Ripeness Prediction in Table Grape Cultivars by Using a Portable NIR Device

In the past years, near infrared (NIR) spectroscopy has been applied to the agricultural industry as a non-destructive tool to predict quality parameters, e.g., ripeness of fruit, dry matter content, and acidity. In two years, 2019 and 2020, berries of four table grape cultivars (Cotton Candy (TM), Summer Royal, Allison (TM), and Autumncrisp (R)) were collected during the season to obtain spectral measurements and quality data for developing predictive models based on NIR spectroscopy to be practically used in the vineyard. A SCiO (TM) sensor was used in 2019 for predicting the ripening parameters of Cotton Candy (TM); in particular, total soluble solids (TSS) (R-2 = 0.95; RMSE = 0.60, RPD = 13.13), titratable acidity (R-2 = 0.97; RMSE = 0.40, RPD = 7.31), and pH (R-2 = 0.96; RMSE = 0.07, RPD = 26.06). With these promising results, in the year 2020, the above-mentioned table grape cultivars were all tested for TSS prediction with successful outcomes: Cotton Candy (TM) (R-2 = 0.97; RMSE = 0.68, RPD = 7.48), Summer Royal (R-2 = 0.96; RMSE = 0.83, RPD = 7.13), Allison (TM) (R-2 = 0.97; RMSE = 0.72, RPD = 8.70) and Autumncrisp (R) (R-2 = 0.96; RMSE = 0.60, RPD = 9.73). In conclusion, a rapid and economic sensor such as the SCiO (TM) device can enable a practical application in the vineyard to assess ripening (quality) parameters of table grapes. Thus, this device or similar ones can be also used for a fast sorting and screening of quality throughout the supply chain, from vineyard to cold storage.