an acid esterification using 1 wt.% H2SO4and a reaction temperature around 52C,during 1h,was performed (molar ratio methanol:oil of 6:1, 600 rpm stirring) to reduce the acid value of a salmon oil (3.5 or 12 mg KOH g ) to values acceptable for alkaline transesterification (considering a maximum of 2 mg KOH g)