A) Frying of potato chips in a blend of canola oil and palm olein:
changes in levels of individual fatty acids and tocols

Mohammed Al-Khusaibi, Michael H.Gordon, Julie A. Lovegrove & Keshavan Niranjan

Abstract: The changes occurring in the levels of nutritionally relevant oil components were assessed during repeated frying of potato chips in a blend of palm olein and canola oil (1:1 w⁄ w). The blend suffered minimal reductions in omega-3 and omega-6 polyunsaturated fatty acids. There was no significant difference between the fatty acid composition of the oil extracted from the product and that of the frying medium, in all three cases. The blend also contained a significant amount of tocols which add nutritional value to the oil. The concentration of the tocols was satisfactorily retained over the period of oil usage, in contrast to the significant loses observed in the case of the individual oils. The blend also performed well when assessed by changes in total polar compounds, free fatty acids, p-anisidine value. When fried in used oil, the product oil content increased progressively with oil usage time. This study shows that blended frying oils can combine good stability and nutritional quality.

Source : International Journal of Food Science and Technology,  47: 1701–1709, 2012

B) Performance of Palm Olein and Soybean Oil during the frying of French fries and its effect on the characteristics of the fried product
Laura Natalia Fernandez-Cedi, Blanca E. Enriquez-Fernandez, Liliana Alvarez De La Cadena Y Yanez and Maria Elena Sosa-Morales.
Abstract: Performance of soybean oil and palm olein during the deep-fat frying of 45 batches of frozen prefried french fries was studied. The peroxide index increased faster for the soybean oil, with a final value of 12 meq/kg. Free fatty acids increased with the number of fried batches and were higher in the palm olein. Total color change was more noticeable in soybean oil in comparison to the palm olein. Viscosity, total polar compounds, and p-anisidine values increased and were higher in soybean oil. A reduction of unsaturated fatty acids was observed from the chromatography analysis. Elaidic and linoelaidic acids, which are trans-fatty acids, had higher concentrations in degraded soybean oil. Palm olein was more stable than soybean oil under the conditions of this study and produced french fries with a lower oil content.

Source: Journal of Culinary Science & Technology, 10:211-222, 2012

Comments: The above are 2 recent studies, examining palm olein’s frying performence. Study A looked at the performence of palm olein/canola blend while study B compared the frying performence of palm olein and soybean oil.
Over the years, many frying studies comparing palm olein (liquid fraction of palm oil) with other types of edible oils has been undertaken to examine their stability at high frying temperature. In those studies, more often than not, palm olein surpassed the other edible oils in terms of its frying performance. Consistent with previous evaluations, study B, which compared the frying performance of palm olein against soybean oil showed very similar outcomes.  The key factor which is responsible for palm olein’s superior frying performance is its stability at high frying temperature. It does not easily breakdown and produce by products of oil deterioration.