Palm oil is currently the most widely produced and consumed vegetable oil globally and is used as a raw material in many industries. Crude palm oil (CPO) is used in various edible products, including cooking oil, margarine, and processed foods. CPO can be refined to remove impurities and improve color, flavor, and odor. Several steps are involved (e.g., degumming, neutralization, bleaching, deodorization) to produce refined bleached deodorized palm oil (RBDPO). RBDPO is used for frying purposes and is also found in foods like instant noodles and ice cream.

If the palm oil composition is found to be out of specification during production, the process stops, and the oil is recycled. Determination of key quality parameters like iodine value and the fatty acid profile of palm oil can be determined easily in just a few seconds without sample preparation using near-infrared spectroscopy (NIRS).

The measured NIR spectra of CPO (Figure 2) and of RBDPO (Figure 3) were used to create prediction models for the quantification of iodine value (IV), linoleic acid (18:2), oleic acid (18:1), and palmitic acid (16:0) for the two different palm oils. A quantification model was created for water content present in palm oil using another set of CPO samples.

The quality of the prediction models was evaluated using correlation diagrams (Figures 4–12) which display a high correlation between the NIR predictions and the results given by primary methods (i.e., GC and KF titration). The respective figures of merit (FOM) display the expected precision and confirm the feasibility during routine analysis.

This Application Note displays the benefit of using the OMNIS NIR Analyzer Liquid for routine analysis in laboratories that measure various palm oil quality parameters. Compared to other conventional methods like Karl Fischer titration and GC, determinations with NIR spectroscopy do not require any sample preparation or chemical reagents. This ultimately leads to a reduction in workload (Table 2) and costs.

Internal reference: AW NIR CH-0066-042023