Application of high resolution melting combined with DNA-based markers for quantitative analysis of olive oil authenticity and adulteration.

A plethora of biotechnological methodologies is used to authenticate quality olive oils. Among the DNA-based approaches, SNPs and SSRs combined with high resolution melting (HRM) provide certain advantages such as speed, simplicity and reliability. SNP-HRM and SSR-HRM were used for the authentication of monovarietal olive oils as well as the quantification of varietal composition in olive oil DNA admixtures and olive oil blends of two different cultivars. The SSR-HRM was more efficient in distinguishing monovarietal olive oils while the SNP-HRM assay was more reliable in discriminating olive oil blends. HRM was also used for the detection of adulteration of olive oil with oils of different plant origin by using plastid indels and SNPs. The trnL-indels-HRM showed higher discrimination power than the -SNP-HRM in determining adulteration in olive oil. These results indicate that traceability of adulteration might be more reliable than authentication of the varietal origin in olive oil blends.