Impact of Air Frying on Cholesterol and Fatty Acids Oxidation in Sardines: Protective Effects of Aromatic Herbs

Ferreira FS, Sampaio GR, Keller LM, Sawaya ACHF, Chávez DWH, Torres EAFS, Saldanha T · Journal of Food Science · 2017 November 10

DOI 10.1111/1750-3841.13967

Objective

This study is the 1st to evaluate the formation of cholesterol oxidation products (COPs) and the degradation of polyunsaturated fatty acids (PUFAs) in air-fried sardine fillets. Furthermore, we evaluated the effect of fresh herbs added as natural antioxidants to sardines subjected to air frying.

Conclusions

Air frying significantly decreased the content of essential PUFAs, and increased the levels of COPs from 61.2 (raw) to 283 μg/g (P < 0.05) in the control samples. However, the use of herbs as natural antioxidants proved to be effective reducing such levels of COPs in most samples. The addition of 4% of cheiro-verde in air-fried sardines presented the best protective effect against lipid oxidation.

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Insights

Adding fresh herbs like parsley and chives to air-fried sardines reduces the levels of harmful cholesterol oxidation products formed during cooking.

To conduct this study, sardine fillets were air fried, a method considered healthier as it allows frying without oil. The research then revolved around the monitoring of two types of substances: cholesterol oxidation products (COPs), theorised to increase with the high heat, and essential polyunsaturated fatty acids (PUFAs), which typically decrease in such conditions. In the analysis of the results, it was observed that, indeed, cooking through air frying escalated the levels of COPs while diminishing that of essential PUFAs. The experiment further introduced fresh herbs, namely parsley, chives and a mix of both, owing to their properties as natural antioxidants. This addition was observed to lower the levels of COPs formed, indicating a healthier outcome. Specifically, air-fried sardines with 4% cheiro-verde (the mixed herbs) offered the best protection against lipid or fat oxidation.