Citrus sudden death (CSD) is a disease that has affected millions of orange trees in Brazil, leading to economic losses in the order of billions of US dollars. This article examines the effects of CSD on the fatty acid composition of triacylglycerides (TAG) extracted from rootstock and scion bark. The fatty acid profile determined by gas chromatography showed a reduction in oleic and linolenic acids, and an increase in the saturated fatty acids and linoleic acid content, which was in line with the severity of CSD. The reduction in linolenic acid content was related to its role in the biosynthesis of jasmonic acid, which is involved in responses to abiotic and biotic stresses, as well as senescence. These alterations in the fatty acid profile were also used to classify plants both with and without CSD symptoms by using chemometric means. This method represents an alternative to support the diagnosis of CSD disease.

A associação da celulose bacteriana com outros polímeros pode ser um método efetivo para aumentar suas características e estrutura, proporcionando novas aplicações industriais. O objetivo do trabalho foi verificar a influência da celulose bacteriana nas propriedades físicas, químicas e de barreira em filmes a partir de blendas de celulose bacteriana e fécula de batata. Os filmes foram produzidos segundo planejamento de mistura ternária, tendo como variáveis independentes a celulose bacteriana, fécula de batata e glicerol. Blendas com maiores concentrações de celulose bacteriana apresentaram aumento na espessura, gramatura, taxa de permeabilidade ao vapor de água e permeabilidade ao vapor de água e, redução da densidade, solubilidade, opacidade, índice de intumescimento em pH 1,8 e 8,0 (1, 10, 30 e 60 minuto). A microscopia eletrônica de varredura mostrou filmes com matriz coesa, porém irregular com presença de partículas insolúveis de celulose bacteriana. O filme de celulose bacteriana pura apresentou aumento na gramatura, opacidade, taxa de permeabilidade ao vapor de água e no intumescimento em pH 1,8 1 minuto e pH 8,0 1, 10, 30 e 60 minutos. A celulose bacteriana promoveu elevada capacidade de retenção, absorção e baixa dessorção a água, proporcionando biofilmes com características de barreira à luz e manutenção da umidade.

The association of bacterial cellulose with other polymers can be an effective method for increasing its characteristics and structure, providing new industrial applications. The purpose of this paper was to verify the influence from bacterial cellulose in the physical, chemical and barrier properties in films of bacterial cellulose blends and potato starch. The films were made according to a ternary mix planning, with bacterial cellulose, potato starch and glycerol as independent variables. Blends with higher concentrations of bacterial cellulose exhibited increase in thickness, weight, permeability rate of water steam and permeability to water steam and reduction of density, solubility, opacity, swelling index at pH 1.8 and 8.0 (1, 10, 30 and 60 minutes). The scanning electron microscopy showed films with cohesive matrix, but with irregular morphology, containing insoluble particles of bacterial cellulose. The pure bacterial cellulose film showed increased weight, opacity, permeability rate of water steam and at swelling at pH 1.8 at 1 minute and pH 8.0 at 1, 10, 30 and 60 minutes. The bacterial cellulose contributed to high capacity of retention, absorption and low water desorption, providing biofilms that acted as barrier for light and kept the humidity constant.

In this work, ¹H Nuclear Magnetic Resonance (¹H NMR) was employed to evaluate changes in apple juice in response to the addition of Panzym® Yieldmash and Ultrazym® AFP-L enzymatic complexes and compare it with premium apple juice. The juice was processed at different temperatures and concentrations of enzymatic complexes. The differences in the results were attributed mainly to the enzyme concentrations, since temperature did not cause any variation. A quantitative analysis indicated that the concentration of fructose increased while the concentrations of sucrose and glucose decreased in response to increasing concentrations of the enzymatic complexes.

In recent years, the interest in polymer recycling has increased. However, in every reprocessing step the material undergoes shear stress and is affected by temperature and oxygen. The aim of this paper is to investigate the influence of multiple extrusion in the generation of functional groups, namely hydroperoxide, carbonyl, and transvinylene. Low density polyethylene was reprocessed three times in a single screw extruder. In each recycling step hot pressed films were prepared. These films were submitted to a heat treatment in an oven with air circulation and renovation to proceed with aging tests at different times and temperatures. The results obtained showed that all functional groups had their concentration increased with the increase in number of reprocessing, the aging time and temperature of the heat treatment. The factorial design was applied to verify the influence of these parameters. All the parameters had significant effects, since their regression coefficients had the same order of magnitude, with the most influential parameter being the aging temperature, followed by the aging time and number of extrusions. Most of the interactions were influential, indicating that the formation of functional groups depends upon their interaction, and not only on their isolated effects.

Acetylation was performed to reduce the polarity of wood and increase its compatibility with polymer matrices for the production of composites. These reactions were performed first as a function of acetic acid and anhydride concentration in a mixture catalyzed by sulfuric acid. A concentration of 50%/50% (v/v) of acetic acid and anhydride was found to produced the highest conversion rate between the functional groups. After these reactions, the kinetics were investigated by varying times and temperatures using a 3² factorial design, and showed time was the most relevant parameter in determining the conversion of hydroxyl into carbonyl groups.