Microgreen-Based Juices: UHPLC Q-ToF MS Metabolomic Analysis, Antioxidant Properties, and Sensory Acceptability

The aim of this study was to develop novel and sensory-acceptable microgreens–apple juices and characterize them using UHPLC Q-ToF MS-based metabolomic analysis. The obtained juices showed reduced sugar content and mild acidity compared with the control apple juice. Untargeted analysis revealed 71 compounds, including phenolics, betalains, and one glucosinolate. Semi-quantification confirmed a high content of sinapic acid and its derivatives and hydroxybenzoic acid in broccoli–apple juice, as well as a predominant amount of phenolic acid diglycosides and hydroxycinnamoyl–isocitric acid derivatives in amaranth–apple juice. Apigenin C-glycosides were the main phenolics in red beet–apple juice, with the highest content of cytisoside derivatives. All microgreen-based juices contained apple-derived flavan-3-ols, procyanidins, dihydrochalcones, and certain flavonols. The formulated juices exhibited promising antioxidant potential evaluated by several screening assays (TPC, DPPH, ABTS, and FRAP), consistent with their phytochemical profiles, while differences among them may be linked to the amounts of certain bioactive molecules, mainly derived from microgreens. Moreover, these juices showed high overall quality and consumer acceptability, successfully masking typical microgreens flavors. Overall, these cold-pressed microgreen–apple juices can be classified as novel, low-calorie, and highly sensory-acceptable beverages, containing diverse bioactive compounds from both apple and microgreens; however, further in vitro and in vivo evidence is needed to support claims regarding their functionalities.