Bl. Upchurch et al., DETECTING INTERNAL BREAKDOWN IN APPLES USING INTERACTANCE MEASUREMENTS, Postharvest biology and technology, 10(1), 1997, pp. 15-19
A technique using body transmittance in the 450- to 1050-nm region was
evaluated as a non-destructive technique for identifying apples with
internal breakdown. Apples with internal breakdown absorbed shorter wa
velengths of light (<750 nm) more than good apples; however, light at
longer wavelengths (>750 nm) was absorbed more by good apples than def
ective ones. A classifier based on the ratio between the light intensi
ty at 720 and 810 nm was used to segregate apples with internal breakd
own from good apples. Only 6.3% of the good apples were incorrectly cl
assified: however, bruises on the apples contributed to the incorrect
classification of good apples. None of the apples with severe internal
breakdown were incorrectly classified. Apples with very slight intern
al breakdown contributed to most of the 12.0% error of misclassifying
defective fruit as good. The number of misclassified apples was reduce
d by adjusting the cut-off; however, the number of good fruit that wou
ld be discarded increased.