Waterless sterilization of oil palm fruitlets using supercritical carbon dioxide

• Published in: The Journal of supercritical fluids 2017-08, Vol.126, p.65-71
• Main Authors: Mohd Omar, A.K., Tengku Norsalwani, T.L., Abdul Khalil, H.P.S., Nagao, H., Zuknik, M.H., Sohrab Hossain, Md, Nik Norulaini, N.A.
• Format: Article
• Language: English
• Subjects: Microbe inactivation; Oil palm fruitlets; Supercritical carbon dioxide (SC-CO2); Supercritical pressure; Waterless sterilization
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2017.02.019

(a) Untreated oil palm fruits; (b) Isolated lipase producing microbes in untreated oil palm fruits; (c) SC-CO2 sterilized oil palm fruit; (d) Absence of microbes colony in SC-CO2 sterilized oil palm fruit. ▪ [Display omitted] •A waterless sterilization process using Supercritical Carbon Dioxide is proposed.•The waterless oil palm sterilization reduced the generation of POME.•SC-CO2 can inactivate the microbes and enzyme that caused palm oil degradation.•The optimum parameters of SC-CO2 sterilization are 10MPa, 80°C and 60min. Conventionally, oil palm fruits (OPF) are sterilized using steam which generates huge amount of palm oil mill effluent (POME). This study focuses on inactivating the lipase-producing microbes (LPM) in OPF using supercritical carbon dioxide (SC-CO2), thus preventing formation of free fatty acids. Pressure, temperature and sterilization time were studied for optimum sterilization conditions by measuring the reduction of microbes before and after treatment of OPF using SC-CO2 and autoclave. Sterilizing OPF with SC-CO2 resulted in major changes in the physical, fruit surface and texture when compared to autoclave. The optimum parameters for complete microbe inactivation were pressure “10MPa” temperature “80°C” and sterilization time “60min”. The findings reveal that the SC-CO2 could be a potential technique to inactivate the LPM in OPF. POME generation from the palm oil mills could be put to an end by replacing the steam sterilization technology with moderate temperature and pressure of SC-CO2.