Evaluation of Nutritional and Bioactive Compounds in Tea and Botanical Marc Following Industrial Liqueur Maceration

ABSTRACT Industrial maceration of plant materials in ethanol‐based spirits generates substantial amounts of marc, a residual by‐product that may retain bioactive compounds. This study investigated the physicochemical and phytochemical characteristics of six botanical samples associated with industrial liqueur production by a Slovak manufacturer: macerated green tea (GT‐M), macerated black tea (BT‐M), non‐macerated oak chips (OAK‐R), macerated oak chips (OAK‐M), macerated dried flowers (FM‐M), and non‐macerated dried flowers (FM‐R). The samples were analyzed for dry matter, total ash, crude fat, total polyphenols, flavonoids, phenolic acids, antioxidant activity, catechin and caffeine profiles, and mineral composition. Among the analyzed samples, the non‐macerated flower blend (FM‐R) exhibited the highest flavonoid content (19.18 ± 0.54 mg QE/g DM) and total ash content (6.50% ± 0.46%). Post‐maceration tea residues (GT‐M and BT‐M) retained detectable levels of epicatechin, caffeine, and epigallocatechin‐3‐gallate, suggesting that these compounds were not completely extracted during industrial ethanol maceration. Principal component analysis (PCA) explained 89.9% of the total variance and, together with hierarchical cluster analysis (HCA), indicated differentiation of the samples according to botanical origin and maceration state. Correlation analysis revealed significant positive associations between total ash and flavonoid content ( r = 0.842, p < 0.001) and between total polyphenol content and antioxidant activity ( r = 0.703, p = 0.001); however, these associations should not be interpreted as evidence of causal relationships. Although the highest Pb (2.46 mg/kg DM) and Cd (0.65 mg/kg DM) concentrations were detected in FM‐M, the measured heavy metal concentrations were below the applicable maximum limits considered in this study. Overall, the results indicate that industrial botanical marc can retain matrix‐dependent phytochemical fractions after maceration and may represent a potential substrate for further investigation aimed at the recovery and valorization of residual bioactive compounds.