Experimental investigation of processing parameters and effects of degumming, neutralization and bleaching on lampante virgin olive oil's quality

• DOI: 10.1016/j.fbp.2015.02.002
• Publication Date: 2015-02-24T01:10:35Z
• Authors: Fatma Marrakchi; Karim Kriaa; Bilel Hadrich; Nabil Kechaou
• Keywords: Phosphoric acid; Refining (metallurgy)

Abstract The refining of crude oil is a purification process which aims to yield a high amount of triglycerides and to produce an acceptable refined oil quality. This work focuses on two topics: (1) the comparison of adsorption performance of four clays having different activation levels (Ads1, Ads2, Ads3, and Ads4) and (2) the identification of the effective factors using a fractional factorial design method of lampante virgin olive oil refining processes involving degumming, neutralization, and bleaching. The effects of the phosphoric acid concentration, ratio (acid/oil), degumming contact time, neutralizing agent excess, earth clay dosage, contact time and temperature of bleaching step were investigated through the determination of residual phospholipids content, free fatty acid percentage, oxidative stability, color, and trans fatty acids content. Based on adsorption isotherms, Ads1 is selected as the adequate clay contributing to color reduction with low formation of oxidation products. The results of a 2 III 7 − 4 model showed that the strength and the amount of phosphoric acid, and the bleaching parameters were the principal factors that controlled bleached oil quality. Residual phospholipids and acidity decreased as degumming agent increased. Additionally, the bleaching parameters were found to significantly affect the lovibond scale and oxidative stability.