Health-related lipids components of sardine muscle as affected by photooxidation

- Photoxidation effects on health-related lipid components of sardines, were evaluated under commercial retail conditions.
- Oxidation of fatty acids and cholesterol was monitored in sardines kept at 4 °C for 4 h under light exposure and at dark.
- After light exposure, PUFA dramatically dropped (up to a 19%), especially docosahexaenoic acid (33%).
- Photoxidation significantly increased peroxide value, thiobarbituric reactive substances and cholesterol oxidation products.
- Cholesterol oxidation rate reached 0.9%, which is equivalent to 3.7 μg/g of sardine.

The aim of this study was to evaluate the oxidative stability of sardine muscle lipids as related to the storage conditions. Whole sardines were stored at 4 °C for 4 h under light exposure and at dark. The lowest levels of peroxide value (PV), thiobarbituric acid reactive substances (TBARs), cholesterol oxidation products (COPs) and the highest level of polyunsaturated fatty acids (PUFAs) content, especially PUFA n − 3, were found in the untreated sardines (time zero). After light exposure, PUFA dramatically dropped (up to a 19% decrease) and a marked increase of PV (11.8 meq O2/kg fat), TBARs (3.7 mg MDA/kg meat) and COPs (3.7 μg/g muscle) was observed; under darkness, the values of the oxidation parameters were similar to those found in untreated sardines. Although cholesterol oxidation rate did not exceed 0.9%, further research is required about toxicity levels of the single COPs, to better understand if the COPs levels found in untreated and photoxidized muscle (0.62-3.72 μg/g of muscle) do not represent a risk for human health.