In this study, 23 biodiesel samples were produced, 20 from used cooking oil and the remaining 3 from refined soybean oil. The following properties were determined in all of the samples (oil and its respective biodiesel): density; viscosity; total acid number and ASTM color. The results indicated high correlation (R > 0.6) between ASTM color of used cooking oil and total acid number of its resultant biodiesel. This high correlation allows prediction of the quality of the biodiesel produced using a simple and fast procedure such as ASTM color.
biodiesel; used cooking oil; ASTM color
