Extraction Of Peptides Research Articles

PSVII-21 Protective Effect of Peptide Extract Derived from Beef Protein By Hydrolysis Against Oxidative Damage

Abstract This study was conducted to determine the protective effects of peptide extract with 3 kDa from beef myofibrillar protein by Alkaline-AK enzyme (AK3K) against oxidative damage in SH-SY5Y cells and in the brains of spontaneously hypertensive rats (SHRs). All data were presented as the mean ± standard deviation of three replicates. All statistical analyses were performed using the one-way analysis of variance procedure in SPSS 20.0. A Tukey's multiple comparison test was used to determine significant differences between mean values, and evaluations were based on a significance level of P < 0.05. The AK3K did not affect cytotoxicity in SH-SY5Ycells (Figure 1). The resulting AK3K decrease the apoptotic ratio by 33.25%, DNA fragmentation, and reactive oxygen species (ROS) generation in oxidative damage induced SH-SY5Y cells (Figure 2). The SHR brains treated with the AK3K (400 mg/kg body weight, AK3K400) showed a significant decrease in malondialdehyde and ROS contents at 0.33 and 23.92 μM, respectively (P < 0.05) compared with the control. The SOD activity for AK3K was 61.26%, around 20% greater than the control. Therefore, this study suggest that the peptide extract from beef have neuroprotective effects such as inhibition of apoptotic factors and increment of antioxidant enzyme against oxidative stress and could possibly be used for neuronal hypertension therapy.

Human blood lipid profiles after dietary supplementation of different omega 3 ethyl esters formulations

The validity of omega 3 fatty acids (ω3 FAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as dietary supplements has been widely proved. It’s well known in fact, that they protect against cardiovascular diseases, reduce the levels of triacylglycerides (TAGs) and cholesteryl esters (CEs) in blood, and have anti-inflammatory activity. For these reasons, in the last few years the production of dietary supplement containing ω3 has increased significantly. In this context, the possibility to obtain ω3 and other high value molecules from alternative sources as fish waste, in accordance with the principles of circular economy, becomes an enormous attractive. In addition, the opportunity of creating new products, with greater health benefits, represents an interesting challenge. The current study was focused on the extraction of ω3 fatty acids and peptides from tuna waste industry, to realize a new dietary supplement. To this purpose, a supercritical fluid extraction (SFE) method was developed to separate, isolate, and enrich the different fractions subsequently used to produce an innovative formulate. The obtained supplement was characterized in terms of fatty acids esterified ester (FAEE) composition by gas chromatography (GC) coupled to both flame ionization detection (FID) and mass spectrometry (MS), and content of heavy metals by inductively coupled plasma–mass spectrometry (ICP-MS).The effects of ω3 supplementation on metabolism and circulating lipid profiles was tested on 12 volunteers and assessed by GC-FID analysis of whole blood collected on paper support (Dried Blood Spot, DBS) at the beginning of the study and after thirty days. The results of plasma fatty acids levels after 30 days showed a significant decrease in the ω6/ω3 ratio, as well as the saturated/polyunsaturated fatty acids (SFA/PUFA) ratio, compared to subjects who took the ω3 ethyl esters unformulated. The novel formulated supplements proved to be extremely interesting and promising products, due to a significant increase in bioavailability, that makes it highly competitive in the current panorama of the nutraceutical industry.

Phycobiliprotein Peptide Extracts from Arthrospira platensis Ameliorate Nonalcoholic Fatty Liver Disease by Modulating Hepatic Lipid Profile and Strengthening Fat Mobilization.

Arthrospira platensis phycobiliprotein peptide extracts (PPEs) exhibit potential mitigative effects on hepatic steatosis. However, the precise role of PPEs in addressing high-fat-induced nonalcoholic fatty liver disease (NAFLD), as well as the underlying mechanism, remains to be elucidated. In this study, NAFLD was induced in rats through a high-fat diet (HFD), and the rats were subsequently treated with PPEs for a duration of 10 weeks. The outcomes of this investigation demonstrate that PPE supplementation leads to a reduction in body weight gain, a decrease in the accumulation of lipid droplets within the liver tissues, alterations in hepatic lipid profile, regulation of lipolysis-related gene expression within white adipose tissues and modulation of intestinal metabolites. Notably, PPE supplementation exhibits a potential to alleviate liver damage by manipulating neutral lipid metabolism and phospholipid metabolism. Additionally, PPEs appear to enhance fat mobilization by up-regulating the gene expression levels of key factors such as HSL, TGL, UCP1 and UCP2. Furthermore, PPEs impact intestinal metabolites by reducing the levels of long-chain fatty acids while concurrently increasing the levels of short-chain fatty acids. The findings from this study unveil the potential of PPE intervention in ameliorating NAFLD through the modulation of hepatic lipid profile and the reinforcement of the fat mobilization of intestinal metabolites. Thus, PPEs exhibit noteworthy therapeutic effects in the context of NAFLD.

Simultaneous extraction and detection of peptides, steroids, and proteins in small tissue samples.

The detection and quantification of hormones are important to assess the reproductive and stress status of experimental models and for the diagnosis of diseases in human and veterinary clinics. Traditionally, steroid, peptide, and protein hormones are analyzed in individual experiments using different extraction methodologies. With the new advancement on HPLC sorbents, the simultaneous measurement of hormones from different categories becomes possible. In this study, we present a novel sample processing strategy for the simultaneous extraction and detection of peptides, steroids, and proteins using high-resolution liquid chromatography tandem mass spectrometry. We demonstrate the sensitivity of our method for small tissues by acquiring data from brain, pituitary gland, and gonads of single zebrafish samples. This approach promises to shed light on the hormonal pathways and their interrelationships, providing knowledge on the integration of hormone systems.

Extraction of Fish Collagen Peptides from Fish Waste through Fermentation using Lactobacillus Bacteria

Objective: To introduce a novel technique for extracting fish collagen peptides from fish waste. It could be a cheap and safe technique for obtaining peptides of fish as well as reducing the fish waste environmental load.Study Design: A comparative study.Place and Duration of Study: The study was conducted at Department of Microbiology, Hazara University Mansehra, Khyber Pakhtunkhwa and National University of Medical Sciences, Rawalpindi, Pakistan from August 2020 to July 2022.Methods: For the extraction of the fish collagen peptides, lactobacillus bacteria fermentation was being performed, in which the bacteria from yogurt and dough were added to fish samples and incubated for one month at 30°C. Lactobacillus bacteria were diluted with serial dilution for colonies isolation and biochemical characterization. Fish waste was cut in small pieces and put in a bottle containing distilled water and lactobacillus bacteria species and kept at 30°C for one month. The Hestrin–Schramm media (HS) was added in small amount as a starter for initial growth of bacteria. The pH was analyzed after every 7 days and 5–10 ml sample was collected from each labelled flask. The collected samples were precipitated using Trichloroacetic acid (TCA) and analyzed on SDS-PAGE.Results: Gel analysis revealed different size of fish collagen with higher concentration include the pattern for α1 and α2 chains with a molecular weight of 145 kDa and 132 kDa, respectively. The biological activity of extracted fish collagen was determined by using HaCaT cells proliferation analysis.Conclusion: The current study concluded that fish waste could be converted to biofunctional collagen using nonpathogenic strains of lactobacillus bacteria for various biomedical applications.
 How to cite this: Khan S, Tauseef I, Ikram M, Rauf S, Saeed RF, Sadiqi S, Lone NA, Ali L, Subhan F. Extraction of Fish Collagen Peptides from Fish Waste Through Fermentation Using Lactobacillus Bacteria. Life and Science. 2023; 4(4): 365-371. doi: http://doi.org/10.37185/LnS.1.1.423

Antioxidant Peptides from the Collagen of Antler Ossified Tissue and Their Protective Effects against H2O2-Induced Oxidative Damage toward HaCaT Cells.

Antler ossified tissue has been widely used for the extraction of bioactive peptides. In this study, collagen was prepared from antler ossified tissue via acetic acid and pepsin. Five different proteases were used to hydrolyze the collagen and the hydrolysate treated by neutrase (collagen peptide named ACP) showed the highest DPPH radical clearance rate. The extraction process of ACP was optimized by response surface methodology, and the optimal conditions were as follows: a temperature of 52 °C, a pH of 6.1, and an enzyme concentration of 3200 U/g, which resulted in the maximum DPPH clearance rate of 74.41 ± 0.48%. The peptides (ACP-3) with the strongest antioxidant activity were obtained after isolation and purification, and its DPPH free radical clearance rate was 90.58 ± 1.27%; at the same time, it exhibited good scavenging activity for ABTS, hydroxyl radical, and superoxide anion radical. The study investigated the protective effect of ACP-3 on oxidative damage in HaCaT cells. The findings revealed that all groups that received ACP-3 pretreatment exhibited increased activities of SOD, GSH-Px, and CAT compared to the model group. Furthermore, ACP-3 pretreatment reduced the levels of ROS and MDA in HaCaT cells subjected to H2O2-induced oxidative damage. These results suggest that collagen peptides derived from deer antler ossified tissue can effectively mitigate the oxidative damage caused by H2O2 in HaCaT cells, thereby providing a foundation for the utilization of collagen peptides in pharmaceuticals and cosmetics.

DPP-IV Inhibitory Peptides from Coix Seed Prolamins: Release, Identification, and Analysis of the Interaction between Key Residues and Enzyme Domains.

Dipeptidyl peptidase IV (DPP-IV) inhibitory peptides can regulate type 2 diabetes by inhibiting the cleavage of glucagon-like peptide-1 and prolonging its half-life. The development of DPP-IV inhibitory peptides is still a hot topic. The primary structure of coix seed prolamins contains peptide sequence fragments that potentially inhibit DPP-IV; however, limited information is available regarding the extraction of peptides from coix seeds and the analysis of their conformational relationships. In this study, novel coix seed prolamin-derived peptides were obtained through single hydrolysis and double-enzyme stepwise hydrolysis. The inhibitory activity of these peptides against DPP-IV was evaluated to explore new functional properties of coix seeds. The results evidenced that the step-by-step enzymolysis (papain and alcalase) compared to single enzymolysis promoted the secondary structure disruption of the hydrolysates, enhanced the β-turn structure, significantly increased the content of peptides below 1 kDa, and exhibited a substantial increase in DPP-IV inhibitory activity (97% inhibition). Three nontoxic DPP-IV inhibitory peptides, namely, LPFYPN, TFFPQ, and ATFFPQ (IC50 = 70.24, 176.87, 268.31 μM), were isolated and identified. All three peptides exhibited strong interactions with DPP-IV (all KA values >103). LPFYPN exhibited competitive inhibition, while TFFPQ and ATFFPQ demonstrated mixed competitive-noncompetitive inhibition. Hydrogen bonding and hydrophobic interactions were the main contributors to the coix seed prolamin peptides binding to DPP-IV. The central residue was a key amino acid in the parent peptide sequence, forming a more stable π-π stacking with residues in the active pocket, which may facilitate peptide activity. This study provides theoretical support for the development of coix seed-derived hypoglycemic peptides.

Effect of reindeer pituitary peptide extract on cognitive functions in rats with changes light regime

BACKGROUND: Disruption of circadian rhythms can cause significant damage to sensory processing, learning, and memory. At the same time, the structure of the endogenous biological clock contributes to the adaptation of the organism to changes in the conditions for the existence of a biosystem in the external environment. The possibility of synchronization of the endogenous rhythms of the organism with disturbed light periodicity is an urgent problem of modern society, where different rhythms of labor, motor, cognitive activity are used.
 AIM: To study the effect of peptides from the pituitary gland of the Reindeer on the parameters of cognitive functions in rats with a long-term change in the light regime on models with altered cellular oscillation due to oxidative stress caused by poisoning of animals with sodium thiopental in a half-lethal dose.
 MATERIALS AND METHODS: The study was conducted on 56 white Wistar male rats after acute poisoning with sodium thiopental at a dose of 85 mg/kg under conditions of light desynchronosis. In the passive avoidance conditioned reflex test, the cognitive functions of animals were assessed after a two-week pharmacological correction with a cellular extract of the pituitary gland of the Reindeer at a dose of 100 mg/kg.
 RESULTS: The peptide extract of the pituitary gland of the Reindeer contributes to the change in the higher integrative functions of the central nervous system in case of disturbed periodicity of the light signal. The results obtained indicate the chronobiotic activity of the peptide extract of the pituitary gland of the Reindeer at a dose of 100 g/kg when administered intranasally.
 CONCLUSIONS: The light regime change for 1 month under conditions of altered cellular oscillation led to impaired of the higher integrative functions of the central nervous system in rats, which was accompanied by an increase in the rate of reflex extinction and a disturbance of the processes of memory consolidation; under conditions of constant light, these disorders are more pronounced. The result of the pharmacological correction of these changes with the reindeer pituitary peptide extract was an improvement in the processes of memory consolidation and information reproduction (an increase in the number of trained animals with a change in the light regime).

Effects of coagulants on peptide profiles and ACE-inhibitory activity in ultrafiltered white (Beyaz) cheese

The present study aimed to evaluate the effects of two different enzymes, one derived from microbial sources and the other from animal sources, on the peptide profile with low molecular weight (<3 kDa) and ACE-inhibitory activity of White (Beyaz) cheese produced from ultrafiltered (UF) milk. The control group's cheeses were produced using pasteurized milk. Throughout the 90-day ripening period, the coagulating enzyme demonstrated no significant effects on the dry matter and protein values (p > 0.05). The protein content of < 3 kDa peptide extracts changed ripening, with no statistically significant effects attributed to the enzyme variation (p > 0.05). ACE inhibition increased in all cheeses by the end of the ripening process (p < 0.05). The ACE-inhibitory activity of < 3 kDa peptide extracts obtained from the UF White cheese produced using the microbial enzyme exhibited an increase corresponding to the observed increase in the total area of RP-HPLC peaks. The LC-MS/MS analysis revealed that the animal-sourced control group yielded the highest number of β-casein and αS1-casein peptides. Many < 3 kDa peptides described in the present possessed proline and positively charged amino acids at their C-terminal, contributing to ACE inhibition.

Identification of hepatoprotective peptides from porcine liver and its interaction with ethanol metabolizing enzymes in vitro

Alcoholic liver disease (ALD) is a worldwide disease caused by excessive ethanol consumption. In current study, hepatoprotective peptides were isolated from the porcine liver while their activities and interactions with ethanol metabolizing enzymes (alcohol dehydrogenase: ADH/acetaldehyde dehydrogenase: ALDH) were analyzed. The alcalase digested porcine liver hydrolysate (PLH) was confirmed to possess ADH/ALDH activation ability in a dose-dependent manner. The peptide sequences of PLH were identified by mass spectrometry. Molecular docking and in silico analysis were federatively used for screening. NTLPHPTAP had the lowest binding energy with ADH (−0.88 kcal/mol) and low toxicity. Fluorescence quenching data showed a dynamic fluorescence quenching constant (Kq) for NTLPHPTAP interacting with ADH/ALDH (ADH: 1.57 × 10−10 M−1 s−1; ALDH:1.961 × 10−10 M−1 s−1). Circular dichroism (CD) spectra and infrared spectrometer (FTIR) revealed that the enzyme secondary structures became flexible and disordered after interaction with NTLPHPTAP. Meanwhile, the ADH/ALDH was speculated to bind NTLPHPTAP via amido and carbonyl groups, respectively. These results indicated that the formation of ADH/ALDH-NTLPHPTAP complexes expanded the overall structure of the original enzymes and further increased the possibility of enzyme-substrate binding. In conclusion, the study proposed a method for the extraction of porcine liver hepatoprotective peptides and suggested further explanation for the interaction between NTLPHPTAP and ADH/ALDH in vitro.

Comparative study on the bioavailability of peptide extracts from Jeju black pigs and three-way crossbred pigs.

This study aimed to compare the changes in the bioactivities of peptide extracts (< 10 kDa) obtained from Jeju black pigs (JBP) and three-way crossbred pigs (Landrace × Yorkshire × Duroc, LYD) before and after digestion. The results showed that the loin peptide extracts of JBP maintained high 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity after in vitro digestion. However, the iron chelating activity and antihypertensive activity of all peptide extracts were decreased. This study suggested that the peptide extracts produced through alkaline-AK digestion have sufficiently high antioxidant and antihypertensive activities; however, these activities were reduced after in vitro digestion. Meanwhile, the JBP loin and ham peptide extracts promoted high superoxide dismutase (SOD) activity than that of LYD when administered to mice. Furthermore, the ham peptide extracts of JBP showed a relatively high antihypertensive activity in mice. Therefore, it is deemed that these peptide extracts from JBP are more bioactive than that of LYD, and can be used as bioactive materials.

Comparative Quantitation of Kokumi γ-Glutamyl Peptides in Spanish Dry-Cured Ham under Salt-Reduced Production.

Salting is a crucial step during the production of dry-cured ham and it is not well known whether it has an impact on the generation of taste-active peptides. The present study focused on the quantitation of kokumi γ-glutamyl peptides in low-salted Spanish dry-cured hams with 12 months of processing. By using mass spectrometry, peptides were quantitated from samples obtained after ethanolic deproteinization-based and non-ethanolic deproteinization-based extraction methods. Peptides γ-EA, γ-EE, and γ-EL registered mean values of 0.31, 2.75, and 11.35 µg/g of dry-cured ham, respectively, with no differences observed between both extraction protocols. However, γ-EF, γ-EM, γ-EV, γ-EW, γ-EY, and γ-EVG presented significantly (p < 0.05) higher concentrations in the ethanolic deproteinized samples showing values of 5.58, 4.13, 13.90, 0.77, 3.71, and 0.11 µg/g of dry-cured ham, respectively. These outcomes reflect the importance of protocols for the extraction of peptides to achieve the most feasible results. In addition, potential precursors for the formation of γ-glutamyl peptides are generated during dry-curing under salt restriction. The kokumi activity of these γ-glutamyl peptides could enhance the sensory attributes countering the taste deficiencies caused by the salt restriction.

Green hydrophobic maltodextrin nanosponges for magnetic solid-phase extraction of hypothalamic peptides from plasma samples

In this work, for the first time, magnetic-phthalated maltodextrin nanosponges (M-PAMDNSs) were synthetized and introduced as efficient and green sorbents. The integration of phthaloyl groups as hydrophobic moieties into networks of maltodextrin nanosponges provided good enrichment for hypothalamic-related peptides (HRPs). The synthesized materials were characterized by 1H nuclear magnetic resonance spectroscopy, water contact angle, attenuated total reflection-Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, pH point of zero charge, acid-base titration, field-emission scanning electron microscopy, Brunauer-Emmett-Teller, and vibrating sample magnetometer. Under the optimized conditions (sorbent amount: 5.0 mg, desorption solvent volume and type: 300 µL of methanol: H2O: trifluoroacetic acid, extraction time: 15 min, and desorption time: 10 min), the developed magnetic solid-phase extraction (MSPE) method in combination with HPLC-UV was used as a novel and sensitive analytical method for the determination of HRPs in plasma samples. The proposed MSPE-HPLC-UV method provided good linearity (1.5–500 ng mL−1 R2 ≥ 0.9988), low limits of detection (0.1–0.2 ng mL−1) and quantification (0.4–0.8 ng mL−1), desirable precision (RSD ≤ 8.8%, n ₌ 5), satisfactory enrichment factor (EFs ≥ 66.0), and well relative recoveries (92.8–108.8%). Overall, the established method effectively expanded the analytical potential of MSPE approach for the quantification of HRPs in biological samples.

Electromembrane extraction of peptides based on hydrogen bond interactions

BackgroundElectromembrane extraction (EME) of peptides reported in the scientific literature involve transfer of net positively charged peptides from an aqueous sample, through a liquid membrane, and into an aqueous acceptor solution, under the influence of an electrical field. The liquid membrane comprises an organic solvent, containing an ionic carrier. The purpose of the ionic carrier is to facilitate peptide solvation in the organic solvent based on ionic interactions. Unfortunately, ionic carriers increase the conductivity of the liquid membrane; the current in the system increases, the electrolysis in sample and acceptor is accelerated, and the extraction system tend to be unstable and suffers from drifting pH. ResultsIn the present work, a broad selection of organic solvents were tested as pure liquid membrane for EME of peptides, without ionic carrier. Several phosphates provided high mass transfer, and tri(pentyl) phosphate was selected since this solvent also provided high operational stability. Among 16 different peptides used as model analytes, tri(pentyl) phosphate extracted those with net charge +1 and with no more than two polar side chains. Tri(pentyl) phosphate served as a very strong hydrogen bond acceptor, while the protonated peptides were hydrogen bond donors. By such, hydrogen bonding served as the primary interactions responsible for mass transfer. Tri(pentyl) phosphate as liquid membrane, could exhaustively extract leu-enkephalin, met-enkephalin, and endomorphin from human blood plasma and detected by LC-MS/MS. Calibration curves were linear (r2 > 0.99) within a concentration range from 1 to 500 ng/mL, and a relative standard deviation within 12% was observed for precision studies. SignificanceThe current experiments are important because they indicate that small peptides of low polarity may be extracted selectively in EME based on hydrogen bond interactions, in systems not suffering from electrolysis.

Inhibition characteristics of peptide extracts of four medicinal plants on activities of bovine trypsin

Aqueous extract of leaves of Momordica charantia, Hymenocardia acida, Lawsonia inermis and fruit of Xylopia aethiopica have been used in sub Saharan Africa in the management of many viral diseases. Their medicinal properties had been reported to be due to their high antioxidant activities, but limited information is available whether these properties are also due to inhibition or modulation of proteases important in the pathology of viral infections. We report the inhibitory characteristics of peptides extracted from these medicinal plants against bovine trypsin, a serine protease.Extraction of the peptides was done using standard procedure and their inhibitory activities were measured against bovine trypsin. Aqueous extract of M. charantia, H. acida, L. inermis and X. aethiopica contain 5.7 ± 0.5 mg/ml, 1.0 ± 0.2 mg/ml, 1.8 ± 0.1 mg/ml and 28.3 ± 4.1 mg/ml of peptides, respectively. Using Nα-benzoyl-DL-arginine 4-nitroanilide (BAPNA) as trypsin substrate, a Km and Vmax of 0.34 mM and 0.6 μmole/min/mg protein obtained, were altered in the presence of the peptide extracts suggesting the extracts modulate trypsin activity. The inhibition was either competitive, non-competitive or mixed-type of non-competitive inhibition. Inhibition constant (Ki) ranging from 81 to 831±120 μg/ml were obtained using Dixon plot with the peptide extract from M. charantia being the most potent.We concluded that the medicinal and antiviral properties of the extracts could also be due to inhibition or modulation of proteases involved in the pathology of viral infection.

Synergistic Effect of Combined Walnut Peptide and Ginseng Extracts on Memory Improvement in C57BL/6 Mice and Potential Mechanism Exploration.

This work aimed to investigate whether there are synergistic effects between walnut peptide (WNP) and ginseng extracts (GSE) treatments to ameliorate the memory impairment caused by scopolamine (SCOP). The Morris water maze trial, hippocampal neuron morphology, neurotransmitters, and synaptic ultrastructure were examined, along with brain-derived neurotrophic factor (BDNF)-related signaling pathway proteins. The results of the Morris water maze trial demonstrated that the combined administration of WNP and GSE effectively alleviated memory impairment in C57BL/6 rats caused by SCOP. Improvement in the morphology of hippocampal neurons, dendritic spines, and synaptic plasticity and upregulation of neurotransmitters AChE, ACh, ChAT, Glu, DA, and 5-HT supported the memory improvement effects of WNP + GSE. In addition, compared with the model group, WNP + GSE significantly enhanced the protein levels of VAChT, Trx-1, and the CREB/BDNF/TrkB pathway in hippocampal and PC12 cells induced by SCOP (p < 0.05). Notably, WNP + GSE boosted memory via multiple pathways, not only the BDNF/TrkB/CREB target.

Aptamer-functionalized stir bar sorptive extraction for selective isolation, identification, and determination of concanavalin A in food by MALDI-TOF-MS

An aptamer-functionalized stir bar sorptive extraction (SBSE) coating is described for the first time devoted to selective isolation and preconcentration of an allergenic food protein, concavanalin A (Con A), followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF-MS) determination. For this purpose, the polytetrafluoroethylene surface of commercial magnetic stir bars was properly modified and vinylized to immobilize a thiol-modified aptamer against Con A via straightforward “thiol-ene” click chemistry. The aptamer-functionalized stir bar was employed as SBSE sorbent to isolate Con A, and several parameters that can affect the extraction efficiency were investigated. Under the optimized conditions, Con A was extracted and desorbed during 30 and 45 min, respectively, at 25 °C and 600 rpm. The SBSE MALDI-TOF-MS method provided limits of detection of 0.5 μg mL−1 for Con A. Furthermore, the SBSE coating was highly selective to Con A compared to other lectins. The developed method was successfully applied to the determination of low levels of Con A in several food matrices (i.e., white beans as well as chickpea, lentils, and wheat flours). Recoveries ranged from 81 to 97% with relative standard deviations below 7%. The aptamer-based stir bars presented suitable physical and chemical long-term stability (1 month) and a reusability of 10 and 5 extraction cycles with standards and food extracts, respectively. The developed aptamer-affinity extraction devices open up the possibility of developing novel highly selective SBSE coatings for the extraction of proteins and peptides from complex samples.Graphical abstract

Improving the Sustainability of Processing By-Products: Extraction and Recent Biological Activities of Collagen Peptides.

Society and consumers are increasingly concerned about food safety and the sustainability of food production systems. A significant amount of by-products and discards are generated during the processing of aquatic animals, which still needs to be fully utilized by the food industry. The management and sustainable use of these resources are essential to avoiding environmental pollution and resource waste. These by-products are rich in biologically active proteins, which can be converted into peptides by enzymatic hydrolysis or fermentation treatment. Therefore, exploring the extraction of collagen peptides from these by-products using an enzymatic hydrolysis technology has attracted a wide range of attention from numerous researchers. Collagen peptides have been found to possess multiple biological activities, including antioxidant, anticancer, antitumor, hypotensive, hypoglycemic, and anti-inflammatory properties. These properties can enhance the physiological functions of organisms and make collagen peptides useful as ingredients in food, pharmaceuticals, or cosmetics. This paper reviews the general methods for extracting collagen peptides from various processing by-products of aquatic animals, including fish skin, scales, bones, and offal. It also summarizes the functional activities of collagen peptides as well as their applications.

Extraction of Novel Bioactive Peptides from Fish Protein Hydrolysates by Enzymatic Reactions

Bioactive peptides derived from fish the byproduct protein hydrolysate have wide potential as functional food ingredients. The preparation of bioactive peptides is commonly achieved via enzymatic hydrolysis; this is the most preferred method because it has high specificity, fewer residual organic solvents in the product, and it is usually carried out in mild conditions. The use of various enzymes such as proteases is widely practiced in the industry, yet there are various limitations as it is of high cost and there is a limited availability of food-grade enzymes in the market. Moreover, high-throughput purification and the identification analysis of these peptides are currently being studied to further understand the functionality and characterization of the bioactive peptides. This review mainly focuses on the novel bioactive peptides derived from fish protein hydrolysates from various fish wastes and byproducts. The hydrolysis conditions, source of hydrolysate, and amino acid sequence of these novel peptides are presented, along with their corresponding methods of analysis in purification and identification. The use of various enzymes yields novel peptides with potent bioactivities, such as antiproliferative, antimicrobial, antihypertensive, antiglycemic, antitumor, and antioxidative biological functions. The increasing interest in proteomics in marine and aquatic waste utilization continues due to these products’ bioactivity and sustainability.

Peptide extraction from silver carp (Hypophthalmichthys molitrix) scales via enzymatic hydrolysis and membrane filtration

In this work, peptides were extracted from Silver carp (SC) scales via protease hydrolysis and separated using two membranes (M1 and M2). The results revealed that the water: SC scale ratios of 50.6 mL/g, alkaline protease 1 (AP1) dose of 2313.6 U/mL, and pH of 8.14 were the optimal hydrolysis conditions, and the peptide yield reached 88.77 ± 0.32%. The optimal conditions of peptide separation were clarified: the operating pressure of the M1 (M2) was 0.25 (0.4) MPa, the liquid temperature was 30°C, and the operation time was 65 min. In this case, the permeability of the M1 (M2) reached 91.73 ± 96% (79.83 ± 7.23%), and the average molecular weight of the peptides was 758 Da (576 Da). Compared with M1 peptides, M2 peptides contained more acidic and aromatic amino acids exhibiting free-radical scavenging and tyrosinase inhibition properties. It might provide a way to utilize SC scales as a promising material to produce bioactive peptides.