Offlavor is a big issue in fish marketing and caused by many reasons such as geosmin from filamentous bluegreen algae, benthos, pollution etc. Consumers don't prefer such fish and as a result, producers lose market. There should be a way to solve this problem. Can anyone make any suggestions?
İf your fish is alive, you can allow to swim they 2-3 days in clear water, even if it possible in clear flow water. So, you can reduce their offlovor or offodour. Then you can process their to fillet or otherwise. İf your fish is dead, so you can keep them in salt water cantain
I may add to what Soner Centinkaya has said that you may increase Oxygen level in the running water either by bubbling the gas, or adding KMnO4 (which will release O2 either in basic or acidic pH) which will invigorate the fish & at the same time will oxidize the dead organic matter.There is a paper published in Fisheries Technology (published by Asso. of Fisheries Technologists -India,Kochy) which say that to remove urea from shark, it may be done by salting,desalting,& resalting in filleted condition. The same may be applied in the above case also.
Dear Chandravadan Trivedi, How KMnO4 addition in water will help to minimize the odour from fish body, Please elaborate it.
The most common off-flavour compounds found in cultivated fish are 2-Methylisoborneol (2-MIB) and geosmin (GSM) (caused by microorganisms such as cyanobacteria- Anabaena spp, Microcystis spp., Oscillatoria spp etc). Due to their high bioaccumulation rates in lipid-rich tissue, even very low concentrations of 2-MIB and GSM in the water can cause an undesirable earthy-musty smell and taste in fish flesh. Purging is still the only reliable, and economical way to remove off-flavour (by moving the fish to clean, odour-free water for a certain time prior to harvest). A recent research reported that earthy and musty offflavored Atlantic salmon containing lower concentrations of geosmin and MIB need to be placed into a system containing water that is both geosmin-free and MIB-free, either recirculating or flow through, for at least 10–15 days to achieve the greatest reduction of the bioaccumlated off-flavor compounds in the fish flesh. Other studies such as with tilapia were found to require 16 days of depuration in “clean” (odor-free) static water to eliminate geosmin from the muscle tissue. For channel catfish, the depuration periods of 13 and 21 days were reported for geosmin and MIB respectively. Aquaculture producers may like to apply algicides such as copper sulfate and/or diuron to the ponds to reduce the abundance of the odor-producing cyanobacteria as well!
See Glencross et al. 2007. - basically everything you want to know about Geosmin taint in Asian Bass (Lates calcarifer) Caution - 230 pages, 6.8MB! )
frdc.com.au/research/Documents/Final_reports/2003-026-DLD.PDF
The reciprocal of the uptake study was the rate of depuration study. In this study barramundi from the cages in Lake Argyle were placed in GSM and MIB free water and fish sampled every 24 hours for five days to assess their level of muddy-flavour taint by sensory evaluation. This study showed that the rate of depuration was substantially longer than that of uptake. The decline in muddy-flavour taint was consistent with rate-turnover kinetics (and exponential function) and showed that the taint halved approximately every 36 hours.
before harvesting the fish, Place them in a pond or a tank with clean chlorine free water for 3 to four days. this will help to clear the offflavour.
Off flavor is an ongoing problem in farm-raised fish because excess feed, feces and other biological built favors off flavor producing algae. You can develop systems, where accumulated waste is recirculated and enriched with oxygen because of water movement (as observed in split ponds). You can also resort to a program that you can selectively kill a portion of the blue green algae (approved in your country). Other management protocol include purging the off flavor by flushing with fresh water for 3 -5 days; harvesting in warmer months when the off flavor accumulation is minimal.
Impressive sharings! Regarding on that matter,somehow people use kind of tamarind whichever in paste or liquid to get rid offlavor on flesh fish,wondering is it live fish can be done that way after post-harvest before being distribute into market?
While cooking fish, people apply flavoring herbs like bay leaf, thyme etc. and various seasonings according to their taste. Even during cooking someone cannot get rid of offlavor but give some taste to fish. Offlavor mostly caused by geosmin from filamentous bluegreen algae, and by benthos, pollution etc. Consumers don't prefer such fish and as a result, producers lose market.
removal of off flavour through depuration has been used as one of the methods that flushes off flavour in fish
- Badges
- Science topic
- Similar topics
- Correction