利用超音波分析牛奶在凝結過程中的物理性質變化

Evaluating Changes in Physical Properties of Milk during Coagulation by Ultrasonic Analysis

艾群(Chyung Ay) ； S. Gunasekaran

《農業機械學刊》 2卷2期 (1993/06) Pp. 49-63

https://doi.org/10.30062/JAM.199306.0005

摘要

凝結過程在牛奶轉換成乾酪時，扮演著一個對乾酪質地品質影響很大的角色。在凝結過程中，牛奶從液態變成半固態，此種變化是隨著其物理性質如密度、堅實度與黏度等而變化。本文是利用一非破壞性的超音波方法，來探討牛奶之凝結過程。且應用超音波脈波穿遞法來求得超音波穿過牛奶的速度與衰減。在凝結過程中，牛奶密度與超音波傳遞速度沒有明顯變化；牛奶的剪力黏度與波擴散度則隨著牛奶堅實度增加而遞增；而牛奶的容量黏度與超音波衰減則隨之遞減。

關鍵字

超音波 ； 容量黏度 ； 波擴散度 ； 牛奶

並列摘要

Coagulation step in conversion of milk into cheese plays a decisive role in contributing textural qualities to the cheese. During coagulation, milk changes its state from liquid to semisolid known as gel or coagulum. This accompanies changes in such physical properties as density, firmness and viscosity. In this research, an ultrasonic method was diveloped as a nondestructive method to study the milk coagulation process. The ultrasonic pulse-transmission method was used to calculate the ultrasonic velocity and attenuation when wave passed through milk. During coagulation, density of milk and ultrasonic velocity without obviously changes but the shear viscosity and wave diffusivity of milk increased; and the bulk viscosity of milk and ultrasonic attenuation decreased.

並列關鍵字

Ultrasonics ； Bulk viscosity ； Wave diffusivity ； Milk