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The aim of the present work was to study the effect of a broccoli phytochemical extract (Br-ex) on the release of fatty acids (FA) from salmon muscle (SM) and salmon oil (SO) during in vitro digestion. The hypothesis of the study was that Br-ex contains polyphenols which might act as pancreatic lipase inhibitors. The effect on the release of specific FA, in particular the long-chain n-3 polyunsaturated fatty acids (PUFAs), EPA (C20:5 n-3) and DHA (C22:6 n-3), was recorded, and the impact of the SM matrix was studied by comparing the release of FA from SM and SO. In vitro digestion was performed and lipolytic activity, measured as the release of fatty acids (FFA) by solid phase extraction and GC-FID, was recorded at 20, 40, 80 and 140 minutes in the intestinal phase. The results showed, unexpectedly, that Br-ex stimulated the release of FA during digestion of SO and SM, showing the highest increases in FFA, 67% and 64%, respectively, at 20 min. No difference in the release of FA from SO compared to SM was observed, suggesting that the SM matrix had minor influence on the lipolytic activity. The results also demonstrated that the increase in lipolytic activity caused by Br-ex was not affected by the SM matrix. However, addition of Br-ex resulted in a lower percentage of EPA and DHA in the FFA fraction, suggesting that the lipase sn-position preference was altered. Whether this affects the bioaccessibility of EPA and DHA needs further investigation.

We hypothesize that the rate of release of lipids from salmon muscle during in vitro digestion is altered by additional meal components. In vitro digestion of salmon was performed using a mixture of porcine gastrointestinal enzymes and bile salts. Broccoli and barley were also added to the digestion simulating a meal. The extent of lipolysis was determined by measuring the release of fatty acids (FAs) during sampling at the simulated gastric phase endpoint (60 minutes) and 20, 40, 60, 80, 110 and 140 minutes simulated small intestinal phase, using solid phase extraction and GC-FID. Adding barley resulted in a lower overall release of FA from salmon, whereas broccoli caused an initial delay followed by increased release from 80–140 min when lipid digestion of salmon alone plateaued. The impact of broccoli and barley on the release of peptides and digesta viscosity were also measured. The effect of different components in the meal shown by this in vitro study suggests that it would be possible to make dietary changes affecting the lipolysis, further triggering specific responses in the gastrointestinal tract. However, these observations need to be validated in vivo, and the mechanisms need to be further examined.