-

From: Prace . Môrskiego Instytutu.Rybackiego (ProceedinWcif the Marine Fisheries Institute):, - I6 : 193-203, 1971-

- Yrranslated.by 'the Translation Bureau(JN0). - - Multilingual.ServiCes Division -.

Department of .the Secretary of . State. of Canada

Department of the Environment Fisheries and Marine Service

Technological Unit - St. John's, Nfld.

14 pages typestript

1974

FIS4ERIES RESEAROi BOARD .OF CANADA

Translation Sens No. 2928;

- Changes in the ccintent of trymèthylamine'OXide,. triméthylamine and total:volatile basic nitrogen in fresh and frozen fish.

by Barbara Karnicka and'Irena Jurewicz

Original title.: Zmiàny zawartcrsci tlenku trkmetyloaMiny,.trdjmetVloaminy • i lotnych zased amonowych.w ribach dwieeych i mroeonych .

DIVISION MULTILINGUES

TRANSLATED FROM - TRADUCTION DE

PoliSh INTO - EN

English AUTHOR - AUTEUR

• •

-DEPARTMENT OF THE SECRETARY OF STATE

TRANSLATION BUREAU

SECRÉTARIAT D'ÉTAT

BUREAU DES TRADUCTIONS

DIVISION DES SERVICES MULTILINGUAL SERVICES CANADA

YEAR

ANNEE VOLUmg

. TRANSLATION BUREAU NO: - •

NOTRE DOSSIER N0 16_5331 • REQUESTING DEPARTMENT, EnVirOnMent MINISTÈRE-CLIENT

• DATE OF . REQUEST

DATE DE LA DEMANDE .. 1923

505-200-1U-6 (PE V. 2/55/

7530-21-029-5333

Barbara Karnicka and irena Jurèwici

TITLE IN ENGLISH - TITRE ANGLAIS

Changes in the content of trynethylaMine:oxide, trimethylamine

and total vOlatil e . basic nitrgen in fresh und frozen fish.

TITLE IN FOREIGN LANGUAGE (TRANSLITERATE EO , EIGN CHARACTERS)

TITRE EN LANGUE ÉTRANGÈRE (TRANSCRIRE EN C.‘RACTLRES ROMAINS)

Zmiany zawartoci tlenkù tre, metyloaminy, •r6jmetyloaminy

lotnych zasad amonoWych w rybach wieiych j mroionych. REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN . CHARACTERS.

RÉFÉRENCE EN LANGUE ÉTRANGÈRE (NOM DU LIVRE OU PUBLICATION), AU COMPLET 'RANSCRIRE EN CARACTÈRES ROMAINS-.

Prace Morskiego Instytutu Rybackieg6

REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS

Proceedings of the Marine lisheries Institute

PUBLISHER - ÉDITEUR

•Marine .FiS,heries Institute

PLACE OF PUBLICATION •

LIEU DE PUBLICATION

• DATE OF PUBLICATION

DATE DE PUB. LICATION .

ISSUE NO. NUMÉRO

PAGE NUMBERS IWORIGINAL

;NUMÉROS ,DES PAGES DANS

L'ORIGINAL

193 T 203 NUMBER OF TYPED PAGES

NOMBRE DE PAGES DACTYLOGRAPHIÉES

111 1921 16 eries Gdynia, 2oland

Uffice BRANCH OR DIVISION of:the Editor

• • DIRECTION OU DIVISION eisherieS Service

• PERSON REQUESTING

• DEMANDÉ PAR

YOUR NUMBER VOTRE DOSSIER NO

• TRANSLATOR (INITIALS) TRADUCTEUR (IN)TIALES) . •

DEPARTMENT OF THE SECRETARY OF STATE

TRANSLATION BUREAU

SECRÉTARIAT D'ÉTAT

BUREAU DES TRADUCTIONS

MULTILINGUAL SERVICES

DiVISION

DIVISION DES SERVICES

MULTILINGUES CANADA

OÉPARTivIENT MINISTÉRE

Environment

OPMSIONaRANCH DIVISION/DIRECIION

Uffice of the 'Editor -Fisheries Service

SOS-200-10-3I

7530-21-079.5332 '

BUREAU NO. LANGUAGE

N o DU BUREAU . LANGUE

Polish

TRANSLATOR (I NI TI ALS)- TRADUCTEUR (INITIALE)

J. iNo. 165331 FEB 1.5 1974 .

• CITY

VILLE

CLIENTS NO. N') DU CLIENT

Prace Morskiego -Instytutu Rybackiego. Tom 16,-seria

st. 193 - 203 .1971

Volume 16, Froceeoings of the ii.arine ?isheries Institute.

suries pp. 193 -• 203. 1971.

-

Changes in the content of trymethylamine exide trimetnylamine

and total volatile. basic -nitrogen in fresh ancLfrozen

Darbara larnicka and Irena jurewicz

Abstract. To investigate the usefulness Of TMAO, TMA and TVS . test, for estimation at

fish quality, determinations we .re made of the contents 0, these compound . " ln the meat of

frozen *fish species from the fishing g-rounds of Northsiést Atlantic' (Goats, rnorhua, SeWastes marinus, Reinhardt(us hippagtossoides, pleuronectes cyrtog , lossur, Dritpanopsetta plateattoidet)

stored st a temperatitre of —25•C and in- the meat of .friath fish .from• the Baltic Sea thy* Reaus, Godus morhua) stored In ice. . , . • .

In - frozen fish. ai opposed to fresh . 'ones, nO' distinct changes in the contents of aboS*

chemical compounds were found. .

INTRODUCT I UN

The Lutensity' and speed or the • jOCESS of spoilage éï fish.

is the cause of. the 'Unceasing Searéh for objective-methods

for evaluating their cualitY. • 'iliany suCh methods'nave been

. . *. , TLe figures in the right- }and margin:indieate.thecorres- . . . pondinF Pages.in - the- original text-

*193

elaborated, based primarily on the investigation of quantita-

tive changes of certain chemical compounds appearing during •

the decomposition of fish. une of these is the quantitative

determination of the content of trimethylamine'oxide (TMAu) . ,

trimethylamine (TMA) and total volatile basic nitrogen (TVB). •

According to J. Bystedt, L. Senne and h. W. Aas (3)

the content of TMAU in the flesh of fishes ranges from several

to several hundred mg k7, depending on the species and the

fishing grounds, and in.many cases also on the degree of

sexual maturity and age of the fish. The determination of

trimethylamine-oxide is a very important practical matter,

since this is not only the main source of TMA but also contri- •

butes to the rapid corrosion Of cans with fish preserves (3);

according to.S. Ltsuka and his co-authors (9) the .11Mu content

may be .an indicator of the freshness of.the fish.

• .The content of TA and ,TVB is accepted in many studies ' 194

concerning the qualitative evaluation of fish as an objective '

indicator of their freshness . . According to:C. H. Castell and

. his coauthors j(5) the admissible:amount.of TMA.in the flesh • ;

of fish of otiality class 1 is less thah 1.00 mg. IN, of class, •

II - frPm 1.01 to 5:00 mg is, and of class III:— more than

5.00 mg •* h.

The studies presented below.weré intended to confirm

the'relationshiP between the content of TM/W e TMA and TVB in

the flesh of fish and the duration of . their . storage, and by

this te form an boinion on the value of theSe tests as objec-

tive indicators-of the duality of the . fish. This was particù- -

'qfirly important in vipw of the proposals dicussed - by the Inter— ,

national Codex'Alimentarius Commission of the FAO/WHO on 2ish • '

and Fish Products concerning the introduction of the TMA test

in international trade.

The investigations were carried out in two series.

The first comprised quantitative determinations of TMAO, TMA

and TVB in fish frozen at sea, the second - quantitative de-

terminations of the changes in the content of these compounds

occurring during the period of storage of fish on ice.

MATERIALS AND METHODS

MATERIALS

For the determinations of the amounts of TMAu e TMA

and TVB in the flesh of fish frozen at sea we utilized: cod•

(Gadus morhua), redfish (Sebastes marinus), Greenland halibut

(Reinhardtius hippoglossoides), witch flounder (Pleuronectes

cynoglossus) and American plaice (Drepanopsetta platessoides).

The cod and redfish were provided for investigation in the

form of fillets, while the halibut, flounder and plaice were

supplied in the form of frozen whole fish or headed and gutted

fish. All of these fish originated from the region of the

North-West Atlantic and were classified in quality class I.

Individual samples of cod fillets were stored for periods of

9 to 33 weeks, while the redfish fillets were stored for 11

to 36 weeks; the flatfishes (halibut, witch flounder, American

plaice), on the other hand, were stored for. about 12 weeks.

The samples for testing were defrosted in still air over a

period of 17 hours and then the tested raw material was in each

case subjected to organoleptic evaluation.

With respect to thé fresh fish the test materials

comprised whole flounder (Platichthys flesus) caught on June

3rd 1969 and headed and gutted cod from Baltic fishing smack

catches (date of catch April 14th 1969). The 'Overall length

of the flounders was 24 - 30 cm, of the headed and gutted cod

- 35 - 43 cm. At the time of commencement of the investiga-

tions both the headed and gutted cod and the flounder were in

rigor mortis. After organoleptic evaluation thèse fiernored

in ice in an isothermal container. The water from the melting

ice was removed and the ice was systematically replenished.

Samples for testing were collected daily over the entire period •

of storage, which was 14 days for the cod and 16 days for the

flounder.

The chemical analises of the freSh and frozen fish

were conducted oh the flesh of fillets without skin. .

METHODS OF CHEMICAL ANALYSES. f - . 195

The content of,TMA and TVB was determined by the methods

proposed by Dyell accOrding to the Codex Alimentarius'fOr Fish •

and Fish Products (7, 8)..: The content of TMAO waS determined

by the method of AntonacOpoulos (2). . • .

The Method elaborated by Dyer for the determination

of TMA. is now .universally employed. This method.depends on

the colorimetric measurementof - the coloured compound that is

formed as a result of the reaction. of TMA 'with picriC acid in

* ln the studies conducted up to the present time in the Marine Fisheries institute the content of. TMA and TV,Ii was determined • by -4hé microdiffusiOnmethOd of Conway. .

anhydrous toluene. It is true that recently Amano and Tozawa

(1) proposed a modification of this method, as they found that .

the presently applied Dyer's method gave excessively high ré-.

sults, caused by the imposition of coloilring formed by dimethyl-

amine and trimethylamine; nevertheless for comparative pur-

poses .the unmodified method of Dyer-was employed ,in this study.-

RESULTS

FROZEN FISH

Cod .

' The results of the tests on the content of TMAU, TMA

and TVE in cod fillets produced at sea are presented in Table

1. 'Depending on the period of storage these values ranged

within the following limitsb TMAU - from 101.55 to 147.47

mg 1, (c N, TMA - from 0.55 to 2.31 mg ?):Q N and TV .6 - from 23.52.

4- o 31.22 mg N.

TablE? 1 Tablica I

Zav.artoSé TMAO, TMA t I.,ZA w mroionych filetach z dors skladowanych w tempèraturze —25°C

(w mg ô N)

• Contents of TMAO, TMA and TVA in frozen cod fillets . stored at a temp. of —25°C

(in mg /4)

Czas skladowa ma • 1tygodnie1 •

" Stoi age t ■ nie .( week s) • 1

9-14

15-- 17

I 21

22 , - 25

26.-33

. TM AO

101,76- -122,05

116,51- -135,82

101,55-147,47 If* ,98---.113,01

10'7.72- 113,1'w

TINA A

0,55-1,09

1,11-- 1,41

0,92-1,75

.1,12-1,69

1,56-2,31 .

1,ZA

". TV . _

26,3—:26,60

24,85-27,40

24,08-28,00

26,04-31,22

:TMA . LZA

TVB, . ... ■

11-16 104,30-104,98

18-21 101,90-114,23

22-24 98,01-- 99,92

27-38 101,09-L-109,85

0,15-0,24 0,35-0,45 0,28-0,57 0,28-0,54

17,92-22,82 21,84-24,22 21,70-22,40 21,56-22,79

Czas skladowania (tygodnie) •

Storage time (weeks)

TMAO

As is evident from this table, the content of TMA and

TVB increased slightly, reaching respective values of 2.31

and 31.22 mg % N after 26-33 weeks. The content of TMAO

showed no tendency to fall.

Redfish

The obtained numerical values of TMAO, TMA and TVB in

the frozen fillets of redfish are presented in Table 2.

Table 2 Tabilea 2

Zawartoie TMAO, TMA I LZA w mroionych filetaeh z karmazyna skladowanyen w temperaturze —25°C

(w mg % N) Contents of TMAO, TMA and TVB In frozen redfish fillets

stored at a temp. of —25 0C (in mg % N)

The analysis of the results presented in this table

does not demonstrate that.any dependence exists between the

content of these different . compounds and the period of storage.

• Flatfishes (Greenland halibut, AMerican plaice, witch flounder)

The contents of TMAL,, TMA and TVB in the flesh of the

tested flatfishes are compared in table 3.

This comparison allows one to state that distinct dif-

ferences between the different species were observed only with

respect to the content of TMAO, which was about three time

greater in the halibut than in the witch flounder. Such dif-

ferences were not found with respect to the contents of TMA and TVB.

LZA

TVB

18,03 18,90 10,83 18,70 17,40 17,80 17,50 20,20 2060, 19,60 32,20 24,20 24,90

_

Table 3 Tablica 3

Zawartoie TMAO, TMA t LZA w mrotonyeb plaotttlIbeit skladowanych w clown ok; truck miestecy w temperaturie —450C

(w mg % N) • Contents of TMAO, TIMM and TYE in frozen flatfish

stored for abt. 3 mounts st a temp. of —25°C (in mg % N)

Gatunek TMAO . ' TMA LZA Species TVB

Halibut Greenland halibut

107,24-138,01 0,24-0,73 17,50-22,08

Szkarlacies 10,37— 59,27 ' 0,19--0,76 18,48-26,80 Witch Niegladzica

Long rough dab* 60,66— 86,83 0,22-0,91 22,84-28,40

FISH STORED ON ICE

Cod

The results of the determinations of the contents, of

. TMAG, TMA and TVB on the.different-days of storage of the

fresh cod on ice are presented table.4, while a graph of

these resuls is.presented in Figure 1.

Table L. Zawartoté TMAO, TMA I I,ZA w dorszach twIetych

akladowanych w Iodate • (w mg % N)

Contents of TMAO, TMA and TVB In fresh cod • stored in ice

(in mg % N)

Tabliea 4

Czas skladowania (dni)

Storage time (days) .

• 0 .1 2 3 4

• 7

9 10 11 12 11

•

TM AO TMA

76,34 0 176 6252 0,140 30,53 0,176 60,74 0,285 37,04 • 0,995 55,79 0,945 49,10 L968 50,15 4,010 99,52 4.020 43,21 4,100 32,83 15.550 29,75 10,160 27,01 16,090

*Translator's note.. :"niegladzica" -,.whioh the aUthorshere trans late as "long rough dab", is translated by me as "American _

.plaice".

X WO • Ft« à 11A TVB

• e tkliéneteit w Wm. •

• time is ( if s

ed.

14-1

11

n -

--- 100 -

-

n- - r

10- i

40- • 4

-

2g-

Bye. 1. Zmiany zawartogci TMAO, TMA t LZA w magi!, donna baltyck1eigo pod- czas skladowania w lodzte .

Fig. 1. Changes In the contents of TMAO, TMA and TVB in the meat of Baltic cod during storage In ice

During the first seven days of storage the changes in

the amounts of the different compounds occurred slowly. The

content of TMAO fell from an initial 76.34 mg % N to 49.18 mg

1\1, the amount of TMA increased from 0.176 to 1.97 mg e N, while the TVB decreased from 18.03 to 17.5 mg % N. At the same

time there occurred some slow organoleptic changes.

Between the eighth and tenth day of storage the quality

of the fish began to fall rapidly. Durirgthis period the TMAO

was found to fall to 43.1 mg % N, while the TMA and TVB

increased correspondingly to 4.18 and 19.6 mg % N. On the

eleventh day of storage the organoleptic evaluation demonstra-

ted that the fish were unsuitable for consumption.

After fourteen days the amount of TMAO comprised,27.01

mg % N, TMA - 16.09 mg % N, while the TVB was 24.90 mg % N.

The lack of an exact relationship between the fairly

steep course of the curve of the increase of TMA and the much

mure gentle decrease of the TMAO (Figure 1) may be explained,

among other fqctors, by the probability that TMA is also pro-

duced from choline, as a result of the action of enzymes from

certain species of bacteria that are found in fish (6). The

course of the TMAG curve has a character very similar to that

described in the study by S. Otsuka and his co-authors (9).

Flounder

The results of the TMAO, TMA and TVB determinations

in the flesh of fresh flounder - stored in ice are presented in

table 5, and a graph of these is presented in Figure 2.

The content of TMAO in the initial sample comprised

11.06 mg % N, of TMA - 0.15 mg %N and of TVB - 21.84 mg % N.

During the first six days no essential quantitative

changes were found in the tested compounds nor were there any

organoleptic changes. Beginning from the seventh day of sto-

rage there appeared the first real organoleptic changes, the

ouality of the fish began to be . decidedly worse. The values

of the various cheMical determinations appeared as follows:

TMAO - 11.72 mg' % N, 1.03 mé % 14- and TVB -.20.72, mg % . N.

On the thirteenth day , ofstorage the organoleptic-evaluation

1 0

x IMA 0 • INA

AL1A TVB

.11

?I

10 ,Ont skiadowehia w Storage In in (in dqs)

!Rye Z. Zmiany zawartoSci TMAO, TMA I LZA w miesie storni baltyckiej pod- czas skladowania w lodzie

Fig. Z. Changes in the contents of TMAO, TMA and TV Et in the meat of flounder during storage in ice

er- >Z1

r

showed that the fish were unsuitable for consumption. On this

day the value of the TMAO fell to ,2.9 Mg % N, while the.TMA

rose to 2.81 mg % N; the value of TVB comprised 22.12 mg .% N.

As is apparent from Figure 2, the graphs of the changes

of the tested compounds have a more gentle course and.are less

emphatic than in thé case of the cod..

LZA TVB

21,84 21,28 22,26 11,84 18,50 20,72 25,84 22,12 24,0,8 28,60 22,12 19,12 22,12 24,92

Czas sk1adowania Wnij

Storage time (days)

0 1 3 4 6 7 8 9

10 11 13 14 15 16

TMAO

11,06 14,38 8,38 7,20

13,65 11,72 14,93 13,12 12,48 9,81 2,90 1,40 5,28 4,97

TMA

0,15 0,13 0,19 0,27 0,42 1,03 2,01 2,19 2,35 4,26 2,81 3,43 3,75 5,14

11

Tablica 5

Zswiu-toiré TMAO, TMA I LZA w stornlach hwletych skladowanyeh w ledsle

(w mg N) Contents of TMAO, 'T111A and TVB in fresh flounder

stored in foe (in mg Ilho N)

■

CONCLUSIONS

FROZEN. FISH

The modest scope of the investigations presented above

does not permit the formulation of definitive and emphatic

conclusions as to the.changes in the contents of the desig-

nated compounds during:the storage of the fish at teperatures

below freezing; it. may bè accepted, however, that the content

of none of these underwent substantial changes. enly in the

frozen cod after.26-33 weeks.of storage under industrial con-

ditions (at a teMperature of -25PC) was there obserVed a very

slight increase in the content .of TMA (from 0.55-1.09 mg . % N.

.to 1.56-2.31 mg % .N) and of . TVB .(frôffi 2352.-26.3 mg % N tô, •

26.04-5122 mg % N). These changes, however, were weakly de-

fined and could have resulted from non-Uniform treatment .of

the fish before this was frozen.

12 .

The contents of TAO, TMA and TVB in the flesh of the

redfish fluctuated within very narrow limits, without manifes-

ting any tendency to fall or to rise.

In the halibut, witch flounder and American Plaice,

which were only tested once, after a three-month period of

storage, there were found very distinct specific differences

with respect to the content of TMAO. The simultaneously ob-

served fairly considerable variations in the trimethylamine

oxide within one species may have resulted from different

treatment of the fish before freezing or from a differing bio-

logical state.

un the basis of the studies that were carried out and 201

also of the literature ( 1-0, the view may be expressed that the

contents of TMAO, TMA and TVB in the flesh of frozen fish do

not provide grounds for making conclusions as to the length

of the period of their storage in a freezer. -

FISH STORED IN ICE

During the period of storage of fresh fish in ice there

were found differences in the contents of all three of the

tested indicators. The changes that occurred during the period

of storage of the Baltic flounder were very similar to the

changes observed in the cod. There was found a fairly close

relationship between the increase in the TMA in the flesh of

these fish and the duration of their storage in ice, with a

simultaneous distinct worsening of the organoleptic properties.

These changes, however, occurred only after six to eight days

of storage. In the cod the greatest increment in the TMA was

1 3

found between the tenth and eleVenth day of storage (froM . 4.18

to 15.55 mg % IV); in the flounder this increase occurred bet- .

ween the ninth and eleventh day of storage (from 2.19 to 4.26

mg 7o N), and at this time there was-found a slightly putrid

to putrid smell. It should be noted that during the periOd

of the storage of the flounder the amount of TMA increased' in

a regular manner, while during the storage of the.cod thiè

increase was irregùlar (Figures 1 and 2).

In connection with the fact that the real increase in

the contents of TMA and TVB in the flesh of the tested fish

occurred only after six to eight days of storage; the useful-

ness of the above tests as objective indicators of quality

seems doubtful.

SUMMAIW

The authors determined the contents of trinaethylamine oxide, trirnethylarnine and the total volatile basic nitrogen in the meat of frozen lish from the Northwest Atlantic (badus morhua, Sebastes marinus, Re(nhardtius hippoglossoides, Pleu-ronectes cynoglossus and Drepanopseita p/atessaides) fand in fresh fish species from the Baltic Sea (Gadus morhua and Platichthys flatus) stored in ice. The in-vestigations aimed at establishing the relationship between the storage period .and the TMAO, TMA and TVB content in the meat of fish and - thus obtain some knowledge as to which of these chemical test may prove useful as objective stan-. . dards of fish quality.

Fresh and frozen skinned fish - fillets, headed .and . gutted fish and whole fish were used for the experiments.

No distinct relationship between the- storage period and the TmAo, TMA and LVB content was observed in frozen fish. Only in cbd, alter being stored for 28-33 weeks, was some increase in the level of TMA. and TVB noted '(table 1); these changes however did not show any regularity and 'might have been cau-sed by different handling of fish prior to freezing. in redfish, the TMAO, TMA and TVB contents oscillated within clearly defined limits and did not show any tendency to either decrease or increaile (table 2). The determination of the ruo content in the meat of flatfish pointed to rather obvious differences in Varioui spedes. As regards TMA and TVB no essential differences were found in peek-cular species (table 3).

As opposed to frozen fish, the TMAO, TMA and TVB contents in fresh fish stored in ice underwent distinctly . marked changes (figures 1 and 2, .tables and 5).

Both the experiments conducted and relevant literature enable us to aim* that the TMAO, TMA and TVB contents in' the. meat of frozen fish are 'nét a• basis for conCluding the lengtli- of storage period in Fold store. Ai 'regards fresh fish kep t . in ice, the TMAO, TMA and •TVB tests. are of 'doubtful value foe objective estimation of their quality ; particularly during the first few.dayeof their: storage... , • •

BIBLIOGRAPHY

14

LJTZIATIJftA

1. Ama no K., Toza w a H.: Freezing and irradiation of fish. Irish Nevi (books) Ltd., London 1969.

2. An t o nacopoulos N.: Simultaneous estimation of trimethylamine oxide. and trirnethylaunine nitrogen and estimation of total volatile basic nitrogen for

testing freshness of marine fish. Technical Conference on Fish Inspection and Quality Control. FE:FIC169/0167, Halifax 1969.

3. 13 ystedt J., S wenne L., A as H. W.: Determination of trimethylamine oxide in fish muscle. J. Sci, Food, Agric., vol. 10, No 6, London 1959.

4. Cast cil C. H., Bishop Y. M., Wanda E. Neal: Production of trimethy-lamine in frozen cod muscle. J. Fish. R. Bd. Canada, vol. 25, No 5, 1988.

3. Castell C. H., Maxine F: Greenough, R.odgers R. S., MacFa'rlane A. S: Grading fish for quality. Trimethylamine values of fillets cut from gra-det fish. J. Fish. Res, Bd. Canada, vol. 15, No 4, 1958.

e Dyer W. J.: Amines in fish muscle. I. Colorimetric determination of trimethy- lamine as the picrate salt. J. Fish. Rea. Bd. Canada, vol. VI, No 5, 194).

7. Method for the determination of trimethylamine (TMA) in fish muscle. Codex Committee on Fish and Fishing Products, Joint FAO/WHO Codex Alimen-tarius Commission, Codex Fish 1/6 (Bergen 19681.

8. Method for the determination of total volatile basic nitrogen (TVB) in fish • muscle Codex Committee on Fish and Fishing ProduCts, Joint FAO/WHO Codex Alittluntarius Commission, Codex Fish 1/7 (Bergen 19681.

9. Otsuk a S., Tominak a T., Okada F., Kato I.: Decrease in trimethyla-mine oxide content during chill storage of marine products and a novel method for estimating freshness. (Abstr. w:I J. Sci. Food Agric., vol. 14 . No 9, Lon-don 1968. •