Photodegradation of Retsina wine: does pine resin protect against light-induced changes?

Retsina is a wine deeply rooted in Greek tradition, often misunderstood, and exclusively produced in Greece by adding pine resin to the must. Typically, it is bottled in flint glass bottles, although it is known that light can damage wine aroma compounds. However, the effect of light exposure in Retsina wines has never been studied. It remains unknown whether the enrichment with resin-derived compounds can protect Retsina from photodegradation. The main aim of this work was to study the behavior of Retsina’s volatile components when stored in flint glass bottles, and so 12 Retsina wines, prepared with three levels of resin addition, were stored for four weeks under light exposure in flint (clear) glass bottles or protected by light in a box, and then they were analyzed by a GC-MS/MS method. Some compounds were influenced by resin addition, others by light exposure and a few by both conditions. Several terpenes increased with resin addition but decreased due to light exposure, while norisoprenoids decreased under light exposure. Some esters were reduced due to resin addition, and 2-aminoacetophenone was increased by light exposure. The study demonstrated that flint glass bottles should be avoided, as resin does not provide sufficient protection against photodegradation.