dry fractionation – Journal of Oil Palm Research

PECULIAR CRYSTALLISATION BEHAVIOUR OF PALM OIL DURING DRY FRACTIONATION

mpob_admin — Wed, 19 Oct 2022 02:30:50 +0000

Multi-step dry fractionation of palm oil generates fractions with specific physicochemical properties suitable for many food formulations. The present study addresses the pilot scale production of palm olein iodine value 56 starting from palm oil. The aim was to investigate the influence of the tri-saturated triacylglycerol content (StStSt) in palm oil on its crystallisation behaviour. Four StStSt contents were investigated: 7.0%, 7.6%, 8.2% and 9.8%, and the palm oil crystallisation was examined during a period of 240 min. Oil temperatures were recorded, and crystallisation kinetics were monitored by p-NMR; crystal morphology and polymorphic forms were characterised by optical microscopy and powder X-ray diffraction. One of the compositions (StStSt: 7.6%) was crystallising faster. All the crystallised matrices were filtered at 25°C with a membrane press filter; the olein yields, iodine values, cloud points and triacylglycerol compositions were analysed. The olein from the matrix crystallising faster showed a yield, an iodine value and a cloud point higher than expected. A more detailed HPLC analysis of this olein indicated unusual enrichment in OPP and depletion in OPO, which led to the conclusion of an unusual crystallisation behaviour at this specific composition.

IMPROVED SUSTAINABLE FRACTIONATION OF PALM OIL USING POLYGLYCEROL FATTY ACID ESTERS

mpob_admin — Sat, 13 Nov 2021 08:10:21 +0000

A series of GRAS polyglycerol esters (PGE) has been produced and investigated for improving the dry fractionation of palm oil. Results show that the hydrophobic PGE can reduce the fractionation time and hence the energy consumed during fractionation. This will help to increase throughput for the process and the overall carbon footprint as a result of reducing energy use in the process. The fractionated oleins also exhibited better cloud points of between 7°C and 8°C, and an average iodine value of 57 Wijs. Crystal size was observed to be homogeneous, with the majority of the crystal sizes being in the range of 100 to 300 microns. It was also observed that this crystal size posed no filtration difficulty, as evidenced by the 76% to 78% olein yield obtained during pressing with a squeezing pressure of 5 bars. The stearins obtained were medium hard with iodine values between 33 and 35 Wijs, and slip melting points between 52°C and 53°C.

X-RAY DIFFRACTION ANALYSIS OF PRODUCTS OBTAINED BY DRY FRACTIONATION OF PALM OIL

mpob_admin — Sat, 13 Mar 2021 16:18:40 +0000

Palm oil was dry fractionated by four different methods, namely (1) cooling at 30ºC and (2) at 23ºC for 18 hours with no agitation, (3) cooling at 3ºC for 18 hours with agitation and (4) at 22ºC for 3 hours with agitation. The yields of stearin were 16%, 30%, 26% and 32% respectively. Filtration rates were good when fractionation took place with no agitation but were poorer with agitation. X-ray analysis showed the stearins from methods 1, 2 and 4 to be in the beta-prime form while that from method 3 was in the beta form. These polymorphic forms were stable when the stearins were stored up to 12 days. When the stearins from methods 1 and 2 were tempered at 40º and 45ºC the polymorphic form changed to the beta form. When melted and then crystallized at 0ºC all the stearins crystallized in the beta-prime form. A hydrogenated palm oil crystallized in the alpha form under these conditions.

The short spacing of the beta-prime form of palm oil and palm products is unique in that it shows two distinct lines of strong intensity at 0.43 and 0.41 nm as opposed to one at 0.42 nm reported in other fats. The softening points of the stearins correlated with the C48 triglyceride content but the dropping points did not.