加工工艺对北方豆腐品质特性的影响

分别以生浆法、熟浆法、热水套法3种工艺制备北方豆腐,以出品率、保水性为指标,获得最佳制浆方式后,研究磨浆料液比、凝固温度、Mg Cl2溶液添加量、凝固时间对北方豆腐品质特性的影响以及出品率、保水性与质构特性的相关性。结果表明:熟浆法制成北方豆腐的出品率、保水性明显高于生浆法和热水套法;豆腐工艺的最佳优化条件为磨浆料液比1∶7(g/m L)、凝固温度80℃、0.6 mol/L?Mg Cl2溶液添加量18 m L/L、凝固时间20 min,制作的北方豆腐出品率和保水性均最高;根据相关性分析得出:不同加工条件下,硬度、内聚性及回复性与北方豆腐出品率、保水性均呈负相关,咀嚼性、胶着性及弹性与北方豆腐出品率、保水性均呈正相关。

Effects of Processing on the Quality Properties of Northern Chinese Tofu

In this research, three different methods namely cooking soybean slurry before filtration, cooking soybean milk after filtration of soybean slurry to remove okara and adding hot water into soybean slurry with stirring before filtration were compared in terms of tofu yield and water retention to find the best one to produce northern Chinese tofu. Furthermore, the effects of soybean-to-water ratio for grounding, curding temperature, MgCl2 dosage and curding time on the quality characteristics of tofu were examined and tofu yield and water retention were correlated with texture properties of tofu. The results showed that tofu yield and water retention obtained from the second method were significantly higher than those obtained from the other two. The optimized conditions that provided maximum tofu yield and water retention were determined as follows: soybean-to-water ratio for grounding, 1:7 (g/mL); curding temperature, 80 ℃, 0.6 mol/L MgCl2 dosage, 18 mL/L; and curding time, 20 min. The correlation analysis showed that under different processing conditions, tofu yield and water retention were correlated negatively with hardness, cohesiveness and resilience but positively with chewiness, gumminess and flexibility.