###### Abstract  
Strawberries are rich in bioactive compounds that may be of health importance. The technological process often significantly reduces the content of such compounds in the product. The study aimed to compare the effect of enzymatic, ultrasonic and thermal mash treatment on the content of ascorbic acid, anthocyanins, phenolic compounds and the antioxidant activity of strawberry juice. In addition, the effect of increased temperature assisting ultrasonic mash treatment and the use of a vacuum for a short period to remove air from the mash during pectinolysis was investigated. A significant increase in the efficiency of juice pressing was obtained for enzymatic treatment (by 40%), thermal and thermosonication (16%). It was found that the applied methods yield different results depending on the tested compounds. In the case of anthocyanin, the most effective method was thermosonication, which contributed to a 40% increase in their content. The enzymatic and thermal methods resulted in a two-fold increase in the content of phenolic compounds. The antioxidant activity of the juice from the treated mash (regardless of the method used) was significantly higher than samples from the untreated mash. A significant correlation (r = 0.77) was noted between antioxidant capacity and non-anthocyanin phenolic compound content in the tested juices.  
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crushing and pressing the strawberry marsh. [PERSON] et al. [9] also indicate significant losses of procyanidins after pressing. These compounds are bound to the polysaccharides of the cell walls and remain in the pomace. Therefore, methods should be sought to improve the efficiency of juice and bioactive compounds extraction, especially at the pressing stage.  
Enzymatic treatment of mash (crashed fruits) has been used as a common method to increase juice yield. The literature shows that the effectiveness of enzymatic treatment largely depends on the appropriate selection of the enzyme and processing time [10; 11; 12]. However, enzymatic maceration is time consuming. Another method is mash heating. This treatment, by denaturing the cell walls in the tissue, facilitates the release of phenolic compounds from the tissue into the juice [13]. On the other hand, thermal treatment may also contribute to the degradation of bioactive compounds [14]. An interesting method is ultrasound treatment. It can be used to extract the desired compounds at low temperature to protect bioactive compounds against degradation [15]. However, some researchers point out that long-term use of ultrasound or the use of high power can also cause the degradation of bioactive compounds [16]. So far, sonication has been used in such applications as extraction, inactivation of enzymes, emulsification, low-temperature pasteurization and homogenization [17]. The impact of ultrasonic mash processing on the efficiency of pressing and the content of bioactive compounds in the juice has not been extensively investigated so far. An attempt to apply this technique to mash treatment was conducted for acerola [12] grape [18; 19], noni [20], black, red and white currant [21] and barberry [22]. Ultrasound treatment can be more effective when combined with heating (thermosonication) [23]. Attempts to use this technique have been made mainly to preserve juice [24]. In this study, an attempt was made to apply it to mash processing.  
This study aimed to compare the effect of enzymatic, thermal and ultrasonic mash processing on the pressing efficiency and the content of bioactive compounds in strawberry juice. In addition, the effect of thermsonication of the mash and the use of a short vacuum period to remove air from the mash during enzymatic treatment on the above-mentioned quality parameters was also investigated.