Okra (Abelmoschus esculentus L.) is a highly nutritious vegetable rich in vitamins, minerals, and bioactive compounds, including polyphenols, offering numerous health benefits. Despite its nutritional value, okra remains underutilized in Europe; however, its cultivation and popularity may rise in the future with increasing awareness of its advantages. In agricultural practices, beneficial soil microorganisms, such as arbuscular mycorrhizal fungi (AMF), Trichoderma spp., Streptomyces spp., and Aureobasidium spp., play crucial roles in promoting plant health, enhancing agricultural productivity together with improved crop nutritional value. This study aimed to investigate the effects of individual and combined inoculation on the polyphenol content of okra fruits, as analyzed by HPLC. Moreover, growth parameters and glutathione-S-transferase enzyme (GST) activities of okra leaves were also estimated. Tested microorganisms significantly increased the yield of okra plants except for A. pullulans strain DSM 14950 applied individually. All microorganisms led to increased GST enzyme activity of leaves, suggesting a general response to biotic impacts, with individual inoculation showing higher enzyme activity globally compared to combined treatments. According to the polyphenol compound analysis, the application of tested microorganisms held various but generally positive effects on it. Only the combined treatment of F. mosseae and Streptomyces strain K61 significantly increased the coumaric acid content, and the application of Aureobasidium strain DSM 14950 had a positive influence on the levels of quercetin and quercetin-3-diglucoside. Our preliminary results show how distinct polyphenolic compound contents can be selectively altered via precise inoculation with different beneficial microorganisms.

The present study was conducted to evaluate recently developed pungent and unpungent red pepper varieties for paprika production with respect to carotenoid and tocopherol composition and content. Varieties with outstanding traits were cultivated using various methods to determine the optimal conditions for maximizing bioactive component levels. The biologically ripe fruits of these varieties were stored under ambient conditions to initiate postharvest overripening. Carotenoids and tocopherols were analyzed using recent HPLC methods. The different varieties of pungent pepper differed significantly in the levels of carotenoid groups and tocopherols. Among pungent breeds, Hetényi Triász (HET-T), CF5, and Uniring (UNIR) showed the highest levels of total carotenoids (1967.39 ± 260.35, 1642.72 ± 67.41, and 1609.07 ± 524.52 µg g⁻¹, respectively). The highest amounts of provitamin A (187.60 ± 8.19 µg g⁻¹) were recorded in the CF5 variety. As regards tocopherols, the highest concentration (547.09 ± 44.20 µg g⁻¹) was recorded for CF5, with no significant differences among the studied varieties. However, the content of vitamin E was significantly higher in CF1 and CF5 than in HET-T and UNIR. Notably, under organic farming conditions, the carotenoid content in UNIR was significantly lower than in the direct-sowing and seedling-transplantation modes. Organic farming of UNIR resulted in lower levels of all carotenoid groups compared with other cultivation modes, particularly conventional seedling transplantation. The indoor cultivation of the unpungent Borbási genotype did not significantly improve the carotenoid content, particularly the total red xanthophylls. Ambient postharvest overripening led to a substantial increase, up to 3-fold, in carotenoid group content in both pungent and non-pungent genotypes. The average value for the total carotenoid content increased from 5005.7 to 8208.3 µg g⁻¹ in unpungent varieties and from 1896.4 to 3426.8 µg g⁻¹ in pungent varieties. For tocopherols, overripening had a slightly positive effect on total tocopherol (from 1375.3 to 1594.7 µg g⁻¹) and esterified forms of vitamin E in pungent breeds with a significantly high increase from 532.0 to 823.7 µg g⁻¹. In conclusion, postharvest overripening is indispensable for obtaining paprika products with an outstanding content of bioactive compounds, particularly red carotenoid diesters. Based on carotenoid content and response to overripening of red and total carotenoids, the UNIR and Borbási varieties are superior to other pungent and unpungent genotypes, respectively. The positive impact of postharvest overripening on carotenoid and tocopherol levels depended mainly on genetic factors.