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

摘要

Non-destructive, portable sensors were studied regarding their feasibility for optimumharvest date determination and fruit quality analysis. Acoustic impulse response sensor andminiaturized spectrometer were applied on apple fruit cvs. 'Idared' and 'Golden Delicious' (n=800) topredict fruit flesh firmness and soluble solids content (SSC). Partial least squares calibration modelson acoustic data and spectra of 'Golden Delicious'/'Idared' apple fruits at the tree were builtpredicting the SSC [°Brix] and the fruit flesh firmness [N]: coefficients of determination (R2) andstandard errors of cross-validation (SECV) of R2=0.20/0.41 (SECV=1.29/0.94) and R2=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'/'Idared' apple fruits were calculated with R2=0.04/0.05(SECV=1.85/1.36) and R2=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 'GoldenDelicious'/'Idared' apple fruits with 64%/66% correct classification and 92%/84% correct plusneighboring class with SECV=0.9/0.9 weeks. Classes of 'Golden Delicious'/'Idared' apple fruit atdifferent quality levels due to different storage conditions were non-destructively discriminated with77%/84% correctly classified fruits and 93%/99% correct plus neighboring class with SECV=0.8/0.5classes.The results show the potential of non-destructive sensors for predicting accepted fruit parametersenabling the optimum harvest date and the fruit quality in shelf life to be determined.