Green Extraction at Scale: Hydrodynamic Cavitation for Bioactives Recovery and Protein Functionalization. A Narrative Review

Hydrodynamic cavitation (HC) is a green, scalable platform for recovering and functionalizing bioactives from agri-food and forestry byproducts. This narrative, expert-led review focuses on citrus and pomegranate peels, softwoods, and plant proteins, emphasizing process performance, product functionality, and routes to market, and comparing HC with other novel green extraction methods. Pilot demonstrations consistently show water-only operation at high solid loadings and short residence times; in most practical settings, downstream water removal—not extraction—drives energy demand, favoring low water-to-biomass ratios. HC uniquely generates stable pectin–flavonoid–terpene phytocomplexes with improved bioaccessibility and early evidence suggests the possibility of enabling protein–polyphenol complexation while mitigating anti-nutritional factors. Two market-oriented translational pathways emerge: (i) direct blending of HC-derived bioactive dry extracts with commercial dry protein isolates to deliver measurable functional benefits at low inclusion levels; and (ii) HC-based extraction of plant proteins to create digestion-friendly isolates and conjugate-ready ingredients. Key gaps include standardized reporting of consumed specific energy, solvent and byproduct mass balances, matched-scale comparisons with subcritical water extraction and pulsed electric field, and continuous multi-ton evidence. Overall, HC shows strong promise for circular biorefineries, contingent on rigorous energy accounting, quality preservation, and clear regulatory documentation.