Simultaneous double cationic and anionic molecule separation from herring milt hydrolysate and impact on resulting fraction bioactivities

The Effects of Enzymes, Species, and Storage of Raw Material on Physicochemical Properties of Protein Hydrolysates from Whitefish Heads

The rest raw materials of whitefish have great potential for increased utilisation and value creation. Whitefish heads have a high protein content and should be considered a healthy protein source for the growing population's demands for sustainable protein. In this study, the heads of four different species of whitefish were processed via enzymatic hydrolysis, namely cod (Gadus morhua), cusk (Brosme bromse), haddock (Melanogrammus aeglefinus), and saithe (Pollachius virens), using three commercially available enzymes. Trials were conducted after 0, 3, and 6 months of the frozen storage of heads. A proximate analysis, molecular weight distribution, and protein solubility were evaluated for each of the products. The results show that, although the enzymatic hydrolysis of rest raw materials from different species of whitefish yielded products of slightly different characteristics, this process is viable for the production of high-quality protein from cod, cusk, haddock, and saithe heads. Six months of frozen storage of heads had a minimal effect on the yield and proximate composition of hydrolysates.

Production of Bioactive Peptides from Baltic Herring (Clupea harengus membras): Dipeptidyl Peptidase-4 Inhibitory, Antioxidant and Antiproliferative Properties

This study aimed to produce bioactive protein hydrolysates from undervalued fish, namely Baltic herring, and its filleting by-products. Protein hydrolysates were produced with Alcalase and Flavourzyme to achieve effective hydrolysis. The hydrolysates were evaluated for chemical composition, molecular weight distribution, antioxidant capacity, dipeptidyl-peptidase 4 (DPP4) inhibitory activity, effects on cell proliferation and surface hydrophobicity. The protein content of the hydrolysates was high, from 86% to 91% (dm), while the fat content was low, from 0.3% to 0.4% (dm). The hydrolysates showed high DPP4 inhibition activities with IC50 values from 5.38 mg/mL to 7.92 mg/mL. The scavenging activity of the hydrolysates towards DPPH was low, but an intermediate Folin–Ciocalteu reducing capacity and Cu2+ chelating ability was observed. The solid phase extraction with Sep-Pak C18 cartridges increased the DPP4 inhibition activity and antioxidant capacity, indicating peptides’ crucial role in the bioactivities. The cytotoxicity of the hydrolysates was evaluated on the HCT8, IMR90, and A549 cell lines. The hydrolysates inhibited cell growth in the cancer and normal cells, although they did not reduce cell viability and were not lethal. Overall, our results indicate that protein hydrolysates from Baltic herring have potential as health-promoting foods and nutraceuticals, especially for enhancing healthy blood glucose regulation.

Impacts of pH and Base Substitution during Deaerator Treatments of Herring Milt Hydrolysate on the Odorous Content and the Antioxidant Activity

Despite the biological interest in herring milt hydrolysate (HMH), its valorization is limited by its unpleasant odor resulting from the presence of mainly amine and carbonyl compounds. Recently, a deaerator was demonstrated as an interesting avenue to reduce the odorous content of HMH. However, the removal rate of amine and carbonyl compounds was highly dependent on the operating conditions, and the impact of such a process on the biological potential of HMH was not considered. Therefore, this study aimed to optimize the deaerator process by assessing the impacts of the combination of deaerator treatments at neutral and basic pH, the increase in pH from 10 to 11, and the substitution of NaOH by KOH on the odorous content and the antioxidant activity of HMH. Results showed that the highest deodorization rate of HMH was obtained when a deaerator treatment at neutral pH was combined with another one at basic pH using KOH for alkalization. This condition resulted in a decrease in the dimethylamine and trimethylamine contents by 70%, while certain compounds such as 2,3-pentanedione, methional, (E,E)-2,4-heptadienal, or (E,Z)-2,6-nonadienal were almost completely removed. Removal mechanisms of the targeted compounds were totally identified, and the performance of the developed process was confirmed by sensory analysis. Lastly, it was shown that the antioxidant potential of HMH was not affected by the deodorization process. These results demonstrated the feasibility of deodorizing a complex matrix without affecting its biological potential.

Semi-Industrial Production of a DPP-IV and ACE Inhibitory Peptide Fraction from Whey Protein Concentrate Hydrolysate by Electrodialysis with Ultrafiltration Membrane

The separation by electrodialysis with ultrafiltration membranes (EDUF), at a semi-industrial scale, of a new whey protein hydrolysate obtained from a whey protein concentrate was assessed. After 6 h of treatment, more than 9 g of peptides were recovered in the peptide recovery fraction, for a recovery yield of 5.46 ± 0.56% and containing 18 major components. Among these components, positively charged peptides, such as ALPMHIR + PHMIR, LIVTQTMK and TKIPAVF, were present, and their relative abundances increased by nearly 1.25 X and up to 7.55 X. The presence of these peptides may be promising, as ALPMHIR has a strong activity against angiotensin-converting enzyme (ACE), and LIVTQTMK has structural properties that could interfere with dipeptidyl peptidase-IV (DPP-IV). Many neutral peptides were also recovered alongside those. Nevertheless, the inhibitory activity against DPP-IV and ACE increased from 2 X and 4 X, respectively, in the peptide recovery fraction compared to the initial hydrolysate, due to the improved content in bioactive peptides. Thus, this new hydrolysate is well-suited for the large-scale production of a peptide fraction with high bioactivities. Furthermore, what was achieved in this work came close to what could be achieved for the industrial production of a bioactive peptide fraction from whey proteins.

Beneficial effects of fish and fish peptides on main metabolic syndrome associated risk factors: Diabetes, obesity and lipemia

The definition of metabolic syndrome (MetS) fairly varies from one to another guideline and health organization. Per description of world health organization, occurrence of hyperinsulinemia or hyperglycemia in addition to two or more factors of dyslipidemia, hypoalphalipoproteinemia, hypertension and or large waist circumference factors would be defined as MetS. Conventional therapies and drugs, commonly with adverse effects, are used to treat these conditions and diseases. Nonetheless, in the recent decades scientific community has focused on the discovery of natural compounds to diminish the side effects of these medications. Among many available bioactives, biologically active peptides have notable beneficial effects on the management of diabetes, obesity, hypercholesterolemia, and hypertension. Marine inclusive of fish peptides have exerted significant bioactivities in different experimental in-vitro, in-vivo and clinical settings. This review exclusively focuses on studies from the recent decade investigating hypoglycemic, hypolipidemic, hypercholesterolemic and anti-obesogenic fish and fish peptides. Related extraction, isolation, and purification methodologies of anti-MetS fish biopeptides are reviewed herein for comparison purposes only. Moreover, performance of biopeptides in simulated gastrointestinal environment and structure-activity relationship along with absorption, distribution, metabolism, and excretion properties of selected oligopeptides have been discussed, in brief, to broaden the knowledge of readers on the design and discovery trends of anti-MetS compounds.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2052261 .

Effects of Herring Milt Hydrolysates and Fractions in a Diet-Induced Obesity Model

Over the past years, promising results from studies have shown that herring milt hydrolysates (HMH) can counter immune-metabolic disorders associated with obesity. However, more studies must corroborate these results. Thus, three commercial hydrolysates (HMH1, HMH2, and HMH3) as well as the fractions of two of them (HMH4 and HMH5) obtained by electrodialysis with ultrafiltration membranes (EDUF) were evaluated in vivo at higher doses compared to a previous study. To achieve this, seven groups of mice were fed for 8 weeks with either a control Chow diet or an obesogenic diet rich in fat and sucrose (HFHS) and supplemented by daily gavage with water or 312.5 mg/kg of one of the five HMH products. In summary, HMH supplements had no impact on weight gain. In the insulin tolerance test (ITT), HMH2 and its HMH5 fraction significantly reduced the blood sugar variation (p < 0.05). However, during the glucose tolerance (OGTT), HMH2 supplement increased the hyperinsulinemia variation (p < 0.05) induced by the HFHS diet. HMH1, HMH2, and HMH5 supplements generated potentially beneficial changes for health in the gut microbiota. These results reveal that HMH do not counteract obesity effects but may decrease certain physiological effects induced by obesity.

Scale-Up and Long-Term Study of Electrodialysis with Ultrafiltration Membrane for the Separation of a Herring Milt Hydrolysate

Electrodialysis with ultrafiltration membrane (EDUF) was selected to separate a herring milt hydrolysate (HMH) in a scale-up and long-term study for the recovery of bioactive peptides. The scale-up was performed to maximise peptide recovery by placing a total membrane area of 0.08 m² for each anionic and cationic compartment. Twelve consecutive runs were carried out, for a total of 69 h, with minimal salt solution cleaning in between experiments. The final peptide migration rate showed that cationic peptides had a higher average migration rate (5.2 ± 0.8 g/m²·h), compared to anionic peptides (4.7 ± 1.1 g/m²·h). Migration was also selective according to peptide identifications and molecular mass distribution where only small molecular weights were found (<1000 Da) in both recovery compartments. The areal system resistance slightly decreased during each run and the averaged values were stable in between experiments since they were all found in the 95% confidence interval. In addition, total relative energy consumption was quite consistent with an average value of 39.95 ± 6.47 Wh/g all along the 12 consecutive runs. Finally, according to membrane characterization, there was no visual fouling on the different membranes present in the EDUF cell after 69 h of treatment. This may be due to the salt cleaning in between experiments which allowed removal of peptides from the membranes, thus allowing recovering initial system working parameters at the beginning of each run. The entire process was revealed to be very consistent and repeatable in terms of peptide migration, global system resistance, and energy consumption. To the best of our knowledge, this is the first time such EDUF conditions (membrane surface, duration, and minimal salt cleaning between experiments) are being tested on a complex hydrolysate.

Glucoregulatory and Anti-Inflammatory Activities of Peptide Fractions Separated by Electrodialysis with Ultrafiltration Membranes from Salmon Protein Hydrolysate and Identification of Four Novel Glucoregulatory Peptides

Natural bioactive peptides are suitable candidates for preventing the development of Type 2 diabetes (T2D), by reducing the various risk factors. The aim of this study was to concentrate glucoregulatory and anti-inflammatory peptides, from salmon by-products, by electrodialysis with ultrafiltration membrane (EDUF), and to identify peptides responsible for these bioactivities. Two EDUF configurations (1 and 2) were used to concentrate anionic and cationic peptides, respectively. After EDUF separation, two fractions demonstrated interesting properties: the initial fraction of the EDUF configuration 1 and the final fraction of the EDUF configuration 2 both showed biological activities to (1) increase glucose uptake in L6 muscle cells in insulin condition at 1 ng/mL (by 12% and 21%, respectively), (2) decrease hepatic glucose production in hepatic cells at 1 ng/mL in basal (17% and 16%, respectively), and insulin (25% and 34%, respectively) conditions, and (3) decrease LPS-induced inflammation in macrophages at 1 g/mL (45% and 30%, respectively). More impressive, the initial fraction of the EDUF configuration 1 (45% reduction) showed the same effect as the phenformin at 10 μM (40%), a drug used to treat T2D. Thirteen peptides were identified, chemically synthesized, and tested in-vitro for these three bioactivities. Thus, four new bioactive peptides were identified: IPVE increased glucose uptake by muscle cells, IVDI and IEGTL decreased hepatic glucose production (HGP) of insulin, whereas VAPEEHPTL decreased HGP under both basal condition and in the presence of insulin. To the best of our knowledge, this is the first time that (1) bioactive peptide fractions generated after separation by EDUF were demonstrated to be bioactive on three different criteria; all involved in the T2D, and (2) potential sequences involved in the improvement of glucose uptake and/or in the regulation of HGP were identified from a salmon protein hydrolysate.

Development of a New Deodorization Method of Herring Milt Hydrolysate: Impacts of pH, Stirring with Nitrogen and Deaerator Treatment on the Odorous Content

Herring milt hydrolysate (HMH) presents the disadvantage of being associated with an unpleasant smell limiting its use. Thus, to develop a new effective and easy-to-use deodorization method, this research aimed to deepen the knowledge regarding the impacts of pH (pH 7 vs. pH 10), overnight stirring with nitrogen (+N vs. −N) and deaerator treatment (+D vs. −D) on the odorous content of HMH. This latter included dimethylamine (DMA), trimethylamine (TMA), trimethylamine oxide (TMAO) and the most potent odor-active compounds of HMH. Results showed that pH had a huge impact on the targeted compounds resulting in higher detected concentrations of DMA, TMA and TMAO at pH 10 than at pH 7 (p < 0.05) while the opposite trend was observed for the most potent odor-active compounds of HMH (p < 0.05). Moreover, independently of the pH condition, the overnight stirring with or without nitrogen had no impact (p > 0.05). Finally, the deaerator treatment was more effective to remove TMA and DMA at pH 10 than at pH 7 (p < 0.05) while the opposite trend was observed for the most potent odor-active compounds (p < 0.05). Sensory analysis confirmed that the application of pH 10 −N +D and pH 7 −N +D + alkalization pH 10 conditions led to the least odorous products (p < 0.05).

Recent Advancements of UF-Based Separation for Selective Enrichment of Proteins and Bioactive Peptides—A Review

Proteins are one of the primary building blocks that have significant functional properties to be applied in food and pharmaceutical industries. Proteins could be beneficial in their concentrated products or isolates, of which membrane-based filtration methods such as ultrafiltration (UF) encompass application in broad spectra of protein sources. More importantly, selective enrichment by UF is of immense interest due to the presence of antinutrients that may dominate their perspicuous bioactivities. UF process is primarily obstructed by concentration polarization and fouling; in turn, a trade-off between productivity and selectivity emerges, especially when pure isolates are an ultimate goal. Several factors such as operating conditions and membrane equipment could leverage those pervasive contributions; therefore, UF protocols should be optimized for each unique protein mixture and mode of configuration. For instance, employing charged UF membranes or combining UF membranes with electrodialysis enables efficient separation of proteins with a similar molecular weight, which is hard to achieve by the conventional UF membrane. Meanwhile, some proposed strategies, such as utilizing ultrasonic waves, tuning operating conditions, and modifying membrane surfaces, can effectively mitigate fouling issues. A plethora of advancements in UF, from their membrane material modification to the arrangement of new configurations, contribute to the quest to actualize promising potentials of protein separation by UF, and they are reviewed in this paper.

Animal and Cellular Studies Demonstrate Some of the Beneficial Impacts of Herring Milt Hydrolysates on Obesity-Induced Glucose Intolerance and Inflammation

The search for bioactive compounds from enzymatic hydrolysates has increased in the last few decades. Fish by-products have been shown to be rich in these valuable molecules; for instance, herring milt is a complex matrix composed of lipids, nucleotides, minerals, and proteins. However, limited information is available on the potential health benefits of this by-product. In this context, three industrial products containing herring milt hydrolysate (HMH) were tested in both animal and cellular models to measure their effects on obesity-related metabolic disorders. Male C57Bl/6J mice were fed either a control chow diet or a high-fat high-sucrose (HFHS) diet for 8 weeks and received either the vehicle (water) or one of the three HMH products (HMH1, HMH2, and HMH3) at a dose of 208.8 mg/kg (representing 1 g/day for a human) by daily oral gavage. The impact of HMH treatments on insulin and glucose tolerance, lipid homeostasis, liver gene expression, and the gut microbiota profile was studied. In parallel, the effects of HMH on glucose uptake and inflammation were studied in L6 myocytes and J774 macrophages, respectively. In vivo, daily treatment with HMH2 and HMH3 improved early time point glycemia during the oral glucose tolerance test (OGTT) induced by the HFHS diet, without changes in weight gain and insulin secretion. Interestingly, we also observed that HMH2 consumption partially prevented a lower abundance of Lactobacillus species in the gut microbiota of HFHS diet-fed animals. In addition to this, modulations of gene expression in the liver, such as the upregulation of sucrose nonfermenting AMPK-related kinase (SNARK), were reported for the first time in mice treated with HMH products. While HMH2 and HMH3 inhibited inducible nitric oxide synthase (iNOS) induction in J774 macrophages, glucose uptake was not modified in L6 muscle cells. These results indicate that milt herring hydrolysates reduce some metabolic and inflammatory alterations in cellular and animal models, suggesting a possible novel marine ingredient to help fight against obesity-related immunometabolic disorders.

Electrodialytic Processes: Market Overview, Membrane Phenomena, Recent Developments and Sustainable Strategies

In the context of preserving and improving human health, electrodialytic processes are very promising perspectives. Indeed, they allow the treatment of water, preservation of food products, production of bioactive compounds, extraction of organic acids, and recovery of energy from natural and wastewaters without major environmental impact. Hence, the aim of the present review is to give a global portrait of the most recent developments in electrodialytic membrane phenomena and their uses in sustainable strategies. It has appeared that new knowledge on pulsed electric fields, electroconvective vortices, overlimiting conditions and reversal modes as well as recent demonstrations of their applications are currently boosting the interest for electrodialytic processes. However, the hurdles are still high when dealing with scale-ups and real-life conditions. Furthermore, looking at the recent research trends, potable water and wastewater treatment as well as the production of value-added bioactive products in a circular economy will probably be the main applications to be developed and improved. All these processes, taking into account their principles and specificities, can be used for specific eco-efficient applications. However, to prove the sustainability of such process strategies, more life cycle assessments will be necessary to convince people of the merits of coupling these technologies.

Assessment of the Performance of Electrodialysis in the Removal of the Most Potent Odor-Active Compounds of Herring Milt Hydrolysate: Focus on Ion-Exchange Membrane Fouling and Water Dissociation as Limiting Process Conditions

Herring milt hydrolysate (HMH), like many fish products, presents the drawback to be associated with off-flavors. As odor is an important criterion, an effective deodorization method targeting the volatile compounds responsible for off-flavors needs to be developed. The potential of electrodialysis (ED) to remove the 15 volatile compounds identified, in the first part of this work, for their main contribution to the odor of HMH, as well as trimethylamine, dimethylamine and trimethylamine oxide, was assessed by testing the impact of both hydrolysate pH (4 and 7) and current conditions (no current vs. current applied). The ED performance was compared with that of a deaerator by assessing three hydrolysate pH values (4, 7 and 10). The initial pH of HMH had a huge impact on the targeted compounds, while ED had no effect. The fouling formation, resulting from electrostatic and hydrophobic interactions between HMH constituents and ion-exchange membranes (IEM); the occurrence of water dissociation on IEM interfaces, due to the reaching of the limiting current density; and the presence of water dissociation catalyzers were considered as the major limiting process conditions. The deaerator treatment on hydrolysate at pH 7 and its alkalization until pH 10 led to the best removal of odorant compounds.

Potential role of natural bioactive peptides for development of cosmeceutical skin products

In recent years, consumers' demand for cosmeceutical products with protective and therapeutic functions derived from natural sources have caused this industry to search for alternative active ingredients. Bioactive peptides have a wide spectrum of bioactivities, which make them ideal candidates for development of these cosmeceutical products. In vitro studies have demonstrated that bioactive peptides (obtained as extracts, hydrolysates, and/or individual peptides) exhibit biological properties including antioxidant, antimicrobial, and anti-inflammatory activities, in addition to their properties of inhibiting aging-related enzymes such as elastase, collagenase, tyrosinase and hyaluronidase. Some studies report multifunctional bioactive peptides that can simultaneously affect, beneficially, multiple physiological pathways in the skin. Moreover, in vivo studies have revealed that topical application or consumption of bioactive peptides possess remarkable skin protection. These properties suggest that bioactive peptides may contribute in the improvement of skin health by providing specific physiological functions, even though the mechanisms underlying the protective effect have not been completely elucidated. This review provides an overview of in vitro, in silico and in vivo properties of bioactive peptides with potential use as functional ingredients in the cosmeceutical field. It also describes the possible mechanisms involved as well as opportunities and challenges associated with their application.

Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis

Electrodialysis (ED) with ion-exchange membranes is a promising method for the extraction of phosphates from municipal and other wastewater in order to obtain cheap mineral fertilizers. Phosphorus is transported through an anion-exchange membrane (AEM) by anions of phosphoric acid. However, which phosphoric acid anions carry the phosphorus in the membrane and the boundary solution, that is, the mechanism of phosphorus transport, is not yet clear. Some authors report an unexpectedly low current efficiency of this process and high energy consumption. In this paper, we report the partial currents of H2PO4-, HPO42-, and PO43- through Neosepta AMX and Fujifilm AEM Type X membranes, as well as the partial currents of H2PO4- and H+ ions through a depleted diffusion layer of a 0.02 M NaH2PO4 feed solution measured as functions of the applied potential difference across the membrane under study. It was shown that the fraction of the current transported by anions through AEMs depend on the total current density/potential difference. This was due to the fact that the pH of the internal solution in the membrane increases with the growing current due to the increasing concentration polarization (a lower electrolyte concentration at the membrane surface leads to higher pH shift in the membrane). The HPO42- ions contributed to the charge transfer even when a low current passed through the membrane; with an increasing current, the contribution of the HPO42- ions grew, and when the current was about 2.5 ilimLev (ilimLev was the theoretical limiting current density), the PO43- ions started to carry the charge through the membrane. However, in the feed solution, the pH was 4.6 and only H2PO4- ions were present. When H2PO4- ions entered the membrane, a part of them transformed into doubly and triply charged anions; the H+ ions were released in this transformation and returned to the depleted diffusion layer. Thus, the phosphorus total flux, jP (equal to the sum of the fluxes of all phosphorus-bearing species) was limited by the H2PO4- transport from the bulk of feed solution to the membrane surface. The value of jP was close to ilimLev/F (F is the Faraday constant). A slight excess of jP over ilimLev/F was observed, which is due to the electroconvection and exaltation effects. The visualization showed that electroconvection in the studied systems was essentially weaker than in systems with strong electrolytes, such as NaCl.

Evaluation of the potential use of a carp (Cyprinus carpio) skin gelatine hydrolysate as an antioxidant component

Gelatine hydrolysates are of increasing interest as potential ingredients used in various health-promoting functional foods. Cyprinus carpio skin gelatine hydrolysates can be a potential source of bioactive peptides with antioxidant properties. Therefore, the aim of this research was to evaluate the potential use of a carp skin gelatine hydrolysate with proven antioxidant properties as a bioactive compound in functional foods as well as its stability under various processing conditions. The analysis of the hydrolysate included its characterisation (ζ-potential, particle size distribution), solubility, antioxidant ability and stability (DPPH, FRAP, chelating properties) under various conditions (heating, pH and NaCl). Additionally, an analysis of residual environmental pollutants (heavy metals, dioxins and pesticides) was also conducted. The hydrolysate had high solubility over a range of pH values from 2 to 12 (84%-98%), and its antioxidant properties remained stable in low concentration NaCl solutions as well as after being heated at temperatures between 40 and 100 °C. The hydrolysate was not contaminated with heavy metals, dioxins or pesticides. According to our study, carp skin hydrolysates can be incorporated into food processing systems without significant loss of their antioxidant activities.

How Charge and Triple Size-Selective Membrane Separation of Peptides from Salmon Protein Hydrolysate Orientate their Biological Response on Glucose Uptake

The valorization of by-products from natural organic sources is an international priority to respond to environmental and economic challenges. In this context, electrodialysis with filtration membrane (EDFM), a green and ultra-selective process, was used to separate peptides from salmon frame protein hydrolysate. For the first time, the simultaneous separation of peptides by three ultrafiltration membranes of different molecular-weight exclusion limits (50, 20, and 5 kDa) stacked in an electrodialysis system, allowed for the generation of specific cationic and anionic fractions with different molecular weight profiles and bioactivity responses. Significant decreases in peptide recovery, yield, and molecular weight (MW) range were observed in the recovery compartments depending on whether peptides had to cross one, two, or three ultrafiltration membranes. Moreover, the Cationic Recovery Compartment 1 fraction demonstrated the highest increase (42%) in glucose uptake on L6 muscle cells. While, in the anionic configuration, both Anionic Recovery Compartment 2 and Anionic Recovery Compartment 3 fractions presented a glucose uptake response in basal condition similar to the insulin control. Furthermore, Cationic Recovery Compartment 3 was found to contain inhibitory peptides. Finally, LC-MS analyses of the bioassay-guided bioactive fractions allowed us to identify 11 peptides from salmon by-products that are potentially responsible for the glucose uptake improvement.