Advancements in Marine-Derived Proteins: Enhancing Nutritional and Functional Properties

Haisheng Lin^1*Duanquan Lin²Lei Du³Lester Geonzon⁴Le Chang Sun²

• ¹College of Food Science and Technology, Guangdong Ocean University, Zhanjiang, China
• ²Jimei University College of Ocean Food and Biological Engineering, Xiamen, China
• ³State Key Laboratory of Bioreactor Engineering, Department of Food Science and Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China, Shanghai, China
• ⁴Institute of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan, Tokyo, Japan

The growing global demand for sustainable and nutrient-dense protein sources has accelerated researches into marine-derived proteins, particularly those recovered from aquaculture and fisheries side streams. This research topic explores innovative strategies to extract, modify and characterize proteins and protein hydrolysates from under-utilized marine biomass, aiming to enhance their nutritional, functional, and bioactive properties. The seven articles in this collection highlight diverse approaches-from enzymatic hydrolysis and membrane fractionation to ultrasonication and in-silico screening-that collectively advance our understanding of how to transform low-value marine by-products into high-value ingredients for food, feed, nutraceutical and biomedical applications. Fish processing by-products represent an abundant reservoir of high-quality proteins whose recovery and valorisation are pivotal for sustainable resource utilization and circular bioeconomy advancement. Two back-to-back studies on Italian sea-bream/sea-bass trims showed how a single pre-processing technology propagates through the entire valorisation chain. Jenssen et al. (2025) first revealed that industrial dehydration, while reducing moisture and transport cost, locked the protein matrix into a less hydrolysable state, yielding ~3 kDa peptides with 30-40% lower antioxidant activity and diminished ACE-inhibitory potency.t. Yet the same groups also demonstrated that a membrane (molecular weight cutoff = 3 kDa) separation can redeem the handicap. The permeate fraction, lighter in colour and rich in low-molecular-weight peptides, accelerated in-vitro wound closure by > 40% and retained hepatoprotective activity. Complementarily, the companion paper maps the full bifurcation: raw trims yield higher dry-matter hydrolysis efficiencies and smaller peptides (< 2600 g mol⁻¹), whereas dehydrated trims deliver bulkier hydrolysates better suited for techno-functional roles-emulsifying, foaming, oil-binding-once recombined with the retentate. Together, the duo delivers a practical blueprint: dehydrate for logistics if needed, but always pair with size-selective fractionation to recover bioactive permeates and functional retentates, thereby converting perishable side streams into dual-purpose ingredients for nutraceuticals and clean-label foods.Similarly, Cropotova et al. (2025) show that post-hydrolysis ultrasonication combined with Aeromonas proteolytica aminopeptidase can shift the molecular-weight distribution of Atlantic mackerel hydrolysates toward smaller, more soluble peptides without increasing bitterness, which proofs that "green" physical/enzymatic finishing steps can fine-tune both nutrition and sensorial quality. Turning shells into high-performance materials begins with recognising that "crustacean" is not a single feedstock but a spectrum of nano-architectures. Yang et al. (2025) remind us that even the supporting polymer matrix-chitin-displays source-dependent nano-architectures. Antarctic krill, white shrimp and crayfish chitins differ in crystallinity (78-87%), thermal stability and surface porosity, dictating downstream suitability for biomedical scaffolds versus food-grade films. Their systematic comparison provides a materials-science rationale for diverting crustacean shells away from landfill and toward biodegradable packaging, reinforcing the principle that understanding intrinsic macromolecular context is prerequisite to any rational up-cycling strategy. The discovery of novel bioactive peptides is a key driver for valorising aquatic proteins, and the development of rapid, high-throughput screening strategies has become a central research priority. Qiao et al.(2024) applied virtual screening to abalone viscera hydrolysates and identified four <1 kDa peptides that inhibit HMG-CoA reductase more effectively than atorvastatin (IC50 equivalent) in hyper-lipidaemic Hep-G2 cells. While Lin et al. (2025) converted Chlamys nobilis muscle into EHCA, achieving 35 % α-glucosidase inhibition and DPPH scavenging; in mice it enhanced glucose tolerance and hepatic SOD while lowering MDA. Two peptides (TDADHKF and KLNSTTEKLEE, IC₅₀=144-137 µM) out-competed acarbose through stable hydrogen-bond interactions, providing scalable marine leads for glycaemic control. These studies showcase how LC-MS/MS de-novo sequencing, molecular docking and 300-ns MD simulations can compress years of empirical screening into weeks, yet still demand rigorous in-cell and in-vivo validation. Li et al.(2025) employed RNA-seq to dissect tropomyosin-driven allergic responses in murine jejunum and Caco-2/RBL-2H3 models, revealing PI3K/Akt/NF-κB as the central axis by which shrimp tropomyosin compromises tight-junction integrity and amplifies histamine release. Their findings not only inform hypo-allergenic processing strategies (e.g., controlled hydrolysis to ablate epitopes) but also exemplify how marine proteins can serve as probes to map fundamental gut-immune interactions. Cropotova et al. (2025) again highlight that endogenous proteases and physical treatments (ultrasound) interact synergistically to modulate peptide size, free amino-acid profiles and colour-critical parameters for industrial acceptance. Real-time monitoring via NIR or Raman spectroscopy, coupled with adaptive process control, is proposed as the next step toward batch-to-batch consistency of marine protein ingredients.Collectively, these studies emphasise several key advancements: Process optimisation: Enzymatic hydrolysis conditions, pre-treatment methods, and post-hydrolysis modifications (ultrasonication, membrane fractionation, aminopeptidase finishing) critically influence hydrolysate characteristics and must be co-designed within a circular biorefinery framework.Functionality and bioactivity: Marine protein hydrolysates exhibit promising emulsifying, antioxidant, wound-healing, anti-diabetic and hypo-cholesterolaemic properties that can be enhanced through targeted processing and in-silico design.Sustainability: Efficient conversion of side streams (heads, viscera, shells) into proteins, peptides and chitin supports circular-economy principles and reduces environmental impact.Future research should focus on (i) pilot-scale validation of energy and mass balances, (ii) systematic allergenicity mapping and mitigation strategies, and (iii) long-term human intervention studies to translate in-vitro promise into dietary guidelines. Integrating multi-omics datasets with machine-learning models will further accelerate the discovery of sequence-defined peptides and optimise process parameters in real time.This research topic provides a comprehensive roadmap for transforming the "blue granary" into a resilient source of sustainable, health-promoting protein ingredients, offering actionable insights for scientists, industry stakeholders and policymakers committed to a sustainable food future.