Thermal and structural behaviour of crude palm oil: Crystallisation at very slow cooling rate
Bibliographic record
Abstract
Abstract The 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 °C/min from melt temperature to –20 °C, 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 β' type, which are correlated to two main exothermic peaks at 26 and 8 °C, respectively. While a time‐dependent slow β'→β irreversible transition is observed even at low temperature, it only affects a few percent of the TAG population. Subsequent heating at 1 °C/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 °C/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 β and β' forms even at high temperature demonstrates that the whole system is not in a two‐phase domain but rather in a three‐phase one (β + β' + liquid) in which all TAG molecules could not fit into a single β' structure. This is likely related with the granular phase separations observed in margarine.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".