The principles and application of non-thermal ultrasound technology in food processing

Abstract
Background and purpose: The growing demand for high-quality food with natural aromas and flavors, free from chemical additives, has led to an increased use of non-thermal food processes. Among these, ultrasound technology plays a significant role. Ultrasound involves sound waves above the human hearing range (<16 kHz) and is generated by ultrasonic transducers that convert electrical energy into vibrational sound energy. This process enhances mass transfer through cavitation. Ultrasound has two primary applications in the food industry: high-intensity ultrasound for processing and low-intensity ultrasound for analysis. As a non-destructive technique, it does not leave physical or chemical residues on processed food, making it ideal for liquid foods like milk and juices. Its applications include cooking, frying, emulsification, homogenization, drying, extraction, and more. As it does not leave physical and chemical effects on food processing with this technology, it is In the dairy industry, ultrasound is utilized for cleaning, microbial disinfection, enzyme inactivation, homogenization, extracting bioactive proteins, and improving cheese production efficiency. This article specifically examines the effects of ultrasound on liquids and beverages, focusing on milk products.
Results: Power ultrasound is a food processing method that utilizes low-frequency sound waves, typically between 20 to 100 kHz, with sound intensities ranging from 10 to 1000 watts per square centimeter. This is achieved through transducers such as piezoelectric, magnetic, and venturi effects, which generate vibrational energy. A key consideration when applying power ultrasound in food technology is determining the appropriate amount of sound energy for the system, which can be assessed using methods like calorimetry and chemical dosimetry. The ultrasonic process is frequently combined with other preservation methods, such as heat and pressure, to more effectively deactivate microorganisms, particularly in the beverage industry. Moreover, the metamorphic technique is often used alongside modern technologies, including microwave processing, supercritical fluid extraction, extrusion, Soxhlet extraction, Cloninger distillation, enzyme extraction, and liquid/solid phase techniques, to enhance the extraction of bioactive substances.
Conclusion: This review summarizes recent advancements in ultrasound technology within the food industry, particularly for liquid foods and beverages. Although ultrasound technology has been utilized for some time, its applications in food processing are relatively new. Different ultrasound frequencies facilitate quality control and processing. Low-intensity, non-destructive ultrasound provides a straightforward method for estimating food ingredients such as shrimp, dairy, fruits, and grains. In contrast, high-intensity, invasive ultrasound alters the biochemical properties of food through cavitation. The benefits of ultrasound in liquid food processing are significant: it enhances emulsification and sterilization while preserving bioactive compounds at lower temperatures compared to conventional methods. Ultrasound can break down fats and caseins, making it suitable for producing dairy probiotic drinks, which reduces processing time and costs while creating products with unique characteristics. Potential adverse effects on key quality parameters, such as color, anthocyanins, and ascorbic acid content, are minimal and generally not problematic. Additionally, quality parameters like turbidity may improve with mild sonication.