Amaranthus cruentus flour edible films: influence of stearic acid addition, plasticizer concentration, and emulsion stirring speed on water vapor permeability and mechanical properties

Films forming solutions composed of Amaranth (Amaranthus cruentus) flour (4.0 g/100 mL), stearic acid (5-15 g/100 g of flour), and glycerol (25-35 g/100 g of flour) were prepared by an emulsification process, with varying stirring speed values (6640-13360 rpm). The influence of these parameters (stearic acid and glycerol concentrations and stirring speed) on the water vapor barrier and mechanical properties of films was evaluated using the response surface methodology (RSM). Other characterizations, including microstructure, water solubility, and oxygen permeability, were performed in optimized films. According to statistical analysis results, the optimized conditions corresponded to 10 g of stearic acid/100 g of flour, 26 g of glycerol/100 g of flour, and a stirring speed of 12 000 rpm. The films produced under these conditions exhibited superior mechanical properties (2.5 N puncture force, 2.6 MPa tensile strength, and 148% elongation at break) in comparison to those of other protein and polysaccharide composite films, low solubility (15.2%), and optimal barrier properties (WVP of 8.9 x 10(- 11) g m(- 1) s(- 1) Pa(- 1) and oxygen permeability of 2.36 x 10(- 13) cm3 m(-1) s(-1) Pa(-1)).     

Accompanying ions of ammonium sources and nitrate : ammonium ratios in tomato plants

The tomato (Solanum lycopersicum L.) cultivar Micro‐Tom (MT) is widely used in physiological studies, but the effects of nitrate ( ) and ammonium ( ) ratios ( : ratios) and, in particular, the effects of the accompanying ions in sources are unknown. To determine whether the accompanying ions in sources influence toxicity, the effects of : ratios on the physiology, electrolyte leakage index, nutrition, and dry weight were studied using hydroponics. The sources were ammonium chloride (NH₄Cl) or ammonium sulfate [(NH₄)₂SO₄], and five : ratios were used: 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100. The source was calcium nitrate [Ca(NO₃)₂], and the nitrogen (N) concentration was 15 mmol L^?1. The results indicate that NH₄Cl or (NH₄)₂SO₄ can be used in studies on toxicity because the accompanying ions did not influence the tomato plants. In addition, : ratios of 100 : 0 and 75 : 25 resulted in the highest dry weight of tomato plants, whereas ratios of 25 : 75 or 0 : 100 were toxic.     

Lethal and sublethal responses of <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> populations to essential oils

The present study aimed to assess the lethal and sublethal responses of five populations of S. zeamais to the essential oils of Ocimum basilicum and Piper hispidinervum, through toxicity, locomotor behavior (flight and walking activities) and physiological (respiration rate and body mass) evaluations. The populations of S. zeamais were obtained from Machado—MG, Paracatu—MG, Piracicaba—SP, Recife—PE and Tunápolis—SC. To estimate the LC₅₀ of each oil for each population, fumigation tests were performed. The population from Recife exhibited the lowest instantaneous rate of increase (ri) as well the lowest consumption of grain mass. However, Piracicaba was considered the susceptibility pattern, presenting the lowest LC₅₀ for both essential oils, no statistical difference was observed among populations or treatments in the flight activity bioassays. The essential oils effect on walking activity and respiration rates varied among populations. The population from Recife presented the highest walked distance and walk speed, with the lowest resting time and number of stops, as well as the lowest respiration rate and body mass. The present study highlights the importance of the study on population responses, as the five populations of S. zeamais exhibited different patterns of toxic and behavioral effects when subjected to the essential oils of P. hispidinervum and O. basilicum.     

Variation of Seed Mineral Concentrations in Seven Quinoa Cultivars Grown in Two Agroecological Sites

Variations in concentration and tissue distribution of mineral elements in seeds of seven quinoa cultivars from both a “natural” habitat (Patacamaya, Bolivia, 3,960 m above sea level) and a “nonnatural” habitat (Encalilla, Argentina, 1,980 m above sea level) were analyzed. Data clearly showed inter‐ and intravarietal differences in seed mineral concentrations between the two sites. Correlation analysis revealed that concentrations of major and minor dietary minerals as well as essential ultratrace elements of Encalilla seeds showed, in general, higher correlations with both seed protein and seed yield than did element concentrations of Patacamaya seeds. Results of scanning electron microscopy combined with energy dispersive X‐ray spectroscopy showed clearly differences in the contents of major mineral elements (calcium, magnesium, potassium, phosphorus, and sulfur) in the pericarp and embryonic axis (cotyledon + radicle). Obtained data could indicate that genotype × environment interactions are responsible for mineral variations occurring in quinoa cultivars. Results can also be useful for developing mineral biofortification strategies for the world's poorest regions.