# Advanced Technologies in Food Processing--Development Perspective
## 4 Application of Ultrasound in Food Processing  
Nowadays, ultrasound is widely used in the food industry. It is considered to be a promising technique for increasing process efficiency while maintaining the quality of food products [71]. Numerous studies showed the potential possible benefits of using ultrasonic technology in optimizing food-freezing processes. Freezing is one of the most effective techniques for the long-term storage of perishable foodstuffs, while allowing them to be reprocessed. The size and distribution of ice crystals are key parameters in the context of frozen foods, and numerous studies have been carried out focusing on these aspects [72]. The ultrasound-assisted freezing process has been proven to effectively increase the freezing efficiency while promoting the formation of small and evenly distributed ice crystals, which can positively affect the quality of frozen products [73]. This effect translates into an improvement in the quality of stored food. The search for innovative freezing techniques can effectively increase the efficiency of the process, given the low efficiency of conventional freezing methods [74]. Ultrasound accelerates the freezing process of food products, such as fruits (apples) and vegetables, including potatoes and broccoli [75]. Additionally, [PERSON] et al. (2013) proved that the rate of freezing the dough using ultrasound was increased, and with the use of ultrasonic power of 288 W or 360 W, the total dough freezing time was significantly reduced by more than 11% [76]. Ultrasound is utilized in the thawing of food as well. The thawing process is characterized by long-term action, but suboptimal methods can promote the development of micro-organisms and thus negatively affect the quality of frozen food. However, the defrosting of food products using ultrasound has some limitations due to the shallow penetration depth and point heating. Nevertheless, the use of ultrasound in the thawing process of Pacific cod has shown that in the temperature range of \(-29\) to \(-1\)\({}^{\circ}\)C, the process efficiency increased by approximately 71% when employing a frequency of 1500 Hz and 60 W [73]. Ultrasonic technology has also been applied in the meat industry. Ultrasound has a beneficial effect on accelerating the maturation of meat, affecting the increased shelf life of meat products. This technique does not adversely affect the overall quality parameters of the meat products. In the context of meat processing, ultrasound can potentially aid the drying, curing, and marinating process to avoid microbial development and re-contamination of meat [77]. Ultrasound technology can be used to inactivate pathogens such as _Salmonella_ and _Escherichia coli_. [PERSON] et al. (2020) found that ultrasonic treatment can be successfully applied to improve the texture of chicken meat [78]. Additionally, ultrasound facilitates cleaning of mould and improve sterilization of equipment surfaces, which affects the hygiene and safety of production. However, despite the promising benefits, further studies are needed before ultrasound can be fully implemented in the meat industry to understand and optimise the processes and to assess the impact on the overall quality parameters of meat products [79]. Ultrasound has also been applied in the drying process. Conventional drying methods have some limitations due to low process efficiency, prolonged drying time, and as they adversely affect the sensory and nutritional quality of products. The use of ultrasound as an alternative method of drying food, e.g., vegetables and fruits, seems to be justified due to low energy consumption, shorter drying time, and the possibility of obtaining high-quality drying [8]. The use of ultrasonic technology for the extraction of bioactive compounds from fruits results from its ability to increase water transport [80]. The ultrasound-assisted fruit-drying process involves several methods, including probe and bath sonification, ultrasonic method, and air ultrasound.