Organoleptic effect of using different plant materials on smoking of marine and freshwater catfish
Freshwater catfish (Clarias gariepinus) and marine catfish (Galeichthys feliceps) were smoked using Acacia raddiana (Moriela), Prosopis julifora (“Mathenge”), Azadirachta indica (Neem) and Cocos nucifera (Coconut husks) in view to assess and compare the organoleptic scores- taste, appearance and overall acceptability of the smoked fish. Insect and mould attack was also monitored during storage. The scores for taste for marine catfish were better than that for freshwater catfish irrespective of the plant materials used. Taste for freshwater catfish and marine catfish smoked with Acacia was significantly different (p<0.05). Appearance and overall acceptability for freshwater catfish smoked with Acacia, Prosopis (Mathenge), Neem, and Coconut husks was better than marine catfish though not significantly different (p<0.05). The scores for taste, appearance and overall acceptability for marine catfish smoked with Acacia, Prosopis, Neem and Coconut husks were not significantly different (p<0.05). Acacia had better taste, appearance and overall acceptability scores. For freshwater catfish smoked with Acacia, Prosopis, Neem and Coconut husks, scores for taste, appearance and overall acceptability were not significantly different (p<0.05). Insects were first detected in the marine catfish smoked by Acacia and Prosopis on day 35, 48 and 56 recording score 1, 2 and 3 respectively. For Coconut husk and Neem smoked marine catfish, insects appeared on day 48 and 56 with scores of 1 and 2 respectively. In the freshwater catfish smoked by Prosopis, insects were first noticed on day 35 and 48 with scores of 2 and 3. For those smoked with Acacia and Coconut husks the first insect attack was on day 48 with a score of 1 and scores of 2 and 3 respectively on day 56. The first insect attack on Neem smoked catfish was day 56. Mould was first detected in the marine catfish smoked with Prosopis and Coconut husks on day 35 and on Acacia and Neem on day 48 of storage. In the freshwater catfish, mould was first detected in the fish smoked by Acacia, Prosopis and Coconut husks on day 14 of storage and on fish smoked with Neem on day 56. The Neem tree delays insect and mould attack in smoked fish during storage. The percentage moisture recorded on day 0, 14, 21, 28, 35, 48 till 56 correspond to days when mould was noticed on the fish during storage and it increased with storage time. The 4 trees can be used in marine and freshwater catfish smoking for human consumption.
Key words: Organoleptic, Smoking, Catfish, Storage, Infestation
Abbreviations: KMFRI: Kenya Marine and Fisheries Research Institute