Oil carries water-insoluble essential elements vital for growth and metabolism, protects brain cells and reduces the risk of heart diseases. It provides essential fatty acids for the human body . However, the fundamental reason for their use in cooking is that they contribute to the flavour and texture of the food, making dishes tasty and giving them a good, smooth mouthfeel . They make baked products crispier and conduct heat while cooking. Thus, oil is an integral part of food preparation. In addition to their culinary applications, oils are utilised for various purposes such as fuel, medical treatments, lubrication, and in the manufacturing of various paints and plastics . They are also used as purifying agents . Lipid-based nanocarriers for pharmaceuticals demonstrate enhanced efficacy compared to conventional drug formulations . soybean oil is the most stable, followed by palm olein and groundnut oil, while, palm kernel oil is the least stable . These results are interesting because soybean oil has higher PUFA (~60%) than palm kernel oil (~15%) and it is documented that oxidative stability of the oil decreases with increase in PUFA content . Thus the results of this paper are contrary to the expectation. A possible differentiating factor may be the presence of antioxidants. However, the paper did not report the antioxidant content of the oils. In a separate study when refined, bleached, deodorised (RBD) palm olein, canola oil, RBD palm olein/sesame oil (1:1 w/w), RBD palm olein/canola oil (1:1, w/w), sesame oil/canola oil (1:1, w/w), and RBD palm olein/sesame oil/canola oil (1:1:1, w/w/w) were heated at 180ºC for five consecutive days; it was discovered that canola oil had the least stability in terms of C18:2/C16:0 ratio and the iodine value. Conversely, the RBD palm olein/canola oil (1:1, w/w) blend shows the best stability . This difference may be due to the difference in the amount of unsaturated fatty acids. The greater the unsaturation in oils, the quicker the oxidation. The rate and amount of primary product formation increase with the increasing levels of unsaturation in oils . This hypothesis was supported by a study on the mono-alkyl esters of different fatty acids, where it was found that even modest amounts of highly unsaturated fatty acid had an inordinately large effect on oxidative stability. The same study also claimed that free acids are less stable than their esters . The negative effect of unsaturation was also supported in a Raman spectroscopic study of the oxidative degradation of edible oils. In this study, sunflower oil exhibited the most significant degradation due to its elevated polyunsaturated fatty acid concentration . Guillaume et.al. also believed that the total concentration of PUFA determines the oil's performance when heated. According to their research, extra virgin olive oil had the highest thermal stability, followed by coconut oil and other virgin oils including avocado and high oleic acid seed oils . In one infrared study, it was found that the spectra of corn oil after boiling or multiple frying with potato produce bands in frequencies range of 2852.7 to 2926.0 cm -1 but for mustard oil, a new peak appears at 3633.8 cm -1 . This difference was possibly due to the formation of different secondary oxidation products . To understand the effect of fatty acid composition on degradation; Wang, T. and Briggs, J.L. artificially modified the fatty acid composition of soybean oils and studied their degradation behaviour by measuring the viscosity and differential scanning calorimetry profile of the oils. The oils investigated include (i) oil with unmodified fatty acid composition, (ii) oil with high-oleic acid, (iii) oil with low saturated fatty acid, (iv) oil with low-linolenic acid and (v) oil from lipoxygenase-free soybean. They found that oil modified to have a high-oleic acid content shows the highest viscosity and viscosity change.