(1) Background: Raisins contain a wide range of hormones, minerals, vitamins, and antioxidant enzymes that may contribute to the health benefits of consumers. (2) Methods: The aim of this research was to compare the hormone, mineral, vitamin, and antioxidant capacities of Gök Üzüm (Vitis vinifera L.) raisins immersed in oak ash (OA) and potassium carbonate (PC) dipping solutions before drying. (3) Results: Abscisic acid (ABA) (5751.18–11,868.40 ng g⁻¹) and riboflavin (95.17–135.54 mg 100 g⁻¹) were the most abundant hormone and vitamin quantified in Gök Üzüm raisins. Glutathione S-transferase (540.07–744.85 EU gr berry⁻¹), 6-glucose phosphate dehydrogenase (214.50–317.43 EU gr berry⁻¹), and glucose-6-phosphate dehydrogenase (208.25–241.86 EU gr berry⁻¹) enzymes presented the highest antioxidant activity in the samples. Raisins obtained after drying by immersion in OA presented higher indol-3-acetic acid (IAA), ABA, salicylic acid (SA), cytokinins (CK), and zeatin contents; glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), glutathione S-transferase (GST), 6 glucose phosphate dehydrogenase (6GPD), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) enzymatic activity; vitamin B1, B2, B6, C, and A contents; and nitrogen (N), phosphorus (P), manganese (Mn), calcium (Ca), sulfur (S), potassium (K), iron (Fe), sodium (Na), and magnesium (Mg) levels compared to the grapes dried after PC applications. (4) Conclusions: Drying Gök Üzüm grapes after the application of OA dipping solution promotes a higher content of hormones, minerals, vitamins, and antioxidant enzymes compared to PC treatments. These results could help raisin producers to make decisions when using a dipping solution to dry grapes.

(1) Background: Italia is a seeded grape variety widely cultivated in the Aegean Region in Turkey, whereas Bronx Seedless is a seedless grape variety, preferred by consumers due to its pink berries and interesting flavor. The goal was to study the volatile compounds of these table grapes throughout berry ripeness. (2) Methods: The volatile compounds were analyzed by GC-MS in six different phenological stages (3) Results: Bronx Seedless grapes presented a higher content of seven terpenes, three aldehydes, one fatty acid, three alcohols, one C6 compound, total aldehydes and total alcohols, and a lower content of eleven terpenes, one fatty acid, four esters, one alcohol, four C6 compounds and its total content than Italia table grapes. The concentration of most of the volatile compounds analyzed increased from “begin of berry touch” to “berries ripe for harvest” stages. Terpenes content in both varieties at harvest was lower than 1.0 mg L⁻¹. β-ionone presented the highest odor activity value (OAV) in both varieties. Bronx Seedless grapes presented higher OAV for (Z)-3-hexenal and cedrol, and lower hexanal to (E)-2-hexenal ratio than Italia grapes. (4) Conclusions: Both varieties could be classified as neutral aromatical varieties and it is probable that to achieve a better aromatic quality, Bronx Seedless should be harvested later than Italia.

Understanding the impact of pre-treatment methods on the phytochemical composition of grapes is essential for optimizing grape quality and producing raisins with desirable characteristics. Therefore, this study meticulously analyzed the impact of two distinct pre-treatment methods, oak ash and potassium carbonate (K₂CO₃), on the composition of essential phytochemical components in grapes. This research encompassed phenolic compounds, anthocyanins, phenolic acids, flavonoids, and phytoalexins. This study investigates the impact of pre-treatment methods, oak ash and K₂CO₃, on the phytochemical composition of grapes. Significant differences were observed in anthocyanins, flavonoids, phytoalexins, and phenolic acids between the treatments. Oak ash exhibited advantages in preserving specific compounds, including higher levels of anthocyanins, flavonols, flavones, flavanones, catechins, resveratrol, pterostilbene, and viniferin, compared to K₂CO₃. Notably, the delphinidin-3-O-glycoside content was significantly higher in the oak ash treatment. An analysis of phenolic compounds revealed distinctions in hydroxycinnamic acids, hydroxybenzoic acids, benzaldehyde, and phenylacetaldehyde. Additionally, gallic acid, vanillic acid, trans-caffeic acid, trans-p-coumaric acid, and (-)-epicatechin were significantly more prevalent in the K₂CO₃ treatment, while ferulic acid and quercetin were more prevalent in the oak ash treatment. These findings underscore the pivotal role of pre-treatment methods in shaping the phytochemical content of grapes, thus holding critical implications for grape-derived products’ quality and potential health benefits.

Bu çalışma, stoma yoğunluğu ve boyutları üzerine çeşidin, kullanılan yöntemlerin (kalıp alma/saydamlaştırma), yaprakların alınma konumlarının (gölge/güneş) ve yaprak yüzeyinin farklı bölgelerinden örnek almanın (uç, orta, dip) etkilerini ortaya koymak ve çeşitlerin toplam klorofil, klorofil a, klorofil b, karotenoid miktarları ile SPAD değerlerini tespit etmek amacıyla 2017 yılında Hizan yöresinde yetiştirilen 28 yerel üzüm çeşidi üzerinde yürütülmüştür. Çalışmada çeşit, yöntem ve yaprağın alındığı konumun stoma yoğunluğu üzerine olan etkisinin önemli olduğu ancak yaprak yüzeyinin farklı bölgelerinden örnek almanın stoma yoğunluğu üzerine etkisinin önemsiz olduğu tespit edilmiştir. Aynı şekilde, çeşit ve yöntemin stoma boyutları üzerine olan etkilerinin önemli olduğu ancak yaprağın alınma konumunun ve yaprak yüzeyinin farklı bölgelerinden örnek almanın stoma boyutları üzerine olan etkisinin önemsiz olduğu belirlenmiştir. Tüylü ve yüzeyi pürüzlü asma yapraklarında daha iyi bir stomatal değerlendirmenin yapılmasında saydamlaştırma yönteminin tercih edilmesi gerektiği kanaatine varılmıştır. Çalışmada çeşidin toplam klorofil, klorofil a, klorofil b ve karotenoid miktarları ile SPAD değerleri üzerine olan etkisinin önemli olduğu ve çeşitler arasında bu değerler bakımından önemli farklılıklar olduğu belirlenmiştir. Güneşte olan yaprakların SPAD değerlerinin gölgede olan yapraklara göre daha yüksek olduğu gözlemlenmiştir.