ZHANG Xingyun, ZHONG Qiuchan, WANG Shuxin, YI Zuxin, WANG Xinyu, LI Mingxuan, WANG Guangqiang, SONG Zibo, AI Lianzhong, ZHANG Hui
To investigate the effect of rheological properties of frozen dessert solutions such as ice cream on the growth of ice crystals in frozen products,sugar solutions containing 0.3% (w/w) of different hydrocolloids (xanthan gum,tamarind seed gum,guar gum,carboxymethylcellulose and locust bean gum,respectively) were prepared.The water content of sugar solutions were sequentially reduced by 0%,15%,30%,45%,60% and 75% to simulate the freezing process.The effects of viscoelasticity of solutions on the rate of recrystallization were studied using rheology and cryomicroscopy techniques.Results showed that the rheology of sugar solutions supplemented with different hydrocolloids had significant effects on the recrystallization rate by comparing with control group without hydrocolloid.And the tamarind seed gum reduced the recrystallization rate from 62.45 μm3/h of control group to 1.66 μm3/h which exhibiting the most significant effect among all the samples.Both standardized breakpoints of viscosity and modulus of sugar solution presented good linear correlations with the rate of recrystallization (correlation coefficients of r2=0.92 and r2=0.95,respectively).Above results indicated that the rheological properties of sugar solutions with hydrocolloids during freezing process were related to the growth of ice crystals.Supplementation of viscous hydrocolloids could reduce the rate of recrystallization,delay ice crystal growth,and predict and judge the ice recrystallization rate,and thus saving costs for industrial production.This study established a theoretical foundation for the application of hydrocolloid,especially tamarind seed gum,on reducing recrystallization rate,controlling ice crystal size and improving sensory quality of frozen desserts.