Coupling of ultrafiltration and enzymatic hydrolysis aiming at valorizing shrimp wastewater

Flavor profile and role of macromolecules in the flavor generation of shrimp meat and valorization of shrimp by-products as a source of flavor compounds: a review

Shrimps are a widely cultivated species among crustaceans worldwide due to their nutritional profile and delicacy. Because of their unique flavor, shrimp-based food products are gaining consumer demand, so there is a need to understand the flavor chemistry of shrimp meat. Further, the processing and macromolecules of shrimp meat play a significant role in flavor generation and suggest a focus on their research. However, shrimp processing generates a large amount of solid and liquid waste, creating disposal problems and environmental hazards. To overcome this, utilizing these waste products, a rich source of valuable flavor compounds is necessary. This review comprehensively discusses the nutritional aspects, flavor profile, and role of macromolecules in the flavor generation of shrimp meat. Besides, recent trends in analyzing the aroma profile of shrimp and the benefits of shrimp by-products as a source of flavor compounds have been addressed. The delicious flavor of shrimp meat is due to its volatile and nonvolatile flavor compounds. Proteins play a major role in the textural and flavor adsorption properties of shrimp meat-based products. Green extraction technologies, especially ultrasonication, are recommended for valorizing shrimp by-products as a source of flavor compounds, which have enormous applications in the food and flavor industries.

Guamara and Cocuixtle: Source of Proteases for the Transformation of Shrimp By-Products into Hydrolysates with Potential Application

Since the fruits of Bromelia pinguin and Bromelia karatas are rich in proteases, the aim of this research was to optimize the hydrolysis process of cooked white shrimp by-products due to the effect of these proteases. A robust Taguchi L_16' design was used to optimize the hydrolysis process. Similarly, the amino acid profile by GC-MS and antioxidant capacity (ABTS and FRAP) were determined. The optimal conditions for hydrolysis of cooked shrimp by-products were pH 8.0, 30 °C, 0.5 h, 1 g of substrate and 100 µg/mL of B. karatas, pH 7.5, 40 °C, 0.5 h, 0.5 g substrate and 100 µg/mL enzyme extract from B. pinguin and pH 7.0, 37 °C, 1 h, 1.5 g substrate and 100 µg/mL enzyme bromelain. The optimized hydrolyzates of B. karatas B. pinguin and bromelain had 8 essential amino acids in their composition. The evaluation of the antioxidant capacity of the hydrolyzates under optimal conditions showed more than 80% inhibition of in ABTS radical, B. karatas hydrolyzates had better higher ferric ion reduction capacity with 10.09 ± 0.02 mM TE/mL. Finally, the use of proteolytic extracts from B. pinguin and B. karatas to optimize hydrolysis process allowed obtaining hydrolyzates of cooked shrimp by-products with potential antioxidant capacity.

Integrated ultrafiltration, nanofiltration, and reverse osmosis pilot process to produce bioactive protein/peptide fractions from sardine cooking effluent

Sardine cooking effluents contain a high level of organic matter, such as proteins and lipids, which allows them to be forward into a chain exploiting high added-value compounds attained from these effluents, increasing their economic value while reducing their environmental effect. Thus, the purpose of this work was to develop an innovative pilot-scale integrated membrane process, with or without enzymatic hydrolysis, to obtain fractions with high protein/peptide and low NaCl contents, as well as optimized bioactive properties. The research strategy followed involved the use of ultrafiltration (UF) and nanofiltration (NF) technologies of the pretreated sardine cooking effluent followed by reverse osmosis (RO) at a pilot scale levels. Moreover, it allowed for the attainment of fractions rich in protein/peptides that might be used in the food, pharmaceutical, or cosmetic industries, particularly after RO, as they present a lower NaCl content. The RO retentate (hydrolyzed sample) coupled with UF and NF resulted in the fractions with the best bioactive properties (higher antioxidant capacity and antimicrobial activity) of all the analyzed samples. Overall, the current work demonstrated the feasibility of exploiting liquid by-products as a source of functional components as well as reinforcing this strategy's potential relevance in future effective management strategies for this type of effluents.

Functional proteins through green refining of seafood side streams

Scarcity of nutritive protein is a major global problem, the severity of which is bound to increase with the rising population. The situation demands finding additional sources of proteins that can be both safe as well as acceptable to the consumer. Food waste, particularly from seafood is a plausible feedstock of proteins in this respect. Fishing operations result in appreciable amounts of bycatch having poor food value. In addition, commercial processing results in 50 to 60% of seafood as discards, which consist of shell, head, fileting frames, bones, viscera, fin, skin, roe, and others. Furthermore, voluminous amounts of protein-rich effluents are released during commercial seafood processing. While meat from the bycatch can be raw material for proteinous edible products, proteins from the process discards and effluents can be recovered through biorefining employing upcoming, environmental-friendly, low-cost green processes. Microbial or enzyme treatments release proteins bound to the seafood matrices. Physico-chemical processes such as ultrasound, pulse electric field, high hydrostatic pressure, green solvent extractions and others are available to recover proteins from the by-products. Cultivation of photosynthetic microalgae in nutrient media consisting of seafood side streams generates algal cell mass, a rich source of functional proteins. A zero-waste marine bio-refinery approach can help almost total recovery of proteins and other ingredients from the seafood side streams. The recovered proteins can have high nutritive value and valuable applications as nutraceuticals and food additives.

Simultaneous hydrolysis of various protein-rich industrial wastes by a naturally evolved protease from tannery wastewater microbiota

Elimination of protein-rich waste materials is one of the vital environmental protection requirements. Using of non-naturally occurring chemicals for their remediation properties can potentially induce new pollutants. Therefore, enzymes encoded in the genomes of microorganisms evolved in the same environment can be considered suitable alternatives to chemicals. Identification of efficient proteases that can hydrolyze recalcitrant, protein-rich wastes produced by various industrial processes has been widely welcomed as an eco-friendly waste management strategy. In this direction, we attempted to screen a thermo-halo-alkali-stable metagenome-derived protease (PersiProtease1) from tannery wastewater. The PersiProtease1 exhibited high pH stability over a wide range and at 1 h in pH 11.0 maintained 87.59% activity. The enzyme possessed high thermal stability while retaining 76.64% activity after 1 h at 90 °C. Moreover, 65.34% of the initial activity of the enzyme remained in the presence of 6 M NaCl, showing tolerance against high salinity. The presence of various metal ions, inhibitors, and organic solvents did not remarkably inhibit the activity of the discovered protease. The PersiProtease1 was extracted from the tannery wastewater microbiota and efficiently applied for biodegradation of real sample tannery wastewater protein, chicken feathers, whey protein, dehairing sheepskins, and waste X-ray films. PersiProtease1 proved its enormous potential in simultaneous biodegradation of solid and liquid protein-rich industrial wastes based on the results.

Biochemical Characterization and Storage Stability of Process Waters from Industrial Shrimp Production

Shrimp boiling water (SBW) and shrimp peeling water (SPW), generated during shrimp processing, were characterized in terms of crude composition, volatile compounds, as well as nutritional and potentially toxic elements over a 13 month sampling period. The storage stability of both waters was also evaluated. Results showed that SBW contained on median 14.8 g/L protein and 2.2 g/L total fatty acids with up to 50% comprising eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Astaxanthin esters, which dominated the total astaxanthin, were 2.8 mg/L on median. SPW, on the other hand, contained on median 1.0 g/L of protein, 0.21 g/L of total fatty acids, and 1.2 mg/L astaxanthin esters. For both side-streams, essential amino acids were up to 50% of total amino acids. For SBW and SPW, the most abundant nutritional elements were Na, K, P, Ca, Cu, and Zn. The contents of all potentially toxic elements were below the detection limits, except for As. SBW was more stable at 4 °C compared to SPW as shown, e.g., by thiobarbituric acid reactive substances and relative changes in total volatile basic nitrogen. The extensive compositional mapping of SBW/SPW provides crucial knowledge necessary in the exploitation and value-adding of such side-streams into food or feed products.

Valorization of Seafood Processing Discards: Bioconversion and Bio-Refinery Approaches

The seafood industry generates large volumes of waste. These include processing discards consisting of shell, head, bones intestine, fin, skin, voluminous amounts of wastewater discharged as effluents, and low-value under-utilized fish, which are caught as by-catch of commercial fishing operations. The discards, effluents, and by-catch are rich in nutrients including proteins, amino acids, lipids containing good proportions of polyunsaturated fatty acids (PUFA), carotenoids, and minerals. The seafood waste is, therefore, responsible for loss of nutrients and serious environmental hazards. It is important that the waste is subjected to secondary processing and valorization to address the problems. Although chemical processes are available for waste treatment, most of these processes have inherent weaknesses. Biological treatments, however, are environmentally friendly, safe, and cost-effective. Biological treatments are based on bioconversion processes, which help with the recovery of valuable ingredients from by-catch, processing discards, and effluents, without losing their inherent bioactivities. Major bioconversion processes make use of microbial fermentations or actions of exogenously added enzymes on the waste components. Recent developments in algal biotechnology offer novel processes for biotransformation of nutrients as single cell proteins, which can be used as feedstock for the recovery of valuable ingredients and also biofuel. Bioconversion options in conjunction with a bio-refinery approach have potential for eco-friendly and economical management of seafood waste that can support sustainable seafood production.

Impact of MWCO and Dopamine/Polyethyleneimine Concentrations on Surface Properties and Filtration Performance of Modified Membranes

The mussel-inspired method has been investigated to modify commercial ultrafiltration membranes to induce antifouling characteristics. Such features are essential to improve the feasibility of using membrane processes in protein recovery from waste streams, wastewater treatment, and reuse. However, some issues still need to be clarified, such as the influence of membrane pore size and the polymer concentration used in modifying the solution. The aim of the present work is to study a one-step deposition of dopamine (DA) and polyethyleneimine (PEI) on ultrafiltration membrane surfaces. The effects of different membrane molecular weight cut-offs (MWCO, 20, 30, and 50 kDa) and DA/PEI concentrations on membrane performance were assessed by surface characterization (FTIR, AFM, zeta potential, contact angle, protein adsorption) and permeation of protein solution. Results indicate that larger MWCO membranes (50 kDa) are most benefited by modification using DA and PEI. Moreover, PEI is primarily responsible for improving membrane performance in protein solution filtration. The membrane modified with 0.5:4.0 mg mL^-1 (DA: PEI) presented a better performance in protein solution filtration, with only 15% of permeate flux drop after 2 h of filtration. The modified membrane can thus be potentially applied to the recovery of proteins from waste streams.

Valorization of snow crab (Chionoecetes opilio) cooking effluents for food applications

BACKGROUND

Seafood processing generates significant amounts of solid and liquid waste in the environment. Such waste represents a potential source of high-value biomolecules for food, pharmaceutic and cosmetic applications. There are very few studies on the valorization of wastewaters compared to solid by-products. However, cooking waters are characterized by a high organic polluting load, which could contain valuable molecules such as proteins, pigments and flavor compounds. Snow crab (Chionoecetes opilio) processing is included among the most important processes in Canadian fisheries, although its cooking effluent composition is not well characterized.

RESULTS

The present study concentrated and valorized the biomass in snow crab cooking wastewaters for the development of products for food applications. A membrane process was designed and optimized to concentrate the effluents. The chemical composition of the concentrates was analyzed, including characterizing the flavor profile compounds. The extracts were mainly composed of proteins (592 g kg^-1 ) and minerals (386 g kg^-1 ) and contained desirable flavor compounds. Their functional properties (solubility, water-holding capacity, oil-holding capacity) and antioxidant activities were also assessed, and their safety was verified.

CONCLUSION

The cooking effluents generated by snow crab processing facilities, usually considered as waste, can be concentrated and turned into a natural aroma for the food industry. © 2019 Society of Chemical Industry.

Characterization, Preparation, and Purification of Marine Bioactive Peptides

Marine bioactive peptides, as a source of unique bioactive compounds, are the focus of current research. They exert various biological roles, some of the most crucial of which are antioxidant activity, antimicrobial activity, anticancer activity, antihypertensive activity, anti-inflammatory activity, and so forth, and specific characteristics of the bioactivities are described. This review also describes various manufacturing techniques for marine bioactive peptides using organic synthesis, microwave assisted extraction, chemical hydrolysis, and enzymes hydrolysis. Finally, purification of marine bioactive peptides is described, including gel or size exclusion chromatography, ion-exchange column chromatography, and reversed-phase high-performance liquid chromatography, which are aimed at finding a fast, simple, and effective method to obtain the target peptides.

Enzymatic Processes in Marine Biotechnology

In previous review articles the attention of the biocatalytically oriented scientific community towards the marine environment as a source of biocatalysts focused on the habitat-related properties of marine enzymes. Updates have already appeared in the literature, including marine examples of oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases ready for food and pharmaceutical applications. Here a new approach for searching the literature and presenting a more refined analysis is adopted with respect to previous surveys, centering the attention on the enzymatic process rather than on a single novel activity. Fields of applications are easily individuated: (i) the biorefinery value-chain, where the provision of biomass is one of the most important aspects, with aquaculture as the prominent sector; (ii) the food industry, where the interest in the marine domain is similarly developed to deal with the enzymatic procedures adopted in food manipulation; (iii) the selective and easy extraction/modification of structurally complex marine molecules, where enzymatic treatments are a recognized tool to improve efficiency and selectivity; and (iv) marine biomarkers and derived applications (bioremediation) in pollution monitoring are also included in that these studies could be of high significance for the appreciation of marine bioprocesses.

Enzyme-Assisted Discovery of Antioxidant Peptides from Edible Marine Invertebrates: A Review

Marine invertebrates, such as oysters, mussels, clams, scallop, jellyfishes, squids, prawns, sea cucumbers and sea squirts, are consumed as foods. These edible marine invertebrates are sources of potent bioactive peptides. The last two decades have seen a surge of interest in the discovery of antioxidant peptides from edible marine invertebrates. Enzymatic hydrolysis is an efficient strategy commonly used for releasing antioxidant peptides from food proteins. A growing number of antioxidant peptide sequences have been identified from the enzymatic hydrolysates of edible marine invertebrates. Antioxidant peptides have potential applications in food, pharmaceuticals and cosmetics. In this review, we first give a brief overview of the current state of progress of antioxidant peptide research, with special attention to marine antioxidant peptides. We then focus on 22 investigations which identified 32 antioxidant peptides from enzymatic hydrolysates of edible marine invertebrates. Strategies adopted by various research groups in the purification and identification of the antioxidant peptides will be summarized. Structural characteristic of the peptide sequences in relation to their antioxidant activities will be reviewed. Potential applications of the peptide sequences and future research prospects will also be discussed.

Optimization of the Extraction and Stability of Antioxidative Peptides from Mackerel (Pneumatophorus japonicus) Protein

This study optimizes the preparation conditions for mackerel protein hydrolysate (MPH) by response surface methodology (RSM) and investigates the stability of the antioxidant activity of MPHs (<2.5 kDa). The optimal conditions were as follows: enzyme concentration of 1726.85 U/g, pH of 7.00, temperature of 39.55°C, time of 5.5 h, and water/material ratio of 25 : 1, and the maximum DPPH scavenging activity was 79.14%. The MPHs indicated significant cellular antioxidant activity at low concentrations. Furthermore, the temperature and freeze-thaw cycles had little effect on the antioxidative stability while pH had significant effect on the antioxidative stability. In addition, the MPHs were sensitive to the metal ions, such as Fe2+, Fe3+, Zn2+, and Cu2+. Notably, when the concentrations of Fe2+ and Fe3+ were 5 mM, the DPPH scavenging activities were only 1.1% and 0.6%, respectively; furthermore, Cu2+ at a 5 mM concentration could completely inhibit the DPPH scavenging activity of MPHs. In contrast, K+ and Mg2+ had no notable effect on the antioxidant activity of MPHs. These results may provide a scientific basis for the processing and application of MPHs.