Off-Flavors in Aquacultured Fish: Origins and Implications for Consumers

Abstract

Off-flavors in fish and water are considered a worldwide problem. Several factors, such as the presence of phosphorus, micronutrients, and organic matter, contribute to phytoplankton proliferation and the production of off-flavors. Geosmin and 2-methylisoborneol are the most common off-flavors that confer the smell of earth or mold to water and fish. These metabolites are not considered toxic, but they can be easily transferred from water to living organisms and accumulate in the biota, up the trophic levels and to consumers, including fish species. Numerous processes have been studied to eliminate or reduce the presence of off-flavors in recirculating aquaculture systems. Managing off-flavors must be eco-friendly and consumer-friendly. Strategies against off-flavors must be efficient and low-cost. However, these solutions may be different for each fish production system. We review herein the main compounds produced by cyanobacteria that can accumulate in fish used in aquaculture that can affect the quality of food, as well as production costs and consumer preference.

Off-flavors and lipid components in rainbow trout (Oncorhynchus mykiss) reared in RAS: Differences in families of low and high lipid contents

“…The comparison of the correlations of proportional MIB and GSM with fatty acids indicated that the off-flavor compounds may accumulate similarly to other fatty acids. This is in accordance with the similar octanol/water partition coefficients of the two compounds (Howgate, 2004;Lindholm-Lehto and Vielma, 2018;Moretto et al, 2022) and the positive correlation between proportional MIB and GSM. The formulation of fish feeds and genetic selection can be used to change concentrations of individual fatty acids.…”

“…A muddy taste sensation is influenced by the content of off-flavor compounds in the lipid tissue but also by the moisture and protein in the flesh (Howgate, 2004;Moretto et al, 2022). In contrast to proportional MIB and GSM, when measured as absolute content, the results suggested that GSM and MIB were very weakly correlated, and they may not have similar tendency in accumulating in fresh muscle tissue.…”

“…For example, human detection limits of 0.55-0.7 ng g − 1 for MIB and 0.9 ng g − 1 for GSM have been reported for rainbow trout (Oncorhynchus mykiss) and barramundi (Lates calcarifer) (Robertson et al, 2005;Petersen et al, 2011;Jones et al, 2013;reviewed in Lindholm-Lehto and Vielma, 2018), and even a 0.25 ng g − 1 limit value for GSM in channel catfish (Ictalurus punctatus) (Grimm et al, 2004). The detection limits depend not only on the fish species, but on the lipid content of the fish: an increased lipid content leads to a higher detection limit (Howgate, 2004;Moretto et al, 2022).…”

Organoleptic qualities and proximate composition of fish grown in good aquaculture practice-based carp fattening pond

“…Unlike the most other production problems in aquaculture, off-flavour assessed by organoleptic valuation is less detrimental to the growth or health of the animals (Tucker 2000), however, economic importance of organoleptic testing is high, making it one of the most severe challenges of the aquaculture industry worldwide (Moretto et al 2022). Degradation of natural aquatic environment and increasing trend of semi-intensive aquaculture practices with supplementary feed has affected the taste and quality of fish muscle (Zhao et al 2018).…”

Influence of saline environment and depuration time on quality and proximate composition of Nile tilapia fillet (Oreochromis niloticus)

“…However, the depuration can take from a few days to weeks depending on several factors and animals are kept with little or no food during depuration (Lv et al, 2018;Moretto et al, 2022). Food deprivation can degrade endogenous energy sources (lipids, glycogen and proteins) in the maintenance of fish physiological homeostasis, leading to weight loss and alteration of the proximate composition (Poli et al, 2005;Li et al, 2018;Sakyi et al, 2020;Barai et al, 2022).…”