Translucency in cut tomatoes
Translucency is one of the major problems in fresh-cut fruit. This phenomenon affects the use of tomato fruit by the fresh-cut industries. Techniques for measuring translucency are not readily available. As a consequence, the processes that are important in the development of translucency are little understood, let alone described in detail. The colour of produce depends only on the absorption of light by colouring compounds. Translucency does not change the amount of colouring agents in the product, but it does change its appearance by changing the scattering properties. As a consequence the appearance, which is the result of light absorption and scattering combined, is affected by both translucency and colour development. Consumers do buy or reject products based on total appearance. In the short life time of cut fruits, the development of colouring compounds apart from possible oxidation effects will not be very large. Understanding the development of translucency is therefore of major importance for the fresh-cut industry. The development of translucency was visually assessed in tomato slices, obtained from tomatoes at three stages of maturity (mature green, breaker stage and full red) and stored at 5°C. In a second experiment, tomato slices were stored at three temperatures (5, 9 and 13°C) to assess the effects of temperature. In both experiments, non-cut tomatoes were also assessed. The data of both experiments were analysed using a very simple exponential model based on a massive approximation of the mechanism involved. The more precursor is present, the higher the obtainable translucency will be. A model was developed based on this simplified mechanism, and used to analyse all data. The stage of development (maturity) was found to have a major effect on translucency development regulated by the amount of precursor. The rate constant, however, was the same. The temperature only had a minor effect on the rate constant with the same amount of precursor. Explained parts (R2adj) obtained for mean data were well over 97%, for the individual data the explained part was somewhat less.
Tijskens, L.M.M., Schouten, R., van Kooten, O. and Lana, M.M. (2018). Translucency in cut tomatoes. Acta Hortic. 1209, 347-352
appearance, modelling, fresh-cut fruit