Evaluation of Functional Properties in Protein Hydrolysates from Bluewing Searobin (Prionotus punctatus) Obtained with Different Microbial Enzymes

Enhancement of the flavor and functional characteristics of cod protein isolate using an enzyme-microbe system

Cod protein isolate (CPI), a by-product of the cod processing industry, represents a novel source of high value-added products. However, off-flavors in cod protein such as bitterness and fishy odor reduce its acceptability to consumers. Here, CPI was first debittered using aminopeptidase from Streptomyces canus (ScAPase) and then deodorized through probiotic fermentation. This is the first reported demonstration of complete removal of the bitterness of CPI using ScAPase. Subsequently, Syn3 and Syn4, as aromatic CPI (ACPI), were prepared from debittered CPI (DCPI) via fermentation with Lactobacillus acidophilus and Bifidobacterium longum, respectively. These products, DCPI and ACPI, were characterized by the absence of bitterness and fishy odor, along with a strong aromatic scent and high overall acceptability. Additionally, these products exhibited improved physicochemical properties, including enhanced oil-holding capacity, emulsifying activity, and resistance to digestion, compared to untreated CPI. However, significant differences were observed in their radical scavenging activities. The highest scavenging activity was detected in Syn3 against DPPH˙ (63.5%) and ˙OH (79.2%), in DCPI against O2- (32.0%), and in post-digestion Syn4 against ABTS˙+ (95.2%). Furthermore, after digestion treatment, these products significantly promoted the proliferation of probiotics. Notably post-digestion Syn4 showed the most substantial proliferation effect on Lactobacillus reuteri, Lactobacillus rhamnosus, and Bifidobacterium breve compared to other post-digestion samples. These results indicate that the treated CPI has the potential for applications in health food products.

Exploring the Physicochemical Characteristics of Marine Protein Hydrolysates and the Impact of In Vitro Gastrointestinal Digestion on Their Bioactivity

Fish protein hydrolysates (FPHs) were obtained from different fish sources using a combination of microbial enzymes. The industrially produced FPHs from blue whiting (Micromesistius poutassou) and sprat (Sprattus sprattus) were compared to freeze-dried FPHs generated in-house from hake (Merluccius merluccius) and mackerel (Scomber scombrus) in terms of their physicochemical composition and functionality. Significant differences (p < 0.05) were observed in the protein, moisture, and ash contents of the FPHs, with the majority having high levels of protein (73.24-89.31%). Fractions that were more extensively hydrolysed exhibited a high solubility index (74.05-98.99%) at different pHs. Blue whiting protein hydrolysate-B (BWPH-B) had the highest foaming capacity at pH 4 (146.98 ± 4.28%) and foam stability over 5 min (90-100%) at pH 4, 6, and 8. The emulsifying capacity ranged from 61.11-108.90 m2/g, while emulsion stability was 37.82-76.99% at 0.5% (w/v) concentration. In terms of peptide bioactivity, sprat protein hydrolysate (SPH) had the strongest overall reducing power. The highest Cu2+ chelating activity was exhibited by hake protein hydrolysate (HPH) and mackerel protein hydrolysate (MPH), with IC50 values of 0.66 and 0.78 mg protein/mL, respectively, while blue whiting protein hydrolysate-A (BWPH-A) had the highest activity against Fe2+ (IC50 = 1.89 mg protein/mL). SPH scavenged DPPH and ABTS radicals best with IC50 values of 0.73 and 2.76 mg protein/mL, respectively. All FPHs displayed noteworthy scavenging activity against hydroxyl radicals, with IC50 values ranging from 0.48-3.46 mg protein/mL. SPH and MPH showed the highest scavenging potential against superoxide radicals with IC50 values of 1.75 and 2.53 mg protein/mL and against hydrogen peroxide with 2.22 and 3.66 mg protein/mL, respectively. While inhibition of α-glucosidase was not observed, the IC50 values against α-amylase ranged from 8.81-18.42 mg protein/mL, with SPH displaying the highest activity. The stability of FPHs following simulated gastrointestinal digestion (SGID) showed an irregular trend. Overall, the findings suggest that marine-derived protein hydrolysates may serve as good sources of natural nutraceuticals with antioxidant and antidiabetic properties.

Extraction, optimization, and functional quality evaluation of carotenoproteins from shrimp processing side streams through enzymatic process

The study aimed to develop an effective and eco-friendly enzymatic process to extract carotenoproteins from shrimp waste. The optimization of enzymatic hydrolysis conditions to maximize the degree of deproteinization (DDP) of carotenoprotein from shrimp head waste (SHW) and shrimp shell waste (SSW) was conducted separately using the Box-Behnken design of response surface methodology (RSM). To achieve a maximum DDP of 92.32% for SSW and 96.72% for SHW, the optimal hydrolysis conditions were determined as follows: temperature (SSW: 53.13 °C; SHW: 45.90 °C), pH (SSW: 7.13; SHW: 6.78), time (SSW: 90 min; SHW: 61.18 min), and enzyme/substrate ratio (SSW: 2 g/100 g; SHW: 1.18 g/100 g). The carotenoprotein effluent obtained was subjected to spray drying and subsequently assessed for color, nutritional, and functional characteristics. The carotenoprotein from shrimp shell (CpSS) contained a higher essential amino acid score than carotenoprotein from shrimp head (CpSH). CpSS had a higher whiteness index of 82.05, while CpSH had 64.04. Both CpSS and CpSH showed good functional properties viz solubility, emulsion, and foaming properties. The maximum solubility of CpSH and CpSS was determined to be 92.94% and 96.48% at pH 10.0, respectively. The highest emulsion capacity (CpSH: 81.33%, CpSS: 70.13%) and stability (CpSH: 57.06%, CpSS: 63.05%) were observed at 3% carotenoprotein concentration. Similarly, the highest values of foaming capacity (CpSH: 27.66%, CpSS: 105.5%) and stability (CpSH: 23.83%, CpSS: 105.33%) were also found at the same 3% carotenoprotein concentration. In conclusion, the carotenoproteins obtained from shrimp waste showed favorable attributes in terms of color, amino acid composition, and functional properties. These findings strongly suggest the potential applicability of CpSS and CpSH as valuable resources in various domains. CpSS, with its higher whiteness index, greater amino acid content, and superior functional characteristics, may find suitability as functional ingredients in human food products. Conversely, CpSH could be considered for incorporation into animal feed formulations.

Development of a Two-Step Hydrolysis Hypoallergenic Cow's Milk Formula and Evaluation of Residue Allergenicity by Peptidomics and Immunoreactivity Analysis

Cow's milk allergy (CMA) is an abnormal immune response that severely affects the nutritional supplementation of allergic infants. Currently, only a limited number of hypoallergenic formulas are available on the market, and these are only categorized according to their degree of hydrolysis, which still poses an allergy risk and cannot be consumed by CMA patients, especially infants. To address this issue, we developed a two-step hydrolysis hypoallergenic formula targeting destruction of allergen epitope from whey protein. Then, a comprehensive evaluation system was constructed, including peptidomics analysis, in vivo and in vitro allergenicity assessments, revealing allergic changes in the product from the epitope structure level to the immunological level. The results showed that 97.14% of hydrolyzed peptides from α-lactalbumin and β-lactoglobulin did not contain allergenic epitopes after treatment with trypsin and flavourzyme. In vitro and in vivo allergenicity assessment results confirmed that the two-step hydrolysis method effectively reduced the allergenicity of whey protein. Compared with the common milk powder, the hypoallergenic formula induced lower levels of basophil degranulation and relieved the body's anaphylactic symptoms caused by cow milk. This study provides a promising solution to the limited hypoallergenic formula problem and may benefit allergic infants who require nutritional supplements.

Influence of the Degree of Hydrolysis on Functional Properties and Antioxidant Activity of Enzymatic Soybean Protein Hydrolysates

Soybean protein hydrolysates were prepared using two proteolytic enzymes (Alcalase and Protamex) and the degree of hydrolysis (DH) and their functional and antioxidant properties were evaluated. The highest DH value was 20%, with a yield of 19.77% and protein content of 51.64%. The total amino acid content was more than 41% for all protein hydrolysates. The protein hydrolysates from Protamex at pH 2.0 had excellent solubility, emulsifying activity, and foaming capacity, at 83.83%, 95.03 m²/g, and 93.84%, respectively. The water-holding capacity was 4.52 g/g for Alcalase, and the oil-holding capacity was 4.91 g/g for Protamex. The antioxidant activity (62.07%), as measured by the samples' reaction with DPPH (2,2-diphenyl-1-picrylhydrazyl) and the reducing power (0.27) were the strongest for Protamex. An ABTS activity rate of 70.21% was recorded for Alcalase. These findings indicated a strong potential for the utilization of soybean protein hydrolysates to improve the functional properties and antioxidant activity of soybeans as well as their nutritional values.

Effect of hydrolytic degree on antioxidant activity and functional properties of Acetes japonicus proteolysate

This study aims to examine the effect of hydrolysis degree (DH) on both antioxidant activity and functional properties of Acetes japonicus proteolysate (AP). Consequently, the AP showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (SA) and ferric reducing antioxidant power (FRAP) at DH of 66.7%. Whereas, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical (ABTS•+) SA and superoxide anion radical (O2 •–) SA of the AP peaked at DH of 75.8%. In addition, its strongest Fe2+-chelating rate was found at DH of 72.1%. In the pH range from 3 to 8, the AP showed solubility over 55% even after heat treating, foaming capacity (FC) of 5.7–80.0%, foaming stability (FS) of 2.9–77.0%, emulsifying-activity index (EAI) of 16.1–56.3 m2 g−1, and emulsifying stability index (ESI) of 12.4–156.7 min. The highest water-holding capacity (WHC) and oil-holding capacity (OHC) of the AP were observed at DH of 66.7% and 50.6%, respectively. This study enhanced value of the Acetes by producing antioxidant AP possessing functionalities.

Comparative study of two types of pre-extraction treatment (drying or non-drying) on physicochemical, structural and functional properties of extracted insect proteins from Tenebrio molitor larvae

Microwave drying (MD) or freeze drying (FD) was commonly used as a drying treatment prior to the extraction of edible insect proteins. However, some quality defects (e.g., lipid oxidation or protein denaturation) were probably occurred via the drying step. To this end, the effect of drying or non-drying treatments (ND) after slaughtering by liquid nitrogen freezing on the physicochemical characteristics, structural and functional properties of Tenebrio molitor larvae protein (TMP) was investigated. The results indicate that TMP extracted from the ND group showed higher essential/total amino acid content, total/free sulfhydryl content, surface hydrophobicity, solubility, water/oil holding capacities, and emulsifying/foaming properties than those extracted from the MD or FD groups (P < 0.05). Moreover, the ND group had minimal impact on the structural changes of TMP which was associated with protein denaturation. Therefore, it can be concluded that a non-drying strategy prior to TMP extraction can improve functional properties and retard protein denaturation, while also conserving energy.

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Tenebrio molitor larvae was firstly slaughtered by liquid nitrogen freezing.

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Frozen larvae were subjected to either drying or non-drying treatment.

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Tenebrio molitor larvae protein (TMP) was extracted from dried or non-dried group.

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TMP extracted from the non-dried group had optimum functional properties.

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TMP extracted from the non-dried group had least degree of protein denaturation.

Performance evaluation of the commercial aquafeeds available in the market of Pakistan on Channa marulius (Sole)

The present study aimed to determine the effect of different levels of protein on the growth, body composition, amino acid profile and serology of Channa marulius fingerlings. The experiment was conducted in ten happas installed in earthen ponds, each stocked with 10 fishes for 90 days. Four commercial fish feeds having 25%, 30%, 32% and 40% crude protein (CP) levels were fed to fish at 3% of their wet body weight three times a day. The results of the study revealed that highest weight gain, feed conversion ratio and survival rate were observed in 30% protein feed. Meanwhile, moisture content was higher in fish fed with 30% CP feed while highest crude protein was recorded in 40% CP fed fish. Lowest fat content was observed in 32% CP feed. Amino acid profile of fish revealed better results in 30% CP feed. Total protein, glucose and globulin were also highest in fish feeding 30% CP feed, while albumin was highest in 40% CP feed. It is concluded that 30% CP feed showed better results in terms of growth, amino acid profile and serological parameters without effecting fish body composition.

Degree of hydrolysis, functional and antioxidant properties of protein hydrolysates from Grass Turtle (Chinemys reevesii) as influenced by enzymatic hydrolysis conditions

Grass turtle muscle was hydrolyzed with papain enzyme to produce protein hydrolysate (PH) and the degree of hydrolysis (DH) was determined. Under optimal conditions, the highest DH was 19.52% and the yield was recorded as 17.26%. Protein content of the hydrolysates was ranged from 73.35% to 76.63%. Total amino acids were more than 96.77% for each PH. The PH obtained at DH 19.52% achieved excellent solubility and emulsifying activity which were 95.56% and 108.76 m2/g, respectively at pH 6. Foam capacity amounted 100% in PH of DH 19.52% at pH 2, and water-holding capacity was 4.38 g/g. The antioxidant activity showed the strongest hydroxyl radical scavenging activity (95.25%), ABTS (84.88%), DPPH (75.89%), iron chelating (63.25%), and cupper chelating (66.90%) at DH 11.96%, whereas reducing power (0.88) at DH 19.52%. Thus, the findings indicated that utilization of grass turtle muscle protein hydrolysate is a potential alternative protein resource to improve the nutritional and functional properties in food ingredients and product formulations.

Muscle Protein Hydrolysates and Amino Acid Composition in Fish

Fish muscle, which accounts for 15%-25% of the total protein in fish, is a desirable protein source. Their hydrolysate is in high demand nutritionally as a functional food and thus has high potential added value. The hydrolysate contains physiologically active amino acids and various essential nutrients, the contents of which depend on the source of protein, protease, hydrolysis method, hydrolysis conditions, and degree of hydrolysis. Therefore, it can be utilized for various industrial applications including use in nutraceuticals and pharmaceuticals to help improve the health of humans. This review discusses muscle protein hydrolysates generated from the muscles of various fish species, as well as their amino acid composition, and highlights their functional properties and bioactivity. In addition, the role of the amino acid profile in regulating the biological and physiological activities, nutrition, and bitter taste of hydrolysates is discussed.

Antioxidant and functional properties of cowhide collagen peptides

In the present study, antioxidant activities and functional properties of cowhide collagen antioxidant peptides (CCAPs) with different molecular weight (MW) were investigated. The optimum preparation conditions of CCAPs were hydrolysis time of 1.53 hr, temperature of 54.9 °C, pH 7.38, and neutral enzyme to trypsin ratio of 0.048 g: 0.016 g according to single factor test and response surface methodology (RSM). Three fractions (CCAP-I, CCAP-II, and CCAP-III) were obtained by ultrafiltration and lyophilization. Antioxidant activities revealed that CCAP-III had high reducing power activity (0.323 ± 0.035) and scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (64.30 ± 5.99%), 2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radicals (75.25 ± 3.14%), and hydroxyl radicals (68.26 ± 6.74%) compared to the other fractions. In addition, LC-MS/MS analysis showed that Ala-Gly-Glu-Arg, Gly-Ile-Ala-Gly-Glu-Arg, Gly-Pro-Ala-Gly-Pro-Ala-Gly-Pro-Arg, Gly-Val-Val-Gly-Pro-Glu-Gly-Ala-Arg and Gly-Phe-Ser-Gly-Leu-Asp-Gly-Ala-Lys were the major peptides of CCAP-III. CCAP-III showed good hygroscopicity (HYG), water holding capacity (WHC), and oil holding capacity (OHC) when compared with CCAP-I and CCAP-II. However, CCAP-II has great emulsifying properties, and CCAP-I has excellent foaming properties. Therefore, CCAPs can be used as a promising source of functional peptides with antioxidant properties. PRACTICAL APPLICATION: This study demonstrated the peptides of cowhide collagen has superior antioxidant and functional properties. This study provided a scientific basis for the preparation of antioxidant peptides from cowhide collagen.

EGLLGDVF: A Novel Peptide from Green Mussel Perna viridis Foot Exerts Stability and Anti-inflammatory Effects on LPS-Stimulated RAW264.7 Cells

BACKGROUND

Green mussel Perna viridis is a bivalve mollusc which is native to the Indian coast and can be found in the Indo-Pacific as well as Asia-Pacific regions. This study evaluates the P. viridis foot (PVF) as a source of an anti-inflammatory peptide.

OBJECTIVE

To characterize and evaluate the possibility of pro-inflammatory cytokines, nitric oxide (NO) as well as cyclooxygenase (COX)-2 reduction in RAW264.7 cells and to analyze functional aspects of the derived peptide from PVF.

MATERIALS AND METHODS

The PVF was hydrolysed with different enzymes and the antiinflammatory activity of hour hydrolysates were evaluated using HRBC Membrane Stabilization (HMS) against hypotonicity induced haemolysis and Albumin Denaturation (AD) inhibition from induced heat assays. Later, the active hour hydrolysate was separated by ultrafiltration and purified using Size-Exclusion Chromatography (SEC). Further, the purified peptide's sequence was identified using LC-MS/MS and functional properties were determined. Also, the peptide was observed for its anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW264.7 cells for pro-inflammatory cytokines, NO production and COX-2 activation.

RESULTS

Among the four enzymes 6th hour alcalase hydrolysate exhibited potent anti-inflammatory activity and was sequentially fractioned with molecular weight cut-offs; further active fraction (30- 10 kDa) was purified. The active peak-II was identified as EGLLGDVF (849.435 Da) and exhibited decent functional aspects. The peptide successfully reduced the production of pro-inflammatory cytokines, NO and COX-2 activation; and down-regulated the iNOS and COX-2 protein expression in LPS-stimulated RAW264.7 cells.

CONCLUSION

Our study indicates that EGLLGDVF derived from PVF has potential antiinflammatory applications applicable in food and pharmaceutical industries.

Functional and Bioactive Properties of Peptides Derived from Marine Side Streams

In fish processing, a great amount of side streams, including skin, bones, heads and viscera, is wasted or downgraded as feed on a daily basis. These side streams are rich sources of bioactive nitrogenous compounds and protein, which can be converted into peptides through enzymatic hydrolysis as well as bacterial fermentation. Peptides are short or long chains of amino acids differing in structure and molecular weight. They can be considered as biologically active as they can contribute to physiological functions in organisms with applications in the food and pharmaceutical industries. In the food industry, such bioactive peptides can be used as preservatives or antioxidants to prevent food spoilage. Furthermore, peptides contain several functional qualities that can be exploited as tools in modifying food ingredient solubility, water-holding and fat-binding capacity and gel formation. In the pharmaceutical industry, peptides can be used as antioxidants, but also as antihypertensive, anticoagulant and immunomodulatory compounds, amongst other functions. On the basis of their properties, peptides can thus be used in the development of functional foods and nutraceuticals. This review focuses on the bioactive peptides derived from seafood side streams and discusses their technological properties, biological activities and applications.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.

Effects of different drying methods on the structures and functional properties of phosphorylated Antarctic krill protein

Antarctic krill protein (AKP) was extracted from Antarctic krill by an alkali dissolution-isoelectric precipitation method and then it was phosphorylated with sodium tripolyphosphate. The phosphorylated Antarctic krill protein (P-AKP) powder was obtained by spray-drying (SD), freeze-drying (FD), and hot-air drying (AD), and the effects of these drying methods on the structures and functional properties of proteins were investigated. The P-AKP powder dried by SD had the best sensory performance, and its particle size was much smaller than that of FD and AD. Scanning electron microscope displayed a uniform particle size of SD powder and the particles were uniformly dispersed. X-ray diffraction analysis showed a higher crystallinity of SD sample than AD and FD. Differential scanning calorimeter analysis revealed that SD sample had the best thermal stability and less protein denaturation (ΔH = 210.80 J/g), followed by FD (ΔH = 80.48 J/g) and AD (ΔH = 73.94 J/g; P < 0.05). Fourier transform infrared showed that SD sample contained more protein secondary structure. Compared with SD, the phosphorylated group-related chemical bonds in FD and AD samples were partially destroyed. SD sample had the highest protein solubility, oil absorption capacity, emulsifying, and foaming activities than FD and AD (P < 0.05). Although FD had the highest water absorption capacity, sample prepared with AD had the worst functional performance. Therefore, different drying methods used for preparation of the P-AKP can affect its physicochemical and associated functional properties, and SD could be an appropriate drying method for the industrial mass production of P-AKP powders with better functionalities. PRACTICAL APPLICATION: The optimal drying method for preparing the phosphorylated Antarctic krill protein (P-AKP) powder was proved to be spray-drying (SD), because the physicochemical and functional properties were better for P-AKP dried by SD than the other drying methods. Hence, SD was recommended for the industrial mass production of P-AKP powders with better functionalities. This research can provide theoretical guidance for the further processing and utilization of P-AKP, and offer technical reference for food processing and preservation.

Antioxidant mechanism, antibacterial activity, and functional characterization of peptide fractions obtained from barred mackerel gelatin with a focus on application in carbonated beverages

The present study aimed to use fish by-products to generate gelatin peptides with potential applications in carbonated beverages. After ultrafiltration, the F < 3 kDa (fraction < 3 kDa) showed the highest peptide concentration (227.22 mg/g) as well as antibacterial (MIC of ≤ 0.5 mg/mL) and antioxidant activities, including hydroxyl and superoxide radical scavenging, ferrous chelation, and ferric reduction (with IC₅₀ values of 0.88, 1.04, 0.50 mg/mL, and 0.58, respectively). 2,2-diphenyl-1-picrylhydrazyl scavenging was the highest in the 3 < F < 10 kDa (IC₅₀ of 0.64 mg/mL). In vitro gastrointestinal digestion significantly decreased all biological activities. Solubility, water holding capacity, and emulsifying activity of the F < 3 kDa were the highest while foaming properties and overfoaming were reversibly related to the molecular weight. All abovementioned properties, in addition to in vitro cytotoxicity analysis in different cell lines and better flavor characteristics, indicated that the F < 3 kDa could be safely and properly used as an ingredient for the fortification of carbonated beverages.

Characterization and potential strategies for the valorisation of the Southwest Atlantic butterfish (Stromateus brasiliensis)

The waste of fish resources constitutes a serious environmental problem that must be avoided. The valorisation of by-catch species and decreasing the discard rate constitute a more efficient and sustainable use of these marine biomasses. In this work, we characterize and propose different potential uses for Stromateus brasiliensis, another frequently discarded (≥ 90%) and poorly studied by-catch species captured in the South Atlantic Ocean (FAO 41) by trawler fishing fleets. Furthermore, in the case of this species, freezing and frozen storage of the whole fish is the only strategy currently employed for its exploitation. The results revealed that muscle from S. brasiliensis presented a high content of polyunsaturated fatty acids (20.34%) and that the concentrations of both total diacyl glyceryl ethers (2.41%) and heavy metals (Hg 0.038, Pb 0.006 and Cd 0.018 mg/kg) were below the established limits for safe human consumption. Likewise, the protein hydrolysates proved to be a good source of amino acids for human consumption or animal feeding. Minced muscle blocks could be made by a mechanical separation process of the flesh, and the composition of minced muscle did not differ much from that of the whole fish. Furthermore, this process allows the incorporation of cryoprotectants and antioxidants to extend the frozen shelf life of this fatty fish. An extraction process from mechanically mixed skin and bones yielded a good source of collagen that should not be neglected.

Optimization of Enzymatic Conditions of Sturgeon Muscles and Their Anti-Inflammatory Potential

The objective of this study was to investigate the effects of different enzymolysis conditions on the NO inhibition rate and DH (degree of hydrolysis) of sturgeon hydrolysates (SH) prepared by Alcalase. The NO inhibition rate of 60.23% was attained under the optimum enzymolysis conditions as follows: pH 9.0, enzymolysis time of 4.92 h, enzymolysis temperature of 55°C, solid/liquid ratio of 1 : 20, and enzyme additive amount of 7674.22 U/g protein, which was well matched with the predicted value 61.44% of the Box–Behnken design model. After the ultrafiltration of SH, SH-3 (SH < 3 kDa) could significantly decrease the levels of NO and proinflammatory cytokine level IL-6. Also, we found that the obtained SH-3 contained good properties of emulsification and possessed good WHC and OHC. SH-3 demonstrated appreciable antioxidant potential on DPPH and ABTS radical scavenging activities. These results suggested that SH-3 derived from sturgeon muscles could potentially be used as a promising ingredient against inflammatory and oxidative stress-associated diseases.

Evaluation of physicochemical and functional properties of spray-dried protein hydrolysate from non-penaeid shrimp (Acetes indicus)

BACKGROUND

Protein hydrolysate powder was prepared from non-penaeid shrimp (Acetes indicus) by enzymatic hydrolysis using Alcalase enzyme. Extraction conditions such as pH (6.5, 7.5 and 8.5), enzyme to substrate ratio (1.0, 1.5 and 2.0) and temperature (40, 50 and 60 °C) were optimized against the degree of hydrolysis using response surface methodology.

RESULTS

Protein hydrolysate comprised of 740 g kg^-1 protein, 150 g kg^-1 ash and 90 g kg^-1 fat contents. The amino acid score showed superior attributes with 56% essential amino acids. Furthermore, the functional properties of spray-dried protein hydrolysates were evaluated. Protein solubility was found to be the 90.20% at pH 2 and 96.92% at pH 12. Emulsifying properties were found to vary with the concentration of protein hydrolysates and the highest emulsifying capacity (26.67%) and emulsion stability (23.33%) were found at a concentration of 20 mg mL^-1 . The highest and the lowest foaming capacity were observed at pH 6 and pH 10 with a concentration of 20 mg mL^-1 . The water holding capacity of protein hydrolysate was found to increase with concentration, with a value of 5.4 mL g^-1 at a concentration of 20 mg mL^-1 .

CONCLUSION

The results of the present study indicate that the use of A. indicus for the production of protein hydrolysate has good functional properties and nutritional value, rendering it suitable for broad industrial food applications. © 2019 Society of Chemical Industry.

Dietary tuna hydrolysate modulates growth performance, immune response, intestinal morphology and resistance to Streptococcus iniae in juvenile barramundi, Lates calcarifer

This study investigated the effects of tuna hydrolysate (TH) inclusion in fishmeal (FM) based diets on the growth performance, innate immune response, intestinal health and resistance to Streptococcus iniae infection in juvenile barramundi, Lates calcarifer. Five isonitrogenous and isoenergetic experimental diets were prepared with TH, replacing FM at levels of 0% (control) 5%, 10%, 15% and 20%, and fed fish to apparent satiation three times daily for 8 weeks. The results showed that fish fed diets containing 5% and 10% TH had significantly higher final body weight and specific growth rate than the control. A significant reduction in blood glucose was found in fish fed 10%, 15% and 20% TH compared to those in the control whereas none of the other measured blood and serum indices were influenced by TH inclusion. Histological observation revealed a significant enhancement in goblet cell numbers in distal intestine of fish fed 5 to 10% TH in the diet. Moreover, fish fed 10% TH exhibited the highest resistance against Streptococcus iniae infection during a bacterial challenge trial. These findings therefore demonstrate that the replacement of 5 to 10% FM with TH improves growth, immune response, intestinal health and disease resistance in juvenile barramundi.

PH levels effect on functional properties of different molecular weight eel (Monopterus sp.) protein hydrolysate

The aim of this study is to investigate the effect of pH levels on functional properties of various molecular weights of eel (Monopterus sp.) protein hydrolysate (EPH). The eel was enzymatically hydrolyzed and fractionated through membranes filter (10 kDa, 5 kDa and 3 kDa). The foaming capacity and stability, emulsifying capacity and stability index, water holding capacity and fat binding capacity between pH 2 and 10 were determined. The 5 kDa EPH was found to have the highest foaming capacity at pH 2, pH 4 and pH 6, and foaming stability and emulsifying activity index at all pH levels, except pH 8 and fat binding capacity at pH 2, as compared to 10 kDa and 3 kDa EPH fractions. The 10 kDa EPH had the highest emulsifying stability index and water holding capacity at all pH levels. This study shows that the EPH fractions at low pH level had high foaming and oil binding capacity, while at neutral pH, the fractions had high foaming stability and water holding capacity. These properties are important in making whipped cream, mousse and meringue. In contrast, EPH fractions demonstrated strong emulsifying properties at high pH levels and show potential as an emulsifier for breads, biscuits and frozen desserts.

Marine Waste Utilization as a Source of Functional and Health Compounds

Consumer demand for convenience has led to large quantities of seafood being value-added processed before marketing, resulting in large amounts of marine by-products being generated by processing industries. Several bioconversion processes have been proposed to transform some of these by-products. In addition to their relatively low value conventional use as animal feed and fertilizers, several investigations have been reported that have demonstrated the potential to add value to viscera, heads, skins, fins, trimmings, and crab and shrimp shells by extraction of lipids, bioactive peptides, enzymes, and other functional proteins and chitin that can be used in food and pharmaceutical applications. This chapter is focused on reviewing the opportunities for utilization of these marine by-products. The chapter discusses the various products and bioactive compounds that can be obtained from seafood waste and describes various methods that can be used to produce these products with the aim of highlighting opportunities to add value to these marine waste streams.

Separation and Characterization of Antioxidative and Angiotensin Converting Enzyme Inhibitory Peptide from Jellyfish Gonad Hydrolysate

The gonad of jellyfish (RhopilemaesculentumKishinouye), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptides were characterized with HPLC-MS/MS. One peptide with amino acid sequence Ser-Tyr (SY) was identified and synthesized, which showed good ACE inhibitory and antioxidant activity. The IC50 of this peptide on DPPH, ·OH, super oxygen anion scavenging activities, and ACE inhibitory activity are 84.623 μM, 1177.632 μM, 456.663 μM, and 1164.179 μM, respectively. The anchor in the binding site of SY and ACE C-domain (ACE-C) was obtained by molecular simulations. The results showed that the dipeptide purified from jellyfish gonad protein hydrolysates can be used as functional food material and is helpful in the study of antioxidant and inhibition of ACE.