Ethylene, salicylic acid and 1-MCP affect must quality of 'Cabernet Sauvignon' winegrape

This study aimed to evaluate the effects of the postharvest application of exogenous ethylene and two ethylene inhibitors on must and wine quality of the winegrape 'Cabernet Sauvignon'. Fruit were harvested in the region of Dom Pedrito, RS, Brazil, in the 2014/2015 season and divided into 12 kg cardboard boxes. The following four treatments were then applied for 18 h at 18°C: 1) control; 2) 1000 ppb of 1-methylcyclopropene (1-MCP); 3) 100 uM of salicylic acid (SA); and 4) 1000 ppm of ethylene (C₂H₄), with three boxes (replicates) per treatment. In the must, soluble solids content (SSC), density, pH, total acidity (TA) and potassium (K) concentration were assessed using Fourier transform infrared spectrometry (FTIR), whereas in the wine, alcohol content and color index were determined using spectrophotometry. In the must, ethylene significantly increased SSC compared to the other treatments, whereas 1-MCP resulted in higher pH levels compared to control and SA. Conversely, SA resulted in higher TA than control and 1-MCP. Compared to control, the other three treatments increased K concentration. There were no treatment effects on must density. In the wine, there were no treatment differences for either alcohol content or color index. Results suggest that, although grape fruit is non-climacteric, ethylene could be used as a potential option to improve fruit ripening and must quality, but these differences may not necessarily affect the wine, which warrants further research in this area.