Effect of Sterilisation Time on the Physicochemical Properties of Palm Oil Produced in a Special Palm Oil Plant

Crude palm oil produced by small and medium scale palm oil mills is often of varying quality due to inadequate process control, particularly during sterilisation. The current research assessed the impact of sterilisation time on the efficiency and quality of crude palm oil extracted from the new Special Palm Oil (SPO) mill built at the Obafemi Awolowo University Teaching and Research Farm in Ile-Ife, Nigeria. Fresh fruit bunches were subjected to two sterilisation times: Sample A - 45 minutes and Sample B - 60 minutes, while maintaining a pressure of 5 bar. The parameters like oil yield, extraction percentage, free fatty acids, moisture content, solids, viscosity, and carotenoid content were found and compared to those of selected commercial palm oil samples. The study showed that increasing the sterilisation time from 45 to 60 minutes marginally increased the yield from 17.22% to 17.43%, while extraction efficiency increased moderately from 86.0% to 87.17%. Oils from the SPO plant had low FFA contents (2.44 to 2.51%), low moisture contents (0.90 to 1.21%), lower impurities (2.31–2.6), acceptable viscosity (562.1 to 641.2 mPa· s), and high carotenoid retention (654.52 to 657.83 mg kg-1). In contrast, market samples had higher free fatty acid (FFA) levels, moisture content, and impurities (7.52%–29.42%, 1.09%–1.62%, and 1.21%–7.22%, respectively), suggesting poor processing and storage practices. The quality of crude palm oil produced at the SPO plant was in accordance with Codex Alimentarius and Nigeria Industrial Standards. The experiment demonstrates that a 45-minute sterilisation process yields oil quality comparable to that achieved with a 60-minute process. These findings underscore the importance of advanced processing systems for enhancing palm oil quality, ensuring food safety, and increasing post-harvest value.