低温超微粉碎对龙眼果肉全粉物理性质的影响

采用低温振动研磨方式对龙眼干进行超微粉碎,探讨该粉碎方式对龙眼果肉全粉粒度分布、表观密度、流动性、溶解性、水分吸附特性及流变性等物理特性的影响。结果表明:随着粉碎时间的增加,龙眼果肉全粉粒径不断下降,且分布变窄;表观密度总体呈下降趋势;休止角和滑角不断增大,龙眼果肉全粉流动性下降;溶解时间呈先下降后上升的趋势;龙眼果肉全粉平衡水分含量不断增大;龙眼果肉全粉悬浮液的表观粘度呈现先增大后减小的趋势,为假塑性流体。说明该粉碎方式能对龙眼果肉干进行有效超微粉碎,但不同粉碎时间处理的龙眼果肉全粉物理特性具有一定的差异,其中粉碎30～50 min得到的龙眼果肉全粉最好。

Effects of micro-comminution on physical properties of longan flour

Longan flour was processed by vibration-grinding micro-comminution at low temperature and the effects of this microcomminution on particle size distribution,apparent density,fluidity,dissolution,isotherms of water absorption and rheological characteristic of longan flour were researched.As the result,along with prolongation of comminuting time,particle size of longan flour gradually declined and was of narrower distribution.The other properties of the longan flour exhibited the following change trend: apparent density continually diminished;angle of repose and slide angle enlarged,so the fluidity weakened;the time of dissolution decreased first but then increased;moisture content of longan flour at equilibrium continually increased;the apparent viscosity of longan suspension liquid increased first but decreased next,and they were all the pseudoplastic flow.The results indicated that dried longan could be effectively micro-comminuted by this comminution mode,and the physical properties of longan flour processed by micro-comminution on different time were different,which the longan flour processed for 30～50 minutes was the best.