Study on the rheological and gel properties of Auricularia auricula pulp and konjac glucomannan compound system

We examined the rheological and gel properties of Auricularia auricula pulp solution and konjac glucomannan solution at different concentrations (1.2, 2.4, 3.6, 4.8, and 6.0 g/100 mL) as well as A. auricula pulp/konjac glucomannan compound system at different mass ratios (4.8:1.2, 3.6:2.4, 2.4:3.6, and 1.2:4.8) and discussed the interaction mechanism. The results showed that the apparent viscosity, dynamic viscoelasticity, energy storage modulus (G'), and loss modulus (G") of the compound system increased with the increase of A. auricula pulp mass ratio. The thixotropic ring decreased with the increase of A. auricula pulp mass ratio, indicating that A. auricula pulp could improve the thixotropy of the compound system. The results of the texture analysis and water retention test showed that konjac glucomannan was the decisive factor for the strength and hardness of A. auricula pulp/konjac glucomannan compound gel, and A. auricula pulp could significantly improve the elasticity, viscosity, and water-holding capacity of the compound system. Based on Fourier transform infrared spectroscopy and cryo-scanning electron microscopy (cryo-SEM) analyses, we preliminarily concluded that an interaction occurred between A. auricula pulp and konjac glucomannan in the compound system, and a gel network structure was formed.