Effect of Olive Oil Adulteration on Peroxide Value, Delta-K and on the Acidity Nabali-Baladi Olive Oil Quality

Abstract

The purpose of the study was to evaluate the effects of olive oil adulteration on the peroxide value and oil acidity, and also to evaluate the effects of the olive oil adulteration on the delta K value, which classifies the purity (grade) of olive oil. The study was begun by collecting several samples of olive oil from northern governorates of Palestine. Also, sunflower, corn, and soybean oil samples were purchased at the local market. Olive oil simples were analyzed for delta K value, peroxide value and acidity. Olive oil samples were analyzed at 232, 268, 270 and 274 nm using UV-VIS instrument. Then, the samples were mixed with other oils at certain ratios and evaluated at the same wavelength. All samples were analyzed using quartz cuvetts. Cyclohexane was used as solvent for the oil. The same samples were evaluated in the same manner by titrating the samples with thiosulfate to get the peroxide value, and also with potassium hydroxide to get the acidity of oils. The IOC standard is <b20 mEq O2 / kg oil. The acidity test ( the IOC standard for free fatty acids in extra virgin olive oil is a maximum of 0.8%.) can differentiate between authentic versus adulterated oil. Reliable technique was used for measuring the authenticity of olive oil.