# Studies on the Energy Consumption of Material Cutting in the Onion Peeling Process
## 1 Introduction  
The onion is characterised by its important nutritional and health-promoting properties [1; 2; 3; 4]. It contains vitamins, minerals, and powerful plant compounds that support the immune system, and the healing properties of onions have been known since ancient times. All types of onions have health-promoting, anti-inflammatory, antibacterial, and immune-boosting effects, hence it is an ideal remedy for all kinds of upper respiratory infections. It is also used to treat wounds and burns.  
Nowadays, the onion is also used by humans as a flavor addition to dishes, being an ingredient in most salads and canned food. The great importance of the discussed topic is evidenced by the fact that, currently, onion production amounts to over 85 million tons, and the cultivated area in the world is over 4.4 million hectares [5]. This topic is also important in Europe due to its share in world production, which is 15%.  
Irrespective of their further destination, after harvesting, onions are first of all subjected to a procedure to remove the outer, dried layers of the scale and to cut off the tips. Despite the continuous development of medical and food processing techniques, the above-mentioned procedures are mainly performed manually. As the main reason for the lack of comprehensive automation of the onion processing process and, in particular, of the first stage that is peeling, one should mention the high energy consumption of the process, the unsatisfactory efficiency, and the greater amount of waste generated than in the case of manual peeling. Consequently, there exists a need to identify the energy consumption of the cutting process in the machine processing of onions.  
The leading manufacturers of onion peeling machines include producers from China, the USA, England, and the European Union.  
Known design solutions of machines for the industrial processing of ionic material operate in three systems: the first system involves cutting off the onion skin, blowing it, and then cutting off the ends, the second system involves cutting off the onion skin and blowing it off without cutting off the ends, and the third system involves first cutting off the ends material, then cutting off and blowing off the scales.  
Despite the existence on the food processing industry market of onion peeling machines, there is a lack of data in the available literature regarding ongoing research on the existing design solutions. The topics dealt with include the cutting and grinding of plant material [6; 7; 8] and the efficiency of machinery operation [9; 10] with consideration also of methods for processing onions [11; 12; 13; 14; 15; 16; 17] and of the ecological aspects of processes [18; 19], taking into account materials intended for consumption or energy purposes in the manufacturing and processing systems. On the other hand, there is a lack of results available in the publications from the conducted studies on vegetable cutting, especially related to the mechanisation of the onion peeling process. Manufacturers of machines available on the market do not provide detailed information to the public on the effectiveness of the machines, i.e., research is not conducted or the data is not disclosed. The scientific studies presented in this article make an important contribution to the development of knowledge for the design and operation of machines used for the mechanical peeling of onions. There are currently no scientific publications that describe this issue in detail.  
Therefore, it is not possible to clearly identify which features and design parameters of an industrial onion peeling machine have a decisive impact on the energy consumption of the process. Therefore, within the framework of the study, the authors attempted to solve the research problem in this area by answering the following question: what is the impact of selected design parameters of the authors' onion peeling machine on the energy consumption of the process?