An Impact Force Response Fruit Firmness Sorter

ABSTRACT Asingle lane firmness sorting system was developed which conveyed fruit horizontally at a constant speed (76.7 cm/s) and caused them to impact on a rigid surface. Impact force characteristics (C2 = (peak force)/(time to peak force)^) were used to sort fruit into hard, firm and soft categories, at 5.1 fruit/s. Correlation coefficients between C2, penetrometer firmness, and eleasticity were 0.84 and 0.90 for fresh market peaches, and 0.78 and 0.81 for processing pears. Approximately 74% of the peaches were sorted into the correct firmness range.