Epsilon Archive for Student Projects

Abstract

Aquaculture is a food industry that has grown over the past century, and which still is growing. Development also entails challenges. The largest challenge in sustainable aquaculture development is the feed. Today, raw materials such as fish oil, fish meal, and soybeans are utilized. These are often considered unsustainable, and possible replacements are thus widely investigated. The aim of this thesis was to compare one soy-based control diet (Glycine max; Control) and four novel sustainable alternatives based on: Black solider fly Protein (Hermetia illucens; BSF prot); Black solider fly oil (H. illucens; BSF oil); Seasquirt (Ciona intestinalis; Ciona); and a Singe cell fungi protein (Paecilomyces variotii; SCP), to evaluate their effect on rainbow trout (Oncorhynchus mykiss) muscle metabolite composition and sensorial attributes. Water soluble metabolites were extracted from the white muscle tissue of Rainbow trout, and 1H-NMR was performed to determine the metabolic profile of fishes fed the different feeds. The metabolite data was evaluated statistically by ANOVA, PCA, and sPLS-Da and compared to the sensory data. The results showed that Black Soldier fly protein caused higher tissue concentration of Methionine, and Betaine. The single cell protein diet gave a similar pattern as the control feed. The metabolome of the Seasquirt and Black soldier fly groups were partially overlapping the control, i.e. similar to some extent. The sensorically attributing metabolites did probably affect taste the most. BSF prot was the feed category which indicated the most differences compared to the other treatments. It had lower concentrations of IMP, and higher levels of Hypoxanthine, which indicates that the diet generates a fillet which might lose freshness faster than the other feed categories. AMP acts as a bitterness blocker and is found in higher concentration in the SCP-group. The muscle of the BSF oil group had higher amounts of Lysine which indicates a potentially sweeter taste. Betaine, which was higher in the BSF prot treatment, acts as an osmoregulator in the muscle, and could improve the texture or mouthfeel. The sensory panel did not pinpoint any large differences between the groups, and no clear connections to the metabolite data could be seen. However, sensoric experiences is a complex mixture of several molecules, and it is not possible ta draw a conclusion based on the result from this study.