+ studies on the handling and processing of sea urchin roe. i. fresh product march 1979

.+

Studies on the Handling and Processing of Sea Urchin Roe. I. Fresh Product

By D.E. Kramer and D.M.A. Nordin

Technology Services Branch Fisheries Management, Pacific Region Department of Fisheries and Oceans 6640 N.W. Marine Drive Vancouver, British Columbia V6T 1 X2 Canada

March 1979

Fisheries and Marine Service Technical Report No. 870

Fisheries and Marine ServIce

,

Fisheries and Marine Service

Technical Reports

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• Cover deSign by Chflslme Rusk

1

Fisheries and Marine Service

Technical Report No. 870

March 1979

STUDIES ON THE HANDLING AND PROCESSING OF SEA URCHIN ROE

I. FRESH PRODUCT

by

D.E. Kramer and D.M.A. Nordin

Technology Services Branch

Fisheries Management, Pacific Region

Department of Fisheries and Oceans

6640 N. W. Marine Drive

Vancouver, B.C. V6T 1X2

This is the fourteenth Technical Report from the

Technology Services Branch

Vancouver

i i

© Minister of Supply and Services Canada 1979

Cat~ n9. Fs 97-6/ 870 ISSN 0701-7626

iii

TABLE OF CONTENTS

Page No.

LIST OF PLATES ..................................................... LIST OF FIGUR ES

LIST OF TABLES

.................................................... .....................................................

ABSTRACT ........................................................... INTRODUCTION ....................................................... LITERATURE SURVEY ..................................................

1.

II.

1 I I.

IV .

HARVESTING METHODS A. Diving

Hand Methods B.

C.

D.

Towed Gear ..................................... Trapping

ROE RECOVERY AND CLEANING A.

B. Local Methods Japanese Methods

PRESERVATION OF FRESH ROE A. Fluid Leakage in Fresh Roe . ............ . . . . . . . . B. The Use of Alum for Fi rmi ng Roe . . . . . . . . . ....... C. The Use of Alum for Preventing Fluid Leakage

PACKING AND SHIPPING A.

B.

C.

Size and Color Preference . .................... . Local Methods Japanese Methods

MATERIALS AND METHODS .. ... .. ... .................................... I. MATERIALS .... .... ....... .... .................. ' ...... .

A.

B. C.

Collection Area Firming Agents and Buffers Reagents Used for Proximate Analysis

v

vi

vii

viii

1

2

2

2

2

3

3

3

3

4

6

6

6

7

8

8

8

10

11

11

11

11

11

iv

TABLE OF CONTENTS (Cont'd.)

Page No.

MATERIALS AND METHODS (ContI d.)

II. METHODS 12

A. Sea Urchin Collection and Roe Recovery ••••••••• 12

B. Measurement of Harvesting and Roe Recovery Rates •.••••••••••••••••••••••••••••• 12

C. Treatment of Fresh Roe wi th Buffers ••••••••..•• 12 D. Treatment of Fresh Roe with Firming Agents ••.•• 13 E. Storage of Whole Urchins and Fresh Roe ••••••.•• 14 F. Organoleptic Assessment of Fresh Roe •.•.••••••• 16 G. Shipment of Fresh Roe to Japan ••••••••••••••••• 16 H. Proximate Analysis of Fresh Roe •••••••••••••.•• 17

RESULTS AND DISCUSSION •••.••.•••••••••••••••••.•••••••••••••••••.•• 18

I. PHYSICAL ASPECTS OF FRESH ROE ••••••••••••••.•.••••••• 18 A. Color and Size ••••••••••••••••••••••••••••••••• 18 B. Gonadal Yield ••••••••••••••••.••••••••••••••••• 18

C. Harvesting and Roe Recovery Rates •••••••••••••• 18

II. PROBLEMS IN PROCESSING FRESH ROE ••••••••••••••••••••• 19 A. Fluid Leakage ••••••••••••••••••••••.••••••••••• 19 B. Fi rm; ng the Roe .•••.....•.......•••••...•....•• 19

I~I. STORAGE STUDIES •••••••••..•.••••••••••••••••••••••••• 20 A. Storage of Whole Red Sea Urchins at 2°C •••••••• 20 B. Storage of Roe at 2°C ••••••••••••••••••.••••••• 21

C. Storage of Red Sea Urchin Roe in Salt Solution. 21

IV. ORGANOLEPTIC ASSESSMENT ••...••••••••••••.....••••.••• 22 A. Laboratory Taste Panel Assessment •••••••••••••• 22 B. Shipment to Japan •••. ••••••••••••••..•••••••••• 22

V. PROXIMATE ANALYSIS ••••••.•••••••••••••••••••••••••••• 22

ACKNQWLEDGEMENTS •.•••.••••••.••••••••••••.•.•.•••••••••••••••••.••• 23

REFERENCES ••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 24

APPENDIX: Buffer Preparation .•.••..•••••••••••••••••••••••••••••••• 28

v

LIST OF PLATES

Plate Page No,.

1. A. s. franciscanus, the red sea urchin •••••••••••••••••••••••• 30

B. S. drobachiensis, the green sea urchin ••••••••••••••••••••• 30

c. S. purpuratus, the purple sea urchin •••••.••••••••••••••••• 30

D. Red, green and purple sea urchins •••••••••••••••••••••••••• 30

E. A male red sea urchin spawning •••••••••••.••••••••••••••••• 30

F. A female red sea urchin spawning ••••••.•••••••.•••••••••••. 30

2. A. Roe from the red sea urchin, the green sea urchin and

B.

c.

the purple sea urchin ••••••••••••••••••..•••.•••••••..••. 32

Mottled roe from male and female red sea urchins

Fluid leakage in roe from male and female red

32

sea urchi ns .............................................. 32

3. A. Color variation in roe from male red sea urchins .•.•••••••• 34

B.

C. Color variation in roe from female red sea urchins

Color var i ation in roe from male green sea urchins

34

34

D. Color variation in roe from female green sea urchins ••••••• 34 E. Color variation in roe from male purple sea urchins ••••••.• 34

F. Color variation in roe from female purple sea urchins •••••• 34

...

Figure

1.

~.

vi

LIST OF FIGURES

Page No.

Methods of Preparing Fresh Sea Urchin Roe ••••••••••••••••••• 35

Gonadal Yield of Red (S. franciscanus) and Green (S. drobachiensis) Sea-Urchins over a One-Year Period ••••••• 36

vii

LIST OF TABLES

Table Page No.

1. Harvesting and Roe Recovery Rates of S. franciscanus and S. drobachiensis .............. -:-....................... 37

2. Treatment of Fresh Roe from Male S. franciscanus with Various Buffers to Prevent Fluid Leakage •••••••••••••••••• 38

3. Treatment of Fresh Sea Urchin Roe with Alum

A. Effect of Concentration ••••••••••.• • •••••••••••••.•••• 39

B. Effect of Time •••••••.....••••••••••••••••••.•••••• • •• 40

4. Treatment of Fresh Sea Urchin Roe with Citrate .......... .... 41

5. Treatment of Fresh Sea Urchi n Roe with Alcohol .............. 42

6. Organoleptic Ratings of Fresh Sea Urchin Roe ................ 43

7. Test Shipment Results on Fresh Sea Urchin Roe ............... 44

8. Proximate Analysis of Fresh Sea Urchin Roe

A. S. franciscanus •••••.••••.•••••••.•••••••.•.•••••••••• 45

B. S. dr8bachiensis •.••••...•..•••••.••..•...•••••••.•••. 46

c. S. purpuratus ......................................... 47

viii

ABSTRACT

Harvesting times and methods, processing methods, shipping methods, organoleptic assessment for quality and proximate composition of fresh gonads from Strongylocentrotus franciscanus (giant red sea urchin), Strongylocentrotus drooachiensis (green sea urchin) and Strongylocentrotus purpuratus (purple sea urchin) have been studied. A literature survey is included which covers harvesting, processing and shipping methods used to prepare sea urchin roe for the Japanese market. The term sea urchin roe ~s used in this report to describe gonads from both male and female sea urchins . Using 2 workers, roe from the red sea urchin was harvested and recovered at the rate of 1 kg of roe for 25 minutes of effort while 1 kg of roe from the green sea urchin was harvested and recovered in 45 minutes. A 0.1 M sodium phosphate buffer of pH 6.5 was found to effectively remove white fluid leakage (sperm) from red sea urchin roe. A 10-minute rinse in 2% alum or a 20-minute rinse in 0.5% alum will firm roe from S. franciscanus while a 10-minute rinse in 1% alum is effective in firming S.-drobachiensis roe . Roe from the thre .' species of urchins was rated fair to good in terms of flavor, odor and color by a laboratory taste panel. Contacts in Japan rated red sea urchin roe and roe from female green sea urchins as excellent in color and flavor, with good potential for commercial use there. Proximate analysis indicates sea urchin roe from the above listed species has about 70% moisture,S to 8% lipid and 10 to 13% protein.

, , RESUME

Nous avons etudie les periodes et les methodes de recolte ainsi que les methodes de traitement et de transport des gonades fraiches des oursins Strongylocentrotus franciscanus, Strongylocentrotus drobachiensis et Strongylocentrotus purpuratus et nous avons evalue leurs proprietes organo: leptiques pour en determiner la qualite et la composition approximative. A cela s'ajoute une etude bibliographique des methodes de recolte, de traitement et de transport employees en vue de presenter sur le marche japonais les gonades, males et femelles, d'oursin de mer. Des especes ~. franciscanus et ~ drobachiensis, deux travailleurs en ont recolte et trie 1 kg apres 25 et 45 minutes, respectivement. Une sulution tampon de phosphate de sodium 0,1 M a pH 6,5 a elimine les secretions blanches (sperme) des gonades de S. franciscanus, que le rincage dans une solution d'alun a 2% durant 10 minut~s ou a • 0,5% durant 20 minutes permet de raffermir. Quant aux gonades de S. droba-chiensis, elles sont raffermies par rin~age dans une solution d'al~n a 1% pendant 10 minutes. En laboratoire, les gonades des trois especes ont ete jugees de satisfaisantes a bonnes en ce qui regarde la saveur, l'odeur et la couleur , par un groupe de degustateurs. Selon les rapports en provenance du Japon, la couleur et la saveur des gonades de~. franciscanus et des femelles de S. drobachiensis ont ete considerees comme excellentes. Pour ces produits, les possibilites de commercialisation y seraient bonnes. D'apres l 'analyse approximative de leur composition, les gonades des trois especes sont constituees a 70% d'eau, de 5 a 8% de lipides et de 10 a 13% de proteines.

1

INTRODUCTION

This report is the first in a series of Technical Reports on preparation of fresh, frozen, fermented and canned sea urchin roe. It includes a literature survey and covers harvesting times and methods, processing methods, shipping methods, organoleptic ratings and proximate analysis of fresh roe from Strongylocentrotus franciscanus and S. drobachiensis. -

During the last 8 to 10 years, interest in commercial harvesting of sea urchins has arisen on the West Coast of the U.S. and Canada as well as in several other countries. The prinCipal market for sea urchins is Japan, where the roe (actually gonads) is considered a delicacy and has "been sold for $2 to $8 a pound, depending on the season, species and quality' of t~e , product (Australian Fisheries, 1972; Fuke and Tsuyuki, 1974; Hudnall " 19l0; Kato, 1972b; Marine Fisheries Review, 1972; Miller et al., 1913). ' AlthoJgh roe preCisely means egg mass, for this report the word-roe ' is used to indicate gonads, both male and female, including eggs and sperm.

On the Japanese market, the highest-priced product is fresh roe, which is usually freshly recovered but in some cases has been previously frozen. Canned and salted, fermented products are also marketed. Due to an increasing demand and a reduced supply of sea urchins in Japan at present, the Japanese have imported sea urchin roe from many countries including Korea, Peru and Chile (Commercial Fisheries Review, 1971b), Taiwan (Kato, 1972b), the U.S.A. (Marine Fisheries Review, 1974b; Pacific Northwest Sea, 1977), Canada (Canada Department of Industry, Trade and Commerce, 1974; , Marine Fisheries Review, 1972; Miller et al., 1973) and Mexico (Marine Fisheries Review, 1974a). The Japanese-have also investigated the possibility of importing sea urchin roe from Australia (Australian Fisheries, 1972 and 1975; Commercial Fisheries Review, 1970).

Several years ago in California, kelp beds were being destroyed due to an overabundance of sea urchins. This led to the organization of several urchin-kill projects in which divers armed with hammers and hatchets killed an estimated 800,000 urchins in a single day. Since that time, a sea urchin fishery has developed in southern California, partly as an ' attempt to reduce the population of urchins by harvesting for roe recovery (Australian ' ' Fisheries, 1971b; Kato, 1972a; McDaniel, 1975a; Miller et al., 1973). The first U.S. sea urchin fishery was based in San Diego (Commercial Fisheries Review, 1971a; Commercial Fisheries Review, 1972) and several years later processing of sea urchins was started at Santa Barbara (Fish Farming " Industries, 1974; Fishing News International, 1974). Initial production of fresh roe was for the domestic "sushi" market and when' production increased, the roe was to be exported to Japan.

In Canada, three species of sea urchins are found in shallow waters: S. franciscanus (red sea urchin), S. drobachiensis (green sea urchin) and S. purpuratus (purple sea urchin). These are shown in Plates lA, 1B and 1C -respectively. The relative sizes of the three species are shown in Plate 10. All three species occur along the Pacific Coast, but only S. drobachiensis is found along the Atlantic coast. Indications are that the green sea urchin is quite suitable for the world "sushi" trade (Bedard, 1973) and that a market in France exists for this species if the quality of the product is acceptable (Sandeman, 1977). The resource potential of the green sea urchin

2

in Newfoundland has been i nvestigated with a view to development of a fishery there (Fletcher and Haggerty, 1975; Fletcher et al., June 1974; Fletcher et ~., February 1974; Fowler and Fletcher, 1975;-MTTler and Bishop, 1973). --

In sea urchins, the sexes are separate and reproduction occurs with fertilization external to the animals. During the spawning process, sperm (white) and eggs (yellow) are emitted into the water and fertilization occurs by chance meeting of sperm and egg. Plate 1E shows a male red sea urchin spawning, and plate 1F, a female.

In B.C., stocks of the red sea urchin are sufficient to support a fishery (Bernard and Miller, 1973; Miller, 1974). Due to its large size, S. franciscanus is the only species that has been harvested commercially up to the' present in this province. Sea urchin roe has been processed in the past at plants in Tofino on Vancouver Island (Australian Fisheries, 1971a; Fishing News International , 1971; Hudnall, 1970) and in Prince Rupert (Canada Department of Env i ronment, 1973; Sounder, 1973).

LITERATURE SURVEY

An outline of the methods used in preparing fresh sea urchin roe is given in Figure 1. The Roman numerals correspond to the appropriate section of thi s "Literature Survey".

I. HARVESTING METHODS

In Japan it has been recommended that before taking sea urchins ~ommercially from a new, unharvested bed, all large old ones should be removed and harvesting initiated about two years later (Tsuyuki and Razzell, 1976b).

A. Diving ,

Sea urchins are usually harvested by divers who collect the urchins at depths up to about 40 feet using a three- or four-pronged rake. In B.C., the urchins are raked into wire baskets or cages, brought to the surface and transferred to holding boxes on the boat (Hudnall, 1970). Scuba and hard hat diving gear have both been used (Bernard and Miller, 1973; Miller, 1974).

In southern Califor nia, urchins are collected by divers using rakes and net bags or with suction (Fish Farming Industries, 1974; Fishing News International, 1974; McDaniel, 1975a and b). Cranes are used in some cases to lift 100-lb bags of urchins to the surface. In Washington, divers collect sea urchins in baskets or bags which will hold about 300 lb. A buoyancy device, a large inner tube, is used to bring the urchins to the surface (Watson, 1976). Harvesting at depths less than 10 ft is not allowed in this ~tate (Pacific Northwest Sea, 1977). Sea urchins exported from Ireland to France were collected by divers by hand (Southward and Southward, 1975).

B. Hand Methods

Hand nets have also been used for harvesting sea urchins. In Maine during the 1940's, urchins bound for the domestic market (New York City and Boston) were collected using dip nets with 10-foot handles (Scattergood, 1961). Hand nets and a vi ewing box are used in Japan at the beginning of

3

the season when shallow water urchins are mature; then, as the season progresses, skin divers harvest deeper water urchins which mature later (Fuke and Tsuyuki, 1974). In France, long poles with three curved prongs were used in the early 1900's and are still in use in some areas (Southward and Southward, 1975).

One method that has been successful in Japan for sea urchin harvesting involves using bundles made up of 3 or 4 pieces of seaweed as bait (Tanaka, 1960). Each bundle is tied with a 60 to 80 cm line, one end of which has a 2.5 to 3 kg rock sinker. A floating wood or bamboo marker identifies the location of each bundle. The fisherman sets about 10 bundles. After the last bundle is set, he returns to the first and slowly pulls up the line. A scoop net is used to bring the bundles into the boat and the urchins are removed.

C. Towed Gear

Sea urchins have been harvested with several kinds of towed gear. In Maine (Scattergood, 1961) and in France (Southward and Southward, 1975), dredges have been used but these cause appreciable des truction to the grounds and are usually employed in more profitable fisheries.

In France, nets attached to iron bars, to hoops or to rakes have been towed along the bottom to collect sea urchins (Allain, 1972). Towed gear in use at the present time is made with cotton tufts attached at various points to a long chain. In the 1930's to 1950's, 12-meter lengths of cable with 8 to 12 kg of chain (for weight) and old fishing nets were dragged in sets of 4 to 10 in shallow water (Southward and Southward, 1975). This method, however, destroys small urchins which are caught in the net and smashed on deck when the net is cleaned.

In Newfoundland, trials were conducted with a mop which consisted of d 16- foot length of chain with pieces of nylon rope tied to 10 feet of the chain (Miller and Bishop, 1973). Results showed that 41 lbs of S. drobachiensis over 1 1/2" could be fished in one hour. Quality of the roe from urchins caught in this manner was not checked, however, and this method may shake or batter the urchins enough to break the test or roe, making the roe unsuitable for the fresh or frozen market.

D. Trapping

Trapping has been used in Japan (Motohiro, 1976), although catch rates may limit it to use for a sport fishery rather than for commercial harvesting of sea urchins. The trap consists of an iron ring about 60 cm in diameter with a net stretched across it. Cod skins are used for bait. Miller and Bishop (1973) report limited success in trials in Newfoundland using a hoop trap with herring or seaweed as bait.

II . ROE RECOVERY AND CLEANING

A. Local Methods

Recovery of sea urchin roe usually consists of the following steps (Bernard and Miller, 1973; Canada Department of Environment, 1973;

4

Fish Farming Industries, 1974; Hudnall, 1970; Miller, 1974; McDaniel, 1975a; Pacific Northwest Sea, 1977):

1. After urchins are received at the plant, the test is cracked open with a knife.

2. The roe is carefully removed using a tablespoon or, if available, some type of long-handled narrow spoon.

3. Roe is cleaned of ingested food and adhering membranes using tweezers.

4. Roe is then placed in a wire or plastic basket and immersed in sea water for a rinse.

Aristotle's lantern (the mouth) is often removed prior to cracking the tes t and steps 3 and 4 are sometimes carried out in the reverse order. Spines can be removed before step 1 (possibly by a mechanized method, see Mottet, 1976), but this is not necessary and the added labor makes it impractical in most cases.

In Californ ia, one processor has the cracking of the urchin and removal of the roe (steps 1 and 2) completed by men in a boat located next to the diver's boat; cleaning of the roe is done at the plant (Commercial Fisheries Rev iew, 1971a). Another processor water-chills the roe after step 4 and then dra ins on an absorbent towelling material (Fishing News International, 1974).

A treatment mentioned to us by one of the local companies interested in harvesting sea urchins involves soaking the roe for 2 days in a water:sa lt:brown sugar solution using a ratio of 1 gallon:1 pound:1 pound.

B. Japanese Methods

In Japan, the procedure for recovering sea urchin roe is basically the same as the steps given in the previous section under "Local Methods", with slight variations from area to area. Kato (1972b) reports that in one village , the urchins are taken to the diver's home or to a central process ing area where the diver's relatives clean the urchins. In another area spines are removed at the plant by agitating the urchins in a wicker basket; then the urchins are cleaned using simple hand tools such as a pick, spoon or forceps. Iron or brass tools should not be used to remove or clean gonads since they may cause oxidation, resulting in blackening of the gonads (Tsuyuk i and Razzell, 1976b). Gonads are removed as soon as possible, so the urchins are held live for only a short time (Tsuyuki and Razzell, 1976a).

Ko nno and Kinoshita (1955) describe 3 methods for opening sea urchins and removing gonads. In Yamaguchi, the test is broken in two from the mouth using a straw cutter or a small knife and the gonads are removed with a tool similar to a small spoon. In Nagasaki, a knife or cut branch is inserted into the mouth at an angle and forced through the test, breaking it, then the gonads are carefully removed with a small spoon or bamboo spatula. In the Fukui region, a file (15 to 18 cm long, 1.8 to 2.1 cm wide and 0.9 to 1.2 cm thick) is used to strike the test lightly as the uchin is turned on

5

its oral-anal axis. After two or three rotations, when the spines are nearly all removed, the test is cracked and given to another person who removes the gonads into a bamboo basket.

The following details of roe recovery in Japan are taken from a pamphlet by the Fisheries Section, Aomori Prefecture (1968) :

1. Methods of opening the shell

a. A knife is used to strike along the central line of the shell, separating it into two parts, the upper and lower. Efficiency of labour is poor with this method but, if carried out carefully, shell and spines will not be mixed with the gonads.

b. A cutter is used which has the top blade set downwards and the bottom blade set upwards. The urchin is placed sideways and the cutter separates the upper and lower parts of the shell from the center. The method is fast but shell and spines are often mixed into the gonads.

c. A small, sickle-shaped knife is inserted between the mouth and surrounding green region and these parts are removed with a twist . A tap on the lower surface is used to make a large hole, leaving the upper shell containing gonads and intestines. This method is quite efficient and mixes very few shell or spine fragments into the gonads.

2. Methods of removing gonads from the shell

a. The shell is shaken gently up and down, with the mouth side down,to get rid of some of the viscera and ingested food, then the gonads are removed with a spoon, bamboo scoop or fingernails.

b. In some areas, the upper part of the shell with the gonads is immersed in clean sea water and lifted up quickly. This procedure is repeated two or three times to rinse out the viscera and ingested food. The cleaned gonads are then peeled out of the shell.

3. Rinsing the gonads

Th e gonads are placed in a basket in clean sea water. Viscera and other impurities will float to the surface and can be removed with chopsticks during gentle stirring. Shell and spine fragments sink and can be removed by transferring the gonads from basket to basket.

4. Draining the gonads

The gonads are placed in a thin layer in a shallow basket for draining. This basket is put in a cool, dark place as

6

warmth causes deterioration and oozing. The pamphlet indicates that a refrigerator is not satisfactory for draining the gonads but no reason is given. Once the gonads are removed, they should be protected from direct sunlight.

Oshima (1974) reports two methods for removing sea urchin gonads from the shell:

1. The shell is cut open with a knife near the mouth, then tapped against a cook ing board with the open side towards the board. The gonads come out along with the guts and will adhere to the board. They are carefully cleaned by hand and put into a bowl or wooden pail.

2. The opened shell is swirled around in sea water contained in a wooden pail. The guts will be washed into the sea water leaving the gonads in the shell. A spoon is then used to scoop out the gonads.

The draining procedure described by Oshima involves placing the gonads in a wooden tub with a bottom board which has parallel grooves. This tub is then placed at an angle which will give good drainage.

A shel ling machine is available in Japan for opening sea urchins (Tsuyuki and Razzell, 1976b).

III. PRESERVATION OF FRESH ROE

A. Fluid Leakage in Fresh Roe

Several solutions have been used in Japan to prevent the dripping or oozing of fluid from sea urchin roe. In the Wakayama Prefecture, the roe is placed in wooden boxes and gently immersed in a so l ution of one part sea wate r plus two parts fresh water. This is apparently done to help prevent oozing (Fisheries Section, Aomori Prefecture, 1968). In northern Honshu, the roe is washed in a solution of magnesium chloride plus sea water for this purpose (Kato, 1972b). In some areas, undesirable milkiness is removed by two rinses in sea water (Tsuyuki and Razzell, 1976a).

B. Th e Use of Alum for Firming Roe

In the B.C. and Washington sea urch i n fisheries, alum is used to firm the roe (Bernard and Miller, 1973; Canada Department of Environment, 1973; Miller, 1974; Pacific Northwest Sea, 1977; Watson, 1976). A solution of 0.5% alum has been used by one of the local companies. The Japanese also use alum for this purpose (Kato, 1972b). The roe is usually rinsed in a 0.3% alum solution; too much alum will result in a bitter flavor (Tsuyuki and Razzell, 1976a). It has been indicated to us that 2% alum is used in Japan and also at Santa Barbara, California. Kato (1972b) reports that, in Kagoshima, a much higher concentration of alum is used than previously i ndicated to him. The alum is mixed with a solution of one part fresh water plus three parts sea water and effectively firms the roe in 5 minutes (Kato, 1972b) . A written processing procedure provided by a company in Shimonoseki i ndicates that 1% sodium chloride added to sea water is sometimes used rather than an alum solution to firm the gonads (Tsuyuki and Razzell, 1976b).

7

In Hokkaido, sea urchin roe is rinsed in a solution of 2% burnt alum, about 5% saltpeter and 1 part in 1000 of "flaskin" (Fisheries Section, Aomori Prefecture, 1968). Two methods of rinsing are used:

1. The roe, in a bamboo basket, is gently immersed in the solution, stirred carefully with chopsticks and left. quietly for 5 minutes. The basket is then gently raised and the treated gonads are drained.

2. The fresh roe is transferred to wooden boxes with bottoms made of bamboo-peel matting. Ten boxes are stacked and tied together with string, gently immersed in the solution and left to soak for 5 minutes before being gently lifted out. The immersion and removal should be done with great care so the neatly arranged roe does not float up and become displaced, necessitating rearrangement by hand.

These treatment processes involve satisfactory contact between the chemicals and each of the gonads.

The "flaskin" (phonetic spelling "furasukin") discussed above is a food preservative developed in Japan in 1949 (Motoyama, 1968). It is closely related to furacin, which is a sterilizer. This compound has been mainly used to maintain the freshness of raw fish. It is stable at both low and high temperatures and at high pH. According to the report by the Fisheries Section, Aomori Prefecture (1968), the use of "flaskin" is prohibited so potassium sorbate is used as a replacement at a concentration of one part in one thousand. Sorbic acid or its sodium salt may also be used. Less than 0.5 grams of these additives per kg of product is permitted.

c. The Use of Alum for Preventing Fluid Leakage

Kato (1972b) reports that, in Japan, another reason for rinsing sea urchin roe in alum is to prevent leakage of fluid. In Fukushima, several studies were conducted on the prevention of this leakage using various materials (Fisheries Section, Aomori Prefecture, 1968):

1. Both burnt alum and acetic acid were found to be effective in preventing oozing. However, acetic acid caused cloudiness, resulting in an unacceptable appearance. An alum solution of 1% was the most satisfactory concentration but produced some dehydrated areas. Roe treated with alum had a slightly poorer taste but this was reported as being negligible.

2. Storage tests were also done to compare chlortetracycline (20 ppm), "flaskin" (200 ppm) and burnt alum (1%). All additives were made up in a solution of two parts sea water plus one part fresh water. Twenty grams of roe was immersed in 200 ml of solution for 10 minutes, then stored at 3 to 16°C. The chlortetracycline and "flaskin" extended the acceptable storage time slightly but their use in sea urchin roe is not approved. Alum caused obvious dehydration immediately after treatment. The controls (no treatment) had less dehydration and the roe processed with chlortetracycline or "flaskin"

/

8

had none. Burnt alum was best for preventing fluid leakage. Of the three treated samples, roe treated with "flaskin" was the first to begin to leak. This was observed after several days of storage. The controls had offensive odors and clammy spots on the first day of holding, while none of the treated samples showed this, even on the second day.

IV. PACKING AND SHIPPING

A. Size and Color Preference

The appearance of sea urchin roe dest i ned to be sold fresh on the Japanese market is extremely important. Each package should contain roe of similar size and color.

Kato (1972b) reports that most of t he Japanese sea urchin roe used for the fresh market is about 2.5 to 3 cm long and 1.2 to 1.5 cm wide. The best roe will not be larger than 5 cm in length. Although some reports have indicated that Canadian and American sea urchin roe is too large (Kato, 1972b; Tsuyuki and Razzell, 1976a), at least one Japanese company feels that the size of roe from the red sea urchin, S. franciscanus, is fine (Kato, 1972b). However, another firm has expressed interest in the smaller, and in their opinion more desirable, roe from the green sea urchin, S. drobachiensis (Tsuyuki and Razzell, 1976a).

For the fresh roe market, a bright yellow color is preferred, but orange is acceptable (Australian Fisheries , 1975; Kato, 1972a and b; Pacific Northwest Sea, 1977). Darker colored roe is used for further processing to make products such as fermented sea urch i n roe or is added to other seafoods such as squid or jellyfi sh. Very dark roe is discarded.

B. Loca l Methods

Although sea urchin fisheries aimed at supplying the Japanese market involve shipping of the recovered roe, those which are looking at the European market may wish to ship the whole animal, as whole sea urchins are marketed in France and Italy. Miller and Bishop (1973) have studied the holding and shipping of live sea urchins (S. drobachiensis) from the Atlantic coast. They conclude that live green sea urchins can be kept in cold running sea water without food for at least 2 weeks with no significant mortality or decrease in gonad size or quality. The urchins can also be held for up to 4 days in plastic-lined cardboard cartons at 32 and 45°F with little deterioration. Miller and Bishop report that a few hours of storage at high (68°F) or low (14°F) temperatures will not be harmful to S. drobachiensis.

B.C. sea urchin process i ng involves shipment of the roe to the Japanese market by air. In Prince Rupert, the roe was packed in half-pound flat wooden boxes and shipped directly to Japan (Canada Department of Environment, 1973). In the Tofino fishery, cleaned sea urchin roe was packed in shallow wooden boxes, 3 1/2" x 6 1/2" X 1/2" (Hudnall, 1970). These were kept under refrigeration, trucked at the end of each day to the Vancouver airport and then airfreighted to Tokyo (Bernard and Miller, 1973;

9

Miller, 1974). The boxes used by one' of the local companies were made in Japan and are illustrated below. They have 3 slits for drainage. Those

Phillipine mahogany (0.2 cm thick)

17,5---1

---

«--~=---- rr lj - '

~ fO,25

Lid

----- -

Spruce or birch

(Dimensions are in cm)

_._---_ ...

-----~

used by another company were made in Seattle and are slightly larger than the one illustrated. These have 4 parallel lengthwise slits for drainage. The roe is packed lengthwise with the rounded or convex side up and the narrow ends pointing in the same direction. Small pieces of roe are placed first in the box, then whole undamaged roe is put on top.

In the U.S., processors supply both domestic and Japanese markets. A California firm has delivered fresh sea urchin roe to Los Angeles, some of which was then shipped to Chicago and New York (Commercial Fisheries Review, 1971a). Processors in the state of Washington export roe to Japan. Most U.S. companies pack sea urchin roe in overlapping rows in either wooden or styrofoam trays. One company in Washington packs the roe into trays (with 800 g of roe per tray), and puts 9 to 10 trays into a carton with ice (Watson, 1976). The product is flown to Tokyo every night. A processor at

10

La Conner, Hashington uses slatted white fir trays which go directly to the Tokyo fish auction market, then right to the retail outlet (Pacific Northwest Sea, 1977).

In Mexico, fresh sea urchin roe has been airfreighted to Japan by two Japanese firms (Marine Fisheries Review, 1974a). One company shipped the product to Hokkaido and the other (via Los Angeles) to the Tokyo Central Wholesale Market.

C. Japanese Methods

In Japan, the packing and shipping of sea urchin roe varies greatly from area to area.

According to Kato (1972b), the Tsukiji fish market sells roe in wooden trays about 3 1/2" x 6 1/2" X 1/2", which are packed in stacks 13 high. In Shimonoseki and Kagoshima, the standard wooden tray holds 40 to 50 g of roe. One fishery consultant indicated that a small tray holds 80 g of sea urchin roe while a regular tray holds 200 g of roe. The product is shipped by air in cartons hung by a rubber cord to avoid shock.

Tanaka and Matsuda (1970) give the following dimensions for boxes used to pack fresh sea urchin roe in Japan (length x width x height, all in cm):

Inner dimensions Outer dimensions

Large 18.0 x 10.8 x 2.3 16.0 x 9.5 x 1.2

Sma 11 16.5 x 9.0 x 2.2 14.7 x 7.7 x 1.2

A report by the Fisheries Section, Aomori Prefecture (1968) describes the methods of packing and shipping fresh sea urchin roe in Hokkaido and Wakayama. The roe is carefully packed in rows in small wooden-chip boxes, each containing 400 g of roe. For protection against heat during shipment, the boxes are wrapped in padded cotton cloth and placed in rows in a galvanized iron crate. Vinyl bags containing ice are packed between the small boxes and also between the small boxes and the crate and lid to keep the roe cool. Since the boxes are a standard size, the iron crate and ice packing can also be standardized to fit a specific number of small boxes. Equipment designed specifically for this purpose is used. Fresh roe, wrapped and packed in this way, is then shipped to the major cities by personal carrier using passenger railway mail express. For long-distance shipment, such as to Tokyo, couriers work in relay from the place of origin. At each train stop, ice is inserted into the iron crate. Sale of roe in Tokyo is only to designated traders, not by auction in the fish market.

11

The box illustrated below was obtained from Japan and is used there for pack i ng fresh Japanese roe. This box has Japanese Patent Pending #105394.

Phillipine mahogany (0.2 cm thick)

~o.s _t~ ______ 16'S14 ' ~

~ _ " o:s.... --- 8.3 2 .1 " , "~~~" __ Jo, ~ -~~~ ~ "~ .1 ~1~S ,_"-~~ S.9. ~ All plastic except "'l_ 1:~ ,,-' ''' o.~,~-:-::::.:::::::-____ -;y- for pi ece shown as

J'~- mahogany

.1:tX O.2XO.2 .--r-• 0.9 _,~, ~,-----

Oos==' ~ - \ . t 1.S ' ,- Holl ow through the 1 ength to

fit ridges of box underneath it

(Dimensions are in cm)

MATERIALS AND METHODS

I. ~1ATER IALS

A. Coll ection Area

All samples of S. franciscanus, S. drobachiensis and S. purpuratus were collected using scuba gear in 10 to-30 feet of water near Albert Head on Vancouver Island.

B. Firming Agents and Buffers

Alum was obtained from a local sea urchin processor. Citrate, alcohol and sodium chloride were analytical grade.

Sodium acetate, sodium phosphate and sodium borate used for the buffer washes were also analytical grade.

c. Reagents Used for Proximate Analysis

All reagents used for the proximate analysis of fresh sea urchin roe were analytical grade.

12

II. METHODS

A. Sea Urchin Collection and Roe Recovery

For this study, only medium to large size sea urchins were harvested. S. franciscanus was gathered into a plastic laundry basket fitted with a rope handle. ~. dr8bachiensis and~. purpuratus were collected in a diver's "goody bag". All urchins were transported in covered polyethylene tubs (62 x 46.5 x 50.5 cm). After a maximum of 5 hours travelling time (from Albert Head to Vancouver), the tubs of urchins were stored at 2°C overnight. The following day, the urchins were opened by prying out the mouth parts and splitting the test with a knife (cutting between roe segments so they are not damaged). The gonads were then removed, rinsed in 3.5% NaCl and cleaned using tweezers.

B. Measurement of Harvesting and Roe Recovery Rates

1. Harvesting Rate

Red and green sea urchins were collected by one diver using scuba gear. One helper in a boat took the urchins from the diver and put them into a tub in the boat wh i le timing the collection. S. drobachiensis was gathered using a diver's "goody bag II and S. franciscanus was gathered into a plastic laundry basket fi t ted with a rope-handle. The total number of urchins of each species was counted and the harvesting rate calculated as urchins per hour. The harvesting rate was also calculated as kg roe per hour based on a mean gonad weight of 119.8 g per red sea urchin and 17.3 g per green sea urchin (Kramer and Nordin, 1975 and 1978).

2. Roe Recovery Rate

Red sea urchins (51) and green sea urchins (147) were collected at Albert Head, stored at 2°C overnight and opened the following day at the laboratory. One person opened the test and removed the roe while the second person rinsed the roe in 3.5% NaCl and cleaned it using tweezers. The operation was timed. The roe was then drained for 1 hour at room temperature on screens having 2 mm mesh and weighed.

C. Treatment of Fresh Roe with Buffers

Approximately 40 S. franciscanus were collected for a study on preventing fluid leakage in fresh roe from this species. The roe was removed from male urchins (the white sperm being more visible than the yellow eggs) and one segment from each urchin was placed on each of 5 screens (2 mm mesh). The roe was then drained for 1 1/2 hrs at room temperature.

Two liters of each of the following solutions were prepared and put into five 3-liter beakers:

1 ) 10% NaCl

2) pH 5.0, 0.1 M sodium acetate (CH3 COONa·3H2 0) in 3.5% NaCl 3) pH 6.5, 0.1 M sodium phosphate (NaH2 P0 4 • H2 0) in 3.5% NaCl 4) pH 7.5, ° .1 M sodium phosphate (Na

2HP04 ) in 3.5% NaCl

5 ) pH 9.0, ° .1 M sodium borate (Na2 B4 07 '10H 2 0) in 3.5% NaCl

13

The roe from the 5 screens was transferred to the solutions in the 5 beakers and stirred gently at room temperature for 10 minutes using a magnetic stirrer. The roe was then transferred to the screens for draining and its appearance was noted. The screens of roe were placed in a cold room at 2°C and allowed to drain overnight. The following day. the amount of sperm remaining on the roe was noted and given a numerical rating. Flavor of the roe was evaluated by 2 taste panel members.

D. Treatment of Fresh Roe with Firming Agents

1. Al um

a. S. franciscanus

Red sea urchins (58) were collected. stored overnight at 2°C and opened the following day at the laboratory.

The effect of alum concentration on firming of the roe from these urchins was studied. Red sea urchins (10) were opened and the roe was removed. cleaned with tweezers and rinsed in 3.5% NaCl. One segment of each urchin was placed on each of 5 different screens (2 mm mesh). After draining, the roe from each screen was transferred to a l-liter beaker containing one of the following solutions (prepared in 3.5% NaCl): 0 alum, 0.25% alum, 0.5% alum, 0.75% alum or 1.0% alum. The roe was left in the five solutions for 5 minutes, with occasional gentle stirring. A second experiment was carried out using 0 alum, 0.5% alum, 1% alum, 1.5% alum or 2% alum. The roe was left in these five solutions for 10 minutes, with occasional gentle stirring . It was then removed, rinsed in 3.5% NaCl and drained on the screens. The roe was scored for texture and flavor by 6 trained taste panel members using the organoleptic assessment ratings shown below:

Texture

5 Extremely firm 4 Very fi rm 3 Firm 2 Soft 1 Very soft

Flavor

5 Excellent flavor 4 Good flavor 3 Fair flavor 2 Poor flavor 1 Very poor flavor

Any bitter flavor should be noted under "Comments".

The effect of time in an alum solution on firming of roe from S. franciscanus was also investigated. The sea urchins (10) were opened and the roe was removed , cleaned with tweezers and rinsed in 3.5% NaCl. One segment from each urchin was placed on each of 5 different screens (2 mm mesh). Roe from one screen (the control) was rinsed in 3.5% NaCl and placed back on the screen for draining. Roe from the four remaining screens was placed in four l-liter beakers of 0.5% alum in 3.5% NaCl and stirred gently. The roe was removed at various times (one beaker after 2.5 minutes stirring, another after 5 minutes stirring, the third after 7.5 minutes stirring and the fourth after 10 minutes stirring). A second experiment was carried out using 10, 20, 30 and 40 minutes of stirring. Upon removal from the alum solutions, the roe was rinsed in 3.5% NaCl and drained on screens. The samples of roe were then scored for texture and flavor by 6 trained taste panel members using the ratings given previously.

14

b. S. drobachiensis

Approximately 200 green sea urchins were collected to study the effect of alum concentration on roe from this species. The procedure followed was the same as that described in section l.a. for the study on S. franciscanus. Alum concentrations of 0%, 0.5%, 1.0%,1.5% and 2.0% (all made up in a solution of 3.5% NaCl) were used. Texture and flavor of the roe was scored by 6 taste panel members using the ratings described previously in 1.a.

2. Citrate

S. franciscanus (31 urchins) were collected to determine the effect of citrate concentration on the texture of roe from this species. About 15 urchins with the best-colored roe were used; the others were discarded. The procedure described previously in section 1.a. (on alum concentration) was followed using 3.5% NaCl as the control and concentrations of 5% and 10% citrate in 3.5% NaCl. The roe was scored for texture and flavor by 6 taste panel members according to the ratings shown in 1.a .

3. Alcohol

S. franciscanus (31 urchins) were collected to study the effect of alcohol on the texture of roe from this species. About 15 urchins with the best-colored roe were used, the others being discarded. The procedure described previously in section 1.a. was followed. The control solution was 3.5% NaCl and alcohol concentrations of 5%, 10%, 20% and 30% in 3.5% NaCl were used. The treatment time was changed from 10 minutes to 5 minutes to minimize flavor changes in the roe. The roe was rated for texture and flavor by 6 taste panel members as desc r i bed in section 1.a.

E. Storage of Whole Urchins and Fresh Roe

1. Storage of S. franciscanus at 2°C

Approximately 40 red sea urchins were collected and stored at 2°C in a closed polyethylene container (62 x 46.5 x 50.5 cm) for 3 1/2 days. At 1 1/2, 2 1/2 and 3 1/2 days, the appearance and odor of the intact urchins were noted. Gonads were removed from several urchins at these intervals and their color and texture noted .

2. Storage of Fresh Roe at 2°C

a. S. fra nci scanus

Red sea urc hins (29) were collected , stored overnight at 2°C and opened the follow i ng day at the laborabory . About 40 segments of the best roe from female urch i ns and about 20 segments of the best roe from the males were cleaned, rinsed and placed on screens (2 mm mesh). The screens were placed at about a 45° angle, covered with a clear plastic wrap and stored at 2°C. After 5 days, the roe was examined visually and the odor noted.

15

b. S. drobachiensis

Green sea urchins (50) were collected, stored overnight at 2°C and the roe was recovered the following day. A wooden box (as shown in the first drawing under "Packing and Shipping" in the Literature Survey) was packed with the fresh roe. Segments were placed lengthwise with the rounded side down, a lid was put on top and the box of roe was stored at 2°C. After 6 days, the appearance and odor of the roe were noted. The roe was then rinsed in 3.5% NaCl and its appearance noted.

3. Storage of Roe from S. franciscanus in 3.5% NaCl

Red sea urchins (40) were collected and stored at 2°C. The roe was removed from 20 urchins the following day and from the remaining 20, 2 days later. At each of the two samplings, the 10 urchins which had the best roe were used. Two segments of roe from each of the 10 urchins were placed in two 4-liter beakers, each containing 3 liters of 3.5% NaCl (20 roe segments per beaker as shown below). One of the two beakers was held at room

1st Day after collection

10 Urchins

12 Segments from each

Room t emperature

10 Urchins


2 Days storage of roe in salt solution

2nd Day after collection

10 Urchins


Room temperature

10 Urchins


1 Day storage of roe in salt solution

t emperature and the other in a cold room at 2°C. On the third day after collection of the urchins, the roe was transferred to screens (2 mm mesh) for draining and its appearance, odor and flavor were noted.

16

F. Organoleptic Assessment of Fresh Roe

Collection of sea urchins for organoleptic assessment of the roe involved 2 field trips and taste panels on the following days. Altogether, approximtely 150 S. franciscanus, 500 S. drobachiensis and gO S. purpuratus were collected. Roe was recovered the-following day after overnight storage at 2°C.

Six sets of samples were prepared for each sex of each species (a total of 36 sets). For S. franciscanus, each set consisted of 5 or 6 segments of roe, each from a different urchin. For S. drobachiensis, each set consisted of about 15 segments, each from a different urchin. For S. pur~uratus, each set consisted of about 15 segments, some from the sameurc in. Only roe of quality suitable for the fresh market was used for the taste panels.

Each of the 36 sets of fresh roe was evaluated by 6 trained taste panel members (6 sets from male S. franciscanus, 6 from female S. franciscanus, 6 from male S. drobachiensis, 6 from female S. drobachiensis, 6 from male ~. purpuratus and 6 from female ~. purpuratus). -The roe was rated using the following scoresheet:

Color Odor Flavor

5 Excellent color 5 Excellent odor 5 Excellent flavor 4 Good color 4 Good odor 4 Good flavor

3 Fair color 3 Fair odor 3 Fair fl avor 2 Poor color 2 Poor odor 2 Poor flavor

1 Very poor color 1 Very poor odor 1 Very poor flavor

G. Shipment of Fresh Roe to Japan

About 35 S. franciscanus and 300 S. drobachiensis were collected, stored overnight at 2b C and the roe was recovered the following day. Only roe of good quality was kept; the rest was discarded. The roe was placed on screens (2 mm mesh) to drain. Five g" x g" screens of roe from S. franciscanus (male and female), 2 screens of roe from male S. drobachiensis and 4 screens of roe from female S. drobachiensis were obtaTned. Roe from male ~. drobachiensis was extremeTy ripe and of very poor color.

All roe was drained for about 2 hours at 2°C, then rinsed with a spray of 3.5% NaCl. Roe was then packed into boxes having 3 drainage slits

17

(of the type shown in the first drawing under "Packing and Shipping" in the Literatu re Survey). The boxes were packed as described in the Literature Survey. Three boxes of roe from S. franciscanus, three from male S. drobachiensis and three from female ~. dr8bachiensis were prepared~

Eac h of the 3 contacts in Japan was shipped one of each sample. The three boxes were stacked one on top of the other, with the top one covered with a lid. The stacks were wrapped in about 10 layers of paper towelling and placed in cardboard boxes. They were held at 5 to 10°C during shipment by air to Japan. Total travel time for this shipment was 11 hours.

H. Proximate Analysis of Fresh Roe

Ash was determined using Method I (31.012) of the AOAC Methods (Horwitz, 1970).

Moisture was measured by air-drying as described in Section 24.003(a) of the AOAC Methods (Horwitz, 1970).

Sodium chlori de was determined using Quantab Chloride Titrators from the Ames Chemical Company, Division Miles Laboratories, Inc., Elkhart, Indiana .

Lipid was measured according to the method of Bligh and Dyer (1959).

Total nitrogen was determined by the micro-Kjeldahl method as described by Steyermark (1961).

Non-protein nitrogen was determined by precipitating the protein as outlined in the following steps, then doing a micro-Kjeldahl determination of nitrogen (Steyermark, 1961) on the supernatant:

1) Chop 5 g of roe finely

2) Add 20 ml of cold 10% TCA

3) Homogenize for 1 minute at O°C

4) Centrifuge the homogenate at 12,000 rpm for 1 hour at O°C

5) Decant the supernatant through glass wool into a Kjeldahl flask for determination of nitrogen

18

RESULTS AND DISCUSSION

I. PHYSICAL ASPECTS OF FRESH ROE

A. Color and Size

Plate 2A shows roe of good color from each of the three species of sea urchins found in B.C. waters. "A" is roe from the red sea urchin, "B" is from the green sea urchin and "c" is from the purple sea urchin. The plate clearly shows the size difference between roe from the red urchin and roe from the green or purple urchin. Japanese roe is similar in size to "B" and "C".

Sea urchin roe is sometimes mottled with a purplish-brown coloration, as shown in Plate 2B for S. franciscanus. "A" in this plate is from a male red sea urchin and "B", from a female. Based on our one-year studies on red and green sea urchins, this mottling had frequency ranges of 1.2 to 4.4% in S. franciscanus and 1.0 to 10.5% in S. drobachiensis (Kramer and Nordin, 197~ and 1978). This frequency was not-related to time of year. It was higher in males than in females for both species.

Plate 3 shows the variation in roe color within the population for each sex of each of the three local species of sea urchins (a total of 6 types of variation is shown). This variation is greater in males than females for all three species. Our previous work shows color variation is not related to time of year in S. franciscanus or S. drobachiensis (Kramer and Nordin, 1975 and 1978).

B. Gonadal Yield

Figure 2 is a graphic representation of changes in gonadal yield with time of year for the red and the green sea urchin, as determined in our previous work (Kramer and Nordin, 1975 and 1978). In both species, gonadal yield is highest in the winter and lowest in summer. Gonadal yield for green sea urchins drops and recovers about one month earlier than for red urchins. Spawning in green urchins appears to take place about one month earlier than in reds, as indicated by our data on changes in maturity of roe for these species throughout the year (Kramer and Nordin, 1975 and 1978) .

C. Harvesting and Roe Recovery Rates

Our previous work indicates that, for the best gonadal yield and stage of maturity, S. franciscanus should be harvested from November through February and S. drObachiensis, from September through January (Kramer and Nordin, 1975 and 1978).

19

Table 1 shows harvesting and roe recovery rates for S. franciscanus and S. drobachiensis. It is important to point out that these rates were obtaTned harvesting on very dense beds of these species. They therefore represent maximum harvesting rates obtainable. This data is of use to compare the two species but should not be used to calculate harvesting rates which will be obtained in the commercial fishery.

The data in Table 1A indicates that the high harvesting rate (in urchins per hr) for the green sea urchin is almost completely offset by the larger gonad size of the red urchin. Thus when the harvesting rate is calculated as kg roe per hr, the rate for the green sea urchin is only 1.2 times faster than that for the red urchin.

Due to the extreme size difference in roe from the two species, the roe recovery rate (as reported in Table 1B) is 1.9 times faster for the red sea urchin compared to the green.

When both harvesting and roe recovery rates are considered (in terms of kg roe per hr), calculations show that it would take 25 minutes to harvest and recover 1 kg of roe from red sea urchins and 45 minutes to harvest and recover 1 kg of roe from green sea urchins.

II. PROBLEMS IN PROCESS ING FRESH ROE

A. Fluid Leakage

Just prior to and during spawning, fluid leakage can be a problem in recovered sea urchin roe. In males this f luid (sperm) is white and in females (eggs) it is yellow, as shown i n Plate 2C for 2. franciscanus roe.

Table 2 gives the results of treating fresh roe from male red sea urchins with different buffers to remove fluid leakage. The two sodium phosphate buffers removed most of the sperm, leaving less than 20% of the original amount, and did not appreciably alter the fresh flavor of the roe. Roe treated with the sodium phosphate at pH 6.5 seemed to have the best flavor and this buffer is the one which should be used commercially to remove fluid leakage (details for the preparation of this buffer are given in the Appendix). Although sodium acetate at pH 5.0 effectively removed the sperm, the altered flavor makes it unsuitable for commercial use. The sodium borate at pH 9.0 and the 10% salt sol ution are not acceptable as both form a viscous gel and do not wash away the sperm.

B. Firming the Roe

Although red sea urchin roe has only a slight seasonal change in firmness, roe from green sea urchins is firmest from September to January (Kramer and Nordin, 1975 and 1978). To improve texture of soft roe and to maintain firm texture during shipping, we tested the effect of treatment with alum, citrate and alcohol.

•

20

1. Alum

Table 3 gives the organoleptic assessment for flavor and texture of fresh sea urchin roe treated with alum.

The effect of alum concentration on roe from red and green sea urchins is shown in Table 3A. For S. franciscanus roe, using a 5-minute soak, there is little change in the-texture or flavor with increasing alum concentrations up to 1%. With a 10-minute soak, roe from this species was firmer and there were no significant flavor changes with alum concentrations up to 2%. For S. drobachiensis, a 10-minute soak improved the texture of the roe but the flavor was poorer compared with untreated roe. The taste panel found no bitterness associated with higher alum concentrations (up to 2%) in roe from either species in this part of the study.

Table 3B shows the effect of soaking time using alum solutions on roe from the red sea urchin. The results indicate that texture and flavor are not significantly changed with up to 10 minutes in 0.5% alum. For 20 to 40 minutes in 0.5% alum, the longer the washing time, the more texture was improved. However, the flavor was rated poor to fair. The taste panel comments indicate that with up to 20 minutes in 0.5% alum, there is no significant bitter flavor. However, for 30 or more minutes soaking time, the roe has a significantly more bitter flavor.

The results indicate that alum can be used to improve the texture of fresh sea urchin roe. For roe from the red sea urchin, a 10-minute soak in 2% alum or a 20-minute soak in 0.5% alum is recommended. For roe from the green sea urchin, a 10-minute soak in 1% alum will improve the texture without imparting any bitterness.

2. Citrate

Table 4 gives the taste panel assessment for flavor and texture of S. franciscanus roe treated with citrate.

It is apparent from these results that soaking roe from the red sea urchin in up to 10% citrate for 10 minutes does not change the texture or the flavor of the roe.

3. Alcohol

Organoleptic assessment for flavor and texture of red sea urchin roe treated with alcohol is given in Table 5.

The data shows that a 5-minute soak in 5%, 10%, 20% or 30% alcohol does not significantly improve the texture of roe from S. franciscanus. With increasing concentrations of alcohol, the roe had a poorer flavor which was described as bitter and alcoholic.

III. STORAGE STUDIES

A. Storage of Whole Red Sea Urchins at 2°C

After storage of whole red sea urchins for 1 1/2 days at 2°C, the

21

spines were still very active. Quality of the gonads had changed very little but they were slightly softer and darker.

After storage for 2 1/2 days at 2°C, the spines were much less active. Although the urchins were still alive, they were obviously dying. There was a strong, disagreeable odor from the urchins and the gonads appeared slightly darker.

After 3 1/2 days at 2°C, most urchins appeared to be dead. The spines were very limp; some showed slight movement, but others were falling off. There was a disagreeable odor and the tests were soft and easily broken. The gonads were softer and darker but were still in fair condition.

These results indicate that red sea urchins can be held at 2°C for several days with only slight changes in appearance of the roe. Although these changes may be too adverse for a fresh product, the roe could certainly be used for a fermented or canned product.

B. Storage of Roe at 2°C

1. S. franciscanus

After 5 days of storage at 2°C, roe from red sea urchins appeared slightly softer. However, the eggs and sperm were much more viscous than initially. An unpleasant odor indicated slight spoilage so a taste panel was not conducted on these samples.

Kato (1972b) reports that fresh sea urchin roe has a shelf life of 5 days at DOC and 3 days at 3°e if alum is used.

2. S. drobachiensis

After 6 days of storage at 2°C , roe from green sea urchins looked very unattractive. It appeared to be one clump of product rather than segments, however individual segments could be separated by hand. Although the roe looked very soft, it was only sl i ghtly softer than when packed. There -was no color change. After a rinse in 3.5% NaCl, the roe looked as good as it did prior to storage.

C. Storage of Red Sea Urchin Roe in Salt Solution

After 1 and 2 days of storage in 3.5% NaCl at room temperature or at 2°C, the solutions containing the roe were quite cloudy. Since the 2-day sample at room temperature had an extremely unpleasant odor, it was not tasted. The flavor of the other 3 samples was fair to good and they had very little odor (similar to fresh sea urchin roe).

Storage of sea urchin roe in a salt solution at 2°e may extend its storage life but further work needs to be done to confirm this.

22

IV. ORGANOLEPTIC ASSESSMENT

A. Laboratory Taste Panel Assessment

Table 6 shows the organoleptic ratings for flavor, odor and color of fresh sea urchin roe from 3 species of Strongylocentrotus.

No significant species difference was found between red, green and purple sea urchins. On the average, roe from all three species was rated "fair" for flavor, odor and color. The large range of scores reflects differences in the segments of roe and between taste panel members. Of the 6 panel members, 3 were natives of Japan and their flavor preferences for sea urchin roe were much different than those of the other panel members.

Roe from S. franciscanus females was rated poorer than that from males for flavor but not for odor. For green and purple sea urchins, little difference in flavor or odor was found between the roe from males and that from females. Roe from male and female red sea urchins did not differ significantly in the ratings for color. The color of roe from males of S. drobachiensis and S. purpuratus, however, was rated poorer than that from the females of these 2 species.

B. Shipment to Japan

The test shipment results for fresh sea urchin roe are shown in Table 7.

From the replies, it appears that there is certainly potential in Japan for commercial use of the roe from red sea urchins, provided the proper processing techniques are used.

According to the replies, roe from male green sea urchins is inferior to roe from females of this species. Roe from female S. drobachiensis was given good comments. The color, size, quality and flavor were acceptable and the potential in Japan is quite good for commercial use of green sea urchin roe, in particular that from the females.

V. PROXIMATE ANALYSIS

Tables 8A, 8B and 8C give the proximate analysis results for fresh roe from red, green and purple sea urchins, respectively.

For roe from S. franciscanus, there appears to be a difference in % protein between males-and females, however this may be due to variation in individuals coupled with the small sample size. For both green and purple sea urchins, roe from the females is higher in lipid than roe from males.

Ash , moisture, sodium chloride and total nitrogen are not si gnificantly different among the 3 species. Red sea urchin roe, however, appears to have more lipid and less protein than roe from the other 2 species. This difference is not due to different times of collection as all samples of urchins used for proximate analysis were collected in October and November.

23

According to Nonaka (1975), Japanese sea urchin roe in the raw state has a moisture content of 72%, a protein content of 16% and a lipid content of 9%. This data may be compared with our proximate analysis for fresh roe from S. drobachiensis (the B.C. species which appears to be most similar to the Japanese species). The moisture contents are the same but the Japanese roe is slightly higher in protein and li pid.

ACKNOWLEDGEMENTS

We wish to express our thanks to A. Barnes for technical assistance in the proximate analysis and to T. Matsumoto for the translation of several Japanese articles. We would also like to acknowledge the assistance of the following people who served as taste panel members: S. Fuke, E. Funk, G. Gunstrom, T. Isogai and J. Yokoyama.

24

REFERENCES

ALLAIN, J.Y. 1972. Sea Urchin Fishing Around the World. P~che Marit. ~, 625-630.

AUSTRALIAN FISHERIES. 1971a. Canadian Sea Urchin Roe for Japan. 30(5), 13.

AUSTRALIAN FISHERIES. 1971b. Sea Urchi n Roe for "Sushi II Restaurants. 30 (8), 15.

AUSTRALIAN FISHERIES. 1972. Sea Urchins -- Little Potential. ~(4), 30.

AUSTRALIAN FISHERIES. 1975. Sea Urchins -- A New Victorian Industry? 34(1), 16.

BEDARD, R.W. February 1973. Sea Urchin. Prepared for the Canadian Sea Urchin Fisheries Industry. Fisheries and Fish Products Division, Agriculture, Fisheries and Food Products Branch, Department of Industry, Trade and Commerce, Ottawa, Canada, 25 pp.

BERNARD, F.R. and D.C. MILLER. 1973. Preliminary Investigation on the Red Sea Urchin Resources of British Columbia [Strongylocentrotus franciscanus (Agassiz)]. Fish. Res. Board Can. Technical Report No. 400, 37 pp.

BLIGH, E.G. and W.J. DYER. 1959. A Rapid Method of Total Lipid Extraction and Purification. Can. J. Biochem. and Physiol. ~(8), 911-917.

CANADA DEPARTMENT OF ENVIRONMENT. 1973. Annual Report 1972, Northern Operations and Inspection Branches. Fisheries and Marine Service, Pacific Region, Vancouver, B.C. Pp. 32-33.

CANADA DEPARTMENT OF INDUSTRY, TRADE AND COMMERCE. 1974. The Japanese Market for Fishery Products. Fisheries and Fish Products Division, Agriculture, Fisheries and Food Products Branch, Department of Industry, Trade and Commerce, Ottawa, Canada. P. 14.

COM~1ERCIAL FISHERIES REVIEW. 1970. May Buy Sea Urchin from Australia. ~(4), 60.

COMMERCIAL FISHERIES REVIEW. 1971a. Sea Urchin Gonads to Appear in U.S. II Sus hi" Res ta u ran t s . 33 ( 4 ), 28 •

COMMERCIAL FISHERIES REVIEW. 1971b. Interested in Sea Urchin Resources of Peru and Chile. 33(11-12),48.

COMMERCIAL FISHERIES REVIEW. 1972. Sea Urchin Fishery Starts. 34(3-4), 36.

FISH FARMING INDUSTRIES. 1974. Sea Urchin Processing Pays Ecological Bonus. ~(2), 28.

25

FISHERIES SECTION, AOMORI PREFECTURE. 1968. The Processing of Sea Urchins. Fisheries Section, Aomori Prefecture, 22 pp. Canada Fisheries and Marine Service Translation Series No. 4288, 46 pp.

FISHING NEWS INTERNATIONAL. 1971. Sea Wrack. !Q(9), 96.

FISHING NEWS INTERNATIONAL. 1974. California Kelp Protected by Catching Sea Urchins. ~(6), 42-43.

FLETCHER, G.L. and L.C. HAGGERTY. 1975. A Survey of the Inshore Marine Resources of St. Lewis Bay, Alexis Bay, St. Michaels Bay and Sandwich Bay, Labrador with Particular Reference to Iceland Scallops, Mussels, Clams, Cockles, Sea Urchins and Seaweed. Marine Sciences Research Laboratory Technical Report No. 15, Memorial Univers ity of Newfoundland, St. John's, Newfoundland, Canada, 109 pp.

FLETCHER, G.L., V.A. PEPPER and J.C. KEAN. June 1974. A Study of the Biology of the Newfoundland Sea Urchin with Emphasis on Aspects Important to the Development of a Fishery. Marine Sciences Research Laboratory Technical Report No. 11, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, 41 pp.

FLETCHER, G.L., R.P. SCAPLEN, R.G. BUGGELN and D.R. IDLER. February 1974. A Survey of the Inshore Marine Resources of Forteau Bay, L'Anse au Loup Bay, Pinware Bay and Red Bay, Labrador with Particula r Emphasis on Shellfish, Sea Urchins and Seaweed. Marine Sciences Research Laboratory Technical Report No.9, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, 33 pp.

FOWLER, B.M. and G.L. FLETCHER. 1975. A Survey of the ~1arine Inshore Resources of Bonavista Bay and Belle Bay Fortune Bay with Particular Reference to Giant Scallops, Mussels, Clams, Sea Urchins and Seaweed. Marine Sciences Research Laboratory Technical Report No. 17, ~1emorial University of Newfoundland, St. John's, Newfoundland, Canada, 131 pp.

FUKE, S. and H. TSUYUKI. 1974. Report on Japanese Seafood Processing Methods, Environment Canada, Fisheries and Marine Service, Vancouver Technological Research Laboratory, Vancouver, B.C., 22 pp. I. Roe Processing. Part (iii) Sea-Urchin Roe, pp. 8-14.

HORWITZ, W., ed. 1970. Official Methods of Analysis of the Association of Officia l Analytical Chemists, 11th Edition, Published by the Association of Official Analytical Chemists, Washington, D.C. Pp. 392, 526.

HUDNALL, J. 1970. Sea Urchins -- New Industry for Tofino. Weste rn Fisheries ~(3), 16-18.

KATO, S. 1972a. Sea Urchins: A New Fishery Develops in California. Mar. Fish. Rev. 34(9-10), 23-30.

KATO, S. 1972b. Narrative Report of Trip to Japan. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Tiburon Fisheries Laboratory, Tiburon, California, 18 pp.

26

KONNO, S. and T. KINOSHITA. 1955. Meeting for the Discussion of Sea Urchin Processing Techniques -- Observations on the Producing Regions of Honshu. Hokusuishi Geppo (Monthly Report of the Hokkaido Fisheries Research Laboratory) 12(10),411-421. Translated by M.G. Mottet (in Mottet, 1976). -

KRAMER, D.E. and D.M.A. NORDIN. 1975. Physical Data from a Study of Size, Weight and Gonad Quality for the Red Sea Urchin [Strongylocentrotus franciscanus (Agassiz)] over a One-Year Period. Fish. Res. Board Can. Manuscript Report Series No. 1372, 91 pp.

KRAMER, D.E. and D.M.A. NORDIN. 1978. Physical Data from a Study of Size, Weight and Gonad Quality for the Green Sea Urchin (Strongylocentrotus drobachiensis) over a One-Year Period. Fish. Mar. Servo Manuscript Report Series No. 1476, 68 pp.

McDA NI EL, D. 1975a. Sea Urchin Fishery in California Taking up Slack, Controlling "Pest". National Fisherman, Yearbook Issue. Pp.68, 70.

McDA NI EL, D. 1975b. Special Boat Designed for Divers Proves Highly Effective on Urchins. National Fisherman, Yearbook Issue. P. 69.

MARINE FISHERIES REVIEW. 1972. U.S. and Canadian Firms Seek Sea Urchin Roe t~arkets . 34(9-10), 62.

MARINE FISHERIES REVIEW. 1974a. Japan Likes Roe of Mexican Sea Urchins. l§..(6), 43.

MARINE FISHERIES REVIEW. 1974b. Japanese Buy More U.S. Seafood in 1973. l§..(l2), 35-36.

MILLER, D.C. 1974. Abalone and Sea Urchin Survey 1974. Federal-Provincial Cost-Shared Project. Supported by Marine Resources Branch, Department of Recreation and Conservation and Industrial Development Branch, Fisheries and Marine Service, Environment Canada, 53 pp.

MILLER, R.J. and C.A. BISHOP. 1973. A Sea Urchin Fishery for Atlantic Canada. Fisheries and Marine Service Circular No. 19, Biological Station, St. John's, Newfoundland, Canada, 9 pp.

MILLER, M.M., J . KOLHONEN and G. HALL. 1973. Export Opportunities for U.S. Fishery Products. Mar. Fish. Rev. ~(7), 22-30.

MOTOHIRO, T. 1976. Personal Communication to H. Tsuyuki. Hokkaido Uni versi ty Faculty of Fi sheri es, Laboratory of t~ari ne Food Technology, Hakodate, Hokkaido, Japan.

MOTOYAMA, T. 1968. Encyclopedia of Foods, Published by Heibonsha, Japan, 604 pp.

MOTTET, ~l.G. 1976. The Fishery Biology of Sea Urchins in the Family Strongylocentrotidae. State of Washington Department of Fisheries Technical Report No. 20, 66 pp.

27

NONAKA, J. 1975. Marine Foods of Japanese Preference. Abstracts of Papers, Thirteenth Pacific Science Congress, Record of Proceedings, Volume 1, p. 286.

OSHIMA, H. 1974. Processing of Sea Urchins. In Sea Cucumbers and Sea Urchins (Namako to Uni), 2nd Edition, 208 pp., Published by Uchida Rokakuho Shinsho, Tokyo, Japan, pp. 152-155.

PACIFIC NORTHWEST SEA. 1977. Uni -- The Newest Fishery. 9(2),8-10.

SANDEMAN, E.J. 1977. The Newfoundland Fishery and Its Unused Resources, Fishermen1s Information Bulletin 77-4E, Information Branch, Fisheries and Marine Service, Department of Fisheries and the Environment, Ottawa, Canada, 4 pp.

SCATTERGOOD, L.W. 1961. The Sea Urchin Fishery. United States Department of the Interior, Fish and Wildlife Service, Fishery Leaflet No. 511, 5 pp.

SOUNDER. 1973. Fisheries and Marine Service, Canada Department of Environment. ~(2), 4.

SOUTHWARD, A. and E. SOUTHWARD. 1975. Endangered Urchins. New Scientist 66(944), 70-72.

STEYERMARK, A. 1961. Quantitative Organic Microanalysis, 2nd Edition, Academic Press Inc. (London) Ltd., London, pp. 188-207.

TANAKA, J. 1960. A Sea Urchin Fishing Technique. Suisan Zoshoku (Aquaculture) 7(3), 57-59. Translated by M.G. Mottet (in Mottet, 1976). -

TANAKA, K. and Y. MATSUDA. 1970. Freezing Preservation of Fresh Sea Urchins (Gonad). Reito (Refrigeration) 45(516), 925-931. Canada Fisheries and Marine Service Translation Series No. 4383, 22 pp.

TSUYUKI, H. and W.E. RAZZELL. 1976a. Narrative Report of Japan Trip, Environment Canada, Fisheries and Marine Service, Vancouver Technological Research Laboratory, Vancouver, B.C., 25 pp.

TSUYUKI, H. and W.E. RAZZELL. 1976b. Product Details Report of Trip to Japan, Environment Canada, Fisheries and Marine Service, Vancouver Technological Research Laboratory, Vancouver, B.C., 92 pp. The Processing of Sea Urchin Gonads, pp. 42-45.

WATSON, R. 1976. Washington State Sea Urchin Fishery. Paper submitted by Union Wharf Corporation, Port Townsend, Washington at Man In The Sea Symposium 76, Seattle, Washington, March 20-21, 1976.

APPENDIX : Weights of Monobasic and Dibasic Phosphate for 0.1 M Buffer Preparation.

MONOBASIC SALT (for 0.0685 M)

NaH2 P04 - H20

KH2 P04

(anhydrous)

DIBASIC SALT (for 0.0315 M)

Na 2HP0 4 (anhydrous)

Na2

HP04

-7H2O

Na HPO -12H 0 2 4 2

K2HP04

(anhydrous)

K2

HP04

-3H2O

Formula Weight

137.99

136.09

Formula Weight

141.96

268.07

358.14

174.18

228.23

gms/liter

9.45

9.32

gms/liter

4.47

8.44

11.28

5.49

7.19

gms/U.S. gallon

35.78

35.29

gms/U.S.

16.93

31.96

42. 70

20.79

27.21

gall on

Use the appropriate weight of one monobasic salt and one dibasic salt to make up the 0.1 M phosphate buffer

Calculated pH = 6.50

Measured pH (using KH2P0 4 and Na 2 HP0 4 in distilled water) = 6.52

gms/Imp. gallon

42.97

42.38

gms/Imp. gallon

20.33

38.39

51.28

24.94

32.68

N 00

29

Plate 1

A. s. franciscanus, the red sea urchin

B. s. drobachiensis, the green sea urchin

c. s. purpuratus, the purple sea urchin D. Red, green and purple sea urchins

E. A male red sea urchin spawning

F. A female red sea urchin spawning

1A 18

10 1E

1C

1F

w o

31

Plate 2

A. Roe from the red sea urchin (A), the green sea urchin (B) and the purple sea urchin (C)

b. Mottled roe from male (A) and female (B) red sea urchins

C. Fluid leakage in roe from male and female red sea urchins

2A 28 2C

W N

33

Plate 3

A. Color variation in roe from male red sea urchins

B. Color variation in roe from female red sea urchins

C. Color variation in roe from male green sea urchins

D. Color variation in roe from female green sea urchins

E. Color variation in roe from male purple sea urchins

F. Color variation in roe from female purple sea urchins

" ;.

: .. , .. '~. -f'

" .. -'''-,. ,'~ '\"

l ~ -Ua m II

'1; , f- e, II iii II

11"~

~ p ~~

II iii II

U " " II II II

IJ~ fa " II II II •••• .

Of It ,_ II II • S. 'purpuratus {male} . .

3A 3C 3E

I jIt I~ f' ft- i ~J

II II II 11 iii II

G~ Ie ta , ~

,J ., tf,1 , ~

II II II II II • S. drobachlensis (female) • • . .

38 3D 3F

Figure 1.

Sea water

Rinse in

35

Methods of Preparing Fresh Sea Urchin Roe (the Roman numerals correspond to sections in the Literature Survey).

I. Harvest urchins

1) Usually collected by diving (baited traps have been used)

2) Protect urchins from wind and rain during transport

3) If not processed the same day, store urchins in a cold room

II. Recover roe

1) Crack test with a knife 2) Remove roe carefully with a spoon 3) Clean roe using tweezers 4) Place roe in a basket and rinse in sea

water

III. Treat roe for preservation

Alum

Place in

Other possible treatments

MgCl (concentrati on 1 part sea water plus 2 parts fresh water or rinse twice in

0.3%, 1% or 2% solution in sea water or in one part fresh water plus three parts sea water

not speci fi ed) saltpeter (5%) sorbic acid (less than 0.5 g per kg product) sea water

- Let stand for 5 or 10 mi nutes

IV. Packing and shipping

1) Sort roe by color, size and quality 2) Pack roe in overlapping rows in wooden or

styrofoam boxes 3) Put boxes into a crate with ice 4) Ship crates refrigerated by truck, rail or

air

-~ -C ..J W

> ..J oCt C oCt Z o (!J

C ..J W ->

50

.§. franciscanus

• MALE

D FEMALE

Jan

36

Apr May Jun Jul 1974

s. drobach iensis -.MALE o FEMALE

Aug Sep Oct Nov Dec

Nov Dec

Fi g. 2. Gonadal Yield of Red (S. franciscanus) and Green (~. drobachiensis) Sea Urchins over a One~Year Period.

•

Table 1. Ha rves ti I1g and Roe Recovery Rates of S. franciscanus and S. drobachiensis.

A. HARVESTING RATES*

Mean Gonad Harvesting No. Urchi ns Weight per Harvesting

No. Urchins Time Harvested Urchin Rate as Speci es Harvested (mins) per hr (g) kg Roe/hr t

S. franciscanus 63 11 344 119.8a 41.2

S. drobachiensis 462 9~ 2918 17.3b 50.6

* By 2 people (1 diver using SCUBA gear and one person on a boat taking the urchins from the diver). t Calculated as No. urchins/hr x Mean gonad weight x 10- 3

•

a From Manuscript Report #1372 (Kramer and Nordin, 1975). b From Manuscript Report #1476 (Kramer and Nordin, 1978).

B. ROE RECOVERY RATES**

Roe Roe Recovery Wt . Roe Recovery

No. Urchins Time Recovered Rate Species Opened (mins) (g) (kg Roe/hr)

S. franciscanus 51 109 4610 2.54

S. drobachiensis 147 95 2154 1. 36

** By 2 people (1 person opening the urchins and removing roe and the other person cleaning the roe).

w

"

Table 2. Treatment of Fresh Roe from Male S. franciscanus with Various Buffers to Prevent Fluid Leakage.

Treatment Appearance

0.1 M Sodium acetate, pH 5.0 Sperm effectively washed away, almost none left

U.1 M Sodium phosphate, pH 6.5 Sperm effectively washed away, a bit left but very little

0.1 M Sodium phosphate, pH 7.5 Sperm effectively washed away, a bit left but very little

0.1 M Sodium borate, pH 9.0 Sperm partially washed away; very viscous gel formed, so thick it would not go through screen; a thick coating left on the roe

10% NaCl Only a small amount of sperm washed away; gel formed which went through screen slowly

Estimated Percentage of Sperm Remaining

10

20

20

60

80

Flavor

Altered flavor; not very good

Very good flavor; the best

Good flavor, but pH 6.5 is better

Altered flavor; lacks flavor

Sal ty, but not too salty; sl i ght loss of flavor

w OJ

•

Table 3A. Treatment of Fresh Sea Urchin Roe with Alum .

EF FECT OF CONCENTRAT ION

Mean Organoleptic Score

Speci es Soaking Concentration No . Texture Time of Alum of (mins) Solution Tasters Mean* Range**

S. franc i scanus 5 0 6 3.1(0.6) 2-4 0.25% 6 2.9(0.6) 2-4 0.5% 6 2.8(1.0) 1-4 0.75% 6 3.3(0.8) 2-4 1. 0% 6 3.4(0.6) 2.7-4

10 0 6 2.4(0.7) 1. 5-3 0.5% 6 3.2(0 . 4) 3-4 1. 0% 6 3.3(0.5) 3-4 1. 5% 6 3.4(0.5) 3-4 2.0% 6 3.6(0.7) 3-4.5

S. drobachiensis 10 0 6 2.3(0.8) 1-3 0.5% 6 2.8(0.8) 2-4 1. 0% 6 3.2(0.6) 2.5-4 1. 5% 6 3.4(0.6) 2.7-4 2.0% 6 3.4(0.6) 2.7-4

* Standard deviations are given in parentheses.

** Decimal figures for some ranges indicate values such as 2 to 3 (taken as 2.5), 2+ (taken as 2.3) and 2- (taken as 1.7) are included.

Flavor

Mean* Range**

2.9(0.9) 2-4.3 3.4(1.1) 2-5 3.2(0.8) 2-4 3.4(0.4) 3-4 3.4(0.6) 3-4.3

3.5(0.8) 2-4 2.9(0.6) 2-4 3.0(2.9) 2-4 3.6(0.5) 3-4 3.4(0.8) 2-4

4.0(1.1) 2-5 3.2(1.0) 2-4.5 3.9(0.8) 2.7-5 2.9(0.8) 2-4 3.2(0.7) 2-4

w \.0

Table 3B. Treatment of Fresh Sea Urchin Roe with Alum.

EFFECT OF TIME


Species Concentration Soaki ng No . Texture of Alum Time of

Solution (mins) Tasters Mean* Range**

S. franci scanus 0.5% 0 6 2.5(1.0) 1-4 2.5 6 2.7(0.8) 2-4 5 6 2.7(0.5) 2-3

7.5 6 2.9(0.9) 2-4.3 10 6 3.0(0.9) 2-4

0.5% 0 6 2.6(0.7) 1.5-3 10 6 2.4(0.8) 1-3 20 6 3.0(0) 3 30 6 3.4(0.7) 3-4.5 40 6 3.5(0.6) 3-4.5



•

Flavor

Mean*

3.7(0.8) 3.4(1.0) 3.5(1.0) 2.9(1.1) 3.6(1.1)

2.7(0.5) 2.3(0.8) 2.9(0.8) 2.3(0.5) 2.0(0.9)

Range**

3-5 1-4.3 2-5 1-4 2-5

2-3 1-3.3 .j::>

<:)

2-4 2-3 1-3

•

Table 4. Treatment of Fresh Sea Urchin Roe with Citrate.


Species Soaking Concentration No. Texture Time of Citrate of (mins) Solution Tasters Mean* Range**

S. franciscanus 10 0 6 2.8(0.6) 2-3.5 5% 6 3.0(0.6) 2-4

10% 6 3.0(0.6) 2-4



Flavor

Mean*

3.3(0.8) 3.5(0.8) 3.4(1.0)

Range

2-4 2-4 2-5

Table 5. Treatment of Fresh Sea Urchin Roe with Alcohol.


Species Soaking Concentration No. Texture Time of Alcohol of (mins) Solution Tasters Mean * Range**

S. franciscanus 5 0 6 2.6(0.5) 2-3 5% 6 3.2(0.8) 2-4.3

10% 6 2.4(0.6) 2-3.3 20% 6 2.4(0.6) 2-3.3 30% 6 3.1(0.7) 2-4



Fl avor

Mean*

3.6(0.6) 3.1(0.6) 2.9(0.5) 3.1(1.0) 2.4(1.1)

Range**

3-4 2-3.7 2-3.3 2-5 1-3.3

•

Table 6. Organoleptic Ratings of Fresh Sea Urchin Roe.


No. Flavor Odor of

Species Tasters Mean* Range** Mean* Range**

S. franciscanus Malea 6 3.5(0.9) 1-5 3.2(1.0) 1-4.3 Femalea 6 2.9(0.6) 1. 7-4 3.2(1.0 ) 1-5 Bothb 6 3.2(0.8) 1-5 3.2(1.0) 1-5

S. drobachiensis ~:~:iea 6 3.4(0.8) 2-5 3.3(1.0) 1-4 6 3.4(0.8) 2-5 3.5(0.8) 1-5

Both 6 3.4(0.8) 2-5 3.4(0.9) 1-5

S. ~uq~uratus ~:~:iea 6 3.5(0.9) 1-5 3.2(0.9) 1-4.3 6 3.3(0.9) 1-5 3.3(1.0) 1-5

Both 6 3.4(0.9) 1-5 3.3(0.9) 1-5



a These values represent 6 samples. b These values represent 12 samples (6 Male and 6 Female).

Color

~1ean*

3.6(0.8) 3.7(0.8) 3.7(0.8)

2.9(0.8) 3.9(0.5) 3.4(0.8)

3.0(0.7) 3.7(0.7) 3.4(0.8)

Range**

2-5 2-5 2-5

2-4.3 3-5 2-5

1-5 3-5

~

1-5 w

•

Table 7. Test Shipment Results on Fresh Sea Urchin Roe.

Des ti na ti on

Nikko Trading Co. - examined at Central Fish Market, Tokyo

Tokyo University of Fisheries (Dr. J. Nonaka)*

Taiyo Fishery Co. Ltd . , Tokyo

S. franciscanus

Ma 1 e and F ema 1 e

-quality is excellent, especially color and size of gonads; depending on proper processing technique, good potential for commercial use.

-after defrosting, remained solid.

-no reply.

* Stored one night at -5 °C upon arrival.

•

S. drobachiensis

Male

-is no good, not acceptable.

-female products superior to male products.

-no reply·

Female

-quality is excellent, especially color and size of gonads; depending on proper processing technique, good potential for commercial use.

-female products superior to male products; by no means inferior in taste to red uni; after defrosting,was somewhat degraded; degradation of form (disintegration) is a serious defect when consumed fresh.

-no reply.

Table 8A.

Male

Fema 1 e

Both

Mal e

Fema 1 e

80th

Proximate Analysis

% Ash

Mean* Range

1.58(0.10) 1.51-1.78 1.37(0.34) 1.07-2.03 1.47(0.26) 1. 07-2.03

% Total nitrogen

Mean* Range

2.26(0.11) 2.10-2.40 2.01(O.13)c 1.81-2.14 2.14(O.I7}d 1.81-2.40

of Fresh Sea Urchin Roe

% Moisture

Mean* Range

70.8(1.2) 69.3-72.9

70.7(1.2) 69.1-72.0

70.8(1.1) 69.1-72.9

% Non-protein nitrogen

Mean* Range

0.58(0.04) 0.52-0.64

0.66(O.05f 0.61-0.72 0.61(0.06)d 0.52-0.72


- S. franciscanus.

% NaCl

Mean* Range

0.74(0.14) 0.54-0.90 0.81(0.06) 0.75-0.90

0.78(0.11) 0. 54-0.90

% Protein nitrogen a

Mean* Range

1.68(0.12) 1.46-1.80

1.35(O.12f 1.20-1.53 1.53(O.21)d 1.20-1.80

"Male" and "Female" represent 6 samples and "8oth" represents 12 samples.

a Calculated as Total nitrogen - Non-protein nitrogen.

b Calculated as Protein nitrogen X 6.25.

c These means represent 5 samples.

d These ~~ans represent 11 samples.

% Lipid

Mean* Range

8.40(0.81) 7.44-9.73 8.24(1.06) 6.73-9.62

8.32(0.90) 6.73-9.73

% P . b roteln

Mean* Range

10.5(0.8) 9.1-11.2 c 8.4(0.8) 7.5- 9.6 d 9.6(1.3) 7.5-11.2

Table 8B. Proximate Analysis of Fresh Sea Urchin Roe - S. drobachiensis.

~~a 1 e

Fema 1 e

Both

Male

Female

Both

% Ash

Mean* Range

2.09(0.09) 1. 98-?. 23

1. 54(0. 49) 1. 25-2. 51

1. 82 (0.44) 1.25-2.51

% Total nitrogen

Mean* Range

2.60(0.13) 2.41-2.76

2.68(0.24f 2.32-2.93 d 2.64(0.18) 2.32-2.93

% Moisture

Mean* Range

74.6(1. 2) 73.4-76.6

70.3(1.8) 68.4-72.5

72.4(2.7) 68.4-76.6


Mean* Range

0.54(0.04) 0.51-0.62 0.60(0.05f 0.55-0.68 0.57(0.05)d 0.51-0.68


% NaCl

Mean* Range

0.71(0.14) 0.49-0.84 0.70(0.15) 0.50-0.92

0.70(0.14) 0.49-0.92

% Protein nitrogena

Mean* Range

2.06(0.16) 1.79-2.23 2.08(0.29f 1.64-2.34 2.07(0.22)d 1.64-2.34

"Male" and "Female" represent 6 samples and "80th" represents 12 samples.




d These ~eans represent 11 samples.

• •

% Lipid

Mean* Range

4.90(0.50) 4.24-5.52

7.43(0.86) 6.36-8.75

6.16 (1. 48) 4.24-8.75

% Proteinb

Mean* Range

12.9(1.0) 11.2-13.9 c 13.0(1.8) 10.2-14.6 d 12.9(1.4) 10.2-14.6

Table 8C. Proximate Analysis of Fresh Sea Urchin Roe - S. purpuratus.

Male

Female

Both

Male

Female

Both

% Ash

Mean* Range

1.95{0.16) 1.78-2.13

1. 46 (O. 11) 1. 34-1. 64 1.70{0.28) 1. 34-2.13

% Total nitrogen

Mean* Range

2.45{0.29)c 2.10-2.83

2.46{0.23) 2.20-2.78 2.45{0.24)d 2.10-2.83

% Moisture

Mean* Range

74.2{2.6) 71. 6-7R. 6

69 . 4{4.1) 65.2-76.5 71.8{4.1) 65.2-78.6


Mean* Range

0.52{0.03)c 0.48-0.56

0.45{0.11) 0.30-0.64 O. 48{0. 09)d 0.30-0.64


% NaCl

Mean* Range

1. 00 (O .15) 0.75-1. 20

0.94{0.16) 0.62-1.07 0.97{0.15) 0.62-1.20

% Protein nitrogena

Mean* Range

1.93{0.30)c 1.58-2.35

2.00{0.26) 1.60-2.35 1.97{0.26)d 1.58-2.35

"Male" and "Female" represent 6 samples and "Both" represents 12 samples.




d These means represent 11 samples.

~ Lipid

Mean* Range

4.12{0.85) 3.03-5.14

6.18{1.19) 4.26-7.51 5.15{1.46) 3.03-7.51

% Proteinb

Mean* Range

c 12.1{1.9) 9.9-14.7 12.5{1.6) 10.0-14.7

d 12.3{1.7) 9.9-14.7

+ studies on the handling and processing of sea urchin roe. i. fresh product march 1979

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