Correlation of descriptive analysis and instrumental texture of watermelon cultivars

The textural properties of five seedless watermelon cultivars were assessed by quantitative descriptive analysis (QDA) and instrumental measurements including the standard puncture test with an 11mm Magness-Taylor probe and a new increased shear probe called the UC Davis hollow probe in this study of the same contact area, a 3-point bend test and a measurement of apparent juice content. The use of QDA methodology was an effective mean of generating watermelon sensory profiles for characterizing cultivar sensory characteristics. Initial screening of instrumental measurements by Tukey-Kramer HSD analysis revealed the new hollow probe resulted in more discriminating power than the current standard, the Magness-Taylor solid probe, for texture parameters maximum force, initial slope, and number of peaks predicted sensory firmness (R2 = 0.69) and crispness (R2 = 0.73) well. Watermelon tissue type classification results were 57.6% correct for the Magness-Taylor, and 68% correct for the new UC Davis hollow probe. Puncture tests with six prototype probes of varying emphasis on shear versus compression revealed some impact from differences in probe compactness, but did not find a clear advantage to increasing compactness beyond that of the hollow probe design (compactness = 11 mm2/mm2). The apparent juice content and 3-point bending methods faced various implementation challenges and were not practical in their current form. Overall, the maximum force parameter from puncture tests was efficient and reflected firm and crisp sensory attributes, though initial slope and work after maximum force measurements may also be informative.