Improving Waste Cooking Oil Quality for Biodiesel Production with the Ethanolic By-product of Soybean Oil Extraction

Author(s)

Bueno-Borges, Larissa Braga ^[1] ; Pereira dos Santos, Grasiela Cristina ^[1] ; de Alencar, Severino Matias ^[2] ; Bismara Regitano-d'Arce, Marisa Aparecida ^[1]

Affiliation

^[1] Univ Sao Paulo, Lab Oils & Fats, Dept Agrifood Ind Food & Nutr, Luiz de Queiroz Coll Agr, Av Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Sao Paulo, Lab Biochem, Dept Agrifood Ind Food & Nutr, Luiz de Queiroz Coll Agr, Av Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY; v. 96, n. 12, p. 1379-1388, DEC 2019.
• Web of Science Citations: 0

Abstract

Waste cooking oils (WCO) can be used as feedstock for biodiesel (fatty acid ethyl or methyl esters-FAEE or FAME) production. Their usual high acidity, high moisture, and low stability can impair the reaction yield and generate a low-quality biodiesel. Here, we performed liquid-liquid washings using WCO and ethanol-based solvents with the goal of generating oil-rich miscella as FAEE feedstocks with a higher quality than WCO. Three different solvents were evaluated: 99% ethanol, 95% ethanol, and the soybean oil extraction ethanolic phase (SEP), a by-product with immense unexplored antioxidant potential obtained by extracting soybean oil using ethanol. Washings were performed in a 1000 mL flat-bottom flask at 78.1 degrees C, using a 1:2 (w/v) oil/solvent ratio, under magnetic stirring (1200 rpm) for 10 min. Ethyl esters were prepared via homogeneous alkali transesterification using WCO and oil-rich miscella as feedstocks. Treatments reduced the acid value by 40-61% and the peroxide value by 15-50%. Improvements in feedstock quality generated 24-54% higher biodiesel yields. The oil-rich phase produced with SEP was 15% more resistant to oxidation than WCO. This was attributed to the transference of isoflavones from the SEP. However, biodiesel from treated samples presented equal or lower oxidative stability than FAEE from WCO. High-performance liquid chromatography (HPLC) analysis showed that no isoflavones remained in biodiesel after purification. Pretreatment of WCO with ethanol-based extracts such as the SEP has great potential to improve WCO quality for biodiesel production as it can be a source of plant-based antioxidants. (AU)

• FAPESP's process: 17/02819-8 - Development of a decontamination protocol for Rancimat equipment's components
• Grantee: Marisa Aparecida Bismara Regitano d'Arce
• Support Opportunities: Regular Research Grants