Abiotic factors can alter the chemical profile of crops and the number of compounds they contain. In this study, the anthocyanin and anthocyanidin contents, determined by ultra-performance liquid chromatography (UPLC-MS/MS), and the colour attributes of the calyces of three cultivars of Hibiscus sabdariffa subjected to three water stress regimes during the stage of physiological maturity were investigated. The total anthocyanin content in calyx increased relative to the control content under a 65% moisture irrigation regime. Among the cultivars, UAN16-2 showed the greatest increases in the contents of cyanidin, delphinidin 3-O-glucoside, cyanidin 3-O-glucoside, and cyanidin 3-O-sambubioside. The content of cyanidin 3-O-sambubioside showed the greatest increase, increasing by 55% relative to the control level. The contents of these compounds are correlated with colour attributes such as luminosity. Water stress under the 33% moisture condition during plant development led to decreased anthocyanin contents in all of the roselle cultivars.

The chemical constituents of roselle (Hibiscus sabdariffa L.) vary by environmental stimuli and cultivar. The effect of cultivars produced under hydroponic and greenhouse conditions on the mineral composition, chemical and nutraceutical quality of the calyx was evaluated. An experiment was conducted in greenhouse and hydroponic conditions, in a randomized complete design with three replicates and four plants per experimental unit. Treatments were formed by a six roselle cultivars: Cruza Negra, Criolla Huajicori, UAN25-1, UAN16-2, 4Q4, and UAN6-Puga. Principal component analysis (PCA) showed that 'Cruza Negra' is the best cultivar because it presents the highest values of total and insoluble fiber (395 and 260 g kg -1 dry basis [db]), total phenols (29.178 mg kg -1 db), anthocyanins (18.133 mg kg -1 db), 2,2-diphenyl-1-picrylhydrazyl (DPPH; 645 mg kg -1 db), and the absorption capacity of oxygen radicals (ORAC; 240 mg kg -1 db). The highest contribution of minerals was observed in 'Cruza Negra' (K, Na, Zn, and Cu) and 'Criolla Huajicori' (Ca, Mg, S, and Mn), contributing significantly to the recommended daily intake (RDI). Variability was evident in all the quality characteristics evaluated in the greenhouse roselle calyx. Ash, total and insoluble fiber, phenols, anthocyanins, DPPH, and ORAC contributed the most to the nutritional and nutraceutical quality of the roselle calyx. These variables were influenced by the cultivar.

En los frutos de pitaya silvestre (Stenocereus thurberi) se distinguen cuatro tipos diferentes de coloración (rojo, tinto, amarillo y anaranjado); el estudio se realizó en su estado de maduración y con base en los que presentaron estos colores, para a través de un análisis químico determinar su color, composición mineral, calidad química y nutracéutica. Los frutos tuvieron en promedio 83 % de humedad, 0.8 % de cenizas y 0.1 % de grasa. Los mayores contenidos de fibra total fueron de (38 g kg-1), SST (13.5 °Brix), glucosa (12.6 g 100 g-1), fructosa (6.1 g 100g-1), fenoles totales (1.9 mg EAG g-1) y capacidad antioxidante (ORAC, ABTS+) para el color anaranjado. Los valores altos de betacianinas (125.4 mg 100 g-1) y betaxantinas (275.1 mg 100 g-1) son valores reportados para el color tinto que también contiene un número mayor de minerales (K, Ca, Mg, Fe y Mn), seguidos de los frutos rojos con (N, Na y Cu), anaranjados (P, Zn) y amarillos (N, K). Los valores del ángulo de matiz para la pulpa en los cuatro colores de la pitaya se situaron en la región amarillenta-rojiza, revelando el color visual para cada fruto con el uso del software ColorHexa. La variabilidad en las características evaluadas estuvo influenciada por el color del fruto de pitaya.

Growth dynamics and morphological traits are used to define the characteristics of roselle cultivars Hibiscus sabdariffa. The morpho–agronomic variability of plants was evaluated, as well as the concentration of macro and micronutrients in leaves of Mexican roselle cultivars in hydroponic and greenhouse conditions. The following roselle cultivars were studied: ‘Cruza Negra’, ‘UAN16-2′, ‘Criolla Huajicori’, ‘UAN 6 Puga’, ‘UAN 25-1′ and ‘4Q4′. The relative growth rate of the crops was fitted to a positive cubic, negative quadratic and positive linear model, whereas stem diameter, fitted to a linear model, had a negative quadratic response. The foliar surface of the cultivars ‘4Q4’, ‘Cruza Negra’, ‘UAN16-2’ and ‘Criolla Huajicori’ was directly related to the size of the flower, the calyx and the corolla. Nitrogen and potassium are the elements that showed the highest concentration in the cultivars Criolla Huajicori and Cruza Negra, while in the other four cultivars the highest concentrations of minerals in the leaf were nitrogen and calcium. The leaves of cultivar 4Q4 provided the greatest amount of minerals, with 83,565 mg kg−1 dry basis. Criolla Huajicori was the cultivar that exhibited the tallest height, the most productive branches and the greatest calyx number per plant; however, Cruza Negra exhibited the highest yield by having the longest calyx.