Recent Advances in the Recovery and Improvement of Functional Proteins from Fish Processing By-Products: Use of Protein Glycation as an Alternative Method

Flavor Characterization of Animal Hydrolysates and Potential of Glucosamine in Flavor Modulation

Bovine (meat and heart) and porcine (hemoglobin and plasma) raw materials were hydrolyzed by Protease A (both endo- and exopeptidase activity), with or without glucosamine added during the enzyme inactivation step. Hydrolysates were characterized via peptide analysis (yield, UV- and fluorescence scanning spectroscopy, and peptide size distribution via size exclusion chromatography), sensory evaluation, and volatile compound analysis via gas chromatography mass-spectrometry (GC-MS) to determine if glucosamine-induced Maillard reaction improved taste and flavor. Porcine hemoglobin produced the most flavor-neutral hydrolysate, and could expectedly have the broadest application in food products. Both bovine meat and -heart hydrolysates were high in umami, and thereby good candidates for savory applications. Porcine plasma hydrolysate was high in liver flavor and would be suitable for addition to certain meat products where liver flavor is desirable. All hydrolysates had low perceived bitterness. Glucosamine-induced Maillard reaction had just a minor influence on the sensory profile via an increased perception of sweet taste (p = 0.038), umami taste (p = 0.042), and yolk flavor (p = 0.038) in the hydrolysates, irrespective of raw material. Glucosamine addition had a statistically significant effect on 13 of 69 volatiles detected in the hydrolysates, but the effect was minor and raw material-specific.

Adverse Effects of Thermal Food Processing on the Structural, Nutritional, and Biological Properties of Proteins

Thermal processing is one of the most important processing methods in the food industry. However, many studies have revealed that thermal processing can have detrimental effects on the nutritional and functional properties of foods because of the complex interactions among food components. Proteins are essential nutrients for humans, and changes in the structure and nutritional properties of proteins can substantially impact the biological effects of foods. This review focuses on the interactions among proteins, sugars, and lipids during thermal food processing and the effects of these interactions on the structure, nutritional value, and biological effects of proteins. In particular, the negative effects of modified proteins on human health and strategies for mitigating these detrimental effects from two perspectives, namely, reducing the formation of modified proteins during thermal processing and dietary intervention in vivo, are discussed.

Trehalose and alginate oligosaccharides increase the stability of muscle proteins in frozen shrimp (Litopenaeus vannamei)

The stability of muscle proteins improved during frozen storage.

Protein-peptide nutritional material prepared from surimi wash-water using immobilized chymotrypsin-trypsin

BACKGROUND

In the production process of surimi, large quantities of wastewater are produced. Thus it would be interesting to develop an efficient protocol for the recovery of protein from hairtail surimi wash-water.

RESULTS

A technique involving the use of immobilized chymotrypsin-trypsin (I-CT) was developed, providing a practical method for the preparation of protein-peptide nutritional material (PPNM). Under optimized reaction conditions, the recovery rate of nitrogen of surimi wash-water was measured as 98.3 ± 2.9%. Nutritional evaluation of the protein-peptide fraction demonstrated that it contained all essential amino acids (EAA) for humans, accounting for 44.1% of the total amino acid (TAA) content, which was determined to be 78.2 g per 100 g dry matter. The essential amino acid index (EAAI) and biological value (BV) were 101.7 (>95) and 76.7 respectively. A wide range of volatile flavor compounds (>50), including aldehydes, ketones, alcohols, hydrocarbons and heterocyclic compounds, were identified in PPNM by gas chromatography/mass spectrometry (GC/MS) analysis.

CONCLUSION

An efficient and practical protocol for the recovery of protein from hairtail surimi wash-water has been developed. The PPNM prepared in this work could be used as a nutraceutical and as an ingredient of functional foods. © 2016 Society of Chemical Industry.

Chemical characterization of the glycated myofibrillar proteins from grass carp (Ctenopharyngodon idella) and their impacts on the human gut microbiota in vitro fermentation

Glycation greatly increased the anti-digestibility of myofibrillar proteins derived from grass carp, and affected the production of SCFAs and the microbial community structures inin vitrofecal fermentation.

A comparative study of physicochemical and functional properties of silver carp myofibrillar protein glycated with glucose and maltodextrin

Myofibrillar protein (Mf) from silver carp (Hypophthalmichthys molitrix) was incubated with glucose and maltodextrin for 0–96 h at 50 °C and 75% relative humidity to obtain glycoconjugates in different periods of the Maillard reaction.

Protein hydrolysates produced from rock lobster (Jasus edwardsii) Head: emulsifying capacity and food safety

Lobster protein hydrolysates (LPH) were produced by an enzymatic process using a proteinase Alcalase, and a chemical process at strong alkaline condition (pH of 14), from rock lobster head (RLH), respectively. The chemical process recovered about 30% more protein than the enzymatic process (84.9% recovery of total protein in RLH by the chemical process and 54.5% recovery of total protein in RLH by the enzymatic process). The emulsifying capacity of LPH produced by the chemical process (69.7 m2/g) was significantly higher than the emulsifying capacity of the LPH produced by the enzymatic process (20.7 m2/g), and also exceeds the emulsifying capacity of cow gelatine (50.3 m2/g), a commercial emulsifier in the food industry. LPH produced by the chemical process possess 30.3% essential amino acids. This content is comparable with the essential amino acid content of fish protein, a commonly recognized food resource for essential amino acid supplement for human. The content of heavy metals, including inorganic arsenic, of LPH is lower than the standard levels regulated by Food Standard Australia and New Zealand (FSANZ). These results demonstrated the potential value of LPH used as a safe emulsifier with significant nutritional value for the food industry.

Enzymes from Seafood Processing Waste and Their Applications in Seafood Processing

Commercial fishery processing results in discards up to 50% of the raw material, consisting of scales, shells, frames, backbones, viscera, head, liver, skin, belly flaps, dark muscle, roe, etc. Besides, fishing operations targeted at popular fish and shellfish species also result in landing of sizeable quantity of by-catch, which are not of commercial value because of their poor consumer appeal. Sensitivity to rapid putrefaction of fishery waste has serious adverse impact on the environment, which needs remedial measures. Secondary processing of the wastes has potential to generate a number of valuable by-products such as proteins, enzymes, carotenoids, fat, and minerals, besides addressing environmental hazards. Fishery wastes constitute good sources of enzymes such as proteases, lipases, chitinase, alkaline phosphatase, transglutaminase, hyaluronidase, acetyl glycosaminidase, among others. These enzymes can have diverse applications in the seafood industry, which encompass isolation and modification of proteins and marine oils, production of bioactive peptides, acceleration of traditional fermentation, peeling and deveining of shellfish, scaling of finfish, removal of membranes from fish roe, extraction of flavors, shelf life extension, texture modification, removal of off-odors, and for quality control either directly or as components of biosensors. Enzymes from fish and shellfish from cold habitats are particularly useful since they can function comparatively at lower temperatures thereby saving energy and protecting the food products. Potentials of these applications are briefly discussed.

Aqueous two phase partitioning of fish proteins: partitioning studies and ATPS evaluation

A suitable Aqueous Two Phase System (ATPS) has been identified for the partitioning of crude fish proteins from fish processing industrial effluent. A detailed study has been performed to analyze the influence of various parameters on protein partitioning such as molecular weight of PEG, effect of different salts (MgSO4, K2HPO4, Na3C6H5O7, Na2SO4, (NH4) 2PO4, K3C6H5O7) and their concentrations, pH, temperature, Tie Line Length (TLL), effluent loading and volume ratio. PEG 2000 - sodium sulphate ATPS was found to be a most favourable system among the selected ATPS for higher partition coefficient of proteins. The binodal curve and equilibrium characteristics of PEG 2000 - sodium sulphate were established and fitted to empirical equations. The equilibrium compositions (tie line) were correlated using Othmer-Tobias and Bancroft equations.

Significance of antioxidants for seafood safety and human health

The demand for high-quality seafood products is constantly growing worldwide. Nevertheless, seafood is susceptible to rapid rancidity mainly due to lipid oxidation and microbiological spoilage. Thus, treatment with antioxidants offers a preservation technique that can prolong the shelf life of seafood. However, because of food safety and health concerns about the use of synthetic antioxidants, there is growing interest in the application of natural antioxidants, mainly plant extracts and compounds, as an alternate means of confronting the problem of lipid oxidation. In this review, up-to-date information and recent discoveries about different naturally occurring antioxidants on the oxidation progress, synthetic antioxidants and their health concerns, health benefits of antioxidants, antioxidants used for seafood, and food safety concerns are addressed. The antibacterial effects of natural antioxidants are also reviewed. Finally, the most effective methods for analyzing a wide range of antioxidants in plants are described.