Cassava is a starchy tuberous root of great energetic potential, and can be used for both in natura consumption and for industrial processing, which generates significant amounts of ba-gasse that is potentially useful as a source of dietary fiber. Studies have shown the benefits of functional food, and that has led to an increase in consumer interest. Extrusion technology had been used lately for the development of new food products. Pasta has been incorporated as part of Brazilian cuisine, being served as a main course or a side dish, in many different com-binations. Due to the nutritional advantages of the amaranth, much research has been made on the use of its flour as a substitute for wheat flour in cooking with the final goal of a more nu-tritious product. This work focused on evaluating the effect of temperature of extrusion and moisture on the physical and technological properties of extruded products made trough mix-tures of starch and flour from the cassava (70:30) bagasse. Extrusion was made with a single screw extruder and followed the central rotational composite design with two factors or in-dependent variables for mixture moisture and extrusion temperature, on a total of 12 treat-ments. It was also intended to analyze the effect of the components on the boiling properties of pre-boiled pasta made of cassava (70:30) bagasse and pre-gelatinized starch flour, cassava starch and amaranth flour through mixture design, and to assess the physical, technological and nutritional properties of this pasta. The properties of the extruded products that were ana-lyzed were: expansion index, specific volume, water-absorption index, solubility in water index, oil-absorption index, activity of water and color. Analysis of texture and scanning elec-tron microscopy were performed on the pasta. An ideal formulation was set and its centesimal composition and quality parameters determined and compared to commercial pasta of both standard and wholemeal flour. Clear products with high expansion and intermediate specific volume were obtained at intermediate extrusion temperature conditions (104,10 ºC) and mix-ture moisture [16 g (100 g) -1]. Acceptance tests indicated consumers rated it very good (7,2 score) with a 42% purchase intention. The results obtained showed that the combined use of pre-gelatined starch and cassava (70:30) bagasse flour, cassava starch and amaranth flour, in the proportion of 10:60:30, allowed the creation of instant pasta with a 3min boiling time, 101,46% mass increase and 0,6% loss of solids in boiling water, besides good physical, chem-ical and technological texture conditions, with 9,37 g (100 g)-1 of fibers, 10,41 g (100 g)-1 of proteins, 4449,09 gf of firmness and a low stickness of 324,19 gf, allowing the use of indus-trial waste on human food and a bigger range of healthy gluten-free products.

This thesis combines two fields that are currently viewed as relevant scientific topics: aerogels and reuse of post-consumer residues (PCR) from plastics.Three different types of aerogels were prepared: PCR aerogels, fibers-reinforced PCR aerogels, and PCR fibers-reinforced silica aerogels. The PCR aerogels were obtained from a dissolution/precipitation method, from which a gel was obtained. The gel was then dried by freeze-drying. The reinforcement of PCR aerogels was made with commercial fibers. Silica aerogels were prepared by the sol-gel technique, after a two-step acid-base catalyzed procedure, using a well-established method developed by the Computation & Materials (CeM) group, at the Department of Chemical Engineering of University of Coimbra. The PCR fibers were added right before the addition of the base and subsequent gelation. The gels aged for 6 days and were then subjected to a solvent exchange, with heptane, for two days, followed by a silylation step, with Hexamethyldisilazane (HMDZ), for one day. Finally, the samples were dried at ambient pressure and the aerogels were formed. The PCR aerogels showed a highly porous morphology, with macro and mesopores. In the case of the reinforced aerogels, a good interaction between the fibers and the aerogel matrix was observed. Bulk density, skeletal density and porosity were also analyzed. The results obtained are in line with those presented in literature. The values of thermal conductivity and thermal diffusivity of PCR aerogels were slightly higher than those obtained for silica reinforced aerogels. The values of specific heat were close to those found for fiber-reinforced silica aerogels. The mechanical properties of PCR aerogels (both unreinforced and reinforced) were inferior of those presented for other polymer-based aerogels in literature, but slightly better than the verified for the silica aerogels.Regarding silica aerogels reinforced with PCR fibers, from the SEM analysis, it was observed that the silica bounded to the fibers. The values of thermal diffusivity, thermal conductivity and specific heat were in the range of other fiber reinforced-silica aerogels, although the bulk density was higher.

The reinforcement of stabilized soils with fibers arises as an interesting technique to overcome the two main limitations of the stabilized soils: the weak tensile/flexural strength and the higher brittleness of the behavior. These types of mixtures require extensive laboratory characterization since they entail the study of a great number of parameters, which consumes time and resources. Thus, this work presents an alternative approach to predict the unconfined compressive strength (UCS) and the tensile strength of soil-binder-water mixtures reinforced with short fibers, following a Machine Learning (ML) approach. Four ML algorithms (Artificial Neural Networks, Support Vector Machines, Random Forest and Multiple Regression) are explored for mechanical prediction of reinforced soil-binder-water mixtures with fibers. The proposed models are supported on representative databases with approximately 100 records for each type of test (UCS and splitting tensile strength tests) and on the consideration of sixteen properties of the composite material (soil, fibers and binder). The predictive models provide an accurate estimation (R2 higher than 0.95 for Artificial Neuronal Networks algorithm) of the compressive and the tensile strength of the soil-waterbinder- fiber mixtures. Additionally, the results of the proposed models are in line with the main experimental findings, i.e., the great effect of the binder content in compressive and tensile strength, and the significant effect of the type and the fiber properties in the assessment of the tensile strength.

ABSTRACT The aim of this study was to obtain the equilibrium moisture content of grape (variety ‘Tannat’) pomace through desorption isotherms, to evaluate the drying kinetics, determine the coefficient of effective diffusivity and physico-chemically characterize the grape pomace and the product obtained after drying. The desorption isotherms were determined at 50, 60 and 70 ºC and the experimental data were fitted using the GAB model (Gugghenheim, Anderson and de Boer). Drying was evaluated using a 22 factorial experimental design with three center points and effective diffusivity was obtained through the diffusion model of Fick’s second law. The grape pomace was characterized regarding the contents of moisture, protein, carbohydrates, lipids, ash and dietary crude fiber. The obtained isotherms showed sigmoid shape and the experimental data fitted well to the GAB model. The drying curves showed only a decreasing rate period. The effective diffusivity values were within the range for organic materials. Dry grape pomace showed high contents of protein and fiber and can be used in the development of new products, in order to increase the nutritional content and add value to this byproduct.

Polymeric films have been increasingly investigated due to the ease of miniaturization and integration in several sensor devices. Films obtained from the electrospinning technique have a controlled diameter and homogeneity, and substances can be incorporated into the polymeric network. Electrospinning fiber of chitosan (Ch) and poly(ethylene oxide) (PEO) was obtained from solutions prepared at different concentrations in acetic acid, and varying the distance and the voltage applied. The obtained films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and UV-Visible specular reflectance spectra (UV-SRS). The best conditions for electrospinning were obtained for a 2% m/v (Ch + PEO) solution in the ratio 90:10% m/m (Ch:PEO), applied voltage of 18 kV, and 18 cm distance between the capillary tube and collector. Acridine orange, sodium fluorescein, and erythrosine fluorescence dyes were successfully incorporated into Ch:PEO films. The spectrofluorometric spectra of the films showed excitation and emission processes and the acridine orange film showed evidence of excimer formation by the presence of an excitation peak at 569 nm. Ch-PEO films with the incorporation of fluorescent dyes may well be used as flexible probes or sensors in colorimetric devices in biochemical applications.

The polypeptide H21(30-mer) folds into a two-stranded coiled-coil in which two solvent-exposed histidine residues reside on opposite sides of its surface. This peptide was allowed to react with cobalt(III) protoporphyrin IX, Co(ppIX), to produce [Co(ppIX){(H21(30-mer)}2], as determined by UV-Vis spectroscopy. This bis-axial ligation thus positions a potential coiled-coil oligomerization domain onto each face of the cobalt porphyrin ring. Circular dichroism spectroscopy and high performance size exclusion chromatography provide evidence for the solution-phase self-assembly of these porphyrin-peptide units. Evaporation of the porphyrin-peptide solution on a solid support results in the formation of long rod-like materials having millimeter-scale lengths and micron-scale diameters. The presence of Co(ppIX) in these materials was confirmed by Raman microscopy. However, they were formed only from phosphate buffer, and not from organic buffers or pure water, indicating that their formation might involve a more complicated process than originally anticipated.

In this study, we aimed to determine lignified tissue in young stems of Struthanthus vulgaris Mart. by infrared microspectroscopy and histochemical methods as well as by fluorescence microscopy. Struthanthus vulgaris Mart. is a mistletoe species that belongs to the Loranthaceae family. A brief anatomical description was also carried out. The first procedure for analysis was to elaborate anatomical cross sections (20-30 µm) from young stems before and after treatment with NaOH 1%. This procedure was applied to release possible low molecular mass phenolic compounds. Safranin-astra blue was used to distinguish anatomical tissues while Wiesner test enabled verification of lignified pericyclic fibers. Infrared microspectroscopy analysis confirmed the presence of lignin in this region according to the following spectral signals: 1600 (shoulder), 1511, 1453, 1338 and 1244 cm-1. Analyses of the cross section of young stems under fluorescence microscopy before and after treatment with NaOH 1% allowed us to confirm the presence of low mass phenolic compounds in the region of pericyclic fibers.

The aim of this study was to evaluate the influence of different concentrations of inulin and pectin as fat substitutes on the chemical composition, texture, and sensory acceptance of frankfurter sausages. Six treatments were evaluated to test fat replacement: control (T0); low fat control (T1); low fat with 15% inulin (T2); low fat with 30% inulin (T3); low fat with 7.5% inulin and 7.5% pectin (T4); and low fat with 15% inulin and 15% pectin (T5). The addition of fibers increased the yield (T3 and T5; 98.96%), and the color parameters were slightly reduced (T3). Moisture (61.14%) and ashes (6.96%) of sausages with inulin and pectin were higher (T5), while shear force, hardness, fracturability, gumminess, and chewiness (T3 and T5) were slightly lower than those of the control. The addition of inulin (T2) increased the sensory acceptance of the sausages (5.75). Fat can be replaced with inulin and pectin in frankfurter sausages to produce healthy and functional products.

Abstract Electrospinning is a simple and low-cost way to fabricate fibers. Among the various polymers used in electrospinning, polycaprolactone (PCL) stands out due to its excellent biodegradability and biocompatibility. However, PCL has some limitations such as low bioactivity, hydrophobic surface, and long in vivo degradation. Calcium phosphate ceramics have been recognized as an attractive biomaterial. They are bioactive and osteoinductive, and some are even quite biodegradable. Different contents of particles of beta-tricalcium phosphate (β-TCP) were incorporated in polymer matrix to form fibers of PCL/β-TCP composites by electrospinning for possible application in tissue regeneration. The presence of β-TCP particles promoted some changes in the thermal properties of the fibers. The immersion of PCL/β-TCP 8 wt-% fibers in simulated body fluid (SBF) caused the formation of a denser and homogeneous apatite layer on its surface.