Agriculture Reference
In-Depth Information
(a)
(b)
Figure 14.22
(a) Unloading of field wagon at the packinghouse, and (b) manual unloading of seedless
watermelons for packing into bulk bins.
(a)
(b)
Figure 14.23
(a) Submerged bin unloading system for (b) floating summer squash onto the packing line.
pome fruit and tomato repacking for defect/colour sorting and
sizing. The resultant labour savings can reduce payback of
the initial investment for citrus packers to five years or less
(Miller & Drouillard 1999). Other nondestructive techniques
have also been tested to quantify fruit quality such as soluble
solids content and to detect internal defects due to mechanical
injuries. One method, delayed light emission, quantifies low-
intensity light emissions from chlorophyll in the epidermis to
estimate harvest maturity. Forbus
et al
. (1992) compared the
spectral data from immature- and mature-harvested juan
canary melons with destructively measured quality parameters
(chlorophyll, yellow pigments, soluble solids content and
firmness). This technique shows promise to predict soluble
solids content.
In many cases internal mechanical injuries are not
readily apparent during sorting and grading opera-
tions. Methods to detect these defects have also been
studied. Cucumbers subjected to an impact were
measured with refreshed delayed light emission, and
differences in pericarp chloroplasts could be detected as
soon as one hour after impact (Abbott
et al
. 1991). In a
later study, Miller
et al
. (1995) successfully sorted fresh,
whole cucumbers with damaged carpels from sound
fruits using visible-infrared light transmission. Volatiles
(ethanol, acetaldehyde) from low oxygen stress have
been reported for cucumber (Kanellis
et al
. 1988);
volatiles may serve as indicators of fruit quality or
disease (Forney & Jordan 1998).
