Seed coat plays an important role in the embryo protection and seed germination. This study aimed to characterize the anatomical structure, histochemical and physicochemical aspects of the seed coat of Araucaria angustifolia Kuntze. Light and scanning microscopy usual procedures, and histochemical tests were used to describe and characterize seed layers, as well as to determine their extractive contents. Functional groups of the integument coat layers were observed by Fourier transformed infrared spectroscopy. Color analyses were performed in CIE 1976 L*a*b* color space. Wettability of the layers was evaluated by contact angle analysis. The anatomical and chemical features observed in the seed layers include the rucose cuticle and the presence of many layers of sclerenchyma in the mesotesta; and the chromaticity due to extractive content and phenolic compounds in the endotesta. The wettability varied among layers according to their structure. These features information contribute to a better understanding on the services provided by the Araucaria angustifolia seed coat.
This work aimed to investigate phytochemical prospection in treated and untreated wood of Eucalyptus grandis to understand the dynamics of extractives in relation to heat treatment. Samples of E. grandis wood were collected and grouped into external and internal regions. Half of the samples from each region were submitted to heat treatment at 190 ºC. From the treated and untreated samples, phytochemical tests were performed to detect classes of metabolites present in the E. grandis raw wood, hydrophilic extract and lipophilic extract. Phytochemical analysis detected the presence of alkaloids, phenolic compounds and triterpenoids in all hydrophilic extracts of the studied species. Presence of flavanonols, flavanones and saponins was detected only in the internal region of the wood. Tannins, leucoanthocyanidins, triterpenoids and saponins were influenced by heat treatment. The classes of flavonoids, xanthones and alkaloids are the most resistant to heat treatment. The phytochemical analysis made it possible to identify a new class of extractives that emerged after heat treatment, flavones.
The development of alternatives for reuse of coconut shell allows inadequate solid residues disposal reduction and provides a novelty option close to the production sites. This paper aims to evaluate the tannin extraction potential of the green coconut mesocarp, as well as its adhesive capacity. Tannin extraction was performed with sodium sulfite diluted in water at 0%, 1%, 5% and 8% concentrations. It was observed which extraction resulted in better yield and characteristics to be used as an adhesive agent. The concentration of sodium sulfite at 5% allowed higher yields of tannin extraction. When compared to phenol formaldehyde, the tannin had similar adhesive characteristics such as 153.84 cp viscosity and 54.57% solid content. For the FT-IR spectroscopy analysis, dry samples of the coconut mesocarp were used. The peaks observed in the infrared spectrum of the green coconut mesocarp are characteristic of tannins found in biomass, presenting desirable chemical characteristics to be used as an adhesive agent. The coconut mesocarp is a material with potential for tannin extraction, making it suitable to be used in the gluing of panels.
SUMMARYThe aim of this research was to quantify and identify the types of lignin and characterize its functionalization based on apparent physical resistance in each seed coat layers of Araucaria angustifolia. Each seed layer (exotesta, mesotesta and endotesta) was milled, homogenized and pre-extracted with solvents: cyclohexane, ethyl acetate and methanol for quantification of lignin. Pre-treatment with NaOH 1% was also performed in each layer of the seed for lignin quantification and for infrared spectroscopy. The lignin content obtained in the testa was 32.43 % for the three layers. After alkaline treatment, the lignin content was 31.52 % in exotesta, 16.88 % in mesotesta and 15.48 % in endotesta. Dioxane lignin was isolated from the seed coat and reduced with NaHB 4 . Infrared spectra (FTIR) were obtained from the dioxane lignin, reduced dioxane lignin and alkaline-treated Klason lignin of each layer. Microscopic analyses of the in natura exotesta and mesotesta layers from the seed coat were performed through histochemical test (Wiesner) and fluorescence microscopy. Infrared analyses made possible observation of aldehyde terminations in dioxane lignin and propose the structural profile of Klason lignin in different layers. Fluorescence microscopic analyses allowed identification of highly lignified macrosclereids in exotesta.Key words: lignin, nut, infrared, testa. RESUMENEl objetivo de esta investigación fue identificar y cuantificar los tipos de lignina, y caracterizar su función según la resistencia física aparente de cada capa de la testa de la semilla de Araucaria angustifolia. Cada capa de la semilla (exotesta, mesotesta e endotesta) se molió, homogeneizó y sometió a un ciclo de pre-extracción con solventes (ciclohexano, acetato de etilo y metanol) para preparar el material para cuantificar la lignina. También se realizó en cada capa de la semilla un pre-tratamiento con NaOH 1 % para cuantificar la lignina y para aplicar espectroscopía infrarroja. El contenido de lignina en la testa fue 32,43 % para las tres capas juntas. Después del tratamiento alcalino, el contenido de lignina fue de 31,52 % en exotesta, 16,88 % en mesotesta y 15,32 % en endotesta. Lignina dioxano se aisló del tegumento de la semilla y la misma se redujo químicamente con NaHB 4 . Los espectros infrarrojos se registraron a partir de lignina dioxano, lignina dioxano reducida y de lignina de Klason de cada capa con tratamiento alcalino. Se realizaron análisis microscópicos de las capas de exotesta y mesotesta de la testa de la semilla al natural, por prueba histoquímica (prueba Wiesner) y por microscopía de fluorescencia. El análisis infrarrojo permitió observar la presencia de terminales aldehído en lignina dioxano y trazar el perfil estructural de las ligninas de Klason en capas diferentes. En el análisis microscópico con fluorescencia se identificó en la exotesta la presencia de macroesclereidas altamente lignificadas.Palabras clave: lignina, piñón, infrarrojo, testa. INTRODUCCIÓNUna gran parte de las semillas forestales en Brasil se...
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