24 CO~YERCIAL FI~HERIES REVIEW Vol. 14. No . 12a

FREEZING AND COLD STORAGE OF PACIFIC NORTHWEST FISH AND SHELLFISH

PART I STORAGE LIFE OF VARIOUS ROCKFISH FILLETS By D. T. Miyauchl· and M. E. Stansby··

ABSTRACT

DATA ON INITIAL PALATABILITY AND CO LD-STORAGE (00 f . ) ~E PI N QUA LITY ARE PRESENTED FOR S ING LE SA PL E LOTS OF SEVEN SPEC I ES Of PAC I F I C COAST ROCKF ISH, PA C I F I C OCEA N PERCH, AND FOR OCEAlI PERCH (A T ANTI C) AS A COMPAR IS ON. -------

INTRO eTION

Rockfish of the genera Sebastodes and Sebastolobus are landed in large quan­tities by fishermen along the Pacific coast. These fish are usually filleted and are marketed both fresh and frozen under the general label "rockfish fillets." The various species of rockfish fillets iffer in palata ility, texture, an cold­storage keeping quality. Cold-storage life of the rockfish fillets is limited lar~ely because of the development of rancidity and undesirable chan~es in texture. --~ "'n,... Uto ot .... __ tUb FH . u o' 00 r . -Table 1 - De~crt Vt10D or -}}~ ,p<I90_S ot Rooldl.b 011<1 'A>ld-

lb. or q..J HI ot FW,"l:/ ~c1ee at Rootlhb ~ n11e". ''"'' OJ! An..r 8'o,,~ • .. c.>' F. For:

Coomon Sc1eotitl0 Gounl or _ rib . ~Ual K K I: S

Name N_ ocrlptlon a.",,10 -""" <1., .- t:; 1$-16 l?-.O U -&4 ~ .9-1.O Pao1t1e ocelln peroh Sob.stoeles Colo r ~ bright O~OD dOr84l INrt.ce. l;..,an . " to 6 T" 0 II 11 I1 to F , 0

alutUl lighter Do ~ ntraJ. aurtaee .1 t.,b .tl"l"J ~ _beeD . Le",,"'b. t.o 19 lDeb •••

Lobe~ J •• oo rookr 15. .:Ie~8tode. Color: ro •• -rod '" brlo.-_ o •• 0rMl our- ~. " t.o :. G 11 11 IHoF - U d1plcproa raci. ,UYeI'J abeen em "DUal surtaal . ~

y, _h· ., 12_!noh"' Bo08col0 Sebaet.ode. ..... or J.1LO<-gOOA to """ .. -tre"" 00 oorse' ......... ~ '0 ~ YG " 11 11 F F U

ee.uch:2~DJ.1 _urfaoe· ab.adiae into re4411b-tronze to Call torula w!lite on .ent~l ~.C8. Lent'th: to:- ft.

Chili ""epper .-,e~t.od!!. _'Hor: ~inl<i"" rea oa .'<r~_ .uIl • • • ; -. 4 '0 ~ ,~ 11 , , u £!!2!!.!.!. ahadlDt: lnto pInk on nntnl trurt. e. Celltorula

Le~b: to t2 Ineb., IQrall6e or red Sebaotodes Color" l1gtl:t-o.l.1'Ye ~ .nUl cract, .. -red , BeatU •• 2 t o 3 v, ttt-o ' F Fto U rock1'lah r 1nn1e;er red pred.o naUce. on dar .. l surface : paler • oah1J>gton

i.:~~lY t:!1~!~ r:t~e.utral surf co.

fRed rockt iSh or Sebe.tod • ., Color: deep "I'erm111oD-re4 on Goreal. eurtaoe. :MatUe, 1 t o 2: C 11 , F F U "red snapper" ~ paler on nntral au.rt'ace. LeDt-:t,"l: "03 tt . l: .. hl.,..n.!;

I YIlU'lD..l.~~on ~a I I.AJJ..or; TeIm.l.J.J.O D- rog "D QlUrl:llU. ........ 111.,;:.; ~tt.i ••

uJ/ ,,"OOldish ~ ~!~t.-~~da~:.;~~.:~;~~ dote on llubl.r.£tonl, 1 to 2 C

Cb.annel rockt'ish .:)eboatolobua Color: br ight-red; dark b)otCl1ee on tina ; =. 11 t o 1% - - 1\ •• j - U r " I dIot" ili~cACua cheek s Sllloy. LeD@tll : to 2 t H't . eean p.r~D ~ .. I (,;O~or: oran,ee-rea. or r eel on doraeJ. sur .. 8ce i vlouceat.ar, 40 t o ~ VO G ~ ~ - F 11 (At!~~lCI or ~ paler OD nDt.ral surrac . r.ngt.b: to 2 rt. . 1Iu.

1/ SJ~~T O~r~(~}\£~s;" cJ35~~r~ON ~AV~~I=I:~:~O:f=k~~[~~~;(;r ':;~~'I(~.~I:~~~:.~~~~l ..... ~:c~A~~~·.;; S;· ::·~M r~.~DW; .. COLO fit\M<o"'l ~Q WUtA ."'10 rllLU[D , TH[ fHl(T! ~ ,.,H ..... iM:O " IC) R[ rROlt~

y rACTORS O[T[R~I~I~ QUA 11., AR~ APP£,uUJol,[, n. 1HIQf.~~( . .... , ODOR, VQ • vtllt"l' GOOD h.l,,"u, ~r[R[ " ~). Q : GOOD (..:MlJolol . TT Of '.UN , l ns •• ; • ( ... . J, u"'~~~~~;l~~~~~ 1 ~[~/A R APPfltCIAI!II.[ OtTU ~ QlJ ol .. n). u - ... Ca::P1 AIILC (1I'OCMlI 10 "'(1)1111,.( •

,,"DI(ATLS I'fO 08S(>l'VA1" 0" --- ---- -

The rata of deterioration during storage varies from species to species. This report presents data on the initial palatability and the cold-storage keeping quality of eight species of Pacific coast rockfish (table 1). Data on the ocean perch (Atlantic), Sebastes marinus, a species of rockfish found on the Atlantic coast, are included for comparison. Although this study was limited to storage t ests with only one lot of samples for each species , the information may serve as a guide to the commercial processor in the packing and marketing of these fish. It may be advantageous, for example, for the processor to promote separately those species of rockfish which show high acceptability and good cold-storage keeping quality.

EXPERIMENTAL PROCEDURE

Fillet samples of Pacific ocean perch (S. alutus), bocaccio (S. aucis inis), lobe-jawed rockfish (~. diploproa), orange ~r red rockfish (~. pi~niger , chili-

COi>lMERCIAL * -FISHERY TECHNOLOGIST {FISHERY TECHNOLOGICAL LABORATORY, BRANCH OF ** CHIEF, PACIFIC COAST AND FISHERIES, U.S. FISH AND WILDLIFE SERVICE, ALASKA TECHNOLOGICAL RESEARCH SEATTLE, WASHINGTON.

December 1952 - Supplement COMMERCIAL FISHERIES REVIEW 25

pepper (§.. goodei), and channel rockfish or "idiot" (Sebastolobus alascanus) were prepared and frozen in one-pound packages in commercial filleting plants, using regular commercial procedures.

Samples of vermilion rock­fish (Sebastodes miniatus) and red rockfish or "red snapper" (S. ruberrimus) were prepared at the Seattle Technological Laboratory from fish caught off the coast of Washington by the Service's exploratory fishing PACIFIC OCEAN PERCH (SEBASTODES ALUTUS) vessel, John ~. Cobb. These fish had been frozen whole aboard the vessel. At the laboratory they were thawed in cold running water and filleted. The fillets were packaged and refrozen. The exact effect of this procedure on the cold-storage keeping quality of the fillets is not known. The results of the storagetests on these samples maybe of interest, how­ever, and are included in this report.

The skin was removed from the fillets of red rockfish (Sebastodes ruberrimus), vermilion rockfish (2' miniatus), and orange rockfish (2. pinniger) before packing and freezing. The fillets of the remaining species were packed with the skin on.

RED ROCKFISH (SEBASTODES RUBERRIMUS)

bles that of some of the Pacific Coast rockfish, perch (Sebastodes alutus). For these reasons it basis for comparison.

Samples of ocean perch (At­lantic), Sebastes marinus, fillets were obtained from Gloucester, ~1assachusetts, where theyhad been prepared, packaged, and frozen under regular commercial condi­tions. These filleV samples were shipped frozen (using dry ice) via air express to Seattle, Washing­ton.

The ocean perch (Atlantic), ~. marinus, catch leads that of any other fish in the New England area. Also, the general external appearance of this species resem­especially the Pacific ocean was included in these tests as a

All samples were stored at 00 F. Organoleptic observations were made on the thawed fillets and on the cooked product. These tests were made prior to freezing and storage, and thereafter at periodic intervals of severa] weeks. Two or more packa.ges of fillets of each species were taken from cold stora.ge and allowed to thaw at room temperature. Thawing was hastened by dire.cting the air blown from an electric fan over the packages. Appearance and odor of the thawed fi.llets were noted.

VERMILION ROCKFISH (SEBASTODES MINIATUS)

2 6 COMl-'.ERCIAL FISHERIES REVIEW Vol. 14, No. 128

For te s t s on tne cooked product, 3 to 5 individual fillets were used. These were immersed in a 6- percent br i ne solution for 5 mir.utes; drained; wrapped in vegeta-

(ATlANT1C) OCEAN PERCH (SEBASTES MARINUS)

ble parchment; and then steam­ed for 20 minutes. These cooked fil l ets were judged for quality by members of a select­ed taste panel, which consisted of 4 or 5 testers. Observa­tions were made for appearance, flavor, texture, and odor. A low score for anyone of the factors for the thawed or cook­ed fillets made them unaccept­ab l e. Whenever possible, each series of tests was' repeated in the next day or two to de­termine the consistency of the organoleptic observations and

to eliminate any possible gross error in sampling. Inasmuch as a fresh reference standard of each species could not be used for each test, frozen Pacific ocean perch (Sebastodes alutus) was used as t he standard for comparison.

DISCUSSION

Each test was limited to representat ive samples of 3 or 4 species of rockfish an was repeated within a few days . Therefore, each series of tests after periodic intervals of storage required as much as two weeks to complete. It was not possi­ble to make organolepti c examinations for all species after identical periods of cold stora e. Since samples of some s pecies were obtained at later dates , it was not possible to make all storage periods for any series of organoleptic examina­tions coincide. The general quality of the fi l lets after storage at 00 F. is sum­marized by 4-week periods in table 1 .

Although samples of each species were usually examined at intervals of several weeks, often no definite changes i n qualit y cou l d be observed between any two con­

ecutive examinations.

Th summary of results t hat f ollows pre sents only those data in which the or­anoleptic observations showed a clear - cut change in the quality of the samples.

Pacific Oc>an perch (Sebast o des alu t us)

Fillets of Pacific ocean pe rch had the best cold-storage keeping quality of all the Pacific Coast rockfish test ed . The flavor and texture of the freshly-

n fillets were excellent . After 15 weeks of stora e, some fillets were lack­in flavor, an a few were discol ored along t he edges. After 25 weeks, the fil­

modera ly discolor ed over-al l and were somewhat rancid in flavor . After h fillets were inedible.

dlpl oproa)

t est, t he lobe- j awed rockfi sh fil l ets were rated a­nee ~ flavor, and good i n t extur e . After 12 weeks, the

colorpd over-all, an a few 8 8m les were slightly rancid th fillet s w re modera te ly d iscol ored and moderately

ek , the f illet wer in~ i ble.

December 1952 - SUpplement COMMERCIAL FISHERIES R1~lEW 27

Bocaccio (Sebastode s pau cisp inis)

Bocacciofillets were about equal in initial flavor to Pacific ocean perch but had.a firmer and flakier te~ture. After 12 weeks of storage, the fillets were sllghtly tough but were stl11 rated about equal in flavor to the Pacific ocean perch stored t he same amount of time. After 19 weeks the fiJlets were fairly good in appearance, f l at to slightly rancid in flavo; and somewhat tough in texture • . After 29 weeks, the fillets were inedible becau~e of toughness. Also they were Sllghtly darkened over-all, the light meat was flavorless and the dark meat was rancid. '

Chilipper (Sebas todes goodei)

Chilipepper f illets were found to be about equal in initial palatability to Pacific ocean perch and bocaccio and were rated very good. After 11 weeks in storage, the quality of the fillets had definitely dropped; all the samples show­ed a general discoloration and had toughened somewhat; and a few of the samples had a flat flavor while others had an off-flavor. After 17 weeks, the fillets were discolored, and some samples were rancid in flavor. After 22 weeks the fil­lets were all poor in auality because of rancidity and toughness.

Orange or Red Rockfish (Sebastodes pinniger)

Orange rockfish fillets were about equal to Pacific ocean perch in initial palatabil ity. However, the appearance of the orange rockfish fillets deterior­ated rapi dl y . After 12 weeks of storage, t he fillets were discolored and rancid in odor but only slightly rancid in taste. After 16 weeks, the fillets were also rancid in taste and were only fair in over-all quality. After 22 weeks, the fil­lets were inedible.

Red Ro c kfish or "Red Snapper" (Sebastodes ruberrimus)lI

At the beginning of the test, the red rockfish fillets were flaky in texture and slightly t ough; however, the flavor was considered good. After 9 weeks of storage, the f illets had a slight over-all discoloration and a rancid odor. After 16 weeks the f i llets were only fair in appearance and flavor. After 26 weeks, the fillets were i nedible because of poor appearance and ran id flavor.

Vermilion Rockfish (Sebastodes miniatus )

In initial palatability, the vermilion rockfish fillets were rated good in flavor but were slightly tough. (Vermilion rockfish are usually discarded at sea because of t he poor appearRnce of the skin, which is mottled with gray-bl~ckdots.) After three weeks of storage, the fillets were badly discolored and were rancidin flavor and odor . Because of this rapid deterioration in quality after storage, this species does not appear suitable for freezing.

Channel Rockf ish or "Idiot" (Sebastolobus alascanus)

The first organoleptic test was made on the samples of channel rockfish after 15 weeks of st orage, at which tirr.e the fillets were flat in taste and soft in tex­ture. Aft er 20 weeks, one sample was poor in flavor and mushy in texture~.and the remaining samples were about medium in quality. After 28 weeks, all the ~l~lets were rated inedible because of poor flavor and texture.

OT PREPARED IN THE USUAL COM~ERCIAL MAN ER BUT AS 11 F ILLETS FROM THIS SPECIES OF FISH WEREA~ SEA ABOARD SHIP. AT THE LABORATORY THE FROZE f S~

~~~~O~~~WE~H;N~O~7~L~~~~.WE~~EF~~~~~TS WERE THEN PACKAGED AND REFROZEN.

28 COMMERCIAL FISHERIES REVIEW Vol . 14 , No . 1 28

Ocean Perch (Atlantic) or Rosefish (Sebastes marinus)

In initial palatability, ocean perch (Atlantic) fillets waB preferred over the other species of rockfish. However, there WAS not much difference in palata­bility between ocean perch and Pacific ocean perch. The difference was lar~ely in texture, the ocean perch being somewhat more tender. After 12 weeks of stor­age and for the remainder of its storage life, the quality of the ocenn perch ( At ­lantic) fillets were comparable to that of Pacific ocean perch fillets which had been in storage for the same length of time. After 13 week5, a few of the ocean perch fillets were discolored along the edges and were lacking in flavor . After 25 weeks, some fillets were discolored ove -all and were r~ncid in flavor along the edges. After 29 weeks, the fillets had a moderAte over-all d rke ing, a dis­coloration along the edges, an accumulaticn of fat in patche~J and a rancid fla­vor and odor. They were, therefore, considered inedible after his period of storage.

UMMARY

Singles lots of vari us species of Facific Const rockfish fillets tested prior to freezing and storage at 00 F. differed in appearance, texture, o. fla/or . Pacifjc ocean perch (Seb~stodes alutus), red rockfish (Sebastodes pinniger), bocaccio (Sebestodes paucispinis) , and chilir pper (Seba5todes goodei) were rated very good. The group next in choice, rated good, consisted of red rockfish (Se­bastodes ruberrimus), lobe-jawed rockfish (Seb stodes diploproa), vermilion rock­fish (Sebastodes miniatus). No ocservation wa~ made on the initial palatability of channel rockfish (~etastolobus alascanus).

Pacific ocean perch fillets (Sebastodes alutus) had the best cold-storAge keeping quality and the longest cold-storage life. Althouph ocaccio (Sebastodes paucispinis), fillets had a storage life about equally long, they did becol"e tough . The cold-storage life for Pacific oceAn perch fillets was 32 wee~s and bocaccio 29 weeks. Vermilion rockfish (Sebastodes miniatus) deteriorated so rapidly in quality that they were not considered suitable for frozen storage . The other species of Pacific Coast rockfish fillets tested had a cold-storage life of 5 or 6 months.

Ocean perch (Sebastes marinus) fillets were given a slight preference ove r the Pacific Coast rockfish in i~itiAl palatability. The fillets were quite simi­liar to Pacific ocean perch (Sebastodes alutus) in appearance, flavor, and t ex­ture throughout most of the storage period. They had a cold-storage life of 29 weeks.

ACKNOWLEDGMENT

Clarence R. Lucas of the Market Development Section collected most of the samples used in this investigation and Miss Kathryn Osterhaug, Home Economist,of the Edu~ational and Market Development Section assisted in conducting the organo­leptic tests. Both of these sections are part of the Service ' s Br anch of Commer­cial Fisheries.