【作者】 余权；

【导师】 赵谋明；

【作者基本信息】 华南理工大学 ， 食品科学， 2011， 硕士

【摘要】 乳化剂是食品乳状液的重要组分,对食品乳状液体系的稳定性起着重要作用。单甘酯和蔗糖酯为脂肪多元醇酯,是使用量最大的两种食品乳化剂。本文研究了乳化剂、油脂和界面乳化剂浓度的检测方法,单甘酯、蔗糖酯及其复配比例对酪蛋白乳状液的粒度分布、乳析率、脂肪部分聚结率、液相蛋白浓度、界面乳化剂浓度和显微结构等指标的影响,进一步探讨了乳化剂对酪蛋白乳状液稳定性的作用及作用机理,主要结论如下:(1)采用GC-MS、HPLC-UV对BS-2000进行检测,确定了BS-2000的脂肪酸组成及含量,各组分均得到较好的分离;采用HPLC-UV、HPLC-RI、HPLC-ELSD对单甘酯和蔗糖酯进行检测方法比较,确定HPLC-ELSD为后续实验的检测方法;采用HPLC-ELSD对单甘酯和蔗糖酯界面乳化剂浓度的加标回收率进行检测,平均加标回收率分别为92.91%、92.32%,相对标准偏差分别为2.08、1.10,变异系数分别为2.23%、1.19%,结果表明,检测方法重复性良好,符合方法学对回收率的要求。(2)随着单甘酯用量的增加,乳状液D[3,2]和D[4,3]值呈先减小后增大趋势,在单甘酯用量为0.60%时有最小值;乳析率和粒径分布的变化趋势相同,二者有着较好的相关性;脂肪部分聚结率呈下降趋势,直至趋于定值;界面单甘酯浓度呈先增大后减小再增大的趋势;液相蛋白浓度则呈逐渐增大的趋势;显微结果表明,脂肪球大小呈先减小后增大趋势,在单甘酯用量为0.60%时最小,很好地证明了其粒径分布随单甘酯用量不同而发生的变化。(3)随着蔗糖酯用量的增加,乳状液D[3,2]和D[4,3]值总体呈下降趋势,乳析率也呈下降趋势;脂肪部分聚结率呈下降趋势;液相蛋白浓度呈上升趋势;在酪蛋白用量为0.25%时,界面蔗糖酯浓度呈先下降后上升趋势,在酪蛋白用量为0.50~1.00%时,界面蔗糖酯浓度呈上升趋势;显微结果显示,脂肪球大小呈减小趋势,很好地证明了其粒径分布随蔗糖酯用量不同而发生的变化。(4)随着复配乳化剂中蔗糖酯比例的上升,乳状液D[3,2]和D[4,3]值呈先下降后上升趋势;乳析率与粒径分布呈相同的变化趋势;液相蛋白浓度则呈上升趋势;界面单甘酯浓度呈下降趋势,最大值为10.64 mg/m~2,最小值为7.36 mg/m~2,界面蔗糖酯浓度则呈上升趋势,最大值为9.93 mg/m~2,最小值为1.63 mg/m~2;显微结果显示,脂肪球大小呈先减小后增大趋势,在复配比例为1:1时最小且分布均匀。更多还原

【Abstract】 Emulsifier is an important component of food emulsions, which has essential effect on the stability of food emulsion system. Monoglycerides and sucrose ester, two kind of multi-dimensional alcohol ester emulsifiers, are the largest quantity of food emulsifiers used in emulsions. In this paper, the effects of monoglycerides, sucrose esters and associative emulsifiers on the casein emulsion were investigated, containing particle size distribution, creaming rate, rate of partial coalescence of fat, liquid protein concentration, emulsifier concentration in the interface, microstructure, and so on. The functional mechanism of emulsifier on the casein emulsion stability was also studied. The main conclusions are as follows:(1) GC-MS and HPLC-UV were employed to detect BS-2000. The composition of fatty acids of BS-2000 was investigated, and the compounds were well separated. HPLC-UV, HPLC-RI and HPLC-ELSD were compared to measure the monoglycerides and sucrose esters, and the ELSD was found to the most suitable. Therefore, HPLC-ELSD was employed to determine the standard recovery of interface emulsifier concentration of monoglycerides and sucrose esters. As a result, the average recoveries were 92.9% and 92.3%, respectively. The relative standard deviations were 2.1 and 1.1, respectively. The variation coefficients were 2.2% and 1.2%, respectively. The results showed that the repeatability of the measure method was favorable, which achieved the requirement of the analysis methodology.(2) With the increase in the amount of monoglycerides, D[3, 2] and D[4, 3] values of the emulsion decreased first and increased later. The minimum appeared when the monoglycerides load was 0.60%. The change tendency of creaming rate was similar as the particle size, indicating that both have a good correlation. Moreover, the fatty part coalescence rate declined until a stable value. The interface monoglycerides concentration increase first, then decreased, and at last increased again. The liquid phase protein concentration gradually increased. The microscopy result showed that with the increase in the amount of monoglycerides, the fatty ball decreased first and then increased, and the minimum size was in the amount of 0.60% monoglycerides. It was proved that the fatty ball size changed with the different amounts of monoglycerides. (3) With the increase in the amount of sucrose esters, D[3,2] and D[4,3] values of the emulsion decreased overall. A similar decline tendency of the creaming rate was also found as well as the fat partial coalescence rate. What’s more, the liquid protein concentration increased. When the amount of casein was 0.25%, the interface concentration of sucrose esters decreased first and then increased. However, when the amount of casein was 0.50~1.00%, the interface concentration of sucrose esters increased. The microscopy of emulsions indicated the size had changed with the different amounts of sucrose esters.(4) As to the associative emulsifiers, with increasing the amount of sucrose esters, D[3,2] and D[4,3] values decreased first and then increased. The creaming rate showed a similar change tendency as the particle size. The liquid phase protein concentrations increased. The interface monoglyceride concentration revealed a declining tendency, and the maximum and minimum were 10.64 mg/m~2 and 7.36 mg/m~2, respectively. On the contrary, the interface concentration of sucrose esters showed an increase tendency, the maximum and minimum of which were 9.93 mg/m~2 and 1.63 mg/m~2. The result of microscopic analysis demonstrated that the fatty ball size decreased first and then increased. When the ratio of associative emulsifiers was 1:1, the fatty balls were well-distributed and the size reached the minimum.更多还原