The effect of diet on the sensory quality of cultivated abalone

AJ Smit, Deborah Robertson-Andersson & John Bolton

G. gracilisUlva lactuca

Abfeed™Geldium

spp.P.

corallorhizadry E.

maxima

E. maximaL. pallida

Gracilaria gracilisGracilariopsis

longissimaUlva lactuca

Abfeed™Midae Meal™

Porphyra capensis

fast growth rates, improved fast growth rates, improved vigour and stress resistancevigour and stress resistance

tastes and tastes and smells funnysmells funny??

Sulphur-containing amino acids?Sulphur-containing amino acids?

✕✕

DMSPDMSP

✓✓

In food?In food?

ca. ca. 00, , 2020, & , & 70007000 μg.g μg.g-1-1

In abalone?In abalone?

ca. <ca. <100100, , 15001500 - - 30003000 & & 1600016000 μg.g μg.g-1-1

concentrated in adductor muscleconcentrated in adductor muscle

also in wild-caught abalonealso in wild-caught abalone

depuration of <100 daysdepuration of <100 days

present in canning fluidpresent in canning fluid

COO-

CH3

CH3

S+

DMSP lyase

CH3

CH3

S COO-

H

CH2

H++ +

Dimethylsulphoniopropionate Dimethylsulphide Acrylate

Algal or bacterial DMSP lyaseThermal decomposition of DMSPAlgal or bacterial DMSP lyaseThermal decomposition of DMSP

Highly volatileDistinct taste and odourNoticeable at 0.03 - 0.045 μg.ml-1 in water

Highly volatileDistinct taste and odourNoticeable at 0.03 - 0.045 μg.ml-1 in water

Produced by algaeAccumulates in grazersProduced by algaeAccumulates in grazers

Taste- and odourlessTaste- and odourless

DMSP ➠ DMSDMSP ➠ DMSDMSP ➠ DMSDMSP ➠ DMS

Taste test

Dear taste tester

Thank you for agreeing to be a part of this testing programme.

Testing will be done using two taste test approaches:

A) A quantitative descriptive analysis

B) A difference test (triangle test)

The purpose of this test is three fold:

1) To rank you as a tester

2) To evaluate which is the most acceptable abalone diet

3) To compare all the taste samples to a reference smell of

DMS

This will be done for both cooked and raw abalone.

bread & cheese

n = 51: 15 Asian, 6 farmer, and 30 ‘other’ panelists

≥ ≥ 8 correct (67 % success rate, p = 0.0188)8 correct (67 % success rate, p = 0.0188)

51 % of the original population (n = 26)51 % of the original population (n = 26)

Asian (n = 7), farmer (n = 6), ‘other’ (n = Asian (n = 7), farmer (n = 6), ‘other’ (n = 13)13)

46.7 % of the Asian, 100% of the farmer, 46.7 % of the Asian, 100% of the farmer, and 43.3 % of ‘other’and 43.3 % of ‘other’

uncooked

cooked

Ignoring feed and panelist category, do Ignoring feed and panelist category, do (un)cooked samples taste differently?(un)cooked samples taste differently?

YesYes

UC - surface texture, colour, aroma intensity UC - surface texture, colour, aroma intensity (kelp & (kelp & UlvaUlva fed, wild) fed, wild)

C - surface texture, colour, visual and taste C - surface texture, colour, visual and taste freshness, sweetnessfreshness, sweetness

uncooked

cooked

Ignoring feed and panelist category, do Ignoring feed and panelist category, do (un)cooked samples show same patterns (un)cooked samples show same patterns i.t.o. relationships btw. variable pairs ?i.t.o. relationships btw. variable pairs ?

YesYes

84%84%

uncooked

cooked

Do diff. categories of panelists rely on the Do diff. categories of panelists rely on the same sensory characters?same sensory characters?

NoNo

UC - farmers: taste intensity, acceptability of UC - farmers: taste intensity, acceptability of texture; Asian: taste and odour texture; Asian: taste and odour

characteristicscharacteristics

C - farmers: sweetness and odour freshness; C - farmers: sweetness and odour freshness; Asian: bitterness, sournessAsian: bitterness, sourness

uncooked

cooked

Which sensory variables allow panelists to Which sensory variables allow panelists to distinguish btw. differently fed abalone?distinguish btw. differently fed abalone?

UC - wild-caught vs. rest: odour intensity, UC - wild-caught vs. rest: odour intensity, colour; colour; UlvaUlva-fed vs. rest: texture (visual and -fed vs. rest: texture (visual and

touch)touch)

C - separation more pronounced; each feed-C - separation more pronounced; each feed-type influenced by a different sensory type influenced by a different sensory

variablevariable