52 Priyantha I. Hathurusingha and Kenneth R. Davey
adaptation in experts - and can lead to reduction of perceived sensitivity to
taste-tainting chemicals (Brett and Johnsen, 1996; Johnsen and Brett, 1996).
There is therefore a need to develop a simple, yet effective taste-taint
predictive model to assist farmer’s confidence in harvesting fish that have taint
less than the consumer rejection threshold, without recourse to extensive and
expensive analytical analyses. A timely harvest, with the help of the model
simulation, can possibly eliminate the current purging-step and would avoid
double-handling of fish, reduce labour and increase profits to the farmers by
sending fish to the market without any mass loss.
It is clear one of the key parameters impacting taste-taint in fish-flesh is
the concentration of GSM and MIB in the RAS growth water. If a model can
be synthesized it can be applied to determine the limiting concentrations of
GSM and/or MIB in growth water before reaching the consumer rejection
threshold of the fish-flesh at the time of fish harvest.
Resulting insights could be used to develop an effective protocol to
minimise GSM and MIB in RAS growth water. Clearly, a range of farming
practices could be investigated in this way with a minimum cost, and possible
optimisation.
Judicious use of the validated model could assist famers to develop
growth protocols resulting in fish at harvest that have taste-taint chemicals
concentration lower than the consumer threshold without recourse to extensive
analytical analyses.
A CRITICAL REVIEW OF AN EXTENSIVE RECENT
EXPERIMENTAL VALIDATION OF
ONE PREDICTIVE MODEL
A new quantitative process model to predict concentration of taste-taint,
as either GSM or MIB, to aid RAS management has been developed by
Hathurusingha and Davey (2014).
Their model is based on conservation of mass and energy principles
(Foust et al., 1980) and thermodynamic processes established in (bio)chemical
engineering (Bailey and Ollis, 1986), and a whole-of-process perspective. The
aim was to produce a quantitative guide for RAS farming practice that could
be applied to minimize taint in fish-flesh and promote market growth and
obviate drawbacks with existing models, including (longer term) extensive
experimental evaluation. In their model the taste-taint concentration in fish