Determination of puncture injury susceptibility of tomatoes

Puncture injury leads to large qualitative and quantitative losses of loose tomatoes (Lycopersicon esculentum Mill.) when they pass through handling operations. Some cultivars are less susceptible to puncture injury, which is a desirable characteristic for tomato quality. It is, therefore, important that the puncture injury susceptibility of a new tomato cultivar is known, prior to commercialisation and large-scale production. In this research, a pendulum was designed to evaluate the puncture injury susceptibility of tomato cultivars in an objective way. Logistic regression was used as a statistical tool to model the influence of the impact energy on the incidence of puncture injury. This methodology was applied to two cultivars with different susceptibilities to puncture injury, 'Tradiro' (less susceptible) and 'Blitz' (very susceptible). Their susceptibilities to puncture injury were measured as a function of storage time and colour stage. It was found that: (i) tomatoes at harvest were less susceptible to puncture injury than after storage for several days; and (ii) colour at harvest had no effect on the susceptibility for puncture injury. This research revealed that the pendulum test in combination with logistic regression is a suitable method and a promising measurement tool to determine the puncture injury susceptibility of tomato cultivars. (C) 2002 Elsevier Science B.V. All rights reserved.