Use of Tahiti lemon juice (Citrus latifolia) as natural antioxidant during the thermal preparation of sardines (Sardina
pilchardus) by different cooking methods.
Fatty acids, cholesterol oxidation products, natural antioxidants.
In recent years, consumers are more concerned about their eating habits, boosting the search
functional foods. Marine fish are considered functional foods, due to the presence of high
levels of n3- polyunsaturated fatty acids. However, sardines contain appreciable
concentrations of cholesterol which is highly susceptible to lipid oxidation. The formation of
cholesterol oxides and the degradation of polyunsaturated fatty acids during thermal
processing (thermo-oxidation) play an important role among the factors responsible for the
loss of quality and nutritional characteristics of fish. In addition, the consumption of oxidized
lipids has been the subject of research in the public health area, due to the correlation between
their intake and the induction of pro-inflammatory effects and other chronic degenerative
diseases. Thus, natural antioxidant components that can prevent or minimize the oxidation of
marine fish during the thermal preparation are interesting alternatives. Tahiti lemon (Citrus
latifolia) juice is extensively used in the culinary preparation of fish. In Brazil, lemon Tahiti is
a fruit of great commercial relevance and widely available in retail markets. Besides that,
studies have shown that lemon juice has antioxidant potential due to the presence of bioactive
compounds. This study evaluated the impact of adding Tahiti lemon juice to sardine (Sardina
pilchardus) fillets submitted to air frying, grilling, and deep-fat frying, regarding the
unsaturated fatty acids and the cholesterol oxidation. Firstly, the juice extract was
characterized by its antioxidant capacity and bioactive constituents. Cooking caused the
degradation of unsaturated fatty acids and increased the cholesterol oxides level. However, or
most treatment, lipid oxidation was more pronounced in samples with juice. Lemon juice
induced cholesterol oxidation, mainly in air-fried sardines where the total content of
cholesterol oxides increased from 699.75 ± 3.90 (control) to 1333.51 ± 5.20 μg/g (10% lemon
juice). Thus, the overall data suggests that potential antioxidant compounds may have been
degraded during heating and the acid environment may have induced oxidative reactions.