Upcycling Potato Juice Protein for Sustainable Plant-Based Gyros: A Multidimensional Quality Assessment

The growing demand for sustainable, nutritionally adequate plant-based foods has driven innovation in meat analogues. This study presents a novel approach to upcycling potato juice protein—a by-product of starch production—into plant-based gyros (PBG) enriched with iron and dietary fiber. Four formulations (PBG1–PBG4) were developed using a blend of potato, rice, wheat, and pea proteins, and fortified with either ferritin-rich sprout powder or ferrous sulfate. Comprehensive analyses were conducted to assess nutritional composition, mineral content, glycoalkaloid safety, antioxidant activity, texture, water mobility, sensory appeal, and microbiological stability. All variants met high-protein labeling criteria and exhibited favorable fiber and mineral profiles. In vitro digestion significantly enhanced antioxidant bioaccessibility, particularly phenolic acids. Sensory evaluations favored ferritin-enriched variants, which also demonstrated superior texture and consumer acceptance. Microbiological assessments confirmed safety for up to 10 days under refrigeration. These findings highlight the potential of potato juice protein as a sustainable, functional ingredient in next-generation plant-based meat analogues.