Effect of Steam Heating during Crushing on the Quality and Safety of Cloudy Pear Juice

摘要

To study the effect of steam heating during crushing on the cloud stability and safety of cloudy pear juice, some physical properties of it and the number of microbs in heated puree were assessed in the process of heating at different temperature during crushing. The heating treatment of increased temperature could not only improve the viscosity of juice by releasing more pectin from puree to juice and avoiding the de-polymerizing of the pectin caused by polygalacturonases (PG), but also reduce the size of particles in the juice and increase the Zpotential of particles in juice. Besides, microbs in juice also were killed at higher temperature. The cloud stability of cloudy pear juice and the safety could be improved when it was made by heating the puree to above 92 "C during 80 seconds.