# Forging Prawn and Salmon Flavours with Non-Animal-Based Ingredients
## 3 Results and Discussion
### Presence of Key Prawn and Salmon Odourants in the PB Prototypes  
As highlighted in Figure 2, a range of key prawn and salmon odourants, previously identified as abundant and essential in shaping typical seafood characteristics, were detected in the PB prototypes [17]. For instance, key salmon odourants such as butanoic acid (_sweaty_), (_E_)-penten-1-ol (_mushroom_), 1-octen-3-ol (_mushroom_, _green_), hexanal (_green_, _grass_), heptanal (_green_, _floral_), (_E_)-2-heptenal (_grass_, _roasted_), nonanal (_marine_, _plastic_), (_E_)-2-octenal (_mutty_, _fatty_), (_E_)-2-4-heptalenal (_fatty_, _mushroom_), benzaldehyde (_nutty_, _roasted_), (_E_)-2-nonneal (_earthy_, _green_), (_E_)-2-4-decadical (_fatty_, _plastic_), 2,3-pentanedione (_butter_, _caramel_), and 1-octen-3-one (_mushroom_, _green_) were present. These odourants are known to differentiate cooked salmon from other seafood species [8]. Similarly, typical prawn  
Figure 3: Trimethylamine (TMA) formation through pyrolysis of betaine at 200 \({}^{\circ}\)C for 10 min with different ingredients. Treatment groups include betaine alone (betaine, red solid line), betaine with FAA mix (betaine + FAAs, red dashed line), betaine with sunflower and coconut oils (betaine + oils, yellow solid line), betaine with FAA mix and oils (betaine + FAAs + oils, yellow dashed line), betaine with oils and encapsulated algal DHA (betaine + oils + DHA, blue solid line), and betaine with FAA mix, oils, and encapsulated algal DHA (betaine + FAAs + oils + DHA, blue dashed line). TMA content is expressed as 10\({}^{-5}\) peak area.  
odourants, including 2-pentylfuran (_green_, _grass_), TMA (_fishy_), 2-acetyl-1-pyrroline (_roasted_, _popcorn_), and dimethyl trisulphide (_vegetable_, _sulphur_), were also detected. The presence of these compounds demonstrates the potential of these flavour formulations to impart typical prawn and salmon flavour attributes to the PB matrix.  
A subset of key odourants for prawn and salmon was not detected in the samples. Bromophenols, which are abundant in prawns, particularly wild-caught ones, may play a role in imparting a pleasant marine odour. These compounds are accumulated in prawns through their dietary intake of algae. While the DHA used in our formulation was derived from algae, no other algal ingredients were included in the prototypes, which likely explains the absence of bromophenols. Furthermore, [PERSON], [PERSON] [8] reported the presence of 2,4-dithiapentane (_truffle_) and indole (_faecal_, _musty_) in prawns. The occurrence of these compounds in prawns is likely due to microbial or enzymatic activities that lead to the decomposition of amino acids such as cysteine, methionine, and tryptophan [31; 32]. However, such reactions are unlikely to have occurred during the formulation of the prawn prototypes. Furthermore, two key salmon odourants, (_E_,_Z_)-2,6-nonadienal (_cucumber_, _floral_) and (_E_)-3-hexen-1-ol (_fresh_, _green_), reported in our previous study [8], were not detected. Since these compounds are derived from PUFA degradation, their absence suggests that authentic seafood possesses a more complex PUFA profile, which facilitates the production of these characteristic odourants.