Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2005
Publication Date: 1/30/2006
Citation: Whitelock, D.P., Brusewitz, G.H., Stone, M.L. 2006. Apple shape and rolling orientation. Applied Engineering in Agriculture. 22(1):87-94.
Interpretive Summary: Much research effort has been directed toward developing nondestructive quality measurement for fruits and vegetables. These methods require the commodity to be oriented properly if they are to be incorporated into on-line measurement and grading. Also, methods that could orient different fruit shapes or control their orientation would enhance the ability of a grading system to accommodate new sensing technologies. A study was conducted to examine the effectiveness of a previously developed mechanism for orienting apples and to explore the relationship between apple shape and orientation behavior. Apple cultivars that were characteristically elongated (length/diameter ratios near and greater than 1) oriented better than those that were not elongated (i.e. short and fat apples). Washington Red Delicious apples might be successfully oriented with this system, but probably not other cultivars. Shape characteristics that described elongation (length/diameter) were better predictors of the ability for apples to orient or remain oriented than characteristics that described taper or symmetry. The results of this study are important to the fresh produce industry and researchers developing online sorting and grading systems in that the study revealed the effectiveness of the mechanism for orienting some apple cultivars and ineffectiveness for others, and the study identified key shape characteristics that affected the mechanisms ability to orient.
Technical Abstract: The ability to orient fruit is needed to fully utilize the capabilities of many commercial sorters for defect and shape detection and general quality sensing. Five apple cultivars, representing a range of shape and size, were observed for their ability to orient (stem-calyx axis horizontal and perpendicular to the direction of travel) or remain oriented, depending on their starting position, as they were rolled linearly by a mechanically driven flat paddle up a flat, padded incline between two fixed parallel rails. Apples did not orient particularly well on the apparatus, on average rolled 66.0 cm before orienting and rolled only 70.5 cm before becoming unoriented. Various size and shape parameters were measured and correlated with the distance apples rolled to orient and the distance that the apples remained oriented. Generally, parameters that described elongation were better than those parameters describing taper or symmetry as predictors of an apple’s ability to orient or remain oriented. Elongated cultivars of apples, Red Delicious and Fuji (Washington), Braeburn (New Zealand), and Granny Smith (South Africa), oriented or remained oriented best while Rome and Red Delicious (West Virginia) did not.