The basic purpose of the research was to find if there are any statistical differences between the content of primary and secondary metabolites in different harvest dates of blackberry fruits. The experiment was conducted in the year 2016 at the experimental orchard of Agricultural Institute of Slovenia. The testing was done on different blackberry varieties, such as 'Čačanska bestrna', 'Thornfree', 'Loch Ness', 'Navaho' and 'Smoothstem'. All the blackberries were picked in six different times at their optimal ripeness. We measured their color parameters, soluble solids and pH value of their juice. In our experiment we have extracted sugars, organic acids and phenolics from all the samples. After that all the chemical compounds were analyzed by the High Performance Liquid Chromatography (HPLC). The analysis show that the mass of blackberries was reduced from the first to the last date at all cultivars and content of soluble solids was the highest in the last picking date. The results also show that the average content of vitamin C varied between 4,7 and 12,0 mg/100g of fresh mass. Furthermore, the results show that there were also significant differences in content of single and total sugars and organic acids among different sampling dates. In addition, the differences in anthocyanin content at cultivar 'Loch Ness' were not measured between sampling dates, while for the other cultivars the differences were significant.
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