Vacuum-packed ripened sausages: evolution of oxidative and hydrolytic degradation of lipid fraction during long-term storage and influence on the sensory properties.

An experimental investigation was carried out with the aim to understand the oxidative and hydrolytic phenomena involving the lipid fraction of vacuum-packed sausages during long-term storage (5 months) and to verify their influence on the sensory characteristics. The data obtained pointed out that the oxidation was more pronounced in the initial stages of storage than in the further period, while the hydrolysis of lipid fraction significantly advanced during the whole storage time, supported by the high moisture level of the product. Both these phenomena resulted to be correlated with the sensory decay of the product. In particular, in the first stage of vacuum storage overall acceptability was found to be negatively correlated (p<0.05) with rancid taste, acid value, and oxidized triacylglycerols. In the further stage the oxidative processes slowed down and affected in a lesser extent the sensory properties, which were more distinctly characterized by the onset of pungent perception attributed to compounds arising from multiple origins such as carbohydrate fermentation. This investigation confirmed the unreliability of thiobarbituric acid reactive substances test and the usefulness of high performance size exclusion chromatography analysis of the polar compounds of the lipid fraction to correctly determine the levels of the oxidative and hydrolytic degradation of the lipid fraction of vacuum-packed ripened sausages during long-term storage.