Protein Mining from Agro-Waste: Innovative Extraction and Purification for Sustainable Food and Nutraceuticals

The field of agro-waste valorization is gaining momentum with global agro-industrial operations generating over one billion tonnes of lignocellulosic and oilseed by-products annually. These residues, including cereal brans, oilseed cakes, fruit pomaces, and vegetable peels, often contain substantial protein content (15–40% w/w on a dry basis) but are typically used in low-value applications or disposed of, resulting in significant environmental impacts. Recent advancements in "green" bioprocessing techniques, such as enzyme-assisted extraction, ultrasound‐ and microwave‐enhanced pretreatments, membrane separations, foam fractionation, and aqueous two‐phase systems, have shown promise in recovering high-quality proteins under mild conditions. However, research is often siloed, focusing on optimal methods for specific feedstocks, which limits broader applicability and scalability. There exists an essential need for a systematic and comparative platform that integrates diverse extraction and purification strategies to deliver functional proteins suitable for food and nutraceutical applications.

This Research Topic aims to address the current challenges in agro-waste protein recovery by developing a more comprehensive approach. It focuses on integrating multiple extraction techniques—like enzyme-assisted release, ultrasound/microwave pretreatment, and fermentation—with downstream operations including membrane ultrafiltration, foam fractionation, and aqueous two-phase separation . Researchers are invited to benchmark protein yield, purity, and techno-functional properties (solubility, emulsification, gelling) across diverse agro-waste residues—oilseed meals, cereal brans, fruit and vegetable pomaces—and apply machine-learning or design-of-experiments (DoE) tools for process optimization.. The goal is to enhance recovery efficiency using hybrid workflows and process intensification (e.g., simultaneous extraction–purification systems) to enhance recovery efficiency under mild conditions, as well as to demonstrate the viable incorporation of recovered proteins into food formulations and supplements supported by techno-economic and life-cycle assessments for industry adoption.

To gather further insights into sustainable protein recovery, we welcome articles addressing, but not limited to, the following themes:

• Innovative Extraction Techniques - Enzyme-assisted extraction, ultrasound- or microwave-assisted pretreatment, and fermentation-driven protein liberation.

• Advanced Purification Strategies - Membrane filtration, foam fractionation/flotation, liquid biphasic separation systems (e.g., aqueous two-phase systems), and hybrid integrated downstream workflows.

• Functional Characterization - Amino acid composition profiling, protein digestibility assessment, removal of antinutritional factors; and evaluation of techno-functional properties relevant to food formulation.

• Product Development - Incorporation of upcycled proteins into food and beverage products or dietary supplement formulations, and evaluation of sensory attributes, nutritional value, and bioactive functionality of prototypes.

• Sustainability Assessments - Techno-economic analysis (TEA), life-cycle assessment (LCA), energy and water footprint evaluation, and process scalability studies.

This Research Topic invites original research, reviews, perspective articles, methods papers, and brief communications.