Palm-pressed fibre oil (PPFO) is residual oil extracted from palm pressed mesocarp fibre (PPMF) after the extraction of crude palm oil (CPO) from the digested palm fruits using screw press. PPMF contains substantial amount of residual oil (5%-8%), which is commonly utilised as boiler fuel for palm oil mill operations. Several techniques can be employed to recover the residual oil in PPMF, namely solvent extraction by hexane, enzymatic treatment, supercritical carbon dioxide (SC-CO2) and remnant oil recovery (ROR) system (Lau et al., 2006; Vijaya et al., 2013; Noorshamsiana et al., 2017; Nur Sulihatimarsyila et al., 2019). In Malaysia, solvent extraction using hexane is widely used to recover oil from PPMF.

To date, PPFO does not belong to any oil classification set by the Malaysian Palm Oil Board (MPOB). It is automatically classified as sludge oil, which is the lowest quality of palm oil grade, and sold at lower price than CPO. Consequently, palm oil millers tend to blend PPFO into CPO to increase oil extraction rate (OER), but this practice is not recommended by the Code of Good Milling Practice of Palm Oil Mills (GMP) as it will deteriorate the oil’s quality. This paper intended to investigate the effect of blending various dosages of PPFO into CPO on the quality of the blended oils.