Changes in Characteristics of Palm Oil During Vacuum and Atmospheric Frying Conditions of Sweet Potato

Abstract

The qualities of fried palm oil used under two different sets of frying conditions with sweet potato chips were investigated. The study investigated the effect of vacuum and atmospheric pressure on the total polar compounds (TPC), viscosity, color, acid value and peroxide value of the oil samples. The oil qualities after vacuum frying were studied for 8 h d^-1 for eight consecutive days. The results showed that the TPC reached 12.75%. Viscosity was in the range of 71.13-72.13 cP and the acid value was 0.46 mg KOH/g. The peroxide value gradually increased over the first 4 d and then decreased. The L* value decreased with longer frying time, while a* and b* values increased. The oil qualities of atmospheric frying for 8 h d^-1 for six consecutive days revealed a high percentage of TPC (25.25%); viscosity also increased to 92.35 cP. The acid value was at 1.23 mg KOH/g and the peroxide value increased in the first three days, then decreased. The L* value decreased, while a* and b* values were higher on the first day of frying and leveled off afterward.