Geosmin off-flavour in pond-raised fish in southern Bangladesh and occurrence of potential off-flavour producing organisms

Abstract

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 5:107-116 (2014) - DOI: https://doi.org/10.3354/aei00100 Geosmin off-flavour in pond-raised fish in southern Bangladesh and occurrence of potential off-flavour producing organisms Mikael A. Petersen1, Md. Ariful Alam2, Md. Mizanur Rahman2, Md. Lokman Ali2, Sultan Mahmud2, Louise Schlüter3, Niels O. G. Jørgensen4,* 1Department of Food Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark 2Faculty of Fisheries, Patuakhali Science and Technology University, Dumki, Patuakhali 8602, Bangladesh 3Environment and Toxicology, DHI Group, Agern Allé 5, 2970 Hørsholm, Denmark 4Genetics and Microbiology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark *Corresponding author: nogj@plen.ku.dk ABSTRACT: Pangas Pangasianodon hypophthalmus and tilapia Oreochromis niloticus were cultivated for 6 mo in earthen ponds in Bangladesh to examine occurrence of the off-flavour geosmin in water and fish and to test procedures for reduction of off-flavour. In the ponds (~1 m depth and area of 400 m2), the average geosmin concentration was 3.9 ng l-1 (range 0.2 to 20 ng l-1). No effects of season or water treatment (sand filtration or probiotic microbes) were found. The content of geosmin in the fish was 21 ng kg-1 (range: 0.0 to 91 ng kg-1) for pangas and 17 ng kg-1 (range: 0.0 to 68 ng kg-1) for tilapia. Water treatment reduced the geosmin content by 56 to 74% in pangas, but no effect was found in tilapia. Likewise, depuration for ≥12 h in groundwater lowered the geosmin content in pangas (by 65 to 90%) but not in tilapia. Sensory analysis indicated a positive effect of both water treatment and depuration, and the fish were graded ‘no or mild flavour’ after such treatment, compared to ‘strong off-flavour’ in controls. Abundance analyses of known off-flavour producing microorganisms (streptomycete bacteria and cyanobacteria) showed a high density of streptomycetes (0.5 to 13% of the bacterial population), while cyanobacteria made up a maximum of 9.3% of the phytoplankton biomass or were absent. This first study on off-flavours in pangas and tilapia in Bangladeshi ponds indicates that geosmin was not a major off-flavour in the fish, but improvement of sensory quality by water treatment and depuration suggests that other, unidentified off-flavours were present in the fish. KEY WORDS: Off-flavour · Aquaculture · Pangasianodon hypophthalmus · Oreochromis niloticus · Streptomycetes · Cyanobacteria · Geosmin · GC-MS · Sensory analysis Full text in pdf format PreviousNextCite this article as: Petersen MA, Alam MA, Rahman MM, Ali ML, Mahmud S, Schlüter L, Jørgensen NOG (2014) Geosmin off-flavour in pond-raised fish in southern Bangladesh and occurrence of potential off-flavour producing organisms. Aquacult Environ Interact 5:107-116. https://doi.org/10.3354/aei00100 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 5, No. 2. Online publication date: May 08, 2014 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2014 Inter-Research.