This study was conducted to analyze carotenoids from tomatoes by high-performance liquid chromatography using reversed-phase C18 silica having cross-linked end-capping with diode array and mass spectrometric detection. An efficient gradient elution system was developed to achieve good and reliable separation of both major and minor carotenoids as well as their isomers. Resolution of lycopene, β-carotene and their isomers was 0.91–3.97 and 1.02–2.86 with cross-linked and conventional C18 column, respectively. The % recovery for zeaxanthin, lycopene and β-carotene was found to be in the range of 89–97%. Limits of detection and quantification of 19.44 and 64.79 ng/mL for zeaxanthin, 15.6 and 52.4 ng/mL for lycopene and 8.28 and 27.61 ng/mL for β-carotene were determined. More carotenoid compounds could be separated and detected with the new method as compared with conventional C18 column. Hyphenation of HPLC with photodiode array and mass spectrometry detectors assisted in detection of tetra-dehydrocarotenoid and fatty acid diesters of xanthophylls in tomato products. Content of all-trans-lycopene, β-carotene and total carotenoid in different industrial tomatoes tested was found to range between 41.87 and 84.65, 0.89 and 1.50 and 53.22 and 112.60 µg/g fresh weight, respectively.

In light of the great technological progress in non-destructive quality detection methods, sweetness is no longer the essential parameter in evaluating watermelon quality. There is an aspiration to determine physicochemical quality characteristics to enable us to select the best cultivars, agricultural practices, and harvest dates. In the present work, three different watermelon cultivars (Lady, Galander, and Style) were harvested at three consecutive harvest times. Two pieces were taken from each watermelon sample, one from the middle (part A) and the other from the ends (part B), to track the intensity of quality parameters inside the watermelon. Parts A and B were subjected to Vis/NIR spectroradiometer (475:1075 nm), near-infrared spectroscopy (NIRS) (950:1650 nm), and high-performance liquid chromatography to assess the physicochemical quality. Calibration and prediction models were conducted using partial least squares regressions (PLS). The results indicated that the harvesting time significantly influenced the color and chemical parameters. Quality parameters concentrations markedly degraded towards late harvest. The highest concentrations of quality parameters were sighted for the middle zone (part A), especially in the Galander cultivar. Spectroradiometer achieved the best coefficient of prediction (R²_P) ≃ 0.88 and 0.81 attached with the lowest value of the standard error of prediction (SEP) ≃ 0.03 and 1.06 for chroma (C*) and yellowness index (YI). However, the findings showed the superiority of the NIRS compared to the Vis-NIR method. The highest R²_P was achieved by values 0.92, 0.91, 0.90, 0.89, 0.85, and 0.85 for lycopene, total carotenoids, vitamin C, β-carotene, γ-content, and TSS, respectively. It could be concluded that the NIRS has the ability to monitor the maturity development and determine the harvest dates practically and reliably.

Pungent red peppers and chilis are healthy foods and crucial ingredients of modern diets due to their content of bioactive phytochemicals such as carotenoids, tocopherols, capsaicinoids, polyphenols, and vitamin C. The production of pungent peppers with outstanding nutritional properties is influenced by genetic factors and their interaction with the environments where they are cultivated. This study was conducted to investigate the effects of genotype and climate conditions on the response of capsaicinoids and vitamin C. The extracts of pungent materials and vitamin C were separated and qualitatively determined by HPLC alone or hyphenated with mass spectroscopy. Four genotypes were selected and cultivated under traditional agricultural practices in southern Hungary. The yield properties and the contents of capsaicinoids and vitamin C were significantly influenced by genetic factors and, to a high extent, by the interaction between genotype × environment. The highest yield of 2.86 ± 0.59 kg/m² was recorded for the CS variety. The yield was significantly decreased under high precipitation and low air temperature. The highest concentration of capsaicin of 1586–1734 µg/g dwt was found in the BHJ variety. The lowest level of 514 µg/g dwt of capsaicin was determined in the CS variety, in which the content significantly increased to 772 µg/g dwt with the increase in rainfall and decrease in air temperature in the warmer season of 2022. In most cultivars examined, capsaicin content negatively responded to the change of the climate toward higher precipitation and lower temperature except for SZ178, in which the concentration of capsaicinoids stayed insignificantly varied. The amount of vitamin C ranged between 570 and 135 µg/g dwt, with the highest content being in the BHJ and the lowest in the REK variety. In most varieties except the REK, vitamin C positively responded to a high and negatively to the reduced levels of precipitation. In conclusion, the phytochemical components of hot peppers respond differently to climatic factors—such as high rainfall, elevated air temperature, and intense sunlight—depending on the genotype’s ability to adapt to environmental changes.

Growing conditions and seasonal fluctuations are critical factors affecting fruit and vegetable nutritional quality. The effects of two partially overlapping cropping seasons, early (ECS; January–May) and full (FCS; March–July), on the main carpometric traits and bioactive components of different watermelon fruits were investigated in the open field. Four watermelon genotypes, comprising of three commercial cultivars ‘Crimson Sweet’, ‘Dumara’, ‘Giza’, and the novel hybrid ‘P503 F1’, were compared. The carpometric traits varied significantly between genotypes. Soluble solids and yield were higher under FCS than ECS. The variation affecting colour indexes between the two growing seasons exhibited a genotype-dependent trend. The antioxidant components and radical scavenging activity of watermelon fruits were also significantly affected by differences in received solar energy and temperature fluctuations during the trial period. The average citrulline, total phenolics and flavonoid contents were 93%, 71% and 40% higher in FCS than in ECS. A genotype-dependent variation trend was also observed for lycopene and total vitamin C between cropping seasons. The hydrophilic and lipophilic radical scavenging activities of the pulp of ripe watermelon fruits of the different genotypes investigated varied between 243.16 and 425.31 µmol Trolox Equivalent (TE) of 100 g⁻¹ of fresh weight (fw) and from 232.71 to 341.67 µmol TE of 100 g⁻¹ fw in FCS and ECS, respectively. Our results, although preliminary, show that the functional quality of watermelon fruits is drastically altered depending on the environmental conditions that characterize the ECS and LCS.