Empirical modelling of postharvest changes in the firmness of kiwifruit
Jason R. Benge, H. Nihal De Silva, Nigel H. Banks and Peter B. Jeffery
Postharvest Biology and Technology Vol: 19 Issue: 3 Pages: 211-220.
2000
บทคัดย่อ
Several different types of empirical mathematical models were used to characterise the softening behaviour of `Hayward' kiwifruit (Actinidia deliciosa (A. Chev) C.F. Liang et A.R. Ferguson) during storage at 0°C. Our purpose was to determine whether or not the softening behaviour of fruit conformed to a limited number of patterns. If this were so, such models, coupled with measurements made in a short period after harvest, might form the basis of a quantitative tool that would allow the industry to segregate batches of fruit with differing storage potentials. Initially, three simple models were used to characterise firmness data: a Complementary Michaelis¯Menten type (CMM), Exponential (EXP), and Complementary Gompertz (CG). However, these were unable to characterise firmness changes with sufficient accuracy, either in the early, middle or latter stages of storage. Instead, the firmness data were better characterised by two more complex models that were identified during the course of the study: a segmented Jointed Michaelis¯Menten type (JMM) and Inverse Exponential Polynomial (IEP). With the JMM model, different functional relationships were assumed for different regions of the time domain although its parameters were difficult to estimate accurately when the number of data points for a region of the time domain was limited. The IEP model best characterised the firmness data although its ability to predict the softening behaviour of fruit was poor given a limited window of data. None of the equations that were studied provided a standard curve that could be useful as a predictive model for firmness in storage. Nevertheless, the more complex equations did accurately characterise our firmness data and have potential value for comparing treatment effects in experimental programmes.