Texture characteristics of soymilk gels formed by lactic fermentation: A comparison of soymilk prepared by blanching soybeans under different temperatures

Soymilk can be used as a raw material to produce gel-like food with texture characteristics of yogurt through lactic fermentation. The removal of beany flavors and a soft yogurt-like texture are two fundamental criteria for evaluating the quality of soy yogurt. However, the effect of blanching treatment, which can eliminate beany flavors, on the texture of soy yogurt remains unclear. The objective of this study was to compare the texture of soy yogurt prepared by blanching soybeans under different blanching temperatures. Variations in texture and microstructure of soymilk gels were analyzed by texture profile analysis and scanning electron microscopy. A soft and weak soymilk gel was produced at a blanching temperature above 70 degrees C. The strength and rigidity of the soymilk gel produced at a blanching temperature of 80 degrees C decreased by approximately 50% compared to that obtained by traditional treatment. With the increase in blanching temperature, the microstructure of the soymilk gel transformed from a three-dimensional stranded network with dense crosslinks of string of beads protein polymers to a thick honeycomb, lamellar structure of stacked protein particles and clustered aggregated around the stranded networks. A yogurt-like soymilk gel with soft, tender, and smooth characteristics was obtained with >= 70 degrees C blanching treatment. (C) 2014 Elsevier Ltd. All rights reserved.