Contents I. Introduction
Olive oil is the most expensive edible oil product. Since it highly contains much nutrition that can lower the risk of heart diseases and provide numerous health benefits [1]. Olive oil is the common edible oil product which is being adulterated by a cheaper substance such as lard or soybean oils. Some cases of olive oil fraud were reported since 1993–2015. In 1993, the Food and Drug Administration (FDA) found that oil made of pure canola oil branded as olive oil [2]. In 2013, soya bean oils added with the food coloring were sold as extra virgin olive oils [3]. In 2014 and 2015, mixed refineries oil added with natural food coloring misbranded as olive oils [4]–[5]. Besides, animal-based fats are widely used to increase the apparent value of edible oil and oil-based products. Vegetable oils commonly blended with lard to produce soft margarine, butter, or shortening [6]. The aim of the oil adulteration is to lower production costs and to increase the apparent value. The addition of lard substance in olive oil causes the change in the unsaturated fatty acid compositions in olive oil. It leads to some health issues such as allergy, atherosclerosis, and coronary heart disease. It may also lead to death [7]. Hence, the oil authentication system is important to prevent oil fraud particularly to detect lard substance. In an authentication system, a sensor or detector is the main important components.
