Palm Oil Engineering Bulletin No.132 (Jul - Sept 2019) p18-23
Effect of Double Roll Crusher Complete with Preheating on Bruising Level and Free Fatty (FFA) Acid Content of Oil Palm Fruit Bunches
Che Rahmat Che Mat*; Andrew Yap Kian Chung*; Rohaya Mohamad Halim*; Nu’man Abdul Hadi* and Ummi Kalsum Hasanah Mohd Nadzim*

In conventional milling process, fresh fruit bunches (FFB) is sterilised using pressurised batch steriliser utilises 40-45 PSI saturated. The heating condition is crucial to ensure adequate steam penetration into inner layers of the compact bunches in order to duly condition the fruitlets. The sterilisation process usually needs 90-120 min and prolonged heating induces adverse effect on the crude palm oil (CPO) quality. In order to enhance steam penetration, bunch crushing approach has been explored. Experimental results showed that bunch crushing increases the fruit bruising level significantly which promotes free fatty acids (FFA) formation due to lipase catalyst. However, empirical data demonstrated that 5 min of preheating after bunch crushing inhibits the FFA formation effectively and could last for 60 min. Thus, the new approach to crush open FFB during conventional horizontal sterilisation is feasible. The atmospheric saturated steam heating (1 bar) facilitates steam penetration into FFB and hence reduce oil losses due to high unstripped bunches and kernel losses from improper nut conditioning.

Author information:
*Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. E-mail: