Drying Grapes after the Application of Different Dipping Solutions: Effects on Hormones, Minerals, Vitamins, and Antioxidant Enzymes in Gök Üzüm (Vitis vinifera L.) Raisins

Abstract

(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.

Unveiling the transformations in phytochemicals and grape features: a thorough examination of 'Italia' and 'Bronx Seedless' cultivars throughout multiple berry development stages

“…These observations correspond to previous research, affirming the consistency of the results with established patterns in viticulture. As supported by references in the field [6,14], the increase in berry size, rising TSS values, declining acidity, and the improvement in the maturity index are all indicative of the typical ripening process. These parameters serve as crucial indicators for determining the optimal grape harvest time, a fundamental factor in ensuring the production of high-quality wines and grape-based products.…”

“…Foxy grapes, on the other hand, known as Vitis labrusca, are valued for their distinctive foxy flavor and are used extensively in the production of grape juice, jams, and jellies [5]. They have gained attention for their potential health benefits such as antioxidant properties [6]. Table grapes, namely the 'Italia' and 'Bronx Seedless' cultivars, have gained prominence not only for their exquisite taste [7], but also for their abundant phytochemical content, which encompasses phenolic acids, C 13 -Norisoprenoids; phytoalexins, and flavonoids.…”

Changes of physiological characteristics, element accumulation and hormone metabolism of tea leaves in response to soil pH

“…Environmental changes have been reported to affect the uptake of mineral elements by plants and to alter the synthesis of different classes of hormones in plants, which in turn affects plant growth ( Ulger et al., 2004 ). Keskin et al. (2022) found that indole-3-acetic acid, salicylic acid, cytokinin, and zeatin contents in plants were significantly and positively correlated with the contents of P, Mn, Ca, S, K, and Mg, as well as the activities of catalase, peroxidase, and superoxide dismutase, and significantly and negatively correlated with abscisic acid content.…”

Novel alternative pretreatment approaches for production of quality raisins from grapes: Opportunities and future prospects

“…Effect of pretreatment chemicals namely, oak ash and potassium carbonate on the hormones and some other nutrients like minerals, vitamins, and also on antioxidants have been examined and findings revealed that application of oak ash as pretreatment promoted the content of hormones and other nutritional components of raisins compared to potassium carbonate treatment (Keskin et al, 2022).…”