Utilization of Seafood Processing By-products

A comparative lipid profile of four fish species: From muscle to industrial by-products based on RPLC-Q-TOF-MS/MS

Fish are crucial for the fishing industry and essential nutrient provision, including lipids. This study employed a high-throughput lipidomic approach to evaluate and contrast the lipid profiles of three marine fish species (P. crocea, S. fuscens, and C. saira) and one freshwater species (H. molitrix) across head, muscle, and viscera. Over 1000 molecular lipid species across 17 subclasses were identified. Notably, acylated monogalactosyldiacylglycerol (acMGDG) was detected for the first time in these species, with a high prevalence of saturated fatty acids (44.7 %-87.7 %). Glycerolipids (67.7 - 86.3 %) and PLs (10.7 - 31.8 %) were identified as the dominant lipid classes. Marine fish muscles displayed higher PL content than freshwater species, and P. crocea viscera contained over 30 % PLs of total lipids. In particular, ether phosphatidyl ethanolamine incorporated more DHA than ether phosphatidylcholine. The viscera of four fish species also exhibited a significant abundance of diacylglycerol (DG), indicating their potential as functional lipid sources. Multivariate analysis identified triglyceride (TG) (59:13), DG (16:1/22:5), and MGDG (16:0/18:2) as potential biomarkers for differentiating among fish anatomical parts. This study deepens the understanding of the nutritional values of these fish, providing guidance for consumer dietary choices and paving the way for transforming previously underutilized by-products into resources with high-value potential.

Calcium absorption by Alaska pollock surimi protein hydrolysate promotes osteoblast differentiation

The calcium-binding capacity and osteoblast proliferation and differentiation were studied in Alaska pollock surimi hydrolysate (APSH) using a system that mimics the gastrointestinal digestive system. Evaluation of the calcium absorption-promoting ability of APSH revealed that the best calcium-binding ability was achieved after hydrolysis with a combination of pepsin, α-chymotrypsin, and trypsin, and separation into <3 kDa (APSH-I), 3-5 kDa (APSH-II), 5-10 kDa (APSH-III), and <10 kDa (APSH-IV) fractions. Scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis confirmed that the hydrolysate and calcium ions formed a complex. Comparison of the calcium absorption capacity using Caco-2 cells showed that calcium absorption was promoted by these hydrolysates. Measurement of the osteoblast activation revealed higher alkaline phosphatase activity, collagen synthesis, and mineralization effect for the low-molecular-weight hydrolysate (LMH) than for the other hydrolysates. In addition, LMH promoted the expression of osteocalcin, osteopontin, and bone morphogenetic protein-2 and -4, which are hormones related to bone formation. Expression of the Runx2 transcription factor, which regulates the expression of these hormones, also increased. These results suggest that Alaska pollock surimi protein hydrolysates prepared using a system that mimics gastrointestinal hydrolysis may result in better osteoblast proliferation and bone health than those prepared using other proteases.

Cyprinus carpio Skeleton Byproduct as a Source of Collagen for Gelatin Preparation

Byproducts obtained from fish processing account for up to 70% of their live weight and represent a large amount of unused raw materials rich in proteins, fats, minerals, and vitamins. Recently, the management of the use of predominantly cold-water fish byproducts has become a priority for many processing companies. This paper describes the biotechnological processing of byproducts of warm-water Cyprinus carpio skeletons into gelatins. A Taguchi experimental design with two process factors (HCl concentration during demineralization of the starting material and the amount of enzyme during enzyme conditioning of the collagen) examined at three levels (0.5, 1.0 and 2.0 wt%; 0.0, 0.1 and 0.2 wt% respectively) was used to optimize the processing of fish tissue into gelatin. Depending on the preparation conditions, four gelatin fractions were prepared by multi-stage extraction from the starting material with a total yield of 18.7-55.7%. Extensive characterization of the gel-forming and surface properties of the prepared gelatins was performed. Gelatins belong to the group of zero-low-medium Bloom value (0-170 Bloom) and low-medium viscosity (1.1-4.9 mPa·s) gelatins and are suitable for some food, pharmaceutical, and cosmetic applications. During processing, the pigment can be isolated; the remaining solid product can then be used in agriculture, and H₃PO₄Ca can be precipitated from the liquid byproduct after demineralization. The carp byproduct processing technology is environmentally friendly and meets the requirements of zero-waste technology.

A novel angiotensin I-converting enzyme inhibitory peptide derived from the trypsin hydrolysates of salmon bone proteins

When fish are processed, fish bone becomes a key component of the waste, but to date very few researchers have sought to use fish bone to prepare protein hydrolysates as a means of adding value to the final product. This study, therefore, examines the potential of salmon bone, through an analysis of the benefits of its constituent components, namely fat, moisture, protein, and ash. In particular, the study seeks to optimize the process of enzymatic hydrolysis of salmon bone with trypsin in order to produce angiotensin-I converting enzyme (ACE) inhibitory peptides making use of response surface methodology in combination with central composite design (CCD). Optimum hydrolysis conditions concerning DH (degree of hydrolysis) and ACE-inhibitory activity were initially determined using the response surface model. Having thus determined which of the salmon bone protein hydrolysates (SBPH) offered the greatest level of ACE-inhibitory activity, these SBPH were duly selected to undergo ultrafiltration for further fractionation. It was found that the greatest ACE-inhibitory activity was achieved by the SBPH fraction which had a molecular weight lower than 0.65 kDa. This fraction underwent further purification using RP-HPLC, revealing that the F7 fraction offered the best ACE-inhibitory activity. For ACE inhibition, the ideal peptide in the context of the F7 fraction comprised eight amino acids: Phe-Cys-Leu-Tyr-Glu-Leu-Ala-Arg (FCLYELAR), while analysis of the Lineweaver-Burk plot revealed that the FCLYELAR peptide can serve as an uncompetitive ACE inhibitor. An examination of the molecular docking process showed that the FCLYELAR peptide was primarily able to provide ACE-inhibitory qualities as a consequence of the hydrogen bond interactions taking place between ACE and the peptide. Furthermore, upon isolation form the SBPH, the ACE-inhibitory peptide demonstrated ACE-inhibitory capabilities in vitro, underlining its potential for applications in the food and pharmaceutical sectors.

Functional roles of fish collagen peptides on bone regeneration

Fish collagen peptides (FCP) derived from the skin, bones and scales are commercially used as a functional food or dietary supplement for hypertension and diabetes. However, there is limited evidence on the effects of FCP on the osteoblast function in contrast to evidence of the effects on wound healing, diabetes and bone regeneration, which have been obtained from animal studies. In this narrative review, we expound on the availability of FCP by basic research using osteoblasts. Low-concentration FCP upregulates the expression of osteoblast proliferation, differentiation and collagen modifying enzyme-related genes. Furthermore, it could accelerate matrix mineralization. FCP may have potential utility as a biomaterial to improve collagen quality and promote mineralization through the mitogen-activated protein kinase and Smad cascades. However, there are few clinical studies on bone regeneration in human subjects. It is desirable to be applied clinically through clinical study as soon as possible, based on the results from basic research.

Fishery Wastes as a Yet Undiscovered Treasure from the Sea: Biomolecules Sources, Extraction Methods and Valorization

The search for new biological sources of commercial value is a major goal for the sustainable management of natural resources. The huge amount of fishery by-catch or processing by-products continuously produced needs to be managed to avoid environmental problems and keep resource sustainability. Fishery by-products can represent an interesting source of high added value bioactive compounds, such as proteins, carbohydrates, collagen, polyunsaturated fatty acids, chitin, polyphenolic constituents, carotenoids, vitamins, alkaloids, tocopherols, tocotrienols, toxins; nevertheless, their biotechnological potential is still largely underutilized. Depending on their structural and functional characteristics, marine-derived biomolecules can find several applications in food industry, agriculture, biotechnological (chemical, industrial or environmental) fields. Fish internal organs are a rich and underexplored source of bioactive compounds; the fish gut microbiota biosynthesizes essential or short-chain fatty acids, vitamins, minerals or enzymes and is also a source of probiotic candidates, in turn producing bioactive compounds with antibiotic and biosurfactant/bioemulsifier activities. Chemical, enzymatic and/or microbial processing of fishery by-catch or processing by-products allows the production of different valuable bioactive compounds; to date, however, the lack of cost-effective extraction strategies so far has prevented their exploitation on a large scale. Standardization and optimization of extraction procedures are urgently required, as processing conditions can affect the qualitative and quantitative properties of these biomolecules. Valorization routes for such raw materials can provide a great additional value for companies involved in the field of bioprospecting. The present review aims at collecting current knowledge on fishery by-catch or by-products, exploring the valorization of their active biomolecules, in application of the circular economy paradigm applied to the fishery field. It will address specific issues from a biorefinery perspective: (i) fish tissues and organs as potential sources of metabolites, antibiotics and probiotics; (ii) screening for bioactive compounds; (iii) extraction processes and innovative technologies for purification and chemical characterization; (iv) energy production technologies for the exhausted biomass. We provide a general perspective on the techno-economic feasibility and the environmental footprint of the production process, as well as on the definition of legal constraints for the new products production and commercial use.

Bitter peptides from enzymatically hydrolyzed protein increase the number of leucocytes and lysozyme activity of large yellow croaker (Larimichthys crocea)

The large yellow croakers (Larimichthys crocea) are mainly present in the Chinese coast and near seas with high economic importance, but vulnerable to many diseases, especially in the breeding and aquaculture. The purpose of this research was to boost the innate immune system of the large yellow croaker by administering bitter peptides into their peritoneal cavity. Total 120 Juvenile of large yellow croakers in very even weight of 60 g were divided into 4 different groups in 200/300 L of water tank, respectively. Fish growth were observed for 3 months before and after different treatments. The bitter peptides from pepsin hydrolysis were applied because they possess the highest bitter sensory scores. The blood of fish from the different groups was collected and tested for different immune parameters to evaluate the effectiveness of bitter peptides as immune stimulants after administration for 8 weeks. The average ratio of leukocytes/total blood cells (%) for control was found at 14.6%, for the low dose of bitter peptides 0.6 mg/fish was at 29.3%, for middle dose of 1.2 mg/fish was at 35%, and high dose of 2.4 mg/fish was at 30%. The lysozyme assay showed that the OD (optical density) units of relative progress lysis activity at 60 min were 0.17, 0.101, 0.307 and 0.198, respectively. Similarly in the same order as in phagocyte assay, most importantly the middle dose (1.2mg/fish) gave the highest survival rate throughout the assay. The results showed that bitter peptides can be used as immune boosters for the yellow croakers and the optimum dose was 1.2 mg/fish due to both leukocytes and lysozyme activity in the treated samples increased significantly compared with the control group. According to the results obtained, we suggest that the incorporation of middle dose of bitter peptides into fish feeds may reduce the fish diseases in aquaculture, at least for large yellow croakers.

Chitin and Its Effects on Inflammatory and Immune Responses

Chitin, a potential allergy-promoting pathogen-associated molecular pattern (PAMP), is a linear polymer composed of N-acetylglucosamine residues which are linked by β-(1,4)-glycosidic bonds. Mammalians are potential hosts for chitin-containing protozoa, fungi, arthropods, and nematodes; however, mammalians themselves do not synthetize chitin and thus it is considered as a potential target for recognition by mammalian immune system. Chitin is sensed primarily in the lungs or gut where it activates a variety of innate (eosinophils, macrophages) and adaptive immune cells (IL-4/IL-13 expressing T helper type-2 lymphocytes). Chitin induces cytokine production, leukocyte recruitment, and alternative macrophage activation. Intranasal or intraperitoneal administration of chitin (varying in size, degree of acetylation and purity) to mice has been applied as a routine approach to investigate chitin's priming effects on innate and adaptive immunity. Structural chitin present in microorganisms is actively degraded by host true chitinases, including acidic mammalian chitinases and chitotriosidase into smaller fragments that can be sensed by mammalian receptors such as FIBCD1, NKR-P1, and RegIIIc. Immune recognition of chitin also involves pattern recognition receptors, mainly via TLR-2 and Dectin-1, to activate immune cells to induce cytokine production and creation of an immune network that results in inflammatory and allergic responses. In this review, we will focus on various immunological aspects of the interaction between chitin and host immune system such as sensing, interactions with immune cells, chitinases as chitin degrading enzymes, and immunologic applications of chitin.

Marine Fish Proteins and Peptides for Cosmeceuticals: A Review

Marine fish provide a rich source of bioactive compounds such as proteins and peptides. The bioactive proteins and peptides derived from marine fish have gained enormous interest in nutraceutical, pharmaceutical, and cosmeceutical industries due to their broad spectrum of bioactivities, including antioxidant, antimicrobial, and anti-aging activities. Recently, the development of cosmeceuticals using marine fish-derived proteins and peptides obtained from chemical or enzymatical hydrolysis of fish processing by-products has increased rapidly owing to their activities in antioxidation and tissue regeneration. Marine fish-derived collagen has been utilized for the development of cosmeceutical products due to its abilities in skin repair and tissue regeneration. Marine fish-derived peptides have also been utilized for various cosmeceutical applications due to their antioxidant, antimicrobial, and matrix metalloproteinase inhibitory activities. In addition, marine fish-derived proteins and hydrolysates demonstrated efficient anti-photoaging activity. The present review highlights and presents an overview of the current status of the isolation and applications of marine fish-derived proteins and peptides. This review also demonstrates that marine fish-derived proteins and peptides have high potential for biocompatible and effective cosmeceuticals.

Mycelial Mattress from a Sporangia Formation-Delayed Mutant of Rhizopus stolonifer as Wound Healing-Enhancing Biomaterial

A mycelial mattress of Rhizopus stolonifer obtained from a liquid static culture was utilized for wound dressing and biomedical use. Following screening of mutants induced by UV radiation, F6, exhibiting delayed sporangium formation was selected because its sporangium maturation exhibited a 5-day delay without significant loss of mycelial weight compared to the wild type. The sporangium-free mycelial mattress from the sporangiospore culture of F6 was treated with 1N sodium hydroxide NaOH at 85°C for 2 h to produce a sponge-like membrane named Rhizochitin. The trifluoroacetic acid hydrolysate of Rhizochitin contained 36% N-acetylglucosamine and 53% hexose respectively detected by the Elson-Morgen and phenol-sulfuric acid methods. Results indicated the wound area in rats covered with Rhizochitin was 40% less than that of the uncovered group. Rhizochitin decreased the expression of PDGF in the proliferation stage, increased the expression of TGF-β in the inflammation and proliferation stages, and increased the expression of VEGF in the inflammation and proliferation stages. Rhizochitin inhibited secretion of matrix metalloproteinase-9 on days 1, 7, 9, and 12 and matrix metalloproteinase-2 on days 3, 7, 9, and 12. It was concluded that Rhizochitin has beneficial properties of biocompatible, biodegradable, and wound healing.

A two-step, one-pot enzymatic method for preparation of duck egg white protein hydrolysates with high antioxidant activity

Biocatalytic hydrolysis reactions were designed for preparation of bioactive hydrolysate of duck egg white protein (DEWP) employing two enzymes in one pot. Firstly, the fresh DEWP was thermal treated at 95 °C, for 40 min at pH 10, to effectively deactivate enzyme inhibitors thus facilitating the following two-step enzymatic hydrolysis. Compared with single-enzyme processes, the two-step enzymatic procedures showed much higher reaction efficiency. The first enzymatic step (in the presence of Alcalase or hydrolase SEEP) allowed to hydrolyze DEWP with degree of hydrolysis (DH) of 8.8-10% and soluble peptide yield (SEP) of 60.5-70.2% in a short period (4 h). The second enzymatic step (in the presence of Trypsin or Alcalase) gave a further degradation of DEWP with DH and SEP being more than 26.2% and 90.4%, respectively. The final hydrolysates exhibited high antioxidant activity in an evident DH dependent manner. The hydrolysates achieved by sequential addition of the proteinase SEEP and Alcalase at DH value 21% gave the highest antioxidant activity, which was mainly ascribed to the changes in the amino acid compositions that the contents of some key amino acids and total hydrophobic amino acids were significantly improved by the enzymatic hydrolysis.

Chemical Composition of Salmon Ovary Outer Membrane and Its Protein Increases Fecal Mucins Content in C57BL/6J and Type 2 Diabetic/Obese KK-Ay Mice

Salmon ovary outer membrane (SOM) is a byproduct of the salmon industry; however, the effective utilization of SOM for food materials and supplements is anticipated as the demand for fish and seafood increases worldwide. The purposes of the present study were to assess the chemical composition of SOM, the characteristics of SOM protein (SOMP), and its effects on serum and fecal biochemical parameters in mice. SOM contained high levels of crude protein (61.9 g/100 g) and crude lipid (18.9 g/100 g). The protein pattern of SOMP was different from those of fish muscle protein and roe; it was abundant in collagen, as calculated from the hydroxyproline content. In addition, SOMP exhibited lower protein digestibility during in vitro digestion analyses compared with casein. Male C57BL/6J and KK-A^y mice were fed a casein-based semi-purified diet or a diet with replacement of part of the dietary protein (50%) by SOMP for four weeks. Mice fed the diet containing SOMP showed elevated fecal nitrogen and mucins contents and reduced levels of serum liver injury markers and fecal ammonia. These results show for the first time that chemical composition of SOM, and SOMP, contain a resistant protein fraction and a large amount of collagen. Therefore, SOM is a potential source of marine collagen and functional food material for promoting the health of the liver and colon.

Venus Flytrap (Dionaea muscipula Solander ex Ellis) Contains Powerful Compounds that Prevent and Cure Cancer

Chemoprevention uses natural or synthetic molecules without toxic effects to prevent and/or block emergence and development of diseases including cancer. Many of these natural molecules modulate mitogenic signals involved in cell survival, apoptosis, cell cycle regulation, angiogenesis, or on processes involved in the development of metastases occur naturally, especially in fruits and vegetables bur also in non-comestible plants. Carnivorous plants including the Venus flytrap (Dionaea muscipula Solander ex Ellis) are much less investigated, but appear to contain a wealth of potent bioactive secondary metabolites. Aim of this review is to give insight into molecular mechanisms triggered by compounds isolated from these interesting plants with either therapeutic or chemopreventive potential.

Extract from the zooxanthellate jellyfish Cotylorhiza tuberculata modulates gap junction intercellular communication in human cell cultures

On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778) has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7) and human epidermal keratinocytes (HEKa). The composition of the jellyfish extract included photosynthetic pigments, valuable ω-3 and ω-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC) differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed.

Cyclic chalcone analogue KRP6 as a potent modulator of cell proliferation: an in vitro study in HUVECs

In the present investigation a novel series of chalcone analogues were synthesized and evaluated for their anti-proliferative activity in human umbilical vein endothelial cells (HUVECs). Among 14 tested compounds, chalcone analogue (E)-3-(2'-methoxybenzylidene)-4-chromanone (KRP6) exhibited the most potent activity with IC50 19 μM. Moreover, HUVECs exhibited divergent, even opposing concentration-dependent responses to KRP6. This compound was the most potent inhibitor of cell proliferation and extracellular matrix formation (fibronectin and type IV collagen) at higher concentrations (20-50 μM). In contrast, KRP6 stimulated the compensatory increase in proliferative activity including extracellular matrix formation at low concentrations (1, 10 μM). KRP6 concentration-dependently modulated phosphorylation of Akt and mitogen-activated protein kinases such as extracellular signal-regulated kinase-1/-2 and p38 kinase, suggesting that these pathways play a role in the effect mediated by this compound. In addition, we found a selective effect on activated endothelial cells, in particular with resting endothelial cells. In conclusion, KRP6 is a potent modulator of selected steps of the angiogenic process in vitro. Accordingly, further in vivo research should be performed to facilitate its use in clinical practice.

Chondroitin sulfate, hyaluronic acid and chitin/chitosan production using marine waste sources: characteristics, applications and eco-friendly processes: a review

In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies.