Effect Of Mineral Elements On The Quality Of Dried Bean Curd

This study investigated the migration of mineral elements in the production of dried bean curd. Based on the formulation of evaluation standard for dried bean curd, further study on the effect of mineral elements on dried bean curd was developed, which had application value for the research on enhancing quality of dried bean curd.Through ion detection of the raw materials(soybean and coagulant), bean dregs, yellow whey and dried bean curd in the production process, the combination condition of mineral elements and soybean protein was analyzed. The results showed that about half of the Ca2+and most of Mg2+in soybean combined with soluble protein, when added90mg/L of CaCl2, Ca2+had the largest combination amount with soybean protein. Zn2+,Cu2+and Mn2+had few loss in bean dregs, they mostly combined with soluble protein, and when added1mg/L MnCl2, Mn2+had the largest combination amount with soybean protein. Fe3+firmly combined with insoluble soybean protein, which made Fe3+lost mostly in bean dregs.The method of instrument analysis and sensory evaluation were combined, through correlation analysis and cluster analysis, four texture index (hardness, springiness, shear force and tensile property)were selected as the key indicators for dried bean curd, corresponding instrument analysis parameter value of the sensory evaluation high score in dried bean curd was determined:hardness range:5300-6000g, springiness range:0.25-0.35, shear force range:1100-1600g, tensile property range:130-160g.Adding single and compound mineral elements to deionized water as the production water of dried bean curd, the dried bean curd was analyzed by texture analyzer. The results showed that the four texture index had different tendency. The trends of the effects of single mineral on dried bean curd were:Ca2+and Mg2+increased the hardness, Mg2+increased the springness significantly. Adding less than0.1mg/L Zn2+and Cu2+made the four index of dried bean curd first increasing and then decreasing, with more adding amount the hardness increased. Dried bean curd added with Fe3+had higher index level than added with Mn2+. The synergy effects between minerals were:Ca2+and Zn2+had promoting effect to hardness, springness and shear force within the specific limits. Ca2+and Mn2+could decrease the shear force and tensile property significantly, meanwhile, the adding of Ca2+had promoting effect to this decreasing trend made by Mn2+. Mg2+and Mn2+had inhibited effect within the specific limits, which could decrease the hardness. Mg2+had promoting effect to the decreasing of shear force made by Mn2+. Zn2+had promoting effect to the increasing of springness and shear force made by Mg2+,and the decreasing of shear force and tensile property made by Mn2+within the specific limits.These conclusions provided theoretical basis for producing dried bean curd of high quality, and provided basis for the further study on the influence of mineral elements on soybean protein gel, then could improve the quality of dried bean curd by adding the right amount of mineral composition, which had application value.