Browsing by Subject "lykopeeni"

Tomatoes (Solanum lycopersicum) are one of the most important food crops in the world. Long supply chains force producers to harvest the fruit before ripening. Ripening then happens in super markets or at the end–consumer. Partly due to the early harvest, tomatoes are perceived flavorless, especially in the wintertime. In addition to a demand for more flavorful produce, consumers are also increasingly interested in healthy food and are looking at the nutritional value of their food before the price tag. As tomatoes are a major crop, they could potentially also contribute to the daily nutrient intake of consumers, such as lycopene, which is i.e. suggested to have preventative qualities towards cancer. Several studies have been conducted to find out how light emitting diodes (LED –lights) could influence the plant and its compounds during growth, but post-harvest research to a lesser extent. Research on post-harvest LED–lighting suggests that quality attributes could also be influenced post-harvest. Important parameters to look at are color and firmness, as they are what buying decisions are primarily based on. Further, lycopene, but also total soluble sugars (TSS) and titratable acidity (TA), and especially their ratio, which defines how tomato flavor is perceived, are worth studying. Therefore, this study aimed to find out, how LED–light treatments could be used to steer the post-harvest quality of tomatoes. Three continuous light treatments were used; Blue, far-red, a standard growing light with high red to far-red ratio and dark as control. The study was done on two cultivars by measuring TSS, TA, lycopene, vitamin C and firmness of the tomatoes every fourth day for 12 and 15 days. Additionally, a set of tomatoes was analyzed for changes in weight and color. The results suggest that LED-lights do influence the quality characteristics of tomato fruit. Blue light seemed to decrease firmness, but to increase lycopene. Lycopene accumulation was also enhanced by a high red to far-red ratio, whereas far-red had a reversing effect. Both blue and high red to far-red ratio treatments increased the chroma values, making the tomatoes brighter in color. Far-red seemed to enhance red color development and to retain firmness, but to decrease lycopene accumulation and to make the color duller. Tomatoes kept in the dark had low lycopene content and a dull coloration. Results on TSS and TA indicate differences in genotype responses, which further underlines the need for further research on the topic and especially the effect of cultivar. The results of the study indicate that tomatoes should not be kept in the dark during storage, as then the full potential of their external and internal quality will not be reached. High red:far-red ratio lighting increases lycopene and brightens the coloration, and could be considered to be used during storage. However, other external factors affecting quality, such as ethylene and temperature, should be included in the future research to study their effect and correlation with light in regard to tomato fruit quality.