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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Bio-oils Research » Research » Publications at this Location » Publication #343856
Research Project: Value-added Bio-oil Products and Processes

Location: Bio-oils Research

Title: A greener alternative titration method for measuring acid numbers of fats, oils, and grease

Author
item ZHANG, JUNSONG - University Of Cincinnati
item LU, MINGMING - University Of Cincinnati
item REN, FUMIN - Beijing Jiaotong University
item Knothe, Gerhard
item TU, QINGSHI - University Of Cincinnati

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2019
Publication Date: 8/27/2019
Citation: Zhang, J., Lu, M., Ren, F., Knothe, G., Tu, Q. 2019. A greener alternative titration method for measuring acid numbers of fats, oils, and grease. Journal of the American Oil Chemists' Society. 96(10):1083-1091. https://doi.org/10.1002/aocs.12281.
DOI: https://doi.org/10.1002/aocs.12281

Interpretive Summary: Many vegetable oils, fats or greases used for making various products such as biodiesel or lubricants contain minor constituents known as free fatty acids. These fatty acids influence properties and affect the making of products such as biodiesel. Therefore, it is essential to know how much free fatty acids are contained in a fat, oil or grease. This work describes an improved method for analyzing these free fatty acids. The new method is "greener" and also more economical because it eliminates the use of a hazardous solvent known as toluene. The new method is comparable in its accuracy to existing methods.

Technical Abstract: A greener method is proposed for measuring acid values (AV) of fats, oils, and grease (FOG) based on visual titration. Compared with Official Method Cd 3d-63 of the Amerian Oil Chemists' Society (AOCS), this greener alternative method can eliminate the use of toluene, which in turn reduces toxicity and cost. A total of 44 samples of yellow and brown grease with AV ranging from 0.13 to 170.37 (mg KOH)g-1 were titrated using both methods. The alternative titration method can provide accurate and reliable results to determine AV of FOG by various statistical analyses including repeatability, linear regression, f-test, t-test, and method accuracy calibration with AOCS Cd 3d-63. This low-cost method can be recommended for routine titration in research and development, and in biodiesel plants for most FOG samples.