The chili pepper is a very important plant used worldwide as a vegetable, as a spice, and as an external medicine. In this work, eight different varieties of Capsicum annuum L. have been characterized by their capsaicinoids content. The chili pepper fruits were cultivated in the Comarca Lagunera region in North of Mexico. The qualitative and quantitative determination of the major and minor capsaicinoids; alkaloids responsible for the pungency level, has been performed by a validated chromatographic procedure (HPLC-DAD) after a preliminary drying step and an opportune extraction procedure. Concentrations of total capsaicinoids varied from a not detectable value for Bell pepper to 31.84 mg g⁻¹ dried weight for Chiltepín. Samples were obtained from plants grown in experimental field and in greenhouse without temperature control, in order to evaluate temperature effect. Analysis of the two principal capsaicinoids in fruits showed that the amount of dihydrocapsaicin was always higher than capsaicin. In addition, our results showed that the content of total capsaicinoids for the varieties Serrano, Puya, Ancho, Guajillo and Bell pepper were increased with high temperature, while the content of total capsaicinoids and Scoville heat units (SHU) for the varieties De árbol and Jalapeño decreased. However, the pungency values found in this study were higher for all varieties analyzed than in other studies.

K and N are the nutrients with the highest influence on yield and fruit quality. From this perspective, the aim of this study was to determine the effect of N as NO₃⁻, K⁺ and their interactions on the yield and quality of strawberries grown under soilless conditions. A solution comprised of micronutrients based on an amended Steiner’s Universal Nutrient Solution was mixed with 4 levels of K⁺ (5, 7, 9 and 11 mol m⁻³) and 3 levels of NO₃⁻ (9, 12, and 15 mol m⁻³) to obtain 12 treatments. The results suggest that 15 mol m⁻³ of NO₃⁻ in the nutrient solution produced the highest yield, but fruit with low nutraceutical quality. On the other hand, 11 mol m⁻³ of K⁺ in the nutrient solution produced the highest yield and fruit with the best nutraceutical quality. The ionic concentration of the Universal Steiner’s Nutrient Solution proved to be the best nutritional option to maximize the yield and nutraceutical quality of strawberry fruit. The increase in NO₃⁻ concentration in the nutrient solution produced a higher yield of strawberries, while a higher concentration of K⁺ improved fruit quality, thus reaffirming the significance of nutrients within the plant functioning of this crop.

The potential impact of increased levels of potassium (K⁺) in hydroponic solution on the production of bioactive compounds, which provide added value to products, is relevant for local economy and human health. This research pursues assessing different levels of K⁺ on the nutrition of basil, an important aromatic crop in the arid region of La Laguna, northern México, where water scarcity demands the conversion from open-field agriculture to hydroponics. A randomized complete block design with a factorial arrangement (3 × 4) was used to determine the content of nutraceutical components, including polyphenolic compounds, flavonoids, anthocyanins, vitamin C, chlorophylls, and the antioxidant capacity of three varieties of hydroponic basil, with four doses of K⁺ in the nutrient solution, 7, 9, 11 and 13 mmol L⁻¹. The analysis of variance showed significant differences (p ≤ 0.001) in most of the response variables, caused by the genotype and doses of K⁺. The antioxidant capacity of assessed cultivars was improved when doses of K⁺ were increased in the nutrient solution. Furthermore, the antioxidant capacity was positively correlated to the content of flavonoids (r = 0.621), anthocyanins (r = 0.655) and total phenolic compounds (r = 0.549). In conclusion, the nutraceutical content was increased in basil when controlling K⁺ in the nutrient solution.

Organic fertilizers were evaluated on jalapeno pepper (Capsicum annuum L.) and on their effect on the soil content of nitrogen (N), phosphorus (P), electrical conductivity (EC), pH and organic matter (OM), at the Experimental Station of the Agriculture and Zootechnics Faculty (FAZ-UJED), Ejido Venecia, Durango, México. The assayed experimental fertilizers were vermicompost (VC) with 0 and 3 Mg ha⁻¹, in factorial combination with solarized manure (SM), with 0, 40, 80, and 120 Mg ha⁻¹, and an inorganic fertilization nitrogen-phosphorus-potassium (NPK) at 150–100–00 Mg ha⁻¹. Microbiological analyses were performed to evaluate the presence of Salmonella spp. The highest yield was 56.2 Mg ha⁻¹ with 120 Mg ha⁻¹ SM, which was statistically similar to 40 and 80 Mg ha⁻¹; the highest P content (70.7 mg kg⁻¹) and OM (3.7%) occurred with 120 Mg ha⁻¹ SM. The inorganic fertilizer reflected the lowest OM (1.1%). Nutrients provided by SM were sufficient to satisfy the crop needs. Values of pH, EC and N were not affected by SM. The fruit quality was not affected by the organic fertilizers. Most fruits were classified as Second-Class Quality (60%), followed by First-Class Quality (25%). Microbiological analyses were negative for Salmonella spp., suggesting that the SM is effective in its elimination.