Peroxidation potential of lipid emulsions after compounding in all-in-one solutions

Objective We investigated the peroxidation potential of fat emulsions in all-in-one solutions (AIOs). Methods Three 20% emulsions were compared: soybean oil (SO; 60% polyunsaturated fatty acids [PUFAs], α-tocopherol:PUFAs = 0.44), soybean plus medium-chain triacylglycerol (SO-MCT; 31% PUFAs, α-tocopherol:PUFAs = 0.35), and olive oil (OO; 21% PUFAs, α-tocopherol:PUFAs = 1.42). For each emulsion, six AIO solutions were prepared by adding 250 mL of emulsion to a lipid-free solution. Lipid peroxide (LPX) and malondialdehyde (MDA) concentrations were evaluated in fat emulsions, lipid-free solutions, and AIOs immediately (T0) and 24 h (T24) after lipid addition. Statistical analysis was done with analysis of variance. Results Fat emulsion LPX in SO-MCT was lower than that in SO (P = 0.015) and OO (P = 0.024); LPX in SO was greater than that in OO (P = 0.013); MDA in SO was greater than that in SO-MCT (P = 0.001) and OO (P = 0.013); and MDA in SO-MCT was greater than that in OO (P = 0.001). In comparison with MDA at AIO-T0, MDA at AIO-T24 increased in SO (P = 0.005) and SO-MCT (P < 0.001) and decreased in OO (P = 0.003); at AIO-T24, LPX was greater in SO, but not significantly. Conclusions In AIO bags, LPX occurred within 24 h after the addition of the lipid emulsion and seemed to be directly related to the PUFA content and inversely related to the α-tocopherol:PUFA ratio of the emulsion.