Chemical and Physicochemical Properties of Tilapia (Oreochromis niloticus) Fish Protein Hydrolysate and Concentrate

Comparison of Commercial Fish Proteins' Chemical and Sensory Properties for Human Consumption

To stop overfishing and meet the protein needs of a growing population, more information is needed on how to use marine by-catches, by-products, and undervalued fish species for human consumption. Turning them into protein powder is a sustainable and marketable way to add value. However, more knowledge of the chemical and sensory properties of commercial fish proteins is needed to identify the challenges in developing fish derivatives. This study aimed to characterize the sensory and chemical properties of commercial fish proteins to compare their suitability for human consumption. Proximate composition, protein, polypeptide and lipid profiles, lipid oxidation, and functional properties were analyzed. The sensory profile was compiled using generic descriptive analysis, and odor-active compounds were identified with gas-chromatography-mass spectrometry-olfactometry (GC-MS/O). Results indicated significant differences in chemical and sensory properties between processing methods but not between fish species. However, the raw material had some influence in the proteins' proximate composition. Bitterness and fishiness were the main perceived off-flavors. All samples, apart from hydrolyzed collagen, had intense flavor and odor. Differences in odor-active compounds supported the sensory evaluation results. The chemical properties revealed that the lipid oxidation, peptide profile, and raw material degradation are likely affecting the sensory properties of commercial fish proteins. Limiting lipid oxidation during processing is crucial for the development of mild-tasting and -smelling products for human consumption.

Fish By-Products: A Source of Enzymes to Generate Circular Bioactive Hydrolysates

Fish viscera are usually discarded as waste, causing environmental problems, or as low-value by-products. This study describes a self-sufficient and zero waste approach to obtain enzymes and protein hydrolysates from fish by-products. Firstly, recovery steps of viscera enzymatic extract were applied, and the resulting raw extract was stable at a pH range of 8-9 and at temperatures between 40 and 50 °C. The application of the extracted enzymes and alcalase on fish by-products hydrolysis was also determined. The selected conditions for the enzymatic hydrolysis were 10% (E/S) for 6 h using viscera enzymatic extract and 3% (E/S) for 2 h using alcalase. Fish protein hydrolysates (FPH) proved to have a notable antioxidant capacity with similar activity, ~11 mg ascorbic acid/g dry extract (ABTS assay) and ~150 mg Trolox/g dry extract (ORAC assay). FPH were also able to inhibit the angiotensin-converting enzyme, however, alcalase hydrolysates revealed a higher antihypertensive potential, IC₅₀ of 101 µg of protein/mL. In general, FPH obtained by both enzymes systems maintained these bioactivities after the passage throughout a simulated gastrointestinal tract. The hydrolysates also displayed important technological properties, namely oil absorption capacity (~1 g oil/g sample) and emulsifying property (~40%). Therefore, it will be conceivable to use fish by-products based on a circular economy approach to generate added value compounds for animal and human nutrition.

Production and Evaluation of Quality Characteristics of Edible Fish Powder from Tilapia (Oreochromis mossambicus) and Silver Carp (Hypophthalmichthys molitrix)

Fish is recognised as the most nutritious animal protein source, but because of its high deterioration nature, a huge number of fish are being wasted and susceptible to nutritional losses, resulting in a significant hurdle for expanding fish production. This research aimed to lessen these losses through the use of fish powder and to enhance the nutrients in people’s diets. In order to prepare fine fish powder, a dried fish paste was milled and sieved. Proximate analysis, mineral content, and physical and microbiological qualities were determined using standard analytical procedures. The protein content of Tilapia and Silver Carp fish powder was 63.63 g/100 g and 73.58 g/100 g, respectively. An appreciable amount of potassium, calcium, magnesium, phosphorus, iron, and zinc was also found in Tilapia and Silver Carp fish powder. The powder also holds an angle of repose of 29.4° and 26.7°, which assures a good flow property. Both Tilapia and Silver Carp fish powder have shown a near neutral pH value (6.40 and 6.32). The hedonic rating scale was used to assess the acceptability of fish powder-fortified cakes. The results showed that the cake fortified with Silver Carp fish powder outperforms the control and Tilapia fish powder sample in terms of taste, flavour, colour, texture, and overall acceptance, while the panellists also preferred the Tilapia fish powder sample. As a result of this research, a high-quality nutritious fish powder from Tilapia and Silver Carp can be prepared and adopted as a food fortifier.

Evaluation of Dietary Soluble Extract Hydrolysates with or without Supplementation of Inosine Monophosphate Based on Growth, Hematology, Non-Specific Immune Responses and Disease Resistance in Juvenile Nile Tilapia Oreochromis niloticus

Simple Summary

This study was conducted to elucidate the effects of dietary soluble extract hydrolysates obtained from fishery by-products, such as shrimp soluble extract (SSE), tilapia soluble extract (TSE) and squid soluble extract (SQSE). Furthermore, we used a nucleotide, inosine monophosphate (IMP), as an additive in different concentrations along with shrimp soluble extract to understand their effects on growth, immunity and disease resistance in juvenile Nile tilapia. Our results demonstrated that dietary SSE could improve growth performance, non-specific immune responses and disease resistance against pathogenic bacteria Aeromonas hydrophila in juvenile Nile tilapia. Moreover, IMP did not add further benefits to the SSE diet. Further research is needed to better understand the effects of fishery by-products and IMP on fish diets.

Abstract

We performed an 8-week feeding trial to evaluate dietary soluble extract hydrolysates from fishery by-products, such as shrimp soluble extract (SSE) with or without inosine monophosphate (IMP), tilapia soluble extract (TSE) and squid soluble extract (SQSE), in juvenile Nile tilapia. A diet without feed additives was used as the control diet (CON); and five other experimental diets were formulated with 2% soluble extracts consisting of 100% SSE, 98% SSE + 2% IMP (SSEP₂), 96% SSE + 4% IMP (SSEP₄), 100% SQSE and 100% TSE. The diets were fed to 4.9 ± 0.07 g (mean ± SD) juvenile Nile tilapia in triplicate groups. The weight gain and specific growth rates of fish fed the SSE, SSEP₂ and SSEP₄ diets were significantly higher than those of fish fed the CON and SQSE diets. The superoxide dismutase activity levels of fish fed the SSE and SSEP₄ diets were significantly higher than those of fish fed the CON, SSEP₂, SQSE and TSE diets. Myeloperoxidase activity levels of fish fed the SSE and SSEP₄ diets were significantly higher than those of fish fed the CON, SSEP₂ and SQSE diets. Lysozyme activity levels of fish fed the SSEP₄ and SQSE diets were significantly higher than those of fish fed the SSE and SSEP₂ diets. Feed efficiency, protein efficiency ratio, survival rate, whole body proximate composition and hematological parameters were not significantly different among the groups. After ten days of challenge = against Aeromonas hydrophila, the cumulative survival rate of fish fed the SSE diet was significantly higher than those of fish fed the CON, SQSE and TSE diets. In conclusion, dietary shrimp soluble extract could improve the growth performance, non-specific immune responses and disease resistance in juvenile Nile tilapia, and inosine monophosphate did not add further benefits to this ingredient.

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.

Effect of oven drying and freeze drying on the antioxidant and functional properties of protein hydrolysates derived from freshwater fish (Cirrhinus mrigala) using papain enzyme

Fish protein hydrolysate (FPH) was prepared from fresh water fish Cirrhinus mrigala using papain and dried in oven (OD-FPH) and freeze dryer (FD-FPH). The electron micrographs of FD-FPH samples showed porous structure. The browning intensity of OD-FPH samples was higher than the FD-FPH samples. The DPPH (2, 2 Diphenyl-1-picrylhydrazyl) free radical scavenging activity and linoleic acid peroxidation inhibition activity of FPH were not affected by oven drying process. The sequential digestion of FPH with pepsin and pancreatin reduced the antioxidant properties in both OD-FPH and FD-FPH samples. The solubility of proteins in OD-FPH was lower at pH 5 while for that of FD-FPH it was at pH 7 with water as solvent. The surface active properties of FD-FPH samples were higher than OD-FPH samples. The oven drying of fish protein hydrolysates may be advocated considering the properties and cost of production.

Utilização de enzimas proteolíticas para produção de hidrolisados proteicos a partir de carcaças de frango desossadas manualmente

Resumo O emprego de hidrolisados proteicos, oriundos de fontes animais e vegetais, em formulações específicas, é uma área de crescente interesse. O objetivo deste trabalho foi desenvolver diferentes hidrolisados liofilizados com alto valor proteico, obtidos a partir da hidrólise enzimática de carcaças de frango manualmente desossadas (CMD), um subproduto da indústria avícola, que normalmente é utilizado para a fabricação de carne mecanicamente separada (CMS). A matéria-prima utilizada foram carcaças de frango desossadas manualmente e congeladas (CMD), provenientes de animais abatidos com aproximadamente 42 dias de vida e com peso médio de 2,5 kg, adquiridas em um abatedouro da região sul do Brasil. Antes de serem processadas, foram descongeladas sob temperatura de refrigeração e cortadas em pedaços menores com faca de aço inox para facilitar sua homogeneização durante o tempo de hidrólise. Foram utilizadas três enzimas comerciais, Papaína®, Flavourzyme® e Protamex®. A hidrólise ocorreu em banho termostatizado com temperatura, tempo e pH controlados. Foi realizada a composição proximal da matéria-prima e dos hidrolisados liofilizados, atividade de água dos hidrolisados liofilizados e foram feitas as seguintes análises de controle da hidrólise: grau de hidrólise, teores de proteínas, sólidos totais, cinzas, caracterização de aminoácidos dos hidrolisados, rendimento, percentual de hidrólise e cor dos hidrolisados. Os resultados foram submetidos à análise de variância e teste de Tukey para comparação de médias. O grau de hidrólise maior foi com a Protamex, seguido da Papaína e da Flavourzyme. O teor de proteínas após os 120 minutos de hidrólise não variou estatisticamente (p>0,05) entre a Papaína e a Flavourzyme. A composição de aminoácido demonstra que o hidrolisado obtido da Papaína possui uma composição mais próxima da recomendada pelos órgãos de controle. Concluiu-se que os hidrolisados proteicos obtidos da carcaça manualmente desossada (CMD) de frango apresentaram alto conteúdo proteico, caracterizando-se como matéria-prima promissora na formulação de dietas especiais.

Functional and antioxidative properties of protein hydrolysates from Cape hake by-products prepared by three different methodologies

BACKGROUND

The production of fish protein hydrolysates (FPH) is a convenient technology for upgrading fish by-products. The aim of this work was to study three different methods of FPH preparation from Cape hake by-products to improve yield and quality. Functional and antioxidative properties of all FPHs were determined.

RESULTS

The protein content of hake FPH was in the range 807-860 g kg(-1) and the degree of hydrolysis was between 19% and 22%. The maximum yield (71.9%) was achieved by methodology B but the hydrolysate was darker. The peptide profile of all FPHs was very similar. FPH prepared by methodology C had significantly higher emulsifying activity index and hydrolysate prepared by methodology B had the highest foaming capacity. The solubility of FPH was in the range 71-76% and increased the water-holding capacity of minced fish by about 9%. The fractionation of FPH obtained by methodologies A and B allowed concentrating peptides with higher radical scavenging activity and reducing power.

CONCLUSION

The properties of the FPH prepared indicated that they can be used in food systems as natural additives, particularly to improve their water-holding capacity.