CONCLUSIONS

Onshore strategies for valorising discarded Southwest Atlantic butterfish (Stromateus brasiliensis)

Graciela Ramilo-Fernández, Marta Pérez-Testa, Helena Pazó, Ricardo I. Pérez-Martín and Carmen G. Sotelo*

Food Biochemistry Group, Marine Research Institute (IIM) - Spanish National Research Council (CSIC)

AKNOWLEDGEMENTSThis work was supported by ARVI (Cooperativa de Armadores de Pesca del Puerto de Vigo) in the frame of the study “Valorización de especies no comerciales de la flota de buques congeladores (OPPC-3)”. The authors want to thank WALVISfish for providing the fish, and PROQUIPSA for testing the skin leather production.

* carmen@iim.csic.es

Southwest Atlantic butterfish (Stromateus brasiliensis) is a demersal-pelagic fish which is abundant in some

areas of FAO 41, where many trawlers operate targeting different species such as the Argentinian squid

(Illex argentines) or hake (Merluccius hubbssi). This butterfish species is caught and discarded by these

fleet with discard rates of 90 % or higher (IEO 2010-2014).

There is not a consensus about whether Butterfishes of the genus Stromateus can be safely consumed by

humans since it has been described that problems related with the type of fat, present in these fish, may

produce some mild gastrointestinal issues. A sustainable use of resources as it is established in the

European Common Fishery Policy suggests to find alternative uses for discarded fish. Proteins are one of

the main components of organisms such as fish and, therefore, one valorisation strategy could be to obtain

protein products from the main sources of proteins of discarded fish, such as skin and muscles.

Lyophilized collagen

Collagen were extracted in three stages: (F1) with 0,5 N acetic acid (1:10 w/v) 24 h; (F2) with 0,1 % pepsin in 0.5

N acetic acid (1:10 w/v) 24 h; (F3) with 0,5 N acetic acid (1:10 w/v) 24 h, with a previous treatment with EDTA.

Lyophilized collagen were separated in 7% acrylamide-0,24 % bis-acrylamide gels and subjected to electrophoresis

at a constant current of 15 mA. Gels were stained with 0.04% Coomassie Blue in 25% v/v ethanol and 8% v/v

acetic acid for 30 min at 60°C.

PRODUCTION OF COLLAGEN

PRODUCTION OF FISH PROTEIN HYDROLYSATES

7,82

10,38

55,48

16,02

5,69

Yield (%)

Head

Viscera

Muscle

Skin

Bones

Characterization of the resource

Hydrolysis reaction: 15 g of muscle + 75 ml of water (1:5 w/v)

pH=8 (addition of 1 M NaOH)

Temperature: 55 °C

Enzyme: 150 µl of Alcalase (1% v/w of muscle)

Time: 4 h (under constant stirring)

Stop the reaction: 90 °C for 5 min

Centrifugation: 10000 x g for 10 min at 10 °C

The supernatants were filtrated and lyophilized

FISH SKIN LEATHER PRODUCTION

The production of leather from Stromateus

brasiliensis skins was not suitable because due to

the slim dermis, the separation of the adhering

flesh was difficult and some holes were produced,

also during the tanning process.

0

5

10

15

20

25

30

0 50 100 150 200 250

De

gre

e h

yd

roly

sis

(%

)

Hydrolysis time (min)

Yield: 50 %

Lipid Protein Ash

16,08 % 16,58 % 1,37 %

Proximal composition of S.brasiliensis muscle (wet basis)

Headed and gutted fish

Bones and skins

Mince

Solutions in land

Amino acid ‰

Aspartic acid 107

Threonine 55

Serine 58

Glutamic acid 144

Hidroxyproline 3

Proline 42

Glycine 84

Alanine 93

Cysteine 6

Valine 47

Methionine 31

Isoleucine 38

Leucine 83

Tyrosine 27

Phenylalanine 32

Hidroxylysine 2

Histidine 19

Lysine 81

Arginine 44

Figure 1. SDS-PAGE pattern from three Stromateus brasiliensis

individuals (SBRA 1, SBRA 2 and SBRA 3). F1, F2, and F3 are the

collagen fractions extracted.

Waste

Value added products

for textile industries

• Stromateus brasiliensis has a high muscle and skin-bones yields. Mechanical separation of muscle and frames

in this species is possible. Muscle hydrolysis and collagen extraction can be considered an optimum combined

strategy to efficiently upgrading this biomass. Protein hydrolysates and Type I collagen have several industrial

applications.

Glycine, alanine and prolinewere the most abundantamino acids in SBRA collagen

Yield (%)

Samples Dry weight basis Wet weight basis

Fraction 1 5,0 ± 0,83 2,3 ± 0,39

Fraction 2 4,3 ± 0,61 2,0 ± 0,29

Fraction 3 0,4 ± 0,19 0,2 ± 0,09

Combined yield 9,7 ± 0,1 4,5 ± 0,2

Glutamic acid, aspartic acid and alanine were themost abundant amino acids in the hydrolysates

• Conversion of waste (fish skin) into value added products for textile industries is an option that should be

tested in other species because it would contribute to the protection of the environment from pollution.

Bellido, J. M, et al . Hydrobiologia 2011, 670 (1), 317–333.); Lopes, C., et al. Waste Manag. 2015, 46, 103–112.; Sotelo, C. G.,, et al. J. Aquat. Food Prod. Technol. 2016, 25 (3), 388–399. ; Wang, S., et al. Food Science and Technology (Campinas), (AHEAD), 0-0.; Li, Z. R., et al FoodHydrocoll. 2013, 31 (1), 103–113; Blanco, M., et al. J. Food Biochem. 2015, 39 (4), 368–376.; Chalamaiah, M., et al. Food Chem. 2012, 135 (4), 3020–3038; Huang, Y. R., et al. Food Hydrocoll. 2011, 25 (6), 1507–1513; Duraisamy, R. International Journal of Engineering Trends andTechnology (IJETT), V39(1),10-20, 2016.

REFERENCES

Table 1. Yields (%) of the three collagen fractions from skin and

bones. The results are the mean of three replicates ± standard

deviation.

Table 2. Amino acid profile of S.brasiliensis

hydrolysates (residues/1000 residues). The results

are the mean of three replicates.

Figure 2. Degree hydrolysis curve for Stromateus brasiliensis with Alcalase.

Values are the mean of three replicates analysis. Error bars represent

standard deviation.

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