃薯淀粉（PS）、卡拉胶（Car）等为研究对象，以凝胶强度、凝胶弹性、透明度为主要指标，探讨了卵清蛋白——多糖凝胶最佳形成条件，并研究了不同种类的电解质、非电解质以及表面活性剂对凝胶性能的影响。通过比较pH、蛋白质和多糖配比、电解质和非电解质种类和浓度、变性剂尿素、2-巯基乙醇、丙二醇等因素对凝胶性能的影响，对卵清蛋白——多糖体系凝胶形成的分子力作了初步研究。结果表明： 1)OVA/Car体系形成凝胶的最佳条件为基质浓度2％，配比1：3，pH 5，加热温度70℃，加热时间15min，冷却温度0℃，在此条件下形成凝胶的强度为717g，是单独OVA形成的凝胶的2.04倍。 2)OVA/PS体系形成凝胶的最佳条件为基质浓度10％，配比1：1，pH 4，加热温度80℃，加热时间30min，冷却温度0℃，在此条件下形成凝胶的强度为369g，比OVA凝胶的强度略高。 3)电解质NaCl在浓度小于0.2mol/L时能提高两种体系（卵清蛋白-马铃薯淀粉体系与卵清蛋白-卡拉胶体系）的凝胶强度，但降低了凝胶弹性和透明度，且以卵清蛋白-卡拉胶体系所受影响更大。 4)CaCl₂在浓度小于80mmol/L时能显著提高OVA/PS的凝胶强度，但凝胶弹性和凝胶透明度均有所下降，CaCl₂使OVA/Car不能形成凝胶。 5)蔗糖能提高OVA/PS的弹性和透明度，但降低了凝胶强度。蔗糖浓度低于5％能提高OVA/Car的凝胶强度、弹性和透明度，且在2.5％时透明度最好；高浓度的蔗糖导致凝胶各项性能全面下降。 6)脂肪酸盐中，辛酸钠和月桂酸钠在浓度大于1％时能提高OVA/PS的凝胶强度、弹性和透明度，但二者在任何浓度下使OVA/Car体系凝胶性能全面下降。油酸钠使两种体系均不能形成凝胶。 7)OVA/PS体系是不可逆性凝胶体；OVA/Car是可逆性凝胶体，存在温度滞后现象，滞后温差为10℃。 8)变性剂对凝胶的作用表明：OVA/PS形成凝胶过程中，二硫键和氢键贡献很大，静电作用次之，疏水相互作用最小。OVA/Car形成凝胶时以氢键最大，静电相互作用和疏水相互作用次之，二硫键贡献最小更多还原

【Abstract】 By measuring gel strength, gel elasticity and gel transparency, ovalbumin(OVA) mixed with polysaccharide including carrangeenan(Car) and potato starch(PS) were studied to determine the optimal preparation condition for heat-induced mixed gel. This study examined the influence of NaCl, sucrose on the gel properties. To obtain information on molecular forces involved in gelation of mixed system, the effects of denaturant of urea, propylene glycol, 2-mercaptoethanol on properties of the mixed gel of OVA/Car and OVA/PS were investigated. The results indicated that:1) with the total solid concentration of 2%, ratio of protein to Car 1:3, pH 5, heated at 70℃ for 15min, cooled at 0℃, The mixture of OVA/Car form a good gel with a gel strength(GS) of 717g, which is 2.04-fold higher than that of OVA gel.2) With the total solid concentration of 10%, ratio of protein to Car 1:1, pH 4, heated at 80℃ for 30min, cooled at 0℃, The mixture of OVA/PS form a good gel with a gel strength(GS) of 369.92g, which is little higher than that of OVA gel.3) NaCl can enhance the gel strength(GS) of both mixed gel, but decrease the gel elasticity(GE) and gel transparency(GT) at the concentration below the 0.2mol/L. The NaCl has a heavier effect on OVA/Car than OVA/PS.4) CaCl2 can greatly increase the GS of OVA/PS, and decrease GE and GT when the concentration less than 80 mmol/L. At the same condition, it led the OVA/Car unable to form gel.5) Sucrose can enhance the GE and GT of OVA/PS, but decrease GS. At theconcentration less than 5%, it increases the GS, GE and GT of OVA/Car, and the best effect took place at the concentration of 2.5%. When the concentration of sucrose increased, the properties of the mixed gel decreased.6) Fatty acid salts(sodium caprylate, sodium laurate) can enhance the GS, GE and GT of OVA/PS when the concentration more than 1%. It destroies the OVA/Car texture and decrease the gel properties at any concentration. Both the mixed gel system can’t form gel in the presence of sodium oleate.7)The mixed gel of OVA/PS is thermo-irreversible, while OVA/Car is thermo -reversible which have lagging temperature phenomenon of 10℃.8)The action of denaturants on mixed gel indicated that hydrogen bonds and disulfide bonds is most important, electrostatic attraction the second place, hydrophobic interactions least in the gel formation of OVA/PS. The OVA/Car form mixed gel with contribution of hydrogen bonds first, then electrostatic attraction and hydrophobic interactions, disulfide bonds the last.更多还原