# Effect of Tomato Juice and Different Drying Methods on Selected Properties of Courgette
## 1 Introduction  
Courgettes are a vegetable with a very high water content, oscillating between 93.5% and 95%, and a low energy value of about 21 kilocalories per 100 g [1]. It is a source of many valuable nutrients. It contains folic acid at 24 ug per 100 g, which contributes to the proper functioning of the human body, especially in the context of cell development and nervous system health. In addition, courgettes provide 261 mg of potassium per 100 g, which is important for maintaining normal blood pressure and muscle function. The provitamin A, or beta-carotene, present in courgettes is converted into vitamin A in the body, providing 200 IU per 100 g. This vitamin is important for eye health, skin health, and the immune system. Courgettes are also a source of carbohydrates, fiber, and protein, which are essential for proper digestion and maintaining muscle mass. Courgettes also contain vitamin C, which is known for its antioxidant properties and support for the immune system, as well as potassium and manganese, which are important for bone health and energy production in the body. Courgettes also contain vitamin E, thiamin, niacin, and pantothenic acid, which are important for many metabolic functions in the body [2]. Drying is the process of removing water from raw materials and reducing water activity; this allows the food to last for a prolonged shelf life. During this process, there is a reduction in the volume of dried material, which has a beneficial impact on reducing packaging costs and improving transportation and storage. Reducing the water content of fruits and vegetables reduces its activity, which inhibits the growth of microorganisms. In addition, the drying process slows down enzymatic and non-enzymatic reactions in food products [3, 4]. Convection drying, as one of the methods of removing moisture from raw materials of agricultural origin, is described as a highly destructive process thatsignificantly reduces the final quality of the product compared to unprocessed raw material. Nevertheless, it is widely used in the food industry due to its advantages, such as low cost, manufacturing, and a well-studied theoretical basis [5]. The process of freeze drying is viewed as the most concentrated drying method, characterized by the higher quality of the resulting dried product as opposed to other techniques. The mechanism of this process is involved in the evaporation of water from the material through freeze drying, a phase transformation that allows a direct transition from solid to gas, bypassing the liquid phase. This process makes it possible to obtain a dried product of exceptional quality, which makes this method particularly valued [6; 7]. In addition, due to the formation of ice crystals and its further sublimation, the structure and shape of the product can be preserved [4]. Vacuum drying (VI), on the other hand, allows water to evaporate at lower temperatures than at normal atmospheric pressure, which is particularly beneficial for heat and heat-sensitive compounds. As a result, thermal degradation is minimized and the products retain most of their nutritional value and organoleptic characteristics such as color, flavor, and aroma [8]. Conducting tests based on a number of drying methods makes it possible to determine their effects on the properties of dried materials. In addition, it enables the selection of the optimal drying method for a specific agricultural raw material. Although drying effectively prolongs the shelf life of agricultural products, it is generally accepted that the traditional drying process inevitably results in the loss of sensory and nutritional qualities due to unfavorable textural and biochemical alterations [9]. Pretreatment is used to reduce the adverse effects of the drying process [10]. VI is a process that uses a pressure difference to fill the spaces and capillary channels in the material with an impregnating solution. The process consists of two phases: a reduced pressure phase and an atmospheric pressure phase.