One of the most common types of fraudulent practices in the wine market is associated with grapevine varietal misidentification. Although several technological approaches have already been attempted, this is still a major issue in the wine industry. DNA-based technologies are still the most reliable; however, wine DNA is very hard to recover and most of the time it is very hard to use in PCR-based assays. Therefore, there is a need to seek less costly alternative platforms that can be broadly used.
This work developed a simple and low-cost method for DNA detection and quantification, based on the ssDNA (DNA-probe) immobilization in an optical fiber long period grating (LPG) and subsequent hybridization.
The DNA is not labelled, and the hybridization is monitored in situ by following in real-time the optical sensor response. This strategy was applied using DNA extracted from leaf, must and wine samples using several Vitis vinifera L. varieties. The adopted methodology is able to detect a difference of only one base pair between DNA sequences.
The quality of extracted wine DNA does not seem to have a significant influence in the hybridization process, and therefore in the detection efficiency. This platform constitutes an innovative, simple and low-cost platform that can be broadly applied to grapevine varietal identification in wine samples.
Article based on the paper presented at the SIVE OENOPPIA Awards (12th edition of Enoforum; Vicenza, Italy, May 21-23, 2019)