Study on MgCl2 emulsion and its application in tofu | MgCl2乳化液的制备及其在豆腐生产中的应用

Chinese. 针对豆腐凝固剂MgCl2在点豆浆过程中反应过快的缺点，制备油包水型MgCl2乳化液，以降低MgCl2在豆浆中的分散速度，提高豆腐的细腻度。用MgCl2•6H2O制备油包水型MgCl2乳化液，研究不同乳化剂(卵磷脂、分子蒸馏单甘酯、蔗糖脂肪酸酯、山梨糖醇酐硬脂酸酯、单月桂酸甘油酯)及其用量(质量分数0.5%，1.0%，1.5%，2.0%，2.5%，3.0%)、水相(MgCl2、蒸馏水)/油相(卵磷脂、大豆油)的比例(质量比40/60，50/50，55/45，60/40，65/35，70/30，80/20)、MgCl2•6H2O用量(质量分数15%，20%，25%，30%)及乳化工艺(乳化温度(20，30，40，50，60，70 ℃)、转速(3 000，4 000，5 000，6 000，7 000 r/min)、时间(1，2，5，7，10，15 min))对MgCl2乳化液稳定性和黏度的影响，并对用MgCl2乳化液作为凝固剂制得的豆腐与其他种类豆腐进行品质比较。MgCl2乳化液的配方和乳化工艺：水相(MgCl2•6H2O用量为质量分数30%，蒸馏水30%)/油相(卵磷脂用量为质量分数1.5%，大豆油质量分数38.5%)为60/40，按上述配方分别配制水相和油相，水浴加热到50 ℃，将水相缓慢加入油相中，用高剪切混合乳化机以5 000 r/min乳化10 min，最后进行杀菌和灌装，即可得到均匀稳定的MgCl2乳化液。以制备的MgCl2乳化液作为凝固剂可以降低豆浆的凝固速率，制得的豆腐与其他种类豆腐相比，光滑细腻度更好，风味更佳。制备获得了稳定的油包水型MgCl2乳化液，其可降低豆腐的凝固反应速率，制得风味鲜美、光滑细腻的新型豆腐。

English. In view of coagulant’s high solubility, the objective of this study was to reduce the reaction rate of MgCl2 in soymilk. This paper studied the effect of optimum dosage (0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%) of W/O emulsifiers (lecithin, monoglyceride, sucrose ester, span 60, glycerol monolaurate), concentration of MgCl2•6H2O (15%, 20%, 25%, 30%), the ratio of water/oil (40/60, 50/50, 55/45, 60/40, 65/35, 70/30, 80/20), the optimum emulsifying temperature (20, 30, 40, 50, 60, 70 ℃), stirring speed (3 000, 4 000, 5 000, 6 000, 7 000 r/min) and stirring time (1, 2, 5, 7, 10, 15 min) on the stability and viscosity of emulsion. The emulsion was used as a coagulant for tofu and compared it with other types of tofu. The optimum conditions were as follows: the ratio of water/oil was 60/40, 30% MgCl2•6H2O, 1.5% lecithin, emulsifying temperature 50 ℃, stirring speed 5 000 r/min, and stirring time 10 min. The emulsion can reduce reaction rate of soymilk, and produce delicious and smooth tofu. Emulsifying MgCl2 can reduce reaction rate as new tofu coagulant, and produce delicious and smooth tofu.