Kaya, Ozkan; Karakus, Sinem; Bozkurt, Abdurrahim; Yilmaz, Turhan; Hajizadeh, Hanifeh Seyed; Turan, Metin

Background: The exploration of EOs and their impact on primary metabolites in agricultural products, such as grapes, holds significant importance in the post-harvest preservation and enhancement of berry quality. Therefore, our research aimed to dissect the effects of various EO treatments on the biochemical composition of grapes, specifically examining alterations in sugar, organic acid, and amino acid levels. Results: Our findings highlighted that the OF treatment, a combination of Eugenol and Botrytis cinerea, significantly escalated sugar content, with remarkable increases in sucrose, glucose, and fructose compared to the control group. The SF treatment led to the highest levels of certain organic acids, including tartaric, butyric, and malonic acids, whereas the TO treatment prominently augmented amino acids such as tyrosine and phenylalanine. Utilizing PCA, our study effectively captured the variability within the treatment dataset, revealing distinct clusters of treatments and their correlations with specific metabolites. The PCA biplot underscored the influence of treatments on metabolic profile of grape berries, with treatments like OSF, TO, and TOSF demonstrating close associations with specific amino acids, suggesting positive correlations. Conclusion: Our current results indicate that EOs substantial influence on the metabolic profile of grapes, resulting in enhanced fruit quality and extended shelf life. Variations in sugar, organic acid, and amino acid levels among different EO treatments highlight their potential for improving post-harvest characteristics. To sum up, these findings are valuable for the agricultural and food industries, showcasing the utility of EOs as natural preservatives and enhancers in fruit cultivation and storage. Graphical Abstract: (Figure presented.)

Karakus, Sinem; Kaya, Ozkan; Hajizadeh, Hanifeh Seyed; Gutiérrez-Gamboa, Gastón; Ates, Fadime; Turan, Metin; Araya-Alman, Miguel

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 Gök Üzüm (Vitis vinifera L.) raisins produced from grapes dried before the application of two pre-treatments solutions: wood ash (WA) and potassium carbonate (K2CO3). Results: Gök Üzüm 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 C13 norisoprenoids) and lower contents of (Z)-2-hexenol and 2-hexenoic acid than the raisins produced from grapes dipped into K2CO solutions. Gök Üzüm raisins were characterized by fruity, floral and grass aromas according to their odor activity values. Drying Gök Üzüm 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. Graphical Abstract: [Figure not available: see fulltext.]

Karakus, Sinem; Atıcı, Okkes; Turan, Metin; Azizi, Sahar; Hajizadeh, Hanifeh Seyed; Kaya, Ozkan

Background: Gray mold, attributed to Botrytis cinerea, poses a substantial threat to food security in fruit-growing regions impacted by global climate change. Addressing this disease requires the utilization of either resilient plant varieties or advanced technological interventions. In this study, the research focused on examining the volatile organic compounds (VOCs) emitted by synthetic essential oils, namely thymol, eugenol, 1,8-cineol, and their combination, as potential biological fumigants against B . cinerea on Golden Delicious apples. Results: In this study, a total of 53 compounds were identified and categorized into six distinct classes, which included (1) terpenes, (2) esters, (3) C6 compounds, (4) alcohols, (5) acids, and (6) aldehydes. The results we obtained revealed significant variations in the volatile compounds present in apples after harvest when treated with different essential oils to combat B. cinerea. Among the VOCs found in the fruits, the most abundant ones were pentanal, nerol, and ethyl octanoate. The essential oil combination of thymol, eugenol, and 1,8-cineol (Thy + Eug + Fun) had the most significant impact on the volatile compound content in the fruits. Conversely, both B. cinerea and the essential oils were observed to increase the volatile organic compound content in the fruits after harvest. Conclusion: The findings from this study underscore the significance of essential oils as effective biological fumigants for countering Botrytis cinerea on apples. Furthermore, the study suggests that these essential oils have the potential to influence the composition of volatile organic compounds in postharvest apples. This research offers valuable insights into the intricate interplay between volatile organic compounds and essential oils in apples, emphasizing the critical role of essential oils in preserving fruit quality during the post-harvest period. Graphical abstract: [Figure not available: see fulltext.].