解冻方式对小麦面团双轴拉伸黏度的影响

Effects of thawing methods on the biaxial extensional viscosity of wheat flour dough

利用质构仪采用润滑挤压流动的方法测定了3种方式解冻的冷冻面团的双轴拉伸黏度。结果表明:高压解冻面团的双轴拉伸黏度最大,空气和微波解冻面团的居中,未冻结面团的最小。在应变相同时拉伸黏度随应变速率的变化符合幂率模型。随应变增大,模型参数K值增大,n值在应变较小时增大,在应变较大时减小。未冻结面团的K值最小,高压解冻面团的K值最大、n值最小。

The biaxial extensional viscosity of frozen wheat flour dough after being thawed by three methods were determined using a texture anaylser（TA-XT2i）. The results indicated that high pressure-thawed dough had highest viscosity, air-thawed and microwave-thawed dough had a middle viscosity, and unfrozen dough lowest. The strain rate and the biaxial extensional viscosity at the same strain can be fitted by the power law model. With strain increasing, consistency index K increased, while flow behavior index n increased at small strains then decreased at lager strains. Unfrozen dough gave lowest K, while high pressure-thawed dough took highest K and lowest n.