## 3 Results and Discussion
### Individual Phenolics Profile  
The LC-HRMS assay showed an increase in concentration of many phenolic compounds, e.g., dihydroxybenzoic acid, protocatechuic acid, caffeic acid, vanillic acid, vanillin, _p_-coumaric acid, ferulic acid, and quercetin, when enzyme-assisted extraction was applied compared to enzyme-free acetate buffer extraction (Table 1). Chlorogenic acid, hyperoside, and isoquercitrin were the dominant phenolic compounds in the sample extracted with acetate buffer, while vanillic acid and ferulic acid were found at the highest concentration in extracts after enzyme treatments (Table 1). The vanillic acid (115.6 times), _p_-hydroxybenzaldehyde (113.5 times), and ferulic acid (93.9 times) demonstrated the largest increase in concentration after the _R. miehei_ cellulase enzyme treatment (_p_ < 0.05). The caffeic acid content of the _R. miehei_ cellulase-treated sample is also worth noting, showing a 16.9-fold increase compared to enzyme-free acetate buffer extraction (_p_ < 0.05). The majority of ferulic acid is presented in bound form to fibers in plant residues [45], and the increment in its concentration can be due to the action of degrading enzymes such as cellulases, esterases, and xylanases. Free ferulic acid accumulation was identified, for instance, from wheat bran in the work of [PERSON] et al. [46], which was considered to be the activity of esterases and other fiber-degrading enzymes. The increase in vanillic acid concentration may be the result of lignocellulosic degradation by the crude _R. miehei_ enzyme cocktail and/or by the biotransformation of ferulic acid to vanillic acid [45; 47]. The concentration of individual phenolics did not differ significantly (_p_ > 0.05) when the extracts of enzyme treatments with _R. miehei_ cellulase and _R. miehei_ cellulase-_A. niger_ pectinase cocktails were compared (Table 1). However, it is worth mentioning that the concentrations of chlorogenic acid, hyperoside, and isoquercitrin compounds in the _R. miehei_ cellulase-treated samples were strongly reduced by approximately 5.1, 24.2, and 26.5 times, respectively, compared to enzyme-free extraction (Table 1). This may be attributed to the action of the enzymes found in the cocktails, which caused the degradation of these molecules. For instance, the \(\beta\)-glucosidase activity (2149 U) of the _R. miehei_ cellulase-_A. niger_ luciferase cocktail can be responsible for the hydrolysis of the flavonoid glucoside compound isoquercitrin. Additionally, the esterases can release caffeic acids from the caffeic acid-quinic acid ester chlorogenic acid, while the \(\beta\)-galactosidaseases can degrade the phenolic galactoside hyperoside molecule, releasing quercetin during the treatment. Although these latter enzyme activities have not been measured in the enzyme cocktail used, our previous studies revealed considerable esterase and \(\beta\)-galactosidase activities in enzyme cocktails of _R. miehei_ produced similarly on wheat bran [30; 48]. The enhanced concentration of caffeic acid and quercetin in enzyme-treated extracts could also strengthen this suggestion. The individual phenolic profile can vary from hawthorn residue to residue. For fruit samples, chlorogenic acid, hyperoside, and isoquercetin compounds were generally identified as the main phenolics in many studies [5; 38; 49]. Epicatechin, catechin, quercetin, and rutin were also dominant compounds in _Crataegus pubescens_, _Crataegus azarolus_, and _C. monogyna_ fruit extracts [50; 51; 52]. For _C. orientalis_, [PERSON] et al. [5] quantified chlorogenic acid, rutin, hyperoside, isoquercetin, and quercetin in fruit samples from Iran. (\(-\))-Epicatechin, (\(+\))-catechin, quercetin, chlorogenic acid, vitexin, hyperoside, rutin, and/or \(p\)-coumaric acid were detected as dominant phenolic compounds in fruit samples of _C. orientalis_ collected from Turkey [33; 35; 38]. Many of these compounds, as well as isoquercitrin, were also identified in the _C. orientalis_ berry extract from Macedonia [53].