Work

Towards a better understanding of saponification for the determination of mineral oil hydrocarbons (MOH) in edible oils and fats – Evaluation and optimization of current protocols

Year: 2025

Type: article

Abstract: BACKGROUND: Saponification is the primary procedure employed for the enrichment of saturated MOH (MOSH) and aromatic MOH (MOAH), possibly inducing a considerable variability to the results. Previous studies only investigated this phenomenon following the application of auxiliary methods, which are known as major sources of uncertainty. Consequently, the assessment of saponification has never been conducted exclusively, to evaluate performance, elucidate intertwined uncertainties and identify the most appropriate internal standards (IST) for quantification after saponification. RESULTS: For the first time, saponification protocols of DGF C-VI 22 (20) and ISO 20122:2024 have been assessed in a novel approach. For MOAH and polyaromatic MOAH sufficient recoveries between 100 and 108 % were achieved, but only if 1,3,5-tri-tert-butylbenzene (TBB) was used for quantification. For MOSH, a second extraction was required to achieve satisfactory results with a recovery rate between 102 and 108 %, when bicyclohexyl (Cycy) was used for calculation. The variability of IST ratios could be associated primarily with the free fatty acids formed during alkaline hydrolysis, inducing a discrimination related to the degree of alkylation. To overcome the limitations of IST suitability, a novel saponification/extraction protocol was developed offering decreased IST ratio deviations, improved hydrolysis performance and better purified extracts combined in a robust and routine-suitable approach without the need for specialised equipment. SIGNIFICANCE: This work concludes the most suitable ISTs for the quantification of MOSH and MOAH after saponification. In order to further reduce the variability and enable quantification by other ISTs, an improved method for a broad spectrum of users was developed and tested.

Source: Analytica Chimica Acta

DOI: 10.1016/j.aca.2025.344591

Authors: Maximilian Koch, Gerd Hamscher, Ludger Brühl

Institutions: Justus-Liebig-Universität Gießen, Max Rubner Institut

Language: English

Topic: Edible Oils Quality and Analysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,270

Funders: Bundesministerium für Wirtschaft und Energie, Forschungskreis der Ernährungsindustrie