Phospholipid oxidation, non-enzymatic browning development and volatile compounds generation in model systems containing liposomes from porcine Longissimus dorsi and selected amino acids

Abstract

Lipid oxidation, non-enzymatic browning development and volatile compounds generation were studied in sterile meat-model systems containing selected amino acids and/or liposomes during 35 days at 25 °C under pro-oxidative conditions, in order to simulate the ripening conditions of dry-cured meat products. Liposomes were prepared with polar lipids (PL) from Longissimus dorsi muscle of outdoors pigs fed on grass and acorns (M) or indoors ones fed on concentrates (C). Thiobarbituric acid reactive substances (TBA-RS) in systems containing both amino acids and liposomes were higher than in those containing only liposomes. The higher susceptibility to lipid oxidation of liposomes from C animal was reflected in higher TBA-RS throughout the experiment. All model systems containing liposomes and/or amino acids showed non-enzymatic browning development, as measured by the yellowness index. Major volatile compounds were fatty acid oxidation products. Strecker-derived volatile compounds were predominantly detected in model systems containing both amino acids and liposomes. The chromatographic areas of Strecker-derived volatiles increased over time whereas those of lipid-derived volatiles decreased. The occurrence of lipid oxidation, non-enzymatic browning and Strecker-type degradation of amino acids were shown in sterile meat-model systems at low temperatures.