The frying stability comparison of refined palm oil, canola oil, corn oil, groundnut oil, and sunflower oil during intermittent frying of french fries

Intermittent frying deteriorates frying oil faster than continuous frying due to higher oxidation and hydrolysis rates. This research aims to determine the maximum frying cycles of selected refined vegetable oils namely canola oil (CA), corn oil (CO), groundnut oil (GO), palm oil (PO), and sunflower oil (SO) during intermittent frying of french fries. Frying oil was collected at every 8th interval of the frying cycle and accessed in terms of acid value (AV), peroxide value (PV), p-anisidine value (p-AnV), and TPC of all frying oils. Regression analysis shows that these chemical tests exhibit a positive correlation with the frying cycle. PO and CA reached the maximum limit (TPC > 25%) around 60th to 61st frying cycle whereas the disposal points of CO and SO were at the 56th frying cycle. At the 60th frying cycle, GO has the lowest TPC values, recorded at 24%. Both GO and PO showed comparable oxidative stability during frying based on their significantly lower total oxidation value, TPC and FFA. By contrast, CA and CO showed moderate values for all chemical indices while SO had the highest deterioration rate among all samples. In future, a comprehensive study on the deterioration mechanism of frying oil and fried sample are highly recommended for frying safety assessment.