The effect of light on the composition of some volatile compounds in wine: an HS‐SPME‐GC‐MS study

Summary The HS‐SPME‐GC‐MS analysis of Fiano di Avellino (white wine, Southern Italy) and Aglianico del Vulture (red wine, Southern Italy) showed the presence of ethyl acetate, 2‐methyl‐1‐propanol, 2‐methyl‐1‐butanol (MB), 2‐methylbutyl acetate (MBA), ethyl hexanoate (EH), diethyl butanedioate (DB), ethyl octanoate (EO) and ethyl decanoate (ED). UV irradiation of both the wines in a Pyrex vial with a 15‐W low pressure mercury arc showed an extensive degradation of all the compounds. After 24 h irradiation in the red wine, ethyl acetate decreased from 208 mg L−1 to 58 mg L−1, DB from 16.7 to 4 mg L−1, MBA from 19 to 3 mg L−1, 2‐methyl‐1‐propanol disappeared and MB decreased from 796 to 92.5 mg L−1. Only in the case of DB, MBA, EH, EO and ED in the red wine the degradation occurred after an initial increase of the concentrations of the esters. The irradiation of the esters in the presence of riboflavin showed a clear degradation of the esters (9%–17%). The irradiation of both the wines in the original bottles for 7 days showed an extensive degradation of all the volatile compounds observed in the wines. 2‐Methyl‐1‐propanol disappeared while 90% of MB disappeared. The amount of the esters decreases in the range 65%–91%.