Food processors and consumers frequently worry about the inconsistent colour
of dried tomatoes. To minimize detrimental color changes, process parameters
need to be optimized. Thus, digital imaging with the Photoshop software and
optimization with the Taguchi technique were explored to determine the
surface color of microwave-dried tomato slices. The tomato sample was
pretreated with water blanching (WB), ascorbic acid (AA) and sodium
metabisulphite (SB). In addition, the sample was cut into 4-mm, 6-mm and
8-mm thicknesses and dried at 90W, 180W and 360W microwave power levels
following the Taguchi experimental design. Color characteristics (L*, a*,
b*, change in color, browning index, hue, and chroma) of the dried tomato
slices were determined. The L*, a*, and b* values of fresh tomatoes were
56.73, 44.51, and 38.38, respectively. The optimum processing conditions for
the color characteristics varied significantly (p< 0.05). Pretreatment is
the prime significant processing parameter controlling the L*, b*, ?E, BI,
and hue values. At the same time, the slice thickness considerably
influenced the a* value, the ratio of a*/b* and chroma values. The digital
imaging color measurements of dried tomato slices provide a suitable method
for non-destructive color analysis. The ability to upgrade and modify tomato
processors so they can accommodate bulk color characteristics will be made
possible by this knowledge.