Industrial-Scale Valorization of Low-Grade Fruits Through Green Polyphenol Extraction: Integrating Process Simulation, Techno-Economic Analysis, and Environmental Assessment

Ultrasound-assisted extraction (UAE) processes for the production of standardized polyphenol-rich powders were evaluated as a valorization route for second- and third-grade apples, figs, and pomegranates from Central Macedonia, Greece. Based on experimental results, the scaled-up process was modeled using SuperPro Designer to evaluate a continuous facility treating 7920 tonnes·yr−1 of feedstock. Material and energy balances revealed high utility demands, which were heavily mitigated through optimized closed-loop steam and cooling water regeneration systems. The techno-economic analysis showed that, driven by its high extraction yield (14.63 kg Gallic acid equivalent [GAE]·t−1), the optimized pomegranate extraction was the only profitable scenario, yielding an annual operating cost of EUR 6.35 M/yr and a Net Present value (NPV) of EUR 11.81 M at a EUR 80/kg selling price; low-yield apple and fig lines remained highly unviable. Capacity sensitivity analysis showed that high fixed capital costs limit smaller plants, while market price sweeps identified a break-even point at EUR 66.03/kg. Using 1 kg gallic acid equivalent (GAE) as the functional unit, the life cycle assessment confirmed that pomegranate processing achieved the best environmental performance, primarily governed by reduced feedstock and utility requirements per unit of active extract. Toxicity-related categories constituted the main hotspots across all configurations, with the fig line acting as the worst absolute environmental performer. However, because the regional residue availability of 8483 tonnes·yr−1 is dominated by apples, a standalone pomegranate processing plant is constrained at this scale, indicating that future work must focus on flexible multi-feedstock campaign processing or inter-regional feedstock aggregation.