Composition and thermal profile of crude palm oil and its products

Comparative analysis of triacylglycerol composition, melting properties and polymorphic behavior of palm oil and fractionsPalm oil is without doubt the most widely fractionated oil. Dry fractionation is based on differences in the melting points of triacylglycerols (TAG) which will crystallize selectively during the cooling process. Unfortunately, limitations due to intersolubility, closely linked to polymorphism, induce formation of co-crystals at each crystallization step. For this reason, only restricted TAG enrichments are observed. In this work, a series of samples (24) of palm oil, solid and liquid fractions (stearins, mid fractions, oleins and superoleins) have been selected and examined in terms of TAG composition (by HPLC), differential scanning calorimetry (DSC) melting profile and variable temperature powder X-ray diffraction pattern. Three major endotherms [low-melting, highmelting and very high-melting peaks (LMP, HMP and VHMP)] are detected in the DSC melting profiles (5 7C/min). The VHMP is only recorded for palm stearin which contains more SSS components. The HMP contribution is weak for palm olein and even not observed for palm super oleins. The LMP is usually made up of UUU, SUU and SUS components; SUS components are observed in both LMP and HMP; the HMP is also made up of some SSS, except for palm oleins and super oleins. Sub-a 2 , sub-a 1 , a, b' 2 , b' 1 and b polymorphic forms are recorded; the LMP components preferentially crystallize in sub-a 2 , sub-a 1 and a forms; the HMP components generally crystallize in b' 2 and b' 1 , with a tendency to exhibit b crystals, depending on the SSS content. Components of the VHMP have an increased tendency to stabilize in the b form; in view of the results, we can assume that there is a clear relationship between TAG composition, melting properties and polymorphic behavior and of palm oil and fractions.

Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Comparative analysis of triacylglycerol composition, melting properties and polymorphic behavior of palm oil and fractions

Danthine

Gibon²

2007

“…The main triacylglycerols in palm oil are POP and POO, together amounting to 55%, followed by PLO at 9% and PPP at 6%. Origin and extraction conditions can cause some variability between palm oils [1,2]. Upon cooling the melt below a certain cut-off temperature, palm oil will crystallize into the a-polymorph, with crystals consisting mainly of MMM, PPP, PPS, POS and POP.…”

Section: Introductionmentioning

confidence: 99%

Influence of shear flow on polymorphic behavior and microstructural development during palm oil crystallization

Graef

Puyvelde

Goderis

et al. 2009

The influence of shear on the crystallization of palm oil was studied at four different crystallization temperatures (18, 20, 22 and 25 degrees C). Time-resolved X-ray analyses were carried out to study the effect of continuous shear on the crystallization kinetics of the fat. Rheological measurements were used to assess the effect of a shear step on crystallization, and finally polarized light microscopy was used to follow changes in microstructure due to the applied initial shear step. It was shown that shear enhanced the primary crystallization, even when low shear rates were applied for a short period. Furthermore, a shear step prior to crystallization without shear has a marked influence on the microstructural development

“…The CPO consists of about 50% saturated and 50% unsaturated FA. FA and TAG compositions of CPO, refined, bleached, and deodorized (RBD) palm oil and its fractions (RBD palm olein and RBD palm stearin) have been determined by gas-liquid chromatography and high-performance liquid chromatography (HPLC) [16,17]. The main FA in palm oil are palmitic (P ,45%) and oleic (O ,40%).…”

Section: Introductionmentioning

confidence: 99%

“…The main FA in palm oil are palmitic (P ,45%) and oleic (O ,40%). Linoleic (L ,10%), stearic (S ,4-5%) and myristic (M ,1-2%) are the only FA the concentration of which is .1% [17,18]. The palm oil from Malaysia contains about 94% TAG and 4-7.5% diacylglycerols.…”

Section: Introductionmentioning

confidence: 99%

Thermal and structural behaviour of crude palm oil: Crystallisation at very slow cooling rate

Chong

Kamarudin

Lesieur

et al. 2007

Thermal and structural behaviour of crude palm oil: Crystallisation at very slow cooling rateThe crystallisation behaviour of crude palm oil (CPO) has been examined with a new instrument coupling time-resolved synchrotron X-ray diffraction with high-sensitivity differential scanning calorimetry at cooling rates of 0.1 and 0.4 7C/min from melt temperature to -20 7C, in order to determine the triacylglycerol (TAG) organisations formed as a function of temperature and thermal treatment. At slow cooling rate, CPO TAG sequentially crystallise in apparently two different lamellar structures with double-chain length of 41.9 Å and a triple-chain length of 62.8Å stackings of b' type, which are correlated to two main exothermic peaks at 26 and 8 7C, respectively. While a time-dependent slow b'?b irreversible transition is observed even at low temperature, it only affects a few percent of the TAG population. Subsequent heating at 1 7C/min showed no structural rearrangements of the crystalline forms observed before final melting, indicating that the main moiety of the system is close to equilibrium. Crystallisation at 0.4 7C/min has shown the formation of many additional structures, some of which are evanescent. An unexpected finding was the vicinity of the two lines corresponding to the two 2L (bilayered) structures and the isosbestic point located at 4.42 Å. Only careful analysis allowed the separation of both lines, the coexistence of which was related to the epitaxy/eutectic phenomenon, as evidenced by the simultaneous appearance of the 3L (trilayered) stackings at the same time of the second burst of the 2L stacking and the observation of the isosbestic point. The coexistence of b and b' forms even at high temperature demonstrates that the whole system is not in a two-phase domain but rather in a three-phase one (b 1 b' 1 liquid) in which all TAG molecules could not fit into a single b' structure. This is likely related with the granular phase separations observed in margarine.