Oleic Acid Enhancement in Used Frying Palm Oil via Enzymatic Acidolysis

Abstract

The extensive amount of used frying palm oil (UFO) generated in Malaysia has caused serious environmental problems. Management of the waste faces a significant challenge especially on choosing the appropriate method by considering the possibilities of contaminating the environment. This study aims to add value to UFO by producing high oleic palm oil. Enzymatic acidolysis using lipase was employed to incorporate oleic acid in the UFO. This study also investigated the effect of enzymatic loading, reaction time and water content on the properties of modified UFO as to find the optimum condition for oleic acid incorporation. Oleic acid incorporation was quantified based on peroxide and iodine values. The optimum conditions for acidolysis process were obtained at enzyme loading of 30% (w/w), reaction time of 24 hours, and water content of 2% (w/w) with substrate mole ratio of 1:2 (UFO: oleic acid) and temperature of 50 °C. At optimum conditions, the modified used frying palm oil (MUFO) has peroxide and iodine values of 19.00 ± 0.99 meq/mg and 31.5 ± 0.42 mg/mg, respectively. After the acidolysis reaction, oleic acid concentration has increased from 27.00 ± 0.70% (v/v) to 62.34 ± 1.29% (v/v), demonstrating their feasibility as a substrate for structured lipid production.

Enzyme Kinetic of Lipase Catalysed Acidolysis of Used Cooking Palm Oil

“…The enzyme activity of C. rugosa lipase was determined using olive oil and gum arabic as substrates (Zaharudin et al, 2018;Ifeduba and Akoh, 2014). 5 g of olive oil and 1 g of gum arabic were stirred continuously in a 250 ml conical flask containing 100 ml of sodium phosphate buffer.…”

“…Finally, the sample mixture was titrated with 0.1 N sodium thiosulfate. The endpoint of the titration was from brownish red to colourless (Zaharudin et al, 2018). The iodine value was calculated using the equation below:…”

“…The mixture was titrated with standard potassium hydroxide (KOH) with three drops of phenolphthalein as an indicator. The endpoint of the titration was from pink to cloudy or colourless (Zaharudin et al, 2018). The acid value was calculated using the equation as shown below:…”

“…The higher AV of UCPO compared to FPO was attributed to an increase in fatty acid content during the frying process (Yusuff et al, 2021). The frying process generally raptures the TAG double bond structures and initiates oxidative alteration (Zaharudin et al, 2018). Manzoor et al (2022) specified the increase in the decomposition of double bonds associated with the length of frying time.…”

“…UCO was produced mainly from a variety of sources such as households, restaurants, catering establishments, hotel chains, fast food outlets, and industrial kitchens. An approximate 50,000 tons of UCO are reportedly disposed of without proper treatment in Malaysia (Zaharudin et al, 2018). Since UCO can block collection pipes and create sanitary sewage overflow, they cannot be released directly into the environment or wastewater as waste (Moazeni et al, 2019).The demand for vegetable oil increases each year and the most widely used vegetable oil is palm oil, which is commonly used in Africa, South America, and South East Asia countries.…”