Fruit Texture Measurement: A Review of Biological and Mechanical Interactions

Textural changes are an important aspect of fruit ripening. Accurate measurement of texture allows for a scientific understanding of fruit development including aspects of maturation and ripening, the effect of storage treatments, and the sensory acceptability for a range of fruit species. Texture may also be used as a measure of commercial acceptability. A common method for fruit textural measurement is the penetrometer, where a puncture force is measured, either with or without the fruit skin. Over decades, a range of alternative techniques have been investigated for which the main driving feature has been for a rapid nondestructive measure. Often, these are regarded merely as a proxy for the penetrometer; rarely is the alternative measure considered to offer something unique and valuable. In addition, for some fruit species the penetrometer is not a suitable device or is limited in the information it provides, and thus alternative devices are more important. However, questions still exist about the utility or limitations of some of these methods, both scientifically and commercially. The scientific and commercial relevance of a range of textural measurements are described considering the biological and physical context, largely illustrated with data on kiwifruit.