On-board handling and preservation of anchovy (Engraulis anchoita) catches

On-board handling and preservation of anchovy (Engraulis anchoita) catches C. A. Castafirn and A. O. Barrai Instituto Nacional de Investigacirn y Desarrollo Pesquero (INIDEP), Casilla de Correo 175, 7600 Mar del Plata, Argentina Received 8 April 1988; revised 25 J u l y 1989

The anchovy of the Argentine Sea is an under-exploited resource due to the effect of economic and technological factors. Any proposal to increase the exploitation of this resource must consider on-board handling and preservation of the catch as critical points because the characteristics of the fish (high lipid contents, muscle fragility and a tendency to ventral bursting) make it a technologically fragile species. Three different on-board handling and preservation conditions are reviewed in this paper: (a) in bulk at environmental temperature (12°C); (b) in boxes with flake-ice, stored in a chamber at 0°C; and (c) in bulk inside insulated containers with a mixture of sea water and ice. Two tests were carried out aboard the INIDEP's R.V. Dr Eduardo L. Holmberg; in both instances the three conditions under consideration were simultaneously tried out with fish from the same catch. The variations of organoleptic assessment, total volatile basis, rancidity, moisture, chloride content and bacterial load were assessed for different storage periods. The results indicate that storage as in method (c) was the best of the three techniques assessed. (Keywords:anchovy; food storage; on-boardhandling;insulatedcontainers)

Manutention et conservation d'anchois (Engraulis anchoita) bord de navires de p che L'anchois au large de l'Argentine est une ressource sous-exploitbe h cause de facteurs Oconomiques et technologiques. Pour favoriser la p~che de l'anchois, il convient de consid~rer deux phases critiques: la manutention et la conservation ~ bord des navires parce que, compte-tenu de ses propri~tOs (teneur ~lev~e en lipides, fragilitb des muscles et du ventre qui peut kclater facilement), l'anchois est, d'un point de rue technologique, ime espbce fragile. Cet article examine trois m~thodes diffbrentes de manutention et de conservation h bord." (a) en vrac, h 12°C; (b) dans des caisses avec de la glace en bcailles, entrepos~es dans une chambre ~ O°C," (c) en vrac dans des conteneurs isolOs avec un m~lange d'eau de mer et de glace. On a effectub deux essais h bord du navire expbrimental Dr Eduardo L. Homberg. Au cours de ces deux essais, les trois mkthodes ont btb simultanbment testbes avec des anchois provenant de la m~me pkche. On a btudib les variations des qualitbs organoleptiques, des bases volatiles totales, de la ranciditb, de l'humiditO, des populations bactbriennes et de la teneur en chlorure pour diffbrentes dur~es d'entreposaoe. Les rOsultats grit indiquk que, des trois m~thodes considbrOes, la troisibme (c) est la plus appropri~e.

(Mots clrs: anchois; entreposage d'aliments; manutention ~ bord de navire; conteneursisolrs) Argentine anchovy catches show potential in the development of a comprehensive strategy for the exploitation of marine resources. The fish are caught by a coastal fleet off Mar del Plata during spawning time. This period starts in the spring and lasts for approximately 3 months. At present, catches are landed within 1 day, in bulk with n o ice, and are mainly used in canned and matured salted preparations. Catches are approximately 10 000 ton per year and the average maximum sustainable yield is estimated to be 252 234 ton per year I. A potential increase in the catch is dependent on solving certain technical and economical problems. One of these is on-board handling and preservation of the catch because it will be necessary to increase the length of fishing voyages in order to exploit stocks further from Mar del Plata port. Anchovy may be classed as a fragile species: the scales are loosely attached, they have a weak muscle consistency, high contents of lipids and are prone to ventral bursting. Such characteristics demand quick and efficient on-board handling. Cooling the catch is 0140--7007/90/030203-04 © 1990 Butterworth & Co (Publishers) Ltd and IIR

unavoidable and the large volumes of fish that must be handled require that operations are speeded up as much as possible, Owing to the fragility of the species, bulk-storing techniques, with or without ice, and shelf storing with ice, must be discarded. The alternatives are the utilization of boxes with flake-ice and insulated containers using a sea water and ice mixture as cooling agent. Three different conditions for the on-board handling and preservation of anchovy are discussed in this paper: (1) in bulk with no ice at environmental temperature- this is similar to the traditional method used by the coastal fleet; (2) in commercial boxes with flake-ice, stored in chambers at 0°C; and (3) in containers with a sea water and ice mixture, stored in chambers at 0°C.

Materials and methods The trials were carried out with anchovy (Engraulis anchoita) catches (averaging 35 fish k g - t ) from the R.V. Dr Eduardo L. Holmberg of the Instituto Nacional de

Rev. Int. Froid 1990 Vol 13 Mai

203

On-board handling and preservation of anchovy: C. A. CastahOn and A. O. Barral count (Merck) culture with a 30°C, 5-day incubation period. Samples of the liquid inside the container were frozen to determine dissolved protein using the Kjeldahl technique9. For the anchovy stored in bulk with no ice, determinations were performed every 12 h; two samples were taken for each analysis. The results reported correspond to the average of the two analyses. Results and conclusions

o

0

1

2

3

g

5

6

7

8

9

Time, days

Figure I Raw organoleptic assessment of anchovy. ( A ) In bulk with no ice; ( © ) in boxes with flake-ice; and ( Q ) in containers with a sea water-ice mixture Figure I Evaluation des qualit~s organoleptiques des anchois crus. ( A ) En vrac et sans glace; ( 0 ) dans des caisses avec de la glace en kcailles; et ( 0 ) dans des conteneurs avec un mblange d'eau de mer et de glace Investigaci6n y Desarrollo Pesquero, in September 1981 and July 1986. The trials for the three handling and preservation conditions were performed simultaneously and with fish from the same catch. For the bulk storage with no ice, anchovy was stored in commercial boxes below deck at an ambient temperature of 12°C, approximating to normal storage temperatures in the hold of the fishing vessels. For the anchovy kept at 0°C in boxes with flake-ice, commercial boxes and flake-ice manufactured onboard were used. The handling, fish:ice ratio and the volume of fish per box were those considered to be the optimum for this preservation method 2'3, i.e. those that gave the maximum cooling speed and avoided mechanical damage due to crushing. For the third handling and preservation trial, insulated I m 3 containers with metal external and fibreglass internal surfaces were used 4-6. Three inlets allowed the measurement of the internal temperature from the outside, at three different levels. A perforated pipe, laid on the diagonal of the base, acted as a distributor for compressed air injected to speed up the cooling of the stored fish by agitation. A ratio of 300 kg of sea water-ice mixture (1 : 1 w/w) to 600 kg of fish per cubic metre of the container's internal capacity was used. The sea water-ice mixture was placed inside the container, air was bubbled through at 1.5-2 kg cm -2 pressure and fish was loaded inside. The injection of air was continued for 1 h after the container was loaded. The temperature of the fish at that time was 0°C. The container was stored at 0-5°C. A daily determination was made of the organoleptic acceptability using the method previously reported 7 for fresh whole anchovy and of total volatile bases (TVB) using the Antonacopoulos method 8. Samples were also frozen (for 3-4 h in a horizontal plate freezer at -38°C) for on-shore determination of water content 9, sodium chloride content 9, autoxidation using the thiobarbituric acid index (TBA) 1° and aerobic heterotrophic bacterial load in the muscle by agar plate

204

Int. J. Refrig. 1990 Vol 13 May

The results obtained for the determination of organoleptic characteristics are shown in Figure I. The best results were obtained for anchovy stored in containers with a sea water-ice mixture. The opposite trend was reported by Fernfindez and Barreiro 11. Table 1 shows the main differences in organoleptic characteristics found for anchovy stored in containers and in boxes with ice. Table 1 does not show the results for the fish held at ambient temperature which were found to be unacceptable after storage for 36 h. Figure 2 shows the changes in total volatile base content per 100 g of muscle. Again the results indicated that storage in the containers resulted in the production of lower concentrations of total volatile bases. Similar results were reported previously for sardina espafiola 12. Anchovy stored in bulk at ambient temperatures quickly reached the limit of rejection of 30 mg N per 100 g muscle set by the Argentine Alimentary Code; even after storage for 9 days in boxes with ice, anchovy had not reached this limit. Variations of TVB for anchovy stored in containers show a curve which differs from the general case in that there is a reduction of TVB from time zero up to a point of inflection around day 7; thereafter the concentration increases. These results could be explained as follows. (1) Rapid cooling delays deterioration processes. (2) A washing effect provided by the water in the container causes a reduction of TVB in muscle; such a diffusion process

Table 1 Comparison oforganoleptic characteristics for anchovy stored in boxes with ice and in containers with a sea water-ice mixture Tableau 1 Comparaison entre les qualitbs organoleptiques d'anchois entreposbs clans des caisses contenant de la glace et celles d'anchois entrepos~s dans des conteneurs contenant un mblange d'eau de mer et de glace

Boxes with ice

Containers

General appearance

A rapid loss of fresh fish characteristics, marked dehydration, depressed eyes, blood clots in operculum

For 4-5 days flesh fish characteristics are maintained. No dehydration or crushing. Non-depressed eyes, full body, no blood spots

Muscle

Loss of consistency after day 5; clearly differentiated dark and light muscle; ventral bursting between days 4 and 5

Firm consistency; some blood from the spine diffuses toward muscle; dark and light muscle less differentiated; ventral bursting after day 6-7

Branchia

Maintenance of red colour darkens gradually. A strong fish smell after day 4

Rapid loss of colour; light pink on day 4; a slight fresh fish odour

Guts

Self-digestion alter day 3 together with a rancid odour

Less digested, clearly differentiated up to day 5. Slight odour

On-board handling and preservation of anchovy." C. A. Castah6n and A. O. Barral q0

the mass loss experienced by the anchovy stored in boxes with ice. The superior performance of the container method compared to that of boxes with ice can also be seen in the variation of bacterial load of the anchovy. These results are shown in Figure 5 as total aerobic colonies per gram of muscle. Anaerobic conditions are created inside the container that are reflected not only by the changes in the bacterial count but also by the degree of oxidation of lipids of anchovy stored under this method. Figure 6 shows the variation of the thiobarbituric acid index (rancidity), expressed as absorbance as a function of storage time.

3o

D3

Z

E

o

°

in

z~ 20

o >

77-

1-

76--

10 oo

•

75-

•

o D~ 1 1

I 2

1 3

I 4

1 5

1 6

I 7

I 8

I 9

74-

I

Time, days

~ 3

Figure 2 Total volatile base of anchovy. (&) In bulk with no ice; (O) boxes with flake-ice; and (O) containers with a sea water-ice mixture Figure 2 Base volatile totale des anchois. ( A ) En vrac et sans glace;

72

o

( 0 ) dans des caisses avec de la 91ace en bcailles; et ( 0 ) dans des conteneurs avec un m~lange d'eau de mer et de glace

7069

6r"

I

1

I

I

I

I

I

I

1

1

2

3

4

5

6

7

8

9

I

Time, days

,

/

Figure 4 Moisture content of anchovy muscle. (O) Boxes with flake-ice; and ( 0 ) containers with a sea water-ice mixture Figure4 Teneur en eau du muscle d'anchois. ( O ) Caisses avec de la glace en bcailles; et ( 0 ) conteneurs avec un mblange d'eau de mer et de glace

.~ 4 - +a

E e-

106 -

3

8 t--

105

1 104

0

I

t

I

I

1

I

I

I

I

I

2

3

4

5

6

7

8

9

I .u_

Time, d a y s

.Q

o

Figure 3 Total dissolved protein in the water inside the storage container Figure 3 Protkines totales dissoutes clans l'eau des conteneurs

would be enhanced by the area:volume ratio of anchovy. Figure 3 shows the variation in the concentration of proteins dissolved in the water in the container as a function of time. This shows that nitrogenous material diffuses into the aqueous phase. (3) Absorption of the container's water by the muscle of anchovy results in a decrease in the relative percentage of TVB. The increase in the percentage of moisture for container-stored anchovy is shown in Figure 4, together with the data which indicate

103

102 , 0

1 1

I 2

I 3

I 4

I 5

I 6

I 7

1 8

I 9

I

Time, days 5 Total aerobic colonies per gram of anchovy muscle. (O) Boxes with flake-ice; and ( 0 ) containers with a sea water-ice mixture Figure 5 Colonies de germes a~robies par gramme de muscle d'anchois. ( 0 ) Caisses avec de la olace en bcailles; et ( 0 ) eonteneurs avec un mblanoe d'eau de mer et de 9lace Figure

Rev. Int. Froid 1 9 9 0 Vol 13 Mai

205

On-board handling and preservation of anchovy: C. A. Castah6n and A. O. Barral |

--

1.5

0.9 0.8--

0

0.7-

>" ~ 0.6-

0 1.0

0

e-

"o'0. 5 --

~,

o

c~ 0.4 O

O

O

0.5

0.3

•

0.2 0.1 0 0

I I

I 2

I 3

I I I 4 5 6 Time, d a y s

I 7

I 8

I 9

I

Figure 6 R a n c i d i t y o f a n c h o v y lipids, ( & ) In b u l k w i t h no ice; ( © ) boxes w i t h flake-ice; and ( 0 ) containers w i t h a sea water-ice mixture

Figure 6 Rancidit~ des lipides de l'anchois. ( & ) En vrac et sans glace," ( 0 ) dans des caisses avec de la glace en bcailles; et ( 0 ) dans des conteneurs avec un mblange d'eau de mer et de glace

One of the main objections to the container preservation method is the absorption of salt by the muscle of the fish. This is critical for white fish (hake, cod) as the increase of sodium chloride is easily detected organolepticaUy. In fatty fish, such as anchovy, the main destination of which is canned produce (for which a light salting is carried out at the plant before cooking), or matured salted produce, this becomes less important. Figure 7 shows the variation in percentage of sodium chloride in the muscle of anchovy stored in containers and in boxes with ice versus storage time. Although the sodium content for the anchovy stored in containers for 9 days may be considered too high for fish meal production, this paper reports the preservation of anchovy for human consumption. The amount of anchovy discarded due to break-up or crushing was 2% for the container fish and 5% for those stored in ice. The loss for the fish stored under ambient conditions was greater than 5%. The storage factor for boxes with ice is estimated to be between 11 and 13 boxes per cubic metre of hold, i.e. 440-520 fish per cubic metre. Using the containers, 600 kg of fish were stored per cubic metre of internal capacity. The results show the satisfactory performance of the insulated container with a mixture of sea water and ice for the on-board handling and preservation of anchovy catches.

Int J. Refrig. 1990 Vol 13 May

I 3

I

I

1

I

4 5 6 Time, d a y s

1

I

7

8

9

Pesquero for his helpful collaboration in carrying out this work.

References 1

2 3

4 5

6

7 8 9 10

Acknowledgements

206

I 2'

Figure 7 Sodium chloride contents of anchovy muscle. ((3) Boxes with flake-ice; and (O) containers with a sea water-ice mixture Figure 7 Teneurs en chlorure de sodium du muscle d'anchois. (C)) Caisse avec de la #lace en bcailles; et (Q ) conteneurs avec un mblange d'eau de mer et de glace

11

The authors thank Dr Luis S. Monticelli, Chief of the Laboratorio de Microbiologia y Parasitologia of the Instituto Nacional de Investigaci6n y Desarrollo

I I

12

Hansen, J. E., Gru, D. L. and Perrota, G. Resultados de una campafia de investigaci6n sobre anchoita (Engraulis anchoita) del sector Bonaerense en el otofio de 1983. Distribuci6n, abundancia y algunos aspectos biol6gicos M S (1983) FAO El Hielo en la Pesquerias FAO Fish Report 59 Rev. 1 (issued also in English and French) FAO/WHO Food Standards Programme, Codex Alimentarius Commission Recommended international code of practice for fresh fish, FAO, Rome, Italy C A C / R C P 9 (1976) (issued also in French and Spanish) Petersen, E., Hansen, P. and Feldstedt, B. New catch handling system aboard Chilean trawlers Fish News Int (March 1977) 36 Hansen, P. Situaci6n de la investigaci6n sobre technologia de productos pesqueros. Informe para el Gobierno de Argentina por la Organizaci6n de las Naciones Unidas para la Agricultura y la Alimentaei6n, FAO, Rome, Italy (1979) Barral, A. O. Evaluaci6n de la eficiencia del uso de contenedores con agua de mar-hielo en el manejo y conservaci6n de merluza a bordo. Ind. Cfirnica Latinoamericana (1983) No 50 16 Bergamaschi, N. J., Castafi6n, C. A. and Barrai, A. O. Planilla de puntaje organol~ptico para anchoita (Engraulis anchoita) entera y fresca M S (1981) IRAM, Instituto Argentino de Racionalizaci6n de Materiales, Determinaci6n de las bases voDitiles totales por el m&odo de antonacopoulos Norma 15025 I (1977) AOAC Methods of Analysis (Ed W. Horwitz) AOAC, Washington, DC (1975) Vyneke, W. V. Evaluation of direct thiobarbituric acid method for determining oxidative rancidity in mackerel (Scomber scumbrus L.) Fette Seifen Anstrichn (1970) 77 239 Fermindez, O. and Barreiro, D. Manipulaci6n de anchoita (Engraulis anchoita) a bordo. Evaluaci6n de su calidad para consumo humano. II ° Jornadas para Empresarios de la Pesca, de la Comisi6n T~cnica Mixta del Frente Maritimo, Mar del Plata noviembre (1986) Asenjo, C. I. Expcriencia del uso de contenedores de agua de mar refrigerada en Chile FAO lnforme de Pesca No 340, Suplemento FIIU/R340 (1983) 168