The aim of this study was to analyze in detail the phytochemical composition of amaranth (AMJ), red beet (RBJ), and broccoli (BCJ) microgreens and cold-pressed juices and to evaluate the antioxidant and sensory properties of the juices. The results showed the presence of various phenolic compounds in all samples, namely betalains in amaranth and red beet microgreens, while glucosinolates were only detected in broccoli microgreens. Phenolic acids and derivatives dominated in amaranth and broccoli microgreens, while apigenin C-glycosides were most abundant in red beet microgreens. Cold-pressing of microgreens into juice significantly altered the profiles of bioactive compounds. Various isothiocyanates were detected in BCJ, while more phenolic acid aglycones and their derivatives with organic acids (quinic acid and malic acid) were identified in all juices. Microgreen juices exhibited good antioxidant properties, especially ABTS^•+ scavenging activity and ferric reducing antioxidant power. Microgreen juices had mild acidity, low sugar content, and good sensory acceptability and quality with the typical flavors of the respective microgreen species. Cold-pressed microgreen juices from AMJ, RBJ, and BCJ represent a rich source of bioactive compounds and can be characterized as novel functional products.

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.