Effects of Added Phenolics on the Lipid Deterioration and Antioxidant Content of Deep-Fried Potato Fritters

The health benefits of phenolic antioxidants justify their inclusion in foods like deep-fried potato fritters that are exposed to high heat during processing. In this study, phenolic antioxidants [quercetin, rutin or an apple phenolic extract (APE)] were incorporated into batters that were subsequently used in the preparation of deep-fried potato fritters. The fritters were deep fried at 180 °C for 2.5 min or 165 °C for 3 min using fresh or used canola oil. The study aimed to investigate the effect of added phenolic antioxidants on the lipid deterioration during deep frying potato fritters. The effectiveness of these phenolics against lipid deterioration was also examined for the potato fritters that have been left in the air at room temperature for 0.5 or 1 h after deep frying. The total oxidation (Totox) value (based on the peroxide value and p-anisidine value) and free fatty acid content of the oil extracted from the deep-fried potato fritters, as well as the total extractable phenolic content, of the fritters were evaluated. Results showed that APE, quercetin and rutin suppressed oil deterioration to different extents, and their effectiveness was influenced by deep-frying conditions, the number of times the oil had been used and the time period that the fritter was exposed to the air after deep frying. For the fresh or singly used oil, the recommended deep-frying parameters are 180 °C for 2.5 min ("high heat short time" approach). For oil used more than once, deep frying of potato fritters at 165 °C for 3 min ("low heat long time" approach) is generally recommended. Adding phenolics to the batter used for making potato fritters before deep frying increases product nutritional value and reduces oil oxidation, which indicates the feasibility of producing healthier potato fritters. ©Springer Science+Business Media New York 2012.