Effect of magnesium salt concentration in water-in-oil emulsions on the physical properties and microstructure of tofu

• Published in: Food chemistry 2016-06, Vol.201, p.197-204
• Main Authors: Zhu, Qiaomei, Wu, Feifei, Saito, Masayoshi, Tatsumi, Eizo, Yin, Lijun
• Format: Article
• Language: English
• Subjects: Emulsions - chemistry; Gels; Glycerol - analogs & derivatives; Glycerol - analysis; Magnesium - analysis; Magnesium chloride; Microstructure; Ricinoleic Acids - analysis; Soy Foods - analysis; Stability; Texture; Tofu; W/O emulsions; Water - analysis
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2016.01.065

•The emulsion coagulant significantly promoted the quality of tofu.•Increasing addition of MgCl2 in W/O emulsions quickened tofu’s coagulation rate.•Physical properties of tofu were affected by the content of MgCl2 in W/O emulsions. The aim of this research was to prepare water-in-oil (W/O) emulsions encapsulating different concentrations of magnesium chloride (MgCl2) and to investigate the effect of W/O emulsions on the physical properties and microstructure of tofu. The results showed that the stability of W/O emulsions improved as the concentrations of polyglycerol polyricinoleate (PGPR) and MgCl2 increased. Dynamic viscoelastic measurements indicated that gelation time decreased with increasing MgCl2 concentration in W/O emulsions, suggesting a more rapid reaction between magnesium ions and protein molecules. As the concentration of MgCl2 in W/O emulsions increased, the yield and water content of tofu decreased, while the protein and crude fat contents and hardness values increased. At a concentration of 2.0M MgCl2 in W/O emulsion, the WHC and microstructure of the tofu samples were optimal. The variations in the physical properties of tofu were attributed to the concentration of magnesium ions and the coagulation rate.