NON-DESTRUCTIVE DETECTION OF SUN STRESS COMPROMISED APPLES

Sun stress results in significant annual loss, not only due to injury in the orchard, but also those that appear during the cold chain including sunscald and lenticel blotch. Detection of these disorders before they enter the cold chain could afford producers the capacity to segregate fruit for removal, immediate marketing, or different storage strategy to eliminate injured fruit. Our earlier work has identified fruit compounds present prior to symptom development that may be detected non-destructively. Two non-destructive techniques, near infrared spectroscopy and near UV reflectance, have been tested and show promise, and at least one other technique may also have utility. We will use the same destructive chemical analysis techniques used to identify fruit compounds associated with peel disorder risk to validate the accuracy of the non-destructive techniques. Then, we will validate the use of the non-destructive technique(s) by identifying symptomless, yet sun stressed apples prior to storage, and then wait for symptoms to develop during storage. The goal of this project will be development of a means for sorting symptomless sun stressed fruit from fruit that will not develop sun stress disorders, therefore minimizing or eliminating sun-related postharvest disorders from the cold chain and retail. Objectives: 1. Determine best non-destructive methods to segregate sun stress compromised fruit. 2. Validate accuracy of non-destructive method for detecting chemistries associated with solar stress. 3. Test if non-destructive sorting improves storage outcome for different sun stress related disorders.