## 1 Introduction  
Vacuum impregnation is a technique that allows the quality characteristics of fruits and vegetables [1, 2], meat [3], cheese [4], and fish [5] to be modified. This method involves removing gasses and liquids from the intercellular spaces of the tissue and introducing a solution with a specific composition. The mass exchange is based on a mechanically induced pressure difference. There are two phases in the process: vacuum and relaxation (at atmospheric pressure). The process of tissue impregnation is explained by two phenomena: the hydrodynamic mechanism and the deformation-relaxation phenomenon [6]. Vacuum impregnation is recognized as a relatively quick and efficient process compared to alternatives like osmotic dehydration. It reduces processing time to minutes and minimizes nutrient loss, offering cost benefits in operational efficiency. However, the capital cost for specialized vacuum equipment may be a significant initial investment [7]. Numerous studies have shown that a good matrix for making effective use of this technique is plant raw materials with high porosity [8, 9]. However, the effect of tissue impregnation can also be obtained for raw materials with a compact structures, such as carrot or beetroot [2]. Research conducted by [PERSON] et al. [2] showed that, during the vacuum stage, carrots can lose up to 18% of their native fluids, most of which (16%) are replaced by the impregnation during the relaxation stage. These researchers concluded that only the xylem and phloem are likely involved in the hydrodynamic mechanism and become impregnated; in contrast, however, mass exchange does not affect the densely packed parenchyma cells. They conducted research on one carrot cultivar in two forms: cubes and slices. It seemed advisable to carry out impregnation on cultivars that differ in the length of their growing season, which may affect the structure of the tissue. Moreover, in studies carried out so far, the vacuum stage was set for 3 to 20 min [1; 10; 11; 12]. Extending the vacuum stage may contribute to a better or more homogenous saturation of the tissue. The result of this more effective impregnation was indicated by [PERSON] et al. [13] in research conducted on fruits. Literature data have shown that damage to carrot tissue, for example, by cutting or grinding, can cause so-called wounding stress. This causes the tissue to initiate a defensive reaction, which aims to reduce water loss through lignification. The precursors of lignin in carrot tissue are phenolic compounds, which are synthesized as a result of increasing activity by phenylalanine ammonia-lyase, a key enzyme in the phenylpropanol pathway [14; 15]. Studies have also indicated the possibility of the de novo synthesis of carotenoids under conditions of physiological stress [16]. During the process of vacuum impregnation, the carrot tissue remains viable. Impregnation, especially during the vacuum stage, can also damage the carrot's structure [10]. The effect of vacuum impregnation on tissue reaction related to the synthesis of secondary metabolites due to wounding stress has not been investigated so far. This work investigated an additional aspect, which determining the possibility of impregnating carrot tissue, as an often consumed raw material, with ascorbic acid. To date, the impregnation process has been used to introduce compounds such as calcium ions, lactic acid, trehalose, green tea extract, and malic acid into the tissue structure of carrots. The current research concerned modifying the texture, lowering the pH, and improving the quality of frozen carrots and inhibiting the growth of microorganisms [1; 10; 11; 12].