This article reports on using cassava starch nanocrystals (CSN) to strengthen nanocomposite films from the same matrix. CSN were obtained by acid hydrolysis. Nanocomposite (starch:glycerol:CSN/4.0:2.1:1–10 wt %) were processed by casting and the films were characterized. The CSN (30% yield) presented minimally clustered globular forms, 45 to 178 nm in diameter, with a crystalline index of 46%. Water‐vapor transmission rate, tensile strength, and elastic modulus of the films were influenced by the linear effect of CSN concentration (R2 = −0.92, 0.91, 0.99, respectively), while the other parameters resulted in quadratic relations |0.69–0.96|. The film with 10% CSN presented a 43% reduction in water vapor permeability, associated with increases of 200% in traction resistance, and 616% in elasticity modulus, compared with the control. The hydrolysis of part of the cassava starch into nanocrystals resulted in a reduction in permeability and nano reinforcement of the films due to good compatibility and interaction between both, without influencing biodegradability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45311.

A comparative performance study of cellulose and starch nanoparticles on plasticized starch reinforcement has been presented. Starch nanoparticles were obtained by ultrasound and acid hydrolysis, and cellulose nanoparticles were extracted by acid hydrolysis from microcrystalline cellulose and sisal fibers. The nanoparticles were characterized according to the zeta potential, the particle‐size distribution, transmission electron microscopy, X‐ray diffraction, and thermogravimetric analysis. The influence of the addition of these nanoparticles to starch films on the morphology, water vapor permeability (WVP), and mechanical properties of the nanocomposites films were investigated. The cellulose nanoparticles exhibited higher electrical stability than those originating from starch. Acid hydrolysis produced starch nanoparticles with higher crystallinity than ultrasound. All the nanoparticles significantly reduced the WVP. The cellulose nanoparticles significantly increased the tensile strength of the starch films; however, they reduced the flexibility of the nanocomposites. The results of this work support the application of starch and cellulose nanostructures for the development of reinforced biodegradable materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47001.

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O umbuzeiro, planta pertencente ao gênero das Spondias e família Anacardiaceae, possui 18 espécies que estão localizadas nas Américas, Ásia e Oceania. O fruto tem recebido destaque no mercado nacional e internacional por sua variedade de compostos bioativos, que apresentam efeitos nutracêuticos e terapêuticos. Entretanto, um melhor aproveitamento pode ser obtido através do conhecimento da variabilidade genética desses frutos. Diante disso, objetivou-se realizar uma revisão a respeito da composição bioativa e química como também da atividade antioxidante de frutos de umbu em relação a variação destes parâmetros entre diferentes genótipos do fruto. Apesar das boas propriedades físico-químicas, nutricionais, sensoriais, nutracêuticas e terapêuticas, os frutos do umbuzeiro apresentam comercialização limitada aos locais onde são produzidos devido ao período de sazonalidade, por esta razão, conhecer as características e propriedades específicas de cada genótipo dos frutos do umbuzeiro é de extrema importância, uma vez que, conhecendo tais propriedades, é possível apontar diferentes formas de processamento, melhorias nas técnicas de cultivo, colheita, beneficiamento e processamento e aumento da produtividade, entre outros.