期刊名称：Croatian Journal of Food Technology, Biotechnology and Nutrition
印刷版ISSN：1847-3423
电子版ISSN：1847-7461
出版年度：2009
卷号：4
期号：1-2
页码：18-22
出版社：Hrvatsko društvo prehrambenih tehnologa, biotehnologa i nutricionista
摘要：Ultrasound waves are mechanical vibrations in a solid or fluid with frequencies above 20 kHz. Ultrasound has been used in a many different technologies for a various industry applications and more and more in food industry, as an analytical tool, or for the raw material modification before, during and after the manufacturing of food products. The use of ultrasound in food technology can be globally divided as low-intensity ( 1 Wcm-2). Hi-intensity ultrasound is used to enhance, promote or change physical or chemical properties of foods. Low-intensity ultrasound is non-destructive method that enables data about physicochemical properties of food components and products such as structure, flow rate, thickness, composition, particle size and attendance of foreign bodies. A “foreign body” is any unwanted piece of solid matter present in foodstuffs. It can be piece of wood, glass, rubber, stone, metal, plastic, fibre, dirt, nail or thin hair. Foreign bodies are significantly dissimilar from foodstuffs in terms of acoustic impedance and ultrasonic velocity, consequently a certain ultrasound response is to be registered. Foreign bodies can be detected by registering the reflected, refracted or scattered acoustic signals. In practical applications for detection of foreign bodies in foodstuffs frequency is usually above 50 kHz. In this work theoretical and practical approach for this technology is presented.
