Deep Fat Frying of French Fried Potatoes in Palm Oil and Vegetable Oil

Desanka Rade*, Željko Mokrovčak, Dubravka Štrucelj

Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia

Article history:
Received February 17, 1997
Accepted March 21, 1997

Key words:
deep fat frying, palm oil, oxidative stability, vegetable oil

Summary:
Degradation of palm oil and vegetable oil (a blend of about 80% rapeseed and 20% soybean oil) during deep fat frying of French fried potatoes was investigated. French fries were fried in household fryer in two stages: the blanching was carried out at 160 °C for 5 min and final frying at 180 °C for 4 min. The oil samples were analyzed for free fatty acids, peroxide value, iodine value, p-anisidine value and polar compounds. The oxidative stability (oven test at 98 °C) for palm oil and some vegetable oils (soybean, rapeseed, sunflower oil and a blend of 80% rapeseed and 20% soybean oil) was determined. Free fatty acids increased during frying, but there was no significant difference between the examined oils, and the final content was below 1%. The mass fraction of polar compounds zvas about 26% in vegetable oil, and about 17% in palm oil after 44-hour frying. Anisidine value increased more rapidly in vegetable oil than in palm oil. The best oxidative stability between examined oils was expressed by palm oil, and the least by sunflower oil.