Application of Gypsum (Calcium Sulfate) in Soybean Products

Application of Gypsum (Calcium Sulfate) in Soybean Products

The difference between gypsum and other coagulants

The hardness and chewiness of tofu made with gypsum are lower than the tofu made with brine, but the yield of the tofu made with brine is lower and the water retention is poor.

The salt coagulant such as gypsum and brine is poor on the preserved effect of the isoflavones in soybeans than gluconolactone. But the gypsum is better than brine.

Gypsum is a late-setting coagulant and the solidification time is long. The tofu made with gypsum has more delicate tissue structure.

Application of gypsum in soy products

The concentration of coagulant is mainly determined by the reaction rate of coagulant and soya milk, the amount of coagulant and the quality of tofu.

When the calcium sulfate’s concentration is 0.25mol / l, the tofu’s bean curd tissue is good, coagulant and soy milk’s reaction is easier to control than brine and the mixing is relatively uniform. When the brine’s concentration is 1.9mol / l, the tofu’s bean curd tissue is good, coagulant and soy milk’s reaction is relatively easy to control and the mixing is relatively uniform. When the calcium sulfate and brine’s mixed coagulant ratio is 4: 6, the tofu will get better quality and taste.

There is no significant difference in the quality and taste of the tofu produced using the coagulant after the sterilization, but it contributes to the improvement of tofu’s quality and shelf life.

Gypsum is a late-setting coagulant and the solidification time is long. Excessive use of gypsum will remain calcium sulfate in tofu and affect tofu’s aroma and taste.

Calcium, magnesium and hydrogen can promote tofu solidification; sodium and potassium ions postpone solidification and improve pH at the same time. The calcium or magnesium salts in organic acids also improve tofu flavor.

石膏（硫酸钙）在豆制品中的应用综述

石膏和其它凝固剂的区别

以石膏为凝固剂制得的豆腐的硬度与咀嚼性明显低于用卤水制得的豆腐，用卤水制得的豆腐出品率偏低，保水性较差^[4]。

以石膏和卤水为代表的盐类凝固剂对大豆内异黄酮的含量保存效果没有葡糖糖酸-内酯好，其中石膏对大豆内异黄酮的含量保存效果比卤水好^[5]。

石膏为迟效性凝固剂，它与大豆浆液中的蛋白质作用速度慢，蹲脑时间（凝固时间）长^[6]，其形成的豆腐组织结构细腻^[7]。

石膏在豆制品中应用注意事项

凝固剂浓度的确定主要从凝固剂与豆浆反应的速度、凝固剂的用量以及制成豆腐的质量三个因素考虑。

单独成分的凝固剂卤水浓度为1.9mol/l时，制成豆腐的豆花组织较好，凝固剂与豆浆反应相对容易控制，混合相对均匀。单独成分的凝固剂硫酸钙浓度为0.25mol/l时，制成的豆腐豆花组织较好，凝固剂悬浊液添加前需搅拌、混匀、反应相对容易控制，混合相对均匀。硫酸钙和卤水两者的混合凝固剂比例在4:6时，可以制得质量和口感都比较好的豆腐^[4]。

使用灭菌后的的凝固剂制作的豆腐的质量和口感没有明显差别，但有助于豆腐在卫生质量上的提高，相对延长豆腐的保质期^[4]。

石膏是迟效性凝固剂，凝固时间长，石膏过量使用会在豆腐中残存硫酸钙，产品带有苦涩味，影响豆腐的香气、口感^[6]。

钙、镁和氢离子可促进豆腐凝固，钠和钾离子推迟凝固，提高pH值可推迟凝固。有机酸的钙或镁盐还能改善豆腐风味。