Investigation of pigments, volatile compounds and some quality characteristics of purple basil (ocimum basilicum L.) grown at different pH levels under hydroponic conditions

In the present study, the growth and quality characteristics of purple basil cultivars, which were grown in hydroponic systems, were investigated at different pH levels. For this purpose, two purple basil cultivars (Dark Opal and Arapgir) and three pH levels (5.0, 6.5, and 8.0) were used in the study. The result of the study showed that cultivars, treatments, and cultivar x treatment interactions were found to be significant for all traits examined (P<0.05 and P<0.001). Based on plant height, number of branches, and plant weight, it was determined that Arapgir grew better at pH 6.5, while Dark Opal grew better at pH 5.0. While L*, b* and c* values increased, a* and h° values decreased with the increasing pH levels. SPME analysis was used to determine the amount and numbers of scent compounds at each pH level in purple basil cultivars. The detected number of scent compounds was 49 and 39 at pH 5.0, 48 and 43 at pH 6.5 and 40 and 47 at pH 8.0 for Dark Opal and Arapgir, respectively. To determine the changes in quality characteristics, total of 14 analyses (total chlorophyll, carotene, phenolic, flavonoid, CUPRAC, FIC, soluble and reducing sugars, starch, protein, anthocyanin amounts and PAL activity) were performed. The resutls showed that significant differences fournd for all measured parameters between varieties and pH levels in the study.