不同凝固方式制备豆腐的特性分析

Characteristics analysis of tofu prepared by different solidification methods

中文关键词:  皖豆21551  氯化镁  葡萄糖酸内酯  谷氨酰胺转氨酶  豆腐  凝胶性质

英文关键词:Wandou 21551  magnesium chloride  glucono-δ-lactone  transglutaminase  tofu  gel property

中文摘要:

      目的 研究氯化镁(magnesium chlorid, MgCl2)、葡萄糖酸内酯(glucono-δ-lactone, GDL)和谷氨酰胺转氨酶(transglutaminase, TG) 3种不同的凝固剂对豆腐质构特性、流变特性、微观结构等的影响。方法 以“皖豆21551”大豆品种为原料, 分别添加MgCl2、GDL和TG, 测定凝胶化过程中pH、豆腐凝胶强度、持水性(water holding capacity, WHC)、流变性质、水分分布、微观结构等指标。结果 3种凝固剂(MgCl2、GDL和TG)的最佳添加量分别是0.20%、0.45%和0.20%。MgCl2豆腐(TMgCl2)具有最高的临界应变(γc)、储能模量(G’)和损耗模量(G’’), TG促豆腐(TTG)处于中间值, GDL豆腐(TGDL)最低。3种凝固剂都能导致豆乳蛋白分子的解折叠和重组, 并增加β-折叠含量。低场核磁共振(low-field nuclear magnetic resonance, LF-NMR)结果显示豆腐样品中有3个峰, 分别代表结合水、固定水和自由水。TMgCl2凝胶强度最高[(62.0±0.66) g], 但网络结构粗糙; TGDL凝胶强度为(20.8±1.33) g, 网络结构相对均匀; TTG具有较高的凝胶强度[(54.6±1.63) g], 均匀致密的网络结构。结论 3种凝固剂制备豆腐的特性不同, 可根据加工需要选择不同的凝固剂。

英文摘要:

      Objective To study the effects of magnesium chloride (MgCl2), glucono-δ-lactone (GDL) and transglutaminase (TG) on the texture, rheological properties and microstructure of tofu. Methods The soybean variety “Wandou 21551” was used as raw material, adding MgCl2, GDL and TG to prepare tofu, respectively. The pH during the gelation process, gel strength, water holding capacity (WHC), rheological properties, water distribution and microstructure of Tofu were determined. Results The optimal addition of 3 kinds of coagulants (MgCl2, GDL and TG) was 0.20%, 0.45% and 0.20%, respectively. TMgCl2 had the highest critical strain (γc), storage modulus (G’) and loss modulus (G’’), TTG was in the middle, and TGDL was the lowest. The 3 kinds of coagulants could lead to the unfolding and recombination of soy milk protein molecules and increase the β-sheet content. Low-field nuclear magnetic resonance (LF-NMR) results showed that there were 3 peaks in tofu samples, representing bound water, fixed water and free water. TMgCl2 had the highest gel strength [(62.0±0.66) g], but the network structure was rough. TGDL gel strength was (20.8±1.33) g, and the network structure was relatively uniform. TTG had high gel strength [(54.6±1.63) g], and uniform and dense network structure. Conclusion The characteristics of 3 kinds of coagulants for tofu preparation are different, so different coagulants can be selected according to the needs of processing.