Lipid oxidation of salted freeze-dried fish meats at different equilibrium relative humidities.

Abstract

The rates of lipid oxidation of saled freeze-dried bluefin tuna and sablefish meats, as model of salted dried fish products, wrere investigated as a function of moistrue equilibrium relative humidity at 25°C. The lipid oxidationm in the salted freeze-dried bluefin tuna proceeded rapidly at all relative humidities tested (ranging from 0 to 71%) during storage, resulting in the considerable loss of polyenoic acids; the rates of oxidateve destrcution of polyenoic acids wre higher at lower relative humidity. The oxidative destructions of some of monoenoic acids wre also fornd in the lipids of salted freezedried bluefin tuna. On the other hand, the lipids in salted freeze-dried sablefish were stable to oxidative destruction, even at lower relative humidity such as 11% RH corresponding to the monomolecular layer of water. No changes wre found in the percentages of polyenoic and monoenoic acids in the total lipids of salted freeze-dried sablefish during storage. However, the lipids were hydrolyzed enzymatically at higher relative humidity such as 71% RH.