ABSTRACT: Because of the high level of chlorophyll-type com- pounds found in canola oil, bleaching is an important and criti- cal step in the canola oil refining process. In this study, a new method for reducing the chlorophyll-type impurities prior to the bleaching step was developed. This method is based on precipi- tating the chlorophyll compounds with mineral acids. Concentra- tions of chlorophyll-type compounds of up to 30 ppm could be reduced to amounts of less than 0.01 ppm by mixing the crude canola oil with a 0.4 wt% mixture of phosphoric and sulfuric acids (2:0.75, vol/vol) for 5 min at 50°C. Centrifugation and filtra- tion also were examined as two main methods for separating the chlorophyll precipitates. The results showed that filtration by a precoated textural filter with filter-aid clay could separate the pre- cipitates as well as the centrifugation method. Paper no. J10858 in JAOCS 82, 679–684 (September 2005). KEY WORDS: Bleaching, canola oil, chlorophyll, mineral acid. Canola is one of the most important oilseed crops in the world. Research indicates that the FA composition of canola oil is es- pecially favorable in terms of health benefits when used as part of a nutritionally balanced diet: It has a very low concentration of saturated fat (only 7%), is relatively high in monounsatu- rated fat, is among the highest in n-3 FA (10–11%), and con- tains a moderate level of polyunsaturated fat (32%). Canola oil is also a rich source of the antioxidant vitamin E. In addition, canoloa meal is an important source of protein in animal feeds (1–4).The pigments present in canola and other oilseeds are im- portant factors, as they can impart an undesirable color to veg- etable oils, promote oxidation in the presence of light, and in- hibit the catalysts used for hydrogenation (5–7). The chloro- phyll content in canola oil is significantly higher than those found in other vegetable oils and presents one of the biggest quality impediments for the canola oil industry (8). The re- moval of high levels of chlorophyll pigments from canola oil (50–60 ppm) requires large quantities of bleaching clays, re- sulting in high processing costs and significant losses of oil through adherence to the clays (9,10). Therefore, a cost-effec- tive process for treating the oil extracted from canola seeds is needed to produce purified and degummed oil with low amounts of these chlorophyll-type compounds (9). The main reason high levels of chlorophyll are present in rapeseed is that the seed freezes before it has significantly ma- tured (9,11). Chlorophyll and chlorophyll-type compounds in the seed are mostly converted to pheophytin during the seed- conditioning step that occurs before oil extraction. Pheophytin is the main chlorophyll species present in crude and degummed oil (9). Because chlorophyll-type compounds are oil soluble, when the oil is extracted, it retains a green color, the intensity being proportional to the concentration of chlorophyll in the seed (12). Treating oil with mineral acids, such as phosphoric and sulfuric acids, cleaves the phytol group from the pheo- phytin molecules to form pheophorbide. The pheophorbide be- comes protonated under highly acidic conditions and separates from the oil. Pheophorbide in its natural form is not water sol- uble, but treatment of its protonated form with a caustic, such as sodium hydroxide, causes the pheophorbide to be converted to sodium pheophorbide and become soluble in water (9). Thus, the pheophorbide can be separated from the oil before the neutralization step. This paper examines several treatments of canola oil (con- taining up to 30 ppm chlorophyll-type compounds), with an emphasis on the process fundamentals of conventional refining required to reduce the level of chlorophyll-type impurities prior to the bleaching step. In this study, most of the operating pa- rameters were optimized. As used herein, the term “chloro- phyll-type compounds” refers to chlorophyll compounds mea- sured as chlorophyll a by an automated PFX-990 Lovibond Tintometer. MATERIALS AND METHODS Materials. Rapeseed oils with chlorophyll contents ranging from 10 to 30 ppm were obtained from Behshahr Ind. Co. (Tehran, Iran). A bleaching earth, Tonsil Optimum 233, was purchased from Sue Chemie Co. (Jakarta, Indonesia). A filter- aid clay (Decalite clay) was obtained from Inorganic Ind. Co. (Tabriz, Iran). All chemical materials, including p-anisidine, acids, caustic solutions, reagents, and solvents, were of analyti- cal grade and were obtained from Merck Co. (Darmstadt, Ger- many). TBHQ was purchased from Sinochem Tianjin Import & Export Corporation (Tianjin, China). Textural filters were obtained from Omid Co. (Tabriz, Iran). Methods. Crude canola oil (500 g) and a mixture of sulfuric (98%) and phosphoric (85%) acids in ratios of 4:1 to 2:1 (vol/vol) at concentrations of 0.25 to 0.4 wt% were mixed with a mechanical stirrer at a speed of 200 rpm, at 50°C, for controlled times, which is also an important parameter for precipitating the chlorophyll-type compounds from the oil. The precipitates were Copyright © 2005 by AOCS Press 679 JAOCS, Vol. 82, no. 9 (2005) *To whom correspondence should be addressed at Research and Develop- ment Laboratory of Savola Behshahr Ind. Co., 8th Km Fath Rd., Tehran, Iran. E-mail: e_sabbaghian@yahoo.com or Bahmaei@SBC.ir Development of a Method for Chlorophyll Removal from Canola Oil Using Mineral Acids Manochehr Bahmaei a , Elham sadat Sabbaghian b, *, and Ebrahim Farzadkish b a Islamic Azad University, North Tehran Branch, Tehran, Iran and b Research and Development Laboratory of Savola Behshahr Ind. Co., Tehran, Iran