## 3 Results
### Technological Properties of Enzymatically Treated Apple Pomace  
Pomace as a dietary fibre source can be included in several food matrices as inexpensive substances that partially replace flour, fat, or sugar; as water and oil retention agents; and as substances that improve the stability of emulsions [43]. In order to use pomace in the production of food, it is important to evaluate its technological properties. Pomace with a high water-retention capacity (WRC) and water-swelling capacity (WSC) could increase the thickness and stability of food products and could reduce synresis. AP enzymatic hydrolysis with Viscozyme and Pectinex increased the WSC by 1.8 and 2.4 times, respectively, after 1 h of hydrolysis and 2.4 and 2.5 times after 5 h of hydrolysis (Figure 2a). Pectinex and Viscozyme, which contain several carbohydrates, may effectively degrade pectin and IDF, which leads to the formation of a higher amount of hydrogen bonds and an increase in the WSC [39; 41]. In this study, opposite trends were found after AP hydrolysis with Celluclast (0.04 mL/g), and the WSC decreased by 21.7% after 1 h of hydrolysis. During AP hydrolysis with cellulases, pectin is released from the matrix, whose properties of water swelling depend on the molecular weight and degree of esterification. Low-molecular-weight and low-methylation pectin is characterized by a lower WSC [44]. [PERSON] et al. [45] reported that AP hydrolysis with cellulases releases more low-methylation pectin [46]. The WRC of the enzymatically hydrolys AP ranged from 13.14 to 20.21 g/g (Figure 2b). The lowest WRC value was determined after hydrolysis with Pectinex, which decreased by 33.13%. The ORC values of AP ranged from 3.70 to 5.38 g/g (Figure 2d). Hydrolysis with Pectinex had a negative effect on the ORC, after which the ORC decreased by 21.24 and 45.31% after 1 and 5 h of hydrolysis, respectively. The changes in the IDF and bulk density of the pomace (Figure 3) had a significant influence on the WRC and ORC. The technological properties of the pomace are closely related to the properties of  
Figure 2: Water-swelling capacity **(a)**, water-retention capacity **(b)**, solubility index **(c)**, and oil-retention capacity **(d)** of enzymatically hydrolys AP. Data values are expressed as means with the standard deviation (\(n=3\)). a–d means with different superscripts are significantly different (\(p<0.05\)). the material particles, which are reflected by the bulk density. A higher bulk density is associated with a lower porosity and particle size [47]. Hydrolysis with Viscozyme and Pectinex increased the AP bulk density. During the hydrolysis, the TDF content decreased by increasing the number of lower-molecular-weight compounds and the bulk density of the AP, indicating that the properties of the hydrolys pomace particles changed [47], and reducing the matrix porosity does not retain bound water or oil under additional force (centrifugation) [43]. Hydrolysis for 5 h with Viscozyme increased the SI of the AP, while 1 h hydrolysis had no significant impact. The highest SI of AP was found after the hydrolysis with Pectinex (44 and 58% higher compared with the untreated AP after 1 and 5 h of hydrolysis, respectively). SI reflects the degradation of dietary fibre to form low-molecular-weight compounds. The hydrolysis of AP increased the content of soluble components (RSs) as well as SI values. [PERSON] et al. [48] reported that the low solubility of pomace powder in water is caused by a high content of insoluble polysaccharides, their hydrophobicity, and electrostatic properties, which leads to the formation of aggregates and a decrease in solubility. The influence of hydrolys AP on the stability of emulsions under static and thermal conditions is presented in Figure 4. AP hydrolys with Celluclast had lower emulsion stabilization properties than those hydrolys with Pectinex and Viscozyme.