Characterization of volatile compounds of Gok uzum raisins produced from grapes pre-treated with different dipping solutions

Background Raisins contain a wide range of secondary metabolites, including volatile compounds that may contribute to the health benefits and preference of consumers. To our knowledge, this is one of the first studies concerning the analysis of volatile compounds in raisin. The goal of this study was to compare volatile composition of Gok Uzum (Vitis vinifera L.) raisins produced from grapes dried before the application of two pre-treatments solutions: wood ash (WA) and potassium carbonate (K2CO3). Results Gok Uzum raisins produced from grapes dipped into the WA solution presented higher contents of most of the studied volatile compounds (including the total contents of C6 compounds, alcohols, benzenoids, esters, aldehydes, terpenes and C-13 norisoprenoids) and lower contents of (Z)-2-hexenol and 2-hexenoic acid than the raisins produced from grapes dipped into K2CO solutions. Gok Uzum raisins were characterized by fruity, floral and grass aromas according to their odor activity values. Drying Gok Uzum grapes after the treatment of WA solutions promotes a higher aromatic composition compared to K2CO solutions. Conclusion These findings can greatly assist raisin producers in deciding which dipping solution to use before using a dipping solution to dry the grapes.

Automated summary

This study compares the volatile composition of Gok Uzum raisins produced from grapes treated with wood ash and potassium carbonate solutions. The results show that raisins treated with wood ash have higher levels of volatile compounds and lower levels of (Z)-2-hexenol and 2-hexenoic acid compared to raisins treated with potassium carbonate. Gok Uzum raisins have fruity, floral, and grass aromas based on their odor activity values. These findings are important for raisin producers when choosing a pre-treatment solution before drying grapes.