Sterols oxidation: effecto of heating, unsaturation degree of the surrounding lipids and presence of antioxidants

Dietary sterols are nutritionally interesting compounds which can undergo oxidation reactions during food manufacture and storage, as well as in the human body. Their oxidation products are associated with the development of highly prevalent non infectious diseases. Therefore, it is relevant to evaluate the particular factors which affect sterol degradation and oxysterols formation in foods. In this context, the present work aimed to assess the effect of heating treatment, unsaturation degree of the surrounding lipids and also presence of antioxidants, on sterols degradation and oxides formation. Model systems (which are valuable tools to avoid the influence of interferences), as well as some food applications, were used in the experimental designs. Our study concluded that: sterols thermo oxidation is a multifactorial process which strongly depends on time temperatura combination, producing a high sterol oxidation already from the beginning of the process. Moreover, the presence and unsaturation degree of the lipid matrix, as well as the presence of phenolics and tocopherols, significantly protected sterols from oxidation in our model systems. The addition of plant extracts in foodstuffs to achieve this same goal appeared to be a promising strategy when the sensory aspects and characteristics of the sample are taken into account. In addition, we could establish that the monitoring of sterol oxidation through the measurement of the oxides generated is a complex issue, hence a scientific consensus to achieve a standardized methodology is still needed.