The effects of oil variety (tuna oil, soybean oil, and lard) on the taste of tuna extract were assessed by sensory evaluation and by physicochemical analyses. All the oils tested were mainly composed of triacylglycerol in which tuna oil, soybean oil, and lard were rich in docosahexaenoic acid, linoleic acid, and oleic acid, respectively. The physical properties of tuna oil were similar to those of soybean oil in terms of viscosity and solid fat content. Sensory evaluation showed that the addition of tuna oil to tuna extract as an emulsion did not change whole taste intensity, increased sweetness and decreased sourness and bitterness significantly. There was also a tendency to increase aftertaste. The addition of tuna oil caused a significant decrease in first taste and an increase in aftertaste that were not observed for the extract treated with soybean oil or lard. The addition of up to 30% (w/w) tuna oil did not change whole taste intensity, but significantly increased aftertaste, sweetness, and umami. It decreased first taste, sourness, and bitterness in a dose dependent manner.
These results suggest that the effect of oil on the taste of tuna extract depends on oil variety and the quantity of oil added.