Its timely to consider the product quality lessons gained from the Australian barramundi industry’s first few decades of R&D. The barramundi (Lates calcarifer) is Northern Australia’s foremost aquaculture species in volume, making market differentiation and spread into new product forms vital. To prepare for this, barramundi aquaculture research from the last few decades was examined to identify areas where further research is justified.
Feed researchers have sought to avoid the inadvertent consequences of feed ingredient substitution. Yet, sensory panels accept barramundi fed on a variety of novel ingredients. Subtle differences are reported, for example changes in fatty acid profile influence the rate of lipid oxidation (rancidity). That legacy of feed development revealed the work required to document sensory parameters – and raised questions about how future barramundi selection programs would instil new traits into fingerlings. Indeed, researchers could do more to standardise recording of flesh colour variability.
Off-flavour in freshwater fish is an issue beyond barramundi farming. It occurs in freshwater pond and recirculation aquaculture systems (RAS). Purging is most practical for RAS barramundi, but researchers also identified ways for pond farmers to avoid harvesting off-flavour fish. If there is no taint in marketed fish, then this comes at an undocumented cost to farms. If that status-quo cost is not known, it is difficult to assign cost-benefit to alternatives.
Harvest stress, such as exercise in the crowd, can alter post-mortem flesh quality of fish. Yet harvesting exercised barramundi directly into ice-slurries leaves sensory panels reporting only subtle variations in appearance, texture, or flavour. It is argued though that rapid cold shock, a practice common to many tropical farmed fish, has a levelling effect upon quality. Instantaneous stunning techniques will permit bleeding of barramundi- and a quality dividend is anticipated.
Product portioning brings customer convenience at the cost of shortened shelf life. Transport of whole, un-gutted barramundi easily gives 2-3 weeks shelf-life under tight cold-chain control. The shelf-life of chilled raw packaged fillets/portions of barramundi is less than a week- portioning must occur close to consumers. Smoking is, however, a traditional seafood preservation technique that shows great promise in tests with barramundi. Other studies indicate that consumers could also set aside their misconceptions about quality of frozen fish.
The review concluded that implementing new harvest methods and new products can build from an understanding of existing quality variability in the marketplace (especially colour and flavour). If, as expected, alternative harvest methods raise the average for flesh quality, then this should be followed through with studies of portioned and value-added samples. Understanding how harvesting steps impact processing of product will set up Australia’s barramundi farming sector for a future of successful product innovation.