Quality of vegetable and fruit
To develop nondestructructive, objective, quality indicators for tomatoes we measured delayed luminescence, firmness, soluble solids, dry matter, color and respiration during ripening in cherry tomatoes (Lycopersicon esculentum var.cerasiforme). They were harvested in the same moment at various maturity stages, so they had different initial colour, and ripened in the dark at 20°C and 80% relative humidity. Starting from the day after the picking and for two weeks, the respiration, the absolute chromaticity and the delayed luminescence emitted from the different type of fruits (different initial ripening stages) have been regularly measured at the same time. Ten days after harvest we observed on fruit showing similar color, significant differences in the delayed luminescence, soluble solids and dry matter, directly related to harvest maturity. We suggest that delayed luminescence can be used as a nondestructive indicator of important indicators of tomato fruit quality. This results let to think about the possibility of establishing a correlation between respiration and delayed luminescence, whose parameters are dependent on the initial ripening stage of the fruits. So it could be possible to define a parameter "quality of food", since it is known that the composition (i.e soluble solids, dried substance, etc.) of the fruit depend on its initial ripening stage.
Viability of seeds
We are exploring the possibility of using the parameters connected to Delayed Luminescence (DL) to detect stress conditions in various kind of seeds. At this moment a phenomenological relationship between the total re-emission and the growth velocity was found for Soya and Pepper seeds. On the basis of our results it seems that a "quantitative" relation does exist between the physiological state of the samples and the DL. This fact has important practical consequences because the DL technique can be considered a good one to evaluate the vitality and viability of seeds, with the advantage that the test, performed on dry seeds, is fast and non destructive.