The relationship between fruit position, ripening stage, and variety has not been well studied in pepper plants. To understand the interaction of these factors, a diversity of phytochemical traits as well as antioxidant activity were investigated with agronomic traits in eleven hot pepper varieties collected from the upper and lower parts of the plant and harvested at three maturity stages (green, orange, and red). Capsaicin content (CAP) showed a relatively high genetic effect; on the contrary, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity were more affected by the ripening stage and fruit position. The CAP values ranged from 0.29 (‘FKbM’) to 0.77 (‘Bka’) mg CAP equivalents g⁻¹ DW. The ripening stage was the predominant factor for TPC, TFC, DPPH, and FRAP. There was no significant interaction between A × FP, A × RS, and FP × RS for all agro-morphological fruit traits. Variety, fruit position, and ripening stage effects are more significant than all interactions calculated. Lower fruit positions in all samples showed a maximum fruit size, whereas phytochemical traits and yield per plant were relevant in the upper parts, and Phytochemical traits and yield per plant were significantly correlated. From PCA and cluster analysis, all varieties showed the highest biochemical and antioxidant levels with moderate fruit size, except the ‘Bel’ variety that showed the smallest fruit traits with high yields, and the ‘FKbM’ and ‘FKbK’ varieties that showed the highest fruit size but low yields. This study supplies information to identify interesting cultivars with considerable levels of bioactive and phytochemical metabolites, which is useful for breeding programs of novel varieties.

Portulaca oleracea L., commonly known as purslane, is a weed with worldwide distribution and considerable medicinal uses due to its high levels of phytochemical compounds. However, until now, few studies have been conducted on the biochemical characterization of P. oleracea grown in Tunisia, a possible area of its origin as other North African countries. Therefore, the aim of the present study was to determine the phytochemical composition and antioxidant potential of leaves and stems from a Tunisian spontaneous population of purslane. Particularly, samples were analyzed for their proximate composition, pigments, and volatiles, whereas ethanolic and aqueous extracts were evaluated for their composition in phenolic compounds and in vitro antioxidant activities. Stems showed higher content of moisture (89.9%) and anthocyanins (4.61 µg g⁻¹ dry matter, DM), whereas leaves revealed higher chlorophyll concentrations (7.42 mg g⁻¹ DM). Significantly higher levels of phenolic compounds and antioxidant capacities (p < 0.05) were obtained in ethanolic extracts, compared with water extracts, irrespective of the analyzed plant part. A high antioxidant activity of stems was obtained, especially when extracted with ethanol. Headspace gas chromatography-mass spectrometry (GC-MS) analyses revealed six volatile classes with monoterpene hydrocarbons, oxygenated monoterpenes, and non-terpene derivatives as the highly represented compounds. Limonene (17.3–32.2%), carvone (38–46%), 2,6-dimethylcyclohexanol (2.2–6.4%), and nonanal (3.4–3.8%) were the most abundant volatiles. Based on the results of the present study, Tunisian purslane should deserve major consideration as an edible vegetable due to its richness in phytochemical compounds and, hence, for its potential health effects.

Pepper species have been described as being highly sensitive to climate change. Here, we discuss the variability of the agro-morphological and phytochemical responses of pepper cultivars in the context of ongoing climate changes during seven stages of maturity, including heat stress. The effects and interactions were calculated to determine the source of variation according to rising temperature. Capsaicin content (CAP), total phenolic (TPC) and flavonoid (TFC) levels and antioxidant activity (AA) were also determined at different harvest times (at 10, 25, 40, 55, 70, 85 and 100 days after anthesis, DAA). Agro-morphological data showed that the highest variation was recorded for fruit traits compared to flower and plant ones. In particular, calyx shape margin, calyx annular constriction, fruit shape at blossom end and fruit size had a significant impact on the morphologic diversity among accessions. Levels of bioactive compounds and antioxidant activity depended on the genotype and the harvest time. TPC and AA increased at 100 DAA, while TFC were highly detected at the early harvest. Principal component analysis (PCA) allowed us to separate three clusters with well-defined biochemical traits. In particular, regardless of harvest time, Baklouti Chébika, Baklouti Sbikha and Chaabani accessions presented higher levels of TPC, TFC and AA regardless of the considered harvest time. In conclusion, high genetic variability was noted within the analyzed pepper germplasm, thus suggesting the need for major consideration of both agro-morphological and biochemical traits for pepper breeding programs. The current research was conducted to facilitate better management under high-stress conditions due to global warming