The water quality index (WQI) is an important tool for water resource management and planning. However, it has major disadvantages: the generation of chemical waste, is costly, and time-consuming. In order to overcome these drawbacks, we propose to simplify this index determination by replacing traditional analytical methods with ultraviolet-visible (UV-Vis) spectrophotometry associated with artificial neural network (ANN). A total of 100 water samples were collected from two rivers located in Assis, SP, Brazil and calculated the WQI by the conventional method. UV-Vis spectral analyses between 190 and 800 nm were also performed for each sample followed by principal component analysis (PCA) aiming to reduce the number of variables. The scores of the principal components were used as input to calibrate a three-layer feed-forward neural network. Output layer was defined by the WQI values. The modeling efforts showed that the optimal ANN architecture was 19-16-1, trainlm as training function, root-mean-square error (RMSE) 0.5813, determination coefficient between observed and predicted values (R) of 0.9857 (p < 0.0001), and mean absolute percentage error (MAPE) of 0.57% ± 0.51%. The implications of this work's results open up the possibility to use a portable UV-Vis spectrophotometer connected to a computer to predict the WQI in places where there is no required infrastructure to determine the WQI by the conventional method as well as to monitor water body's in real time.

Plants endue a key role against illnesses caused by oxidative stress. These attributes are frequently associated with polyphenolic compounds. However, presence and concentration of secondary metabolites are affected by abiotic factors. The in vitro culture techniques can solve these drawbacks. Peppers can be a suitable alternative to obtain polyphenols. Aiming to optimise the callus culture stage from Capsicum baccatum to produce polyphenols, this work evaluated systemically the effects of the explant's origin (root, hypocotyl and cotyledon), growth hormone type (2,4-dichlorophenoxyacetic acid (2,4-D), benzylaminopurine (BAP) and a combination of 2,4-D/BAP at five-to-one ratio) and concentration (0.023-10.000 mg L) on callus culture efficiency parameters using a multilevel factorial design. The root explant in combination with BAP at 1.138 mg L ensured the optimal values of the assessed responses; ​callus mass (225.03 mg), antioxidant activity (35.95%), total phenols (11.48 mg of GAE/g DE) and flavonoids (15.92 mg of RU/g DE) production.

The Capsicum genus comprises hundreds of varieties with fruits that differ widely in shape, size, color, and flavor. The Brazilian cuisine consumes Capsicum baccatum L. (pepper) extensively and few reports about chemical composition and biological properties about this pepper were published. The present study determined four factors numeric effects on germination in vitro of this specie, among them, the solution type for osmotic conditioning (water and 1% KNO3 aqueous solution), germination medium (agar and agar + gibberellic acid at 1.88 mgL -1 ), post-seeding time (15 and 30 days) and two genotypes (Pitanga and Cambuci) on two germination parameters (germination and cotyledon emerging rates), as first step for establishing a cell suspension culture to produce secondary metabolites. The methodology was a two-level full factorial experimental design (2 4 ). The results allowed polynomial equations definition which describes the germination phenomena as a function of the four factors under study. The genotype responses to osmotic conditioning and germination medium were different. The optimal combination of treatments for in vitro germination and development of seedlings for Pitanga and Cambuci was water + agar and water + agar-GA3, respectively.

This work aimed to optimize statistically the culture medium composition for cell plant suspension culture using as a model Capsicum baccatum L. var. pendulum cells. The cell growth was maximized as well as the secondary metabolite yields with antioxidant activity, which could find applications in pharmaceutical and food industries. A Box-Behnken statistical design was utilized to optimize the basal Murashige and Skoog medium, which is widely used in plant cell culture. Three relevant ingredients, saccharose (A, 15-45 g L −1), KH 2 PO 4 (B, 0.085-0.255 g L −1) and KNO 3 (C, 0.95-2.85 g L −1) were considered. The cell growth index as well as antioxidant activity, total phenolic compounds and flavonoids from dry extracts (DE) derived of cell cultures, were determined. Growth index (GI) and flavonoids content (F) were sensitive to the changes in nutrient composition in culture medium, and they were modeled statistically according to modified quadratic (GI = 1.76 + 0.59A − 0.32B − 0.42AC) and two-factor interaction (F(mg of rutin∕g DE) = 0.88 + 0.35AC − 0.29BC) models, respectively. Antioxidant activity and total polyphenols were independent of the nutrient concentrations within the range under study. The optimized culture medium composition was defined for two approaches: maximization of the cell growth (45 g L −1 saccharose, 0.09 g L −1 KH 2 PO 4 , 0.95 g L −1 KNO 3) and maximization of flavonoids production (45 g L −1 saccharose, 0.09 g L −1 KH 2 PO 4 , 2.85 g L −1 KNO 3). According to the current results, other elicitation strategies should be assessed to make this bioprocess more efficient for manufacturing secondary metabolites with antioxidant activity from suspension culture of Capsicum baccatum L. var. pendulum cells.