Non-Destructive Tests on the Prediction of Apple Fruit Flesh Firmness and SSC at the Tree and in Shelf Life

摘要

Non-destructive, portable sensors were studied regarding their feasibility for optimum harvest date determination and fruit quality analysis. Acoustic impulse response sensor and miniaturized spectrometer were applied on apple fruit cvs. 'ldared' and 'Golden Delicious' (n=800) to predict fruit flesh firmness and soluble solids content (SSC). Partial least squares calibration models on acoustic data and spectra of 'Golden Delicious'/'Idared' apple fruits at the tree were built predicting the SSC [°Brix] and the fruit flesh firmness [N]: coefficients of determination (R{sup}2) and standard errors of cross-validation (SECV) of R{sup}2=0.20/0.41 (SECV=1.29/0.94) and R{sup}2=0.93/0.81 (SECV=7.73/10.50) were calculated, respectively. Prediction of SSC [°Brix] and fruit flesh firmness [N] of stored 'Golden Delicious'/'ldared' apple fruits were calculated with R{sup}2=0.04/0.05 (SECV=1.85/1.36) and R{sup}2=0.80/0.75 (SECV=10.32/11.28), respectively. The fruit maturity at the tree was predicted as classes based on calendar weeks for 'Golden Delicious'/'ldared' apple fruits with 64%/66% correct classification and 92%/84% correct plus neighboring class with SECV=0.9/0.9 weeks. Classes of 'Golden Delicious'/'Idared' apple fruit at different quality levels due to different storage conditions were non-destructively discriminated with 77%/84% correctly classified fruits and 93%/99% correct plus neighboring class with SECV=0.8/0.5 classes. The results show the potential of non-destructive sensors for predicting accepted fruit parameters enabling the optimum harvest date and the fruit quality in shelf life to be determined.