Phenolic composition of alcoholic beverages and vinegars produced from apple juice and pomace-based fermentation

Abstract

Apple pomace is a major by-product of the apple processing industry and represents a valuable source of phenolic compounds with potential applications in value-added food products. In addition, underutilized apple cultivars may provide an alternative source of bioactive compounds for developing fermented beverages. This study aimed to investigate the phenolic composition of apple juices, ciders, and vinegars produced from underutilized and commercial apple cultivars and to evaluate the influence of cultivar and raw material formulation on phenolic profiles. Phenolic compounds were analyzed using high-performance liquid chromatography coupled with diode array detection and mass spectrometry (HPLC-DAD-MS). Apple-based products were prepared from five cultivars, including three underutilized cultivars (Antonovka, Yltöisten sitruunaomena, and Turso) and two commercial cultivars (Heta and Jaspi). Three formulations were evaluated: juice (J), juice supplemented with pomace (JP), and pomace with water (HP). Statistical analyses were performed using one-way analysis of variance (ANOVA), Tukey’s HSD test, and principal component analysis (PCA). A total of 24 phenolic compounds were identified and quantified, while an additional 24 compounds were detected but remained unidentified. The identified compounds belonged to hydroxycinnamic acids, hydroxybenzoic acids, flavan-3-ols, flavonols, and dihydrochalcones. Hydroxycinnamic acids were the dominant phenolic group in all sample types. Significant differences in phenolic composition were observed among both formulations and cultivars. Juice-based products generally exhibited higher concentrations of total phenolics and most phenolic groups than pomace-water formulations, whereas pomace-containing formulations showed elevated flavonol concentrations. Among the cultivars, Yltöisten sitruunaomena exhibited the highest concentrations of total phenolics, hydroxycinnamic acids, flavonols, and dihydrochalcones, while Turso was characterized by elevated flavan-3-ol concentrations. PCA confirmed clear cultivar-dependent differences in phenolic composition. The results demonstrate that both cultivar selection and raw material formulation significantly influence the phenolic composition of fermented apple products. Furthermore, the findings support the valorization of apple pomace and highlight the potential of underutilized apple cultivars as valuable raw materials to produce phenolic-rich ciders and vinegars.