A Review on Oxidative Stability of Edible Oils during Frying: Insight into Lipid Degradation and Quality Preservation
Manisha Saha
Department of Food and Nutrition, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh-226025, India.
Priyanka Shankar
Department of Food and Nutrition, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh-226025, India.
Anu Ram Kailash Mishra *
Department of Food and Nutrition, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh-226025, India.
Alka Nanda
Department of Food and Nutrition, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh-226025, India.
*Author to whom correspondence should be addressed.
Abstract
Oxidative stability is the important parameter that influence the quality, safety, and nutritional integrity of edible oils in frying. This review paper comprehensively examines the edible oils’ oxidative stability upon repetitive frying, a common cooking practice and elucidates the different mechanisms of lipid degradation. Beginning with the formation of odourless and tasteless hydroperoxides and their subsequent breakdown into volatile secondary oxidation products comprising aldehydes and ketones, which gives off undesirable flavours causing potential health hazards. The paper highlights the crucial influence of fatty acid composition, natural antioxidants and several frying factors including frying duration, temperature and repeated oil on the oxidative stability traits. Coconut oil, rich in saturated fatty acids, exhibits the highest oxidative stability and resistance to thermal degradation during frying. Groundnut oil, with a high proportion of monounsaturated fatty acids, demonstrates moderate oxidative stability, while mustard oil, containing higher levels of polyunsaturated fatty acids, is more susceptible to oxidation under frying conditions. It highlights how their distinct compositions impact resistance to degradation under frying conditions, with coconut oil exhibiting excellent stability because of its high saturated fat content. Furthermore, the paper examines the qualitative physical and chemical characteristics that are used to evaluate the quality of frying oil and critically assesses strategies for optimizing its stability. These encompass the application of innovative frying methods like vacuum frying, ultrasound-assisted and microwave-assisted frying with hybrid approaches, as well as the use of both natural and artificial antioxidants. Ultimately aims to provide valuable insights and practical recommendations for both consumers and the food industry to optimize frying practices, preserve oil quality and minimise the formation of harmful oxidation byproducts.
Keywords: Oxidative stability, frying, lipid oxidation, mustard oil, groundnut oil, coconut oil, quality preservation