Comparative analysis of molecular and chromatographic methods for detecting palm oil adulteration in yogurt

Abstract

Abstract Palm oil adulteration in dairy products poses significant concerns for food authenticity, consumer protection, and regulatory compliance. This study presents a validated combined molecular and chromatographic detection strategy to detect and quantify palm oil adulteration in yogurt fat. Yogurt fat samples were fortified with palm olein at concentrations ranging from 1 to 100% (w/w). DNA was extracted using a modified CTAB protocol and analysed for the oil palm-specific MT3-B gene via conventional and quantitative PCR (qPCR). Concurrently, Gas Chromatography–Flame Ionization Detection (GC-FID) was used to quantify phytosterols in the unsaponifiable lipid fraction. To address this issue, we developed a dual-analytical strategy combining qPCR targeting the chloroplast MT3-B gene of oil palm (Elaeis guineensis) and gas chromatography for sterol profiling. The qPCR assay demonstrated high specificity and sensitivity, with a detection limit of 0.01 ng and a quantification limit of 0.02 ng. GC-FID analysis showed a dose-dependent increase in phytosterol content, with pronounced rises at 50% and 100% substitution. A strong correlation (r = 0.89) was observed between qPCR-detected DNA levels and GC-measured phytosterol concentrations. To evaluate real-world applicability, the method was applied to 15 commercial yogurt samples, all of which tested positive for molecular and chemical markers of palm oil. This integrated approach offers a rapid and reliable strategy for detecting palm oil adulteration, supporting food quality assurance and regulatory enforcement.