ABSTRACT
Anthocyanins are important compounds in grapes and wine and significantly influence their characteristics. Ultraviolet light-C (UV-C) can be used as a tool to induce secondary metabolism, and in this study, it was used in 'Cabernet Sauvignon' grapes in the postharvest period to improve the anthocyanin profile and sensory attributes in wine produced with irradiated grapes. Grapes in the postharvest period were exposed to 0, 2, or 3 kJ m-2 UV-C radiation. After winemaking and storage time (6 months), physicochemical and color analyses, anthocyanin quantification and identification (HPLC-PDA-MS/MS), and sensory analyses were carried out. 'Cabernet Sauvignon' wine produced with grapes irradiated with 3 kJ m-2 UV-C showed increased spectrophotometric color, which is likely due to a 22.5% increase in total anthocyanin monomers, 59.3% of pyranoanthocyanins, 92.3% of direct condensation products, and 62.8% of acetaldehyde-mediated condensation products. In addition, this irradiated dose presented higher perception scores for visual color, aroma, taste, and was preferred by the tasters over the wine produced with non-irradiated grapes. This study is the first of its kind to show that the UV-C radiation treatment of grapes in the postharvest period can be a promising tool to improve the anthocyanin profile and sensorial quality of 'Cabernet Sauvignon' wine. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05191-5.
ABSTRACT
Thermal pest control (TPC) is a technology that applies heated air in the vineyard to reduce pests. However, it can also alter grape anthocyanin synthesis in answer to temperature stress. The aim of this work was to determine the impact of TPC in 'Tannat' grape vineyards on wine quality. The major makers of quality considered in this study were the wine anthocyanin characterization by HPLC-PDA-MSn, beverage's sensory evaluation by descriptive analysis, and color parameters by instrumental analysis. A total of three experiments were performed in different harvesting years. In 2011/12 (Experiment I), four applications were performed from the flowering to fruiting. For the second experiment (2012/13), five applications were used only during fruiting. TPC treatment performed in 2013/14 (Experiment III) had a total of 19 applications from the flowering to harvesting. In the first experiment, TPC had increased wine pigments, color, and sensorial descriptors for visual (translucence) and gustatory (woody and body) perceptions. However, in the second experiment none of the evaluated wine quality parameters was affected by TPC (p≤0.05). In the last and longest experiment (19 applications), TPC has significantly increased some wine pigments content. Nonetheless, wine sensorial parameters were not affected. Since the climate was different among the years, it seems that TPC effect does not depend on the applications number and vegetable cycle period only, but also it can be affected by the weather conditions in which the vine is being cultivated. However, when TPC treatment has resulted in the greatest anthocyanin increment (Experiment I) some wine sensory descriptors were also improved.
