Quality Changes of Common Edible Frying Oils during Frying of Traditional Foods

Abstract

This study aimed to examine the impact of the frying process on the physical and chemical properties of widely consumed edible oils. Soybean, palm, and mustard oils, as well as raw dulpuri and singara products, were procured from the nearby marketplace. The oils underwent five consecutive frying cycles at temperatures exceeding 160°C and were subjected to five hours of heating. Analyses including determination of free fatty acid (FFA), peroxide value (PV), saponification value (SV), iodine value (IV), and optical density (OD) at a wavelength of 425 nm were performed. Following multiple rounds of frying and heating, the levels of FFA, PV, and oxidative stability index exhibited an increase, whereas the IV demonstrated a decrease across all three types of oils. The OD of soybean and palm oils exhibited an upward trend, whereas that of mustard oil initially displayed a decline, followed by a gradual ascent. In comparison to soybean and mustard oils, palm oil exhibited the most noteworthy escalation in FFA, PV, SV, and OD parameters. The levels of FFA, PV, SV, and oxidative stability in palm oil exhibited an increase from 0.23 to 2.6 mg KOH/g sample, 5.0 to 10.2 m.eq/kg, 195 to 206 mg KOH/g sample, and 0.37 to 0.85, respectively. Conversely, IV decreased from 51 to 43 g I2/100 g. Sensory evaluation revealed that the palatability of food items fried in palm oil and soybean oil was comparable, with the products fried in mustard oil being ranked lower in terms of acceptability.