title: Palm-based medium-and-long-chain triacylglycerol (P-MLCT): production via enzymatic interesterification and optimization using response surface methodology (RSM).
abstract: Structured lipid such as medium-and long-chain triacylglycerol (MLCT) is claimed to be able to suppress body fat accumulation and be used to manage obesity. Response surface methodology (RSM) with four factors and three levels (+1,0,-1) faced centered composite design (FCCD) was employed for optimization of the enzymatic interesterification conditions of palm-based MLCT (P-MLCT) production. The effect of the four variables namely: substrate ratio palm kernel oil: palm oil, PKO:PO (40:60-100:0 w/w), temperature (50-70 °C), reaction time (0.5-7.5 h) and enzyme load (5-15 % w/w) on the P-MLCT yield (%) and by products (%) produced were investigated. The responses were determined via acylglycerol composition obtained from high performance liquid chromatography. Well-fitted models were successfully established for both responses: P-MLCT yield (R (2) = 0.9979) and by-products (R (2) = 0.9892). The P-MLCT yield was significantly (P < 0.05) affected by substrate ratio, reaction time and reaction temperature but not enzyme load (P > 0.05). Substrate ratio PKO: PO (100:0 w/w) gave the highest yield of P-MLCT (61 %). Nonetheless, substrate ratio of PKO: PO (90:10w/w) was chosen to improve the fatty acid composition of the P-MLCT. The optimized conditions for substrate ratio PKO: PO (90:10 w/w) was 7.26 h, 50 °C and 5 % (w/w) Lipozyme TLIM lipase, which managed to give 60 % yields of P-MLCT. Up scaled results in stirred tank batch reactor gave similar yields as lab scale. A 20 % increase in P-MLCT yield was obtained via RSM. The effect of enzymatic interesterification on the physicochemical properties of PKO:PO (90:10 w/w) were also studied. Thermoprofile showed that the P-MLCT oil melted below body temperature of 37 °C.
authors.affiliation: Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia.
authors.forename: Yee-Ying
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia.
authors.forename: Teck-Kim
authors.initials: TK
authors.lastname: Tang
authors.affiliation: Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia.
authors.forename: Eng-Tong
authors.initials: ET
authors.lastname: Phuah
authors.affiliation: Sime Darby Research Sdn Bhd, R&D Carey Island-Upstream, Lot 2664 Jln Pulau Carey, 42960 Carey Island, Selangor Malaysia.
authors.forename: Nur Azwani Ab
authors.initials: NA
authors.lastname: Karim
authors.affiliation: Sime Darby Research Sdn Bhd, R&D Carey Island-Upstream, Lot 2664 Jln Pulau Carey, 42960 Carey Island, Selangor Malaysia.
authors.forename: Siti Maslina Mohd
authors.initials: SM
authors.lastname: Alwi
authors.affiliation: Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia ; Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia.
authors.forename: Oi-Ming
authors.initials: OM
authors.lastname: Lai
keywords: Interesterification; Medium-and long-chain triacylglycerol (MLCT); Palm kernel oil; Palm oil; Response surface methodology (RSM); TLIM lipase