Research on the Contribution Ratio of Apple Peel Puncture Behavior to Fruit Firmness

Abstract

The texture of apple peel, as an important quality attribute of the fruit, is directly relevant to a fruit’s ability to resist mechanical injury. In order to explore the variations in texture of two apple peels under different puncture test conditions and evaluate the relation of apple peel puncture force to whole fruit firmness percentage, at 0.1, 1, 5, 11, and 17 mm/s loading speeds, puncture mechanical measurements were performed using an electronic testing machine mounted with 2, 3.5, 7.9 or 11 mm-diameter probes. For the same probe, the mean values of peel puncture force and stiffness, as well as the fruit puncture force, for Danxia and Fuji cultivars increased firstly and then changed a little with the increase of loading speed. Moreover, at the same loading speed, the puncture measurements of each cultivar increased significantly ( ) with increasing probe diameter and the peel puncture force has a significant linear correlation with probe diameter. Among the different cultivars, under the same loading speed, the Fuji peel and fruit samples had the greater puncture force; the Fuji peel contribution change was relatively big with the increasing of loading speed, and Fuji cultivar was more likely to be injured than the other cultivar. The results were expected to serve as a reference for investigating the puncture injury sensitivity of different apple varieties during transportation and storage and to enrich the texture evaluation index of apple peel.