Browsing by Author "Gutierrez-Gamboa, Gaston"

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Drying Grapes After the Application of Different Dipping Solutions: Effects on Hormones, Minerals, Vitamins, and Antioxidant Enzymes in Gok Uzum (Vitis Vinifera L.) Raisins
(Mdpi, 2022) Keskin, Nurhan; Kaya, Ozkan; Ates, Fadime; Turan, Metin; Gutierrez-Gamboa, Gaston
(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 Gok uzum (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 Gok uzum 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 Gok uzum 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.
Study of Volatile Organic Compounds of Two Table Grapes (Cv. Italia and Bronx Seedless) Along Ripening in Vines Established in the Aegean Region (Turkey)
(Mdpi, 2022) Kaya, Ozkan; Incesu, Melek; Ates, Fadime; Keskin, Nurhan; Verdugo-Vasquez, Nicolas; Gutierrez-Gamboa, Gaston
(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. beta-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.