Anderson Schwingel Ribeiro

Xanthan is a highly relevant commercial microbial biopolymer. Its production occurs in two steps: the bacterium is cultivated in a nitrogen-rich medium for cell multiplication, and the obtained biomass is used as an inoculum for the polymer production phase. Different media compositions for cell growth were investigated, seeking to reduce or replace the peptone used in the standard medium. Peptone (P), yeast extract (YE), and rice parboiling water (RPW) concentration combinations were tested in cultivating Xanthomonas arboricola pv. pruni 101. A CRD 2³ design, performed in a shaker, was used to assess the effects of independent variables on xanthan pruni microbial growth, N consumption, yield, viscosity, pseudoplasticity, and xanthan mineral content. After 24 h an increase in N was observed, without any significant impact on cell growth. Xanthan yield increased as a result of the alternative treatments, with P and YE influencing positively. However, T1, with the lowest levels of P, YE, and RPW increased viscosity and pseudoplasticity of xanthan pruni. RPW increased phosphorus, silicon, calcium, and magnesium, and P and YE increased potassium. These results indicate that partial replacement of P by RPW and YE is an economically viable and sustainable approach for the xanthan pruni production.

The objective of this work was to evaluate the total concentration and bioaccessible fractions of Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Pb, V and Zn in berry fruits and analyze the influence of different cultivars and growing conditions on the obtained results. The variations in bioaccessible concentrations were from 7.7-30, 17-29, 22-50, 1.8-96, 22-33 and 20-51% of the total concentration, for Ba, Cu, Fe, Mn, Pb and Zn, respectively. Copper showed greater bioaccessibility in blackberry and blueberry. For Fe, bioaccessibility was observed in all strawberries and blueberries and in some blackberries. Zinc presented higher bioaccessible fractions in strawberries. For V, only the sample Blackberry 124 showed bioaccessible concentration, (11% of the total concentration). Regarding the different forms of cultivation, the strawberries that received radiation from the red and white lamps presented a higher production of fruit compared to the other systems, however, in relation to the absorption of nutrients, a small variation was observed between the fruits.

The study evaluated the use of nano copper in semi-purified diets for laying quails and its effect on performance, metabolic state, and bioavailability. A total of 160 (180-days-old) quails were distributed in a completely randomized design, in a 3x3+1 factorial. The copper sources used were copper sulfate, copper oxide, and nano copper oxide, at levels of 200, 400, and 800 ppm each, totaling nine treatments plus a negative control (with no copper inclusion). The following variables were determined: weight gain, feed intake, egg production, egg weight, hemoglobin, hematocrit, Cu in the tissues and Cu bioavailability. Data were subjected to analysis of variance at 5% probability. The effect of sources and levels, as well as the interaction between the factors were evaluated. When interaction was observed, the effect of sources was evaluated separately by the Tukey’s test and the effect of levels by regression, both at 5% probability. Copper nano oxide can be used at up to 800 ppm in the diet of laying quails without altering the productive performance, and with higher bioavailability than conventional copper oxide. Hemoglobin increases with the inclusion of 200 and 400 ppm of nano copper oxide and the hematocrit with 400 ppm.

The total concentrations and the bioaccessible fractions of Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, V and Zn were evaluated in 10 samples of pseudocereals, being 3 of amaranth, 3 of quinoa and 4 of chia. The samples were decomposed in a digester block with a reflux system under conditions optimized and the analyses were performed by microwave-induced plasma optical emission spectrometry. In all grains investigated, the highest total concentrations were found for the macroelements K, Mg and Ca, as well as the microelements Fe, Mn, and Zn. When the bioaccessible fraction was evaluated, negative correlations were observed between the content of total phenolic compounds and the bioaccessibility for most elements, in all samples. Among the elements considered essential in our diet, K (99%) and Cu (59%) presented the highest percentages of bioaccessible fraction. Among those elements considered potentially toxic, Ba did not exceed 15% bioaccessible fraction and Al presented concentrations lower than the limit of detection in all samples.

Traditional chocolate and whole-meal flour breakfast cereals were analyzed to determine the total concentrations and bioaccessibilities of some elements. For the total concentration, the samples were prepared by microwave digestion. In addition, certified reference materials were used to verify the accuracy of the method, which was 82–106% for the analytes. Great variation in the concentrations was observed, possibly due to the raw materials used to produce the cereals. For the bioaccessibility study, an in vitro digestion method was used, and the accuracy was verified by the addition and recovery method. Cu, Fe, Mn, and Zn had detectable bioaccessibilities from 37% to 47%, 1% to 41%, 8% to 61%, and 4% to 24% of the total concentrations, respectively. Aluminum, Ba, and Mo had concentrations below the limit of quantification. Therefore, breakfast cereals complement a healthy diet, since some essential elements have high bioaccessibilities.