Introduction: Using natural sources and exploring 3D-printing for high-value foods as nutraceutical carriers could enable customized nutrition addressing the growing demand for eco-friendly options. Objectives: This study aimed to develop 3D-printed snacks using apple pomace and lemon albedo flours, pre-treated with ultrasound (US). The obtained snack was functionalized by adding the richest extract in bioactive compounds recovered from apple pomace via US, microwave (MW) and high-pressure-MW (HP-MW) extraction processes. Methodology: The effect of US and the functionalization of the snack on the techno-functional properties of the binary blends and the final product was assessed in terms of color, texture and rheology, FTIR, HPLC, total phenolic content and antioxidant activity. Results: US pre-treatment improved the techno-functional properties, elastic and viscous moduli, printability, extrusion force, and surface smoothness. Lemon albedo flour enhanced phenolic contents (from 1.79 to 3.70 mg GAE/gDW of sample), especially when added to the formulation up to 10% (w/w). Moreover, adding the most promising HP-MW apple pomace extract to the product increased its antioxidant activity by 40% on average from 5.077 to 8.31 mg FeSO4/gDW of sample, and from 5.49 to 7.069 mg Trolox/gDW of sample when using FRAP and
ABTS assays, respectively. Discussion: The post-processing of the 3D-printed snack, consisting of MW drying, preserved the bioactive compounds and antioxidant activity. Conclusions: These promising results demonstrated the potential to create 3D-printed snacks with improved printability, functional properties, and potential health benefits using low-cost, natural ingredients.