This presentation was given at the 2008 Phycological Society of Southern Africa conference in Rocky Bay, Durban. The presentation looks at how diets fed to ablone affect their taste characteristics.

2. G. gracilis Ulva lactuca Abfeed™ Geldium spp. P. corallorhiza dry E. maxima E. maxima L. pallida Gracilaria gracilis Gracilariopsis longissima Ulva lactuca Abfeed™ Midae Meal™ Porphyra capensis

3. fast growth rates, improved vigour and stress resistance

4. tastes and smells funny ?

6. Sulphur-containing amino acids? ✕

7. DMSP ✓ In food? ca. 0 , 20 , & 7000 μg.g -1 In abalone? ca. < 100 , 1500 - 3000 & 16000 μg.g -1

8. concentrated in adductor muscle also in wild-caught abalone depuration of <100 days present in canning fluid

9. Algal or bacterial DMSP lyase Thermal decomposition of DMSP Highly volatile Distinct taste and odour Noticeable at 0.03 - 0.045 μg.ml -1 in water Produced by algae Accumulates in grazers Taste- and odourless DMSP ➠ DMS

10. 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.

15. n = 51: 15 Asian, 6 farmer, and 30 ‘other’ panelists ≥ 8 correct (67 % success rate, p = 0.0188) bread & cheese

16. 51 % of the original population (n = 26) Asian (n = 7), farmer (n = 6), ‘other’ (n = 13) 46.7 % of the Asian, 100% of the farmer, and 43.3 % of ‘other’

17. Ignoring feed and panelist category, do (un)cooked samples taste differently? Yes UC - surface texture, colour, aroma intensity (kelp & Ulva fed, wild) C - surface texture, colour, visual and taste freshness, sweetness uncooked cooked

18. Ignoring feed and panelist category, do (un)cooked samples show same patterns i.t.o. relationships btw. variable pairs ? Yes 84% uncooked cooked

19. Do diff. categories of panelists rely on the same sensory characters? No UC - farmers: taste intensity, acceptability of texture; Asian: taste and odour characteristics C - farmers: sweetness and odour freshness; Asian: bitterness, sourness uncooked cooked

20. Which sensory variables allow panelists to distinguish btw. differently fed abalone? UC - wild-caught vs. rest: odour intensity, colour; Ulva -fed vs. rest: texture (visual and touch) C - separation more pronounced; each feed-type influenced by a different sensory variable uncooked cooked

29. THANK YOU ACKNOWLEDGEMENTS We extend special thanks to the following people and organisations without whose help this project would have been impossible: Swedish and South African Collaborative Program I & J Mariculture farm JSP Mariculture farm Wild Coast Abalone Abagold N R F J SP