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Made available in DSpace on 2018-12-11T17:16:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-29 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Meat extract is a by-product obtained from the cooking broth of meat processing, which is used as a flavoring agent in cooking and in pharmaceutical products. Information on the processing technology of meat extract and its corresponding thermodynamic properties have been seldom reported, making difficult the design of heat transfer processes with accuracy. Thus, the present work aimed to evaluate the boiling-point elevation (BPE) and specific heat (cp) of meat extract in the range of concentrations and temperatures found during its processing. Boiling point temperature was determined experimentally as a function of pressure and soluble solid concentration of meat extract. Different correlations based on Dühring’s rule, Antoine equation, and the model proposed by Crapiste and Lozano were obtained to represent the boiling point temperature and/or BPE in some processing conditions, resulting in good fitting accuracy. The representation of the experimental values of cp was evaluated by four empirical equations. The best fitting was acquired using a quadratic model simultaneously dependent on concentration and temperature of the meat extract. The close agreement between the experimental and predicted values reinforces the applicability of the resulting models for designing evaporation systems. Food Engineering and Technology Department São Paulo State University (Unesp) Institute of Biosciences Humanities and Exact Sciences (Ibilce), Campus São José do Rio Preto JBS–Friboi, Av. Central S/N Food Engineering and Technology Department São Paulo State University (Unesp) Institute of Biosciences Humanities and Exact Sciences (Ibilce), Campus São José do Rio Preto FAPESP: 2010/09614-3 FAPESP: 2013/09344-4

Made available in DSpace on 2018-12-11T17:08:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The thermal behavior, moisture adsorption properties and structural and morphological characteristics of mango powders were evaluated. The powders were obtained by foam mat drying methodology using albumin (ALB), mixture (EB) of monoglycerides of fatty acids, sorbitan monostearate and polyoxyethylene sorbitan monostearate and a combination of the two (EB-ALB) as foaming agents. The evaluation was done by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the moisture adsorption isotherms were also determined. The powder with EB had a glass transition temperature (Tg) of −4.2 °C. The denaturation temperature of pure albumin (82.2 °C) increased in the powders with ALB to 117 °C and in those with EB-ALB to 102 °C, due to the thermal stability provided by the pulp sugars. The moisture sorption isotherm of the EB-powder showed a higher water equilibrium content than the other powders. All the powders were in the amorphous state. The morphology of the powder with EB showed corrugated particles, whereas those with ALB and EB-ALB showed particles with a less porous aspect and more compact surfaces than the powders with EB. Department of Food Engineering and Technology; Institute of Bioscience Language and Physical Sciences (IBILCE) UNESP- São Paulo State University, Rua Cristovão Colombo 2265 Department of Food Engineering and Technology; Institute of Bioscience Language and Physical Sciences (IBILCE) UNESP- São Paulo State University, Rua Cristovão Colombo 2265 FAPESP: 2012/21428-6 FAPESP: 2014/11514-8

Meat extract is a product with a high aggregated value obtained by concentrating cooking broth from meat products. To optimize project design and processing, we determined experimental values of the density and rheological behaviour of meat extract. We evaluated the influences of temperature and solids concentration on the studied parameters. Different concentrations and temperatures were selected based on the main processing steps, ranging from 0–60 gsoluble solids/100 gsolution and 2–98 °C. The model best fitted to density was derived and a thermodynamic relation was applied to calculate the thermal expansion coefficient. Meat extract density had a linear dependence on temperature and quadratic dependence on solids content, while the thermal expansion coefficient remained approximately constant at 5.33 × 10−4 m3 · m−3 · K−1. Concerning rheological analyses, meat extract had Newtonian behaviour from 1.5–20 gsoluble solids/100 gsolution at the temperature range studied. From 30–60 gsoluble solids/100 gsolution, the Power-Law model was better fitted to the data and the consistency coefficient and flow behaviour index could be calculated. Both parameters were sensitive to changes in temperature and concentration. Apparent viscosity increased with increasing the meat extract concentration and lowering the temperature. The dependence of rheological parameters on temperature was expressed through an Arrhenius-type equation.

Made available in DSpace on 2018-12-11T16:55:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 The effect of the partial substitution (0, 10, 15, and 20%) of wheat flour with resistant starch (RS) on dough rheology and structure, and on the quality and staling rate of bread was evaluated. The results from farinograph, extensograph, alveograph, oscillatory rheological tests, and from confocal laser scanning microscopy, indicated that the substitution up to 15% of flour with RS slightly affected the dough structure, weakening it through dilution of gluten protein. Bread made with 15% of RS had specific volume, crumb moisture, and firmness values similar to those of the control bread (without RS), indicating very good quality. During storage, the RS breads had higher crumb moisture, lower firmness, and a lower retrogradation rate than the control bread. The lower retrogradation rate, in conjunction with the higher crumb moisture and high water-retention capacity of RS, was responsible for lower crumb firmness in bread containing up to 15% RS. Using wheat flour of high quality helped to minimize the deleterious effect of RS on the dough and provided high-fiber bread with high quality and low staling. Department of Food Engineering and Technology UNESP - São Paulo State University, R. Cristóvão Colombo, 2265 IFAC - Federal Institute of Acre, R. Coronel Brandão, 1622 Department of Food Engineering and Technology UNESP - São Paulo State University, R. Cristóvão Colombo, 2265

The effect of heat-moisture treatment on structural, physicochemical, and rheological characteristics of arrowroot starch was investigated. Heat-moisture treatment was performed with starch samples conditioned to 28% moisture at 100℃ for 2, 4, 8, and 16 h. Structural and physicochemical characterization of native and modified starches, as well as rheological assays with gels of native and 4 h modified starches subjected to acid and sterilization stresses were performed. Arrowroot starch had 23.1% of amylose and a CA-type crystalline pattern that changed over the treatment time to A-type. Modified starches had higher pasting temperature and lower peak viscosity while breakdown viscosity practically disappeared, independently of the treatment time. Gelatinization temperature and crystallinity increased, while enthalpy, swelling power, and solubility decreased with the treatment. Gels from modified starches, independently of the stress conditions, were found to have more stable apparent viscosities and higher G′ and G″ than gels from native starch. Heat-moisture treatment caused a reorganization of starch chains that increased molecular interactions. This increase resulted in higher paste stability and strengthened gels that showed higher resistance to shearing and heat, even after acid or sterilization conditions. A treatment time of 4 h was enough to deeply changing the physicochemical properties of starch.

An accurate determination of the thermal properties of biomass is particularly important when studying biomaterials for the second-generation ethanol industry. This study presents the thermograms of aqueous solutions of banana flower stalks obtained using differential scanning calorimetry. The samples were prepared using a detailed procedure to obtain normalized specific heat values as a function of temperature, pH, and biomass concentration. The specific heat capacity data were fitted using empirical first-order equations with an algorithm for nonlinear regression, followed by a statistical analysis. All the models applied in modeling of the specific heat capacity showed statistically significant goodness of fit ( Radj2 > 0.996) for all the parameters in the selected expressions. The results obtained in this research can provide information for the modeling, design, and control of the unit operations involved in the second-generation ethanol industry. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1221–1228, 2015

Mango pulp mixed with drying aids (maltodextrin and skimmed milk) was spray dried to obtain three powder formulations. The water sorption behavior of these mango mix formulations was determined at temperatures of 20, 30, 40 and 50 °C in water activity ranging between 0.059 and 0.907. The Guggenheim, Anderson and De Boer (GAB) model was applied to modeling the adsorption isotherms of mango mix powders, resulting in statistical values of mean relative error (MRE ≤ 5.14%). Differential and integral thermodynamic properties related to water sorption for the mango powders were determined by the analytical derivation of the water activity with respect to temperature based on the GAB model fitting. The differential thermodynamic properties indicated a decrease in the water sorption energy with increasing water content and the negative values of the Gibbs free energy revealed that the sorption process was spontaneous for the three powder formulations. In spite of the formulation containing skimmed milk have shown the higher monolayer water contents, the minimal integral entropy zone observed at similar values of water activity for the three mango mix powders indicated that all of them could be safely stored at the same relative humidity condition.

The objective of this work was to optimize the spray drying of jussara pulp using mixtures of modified starch (MS) with whey protein concentrate (WPC) or soy protein isolate (SPI) as the carrier agents. Two central composite rotatable designs were used to evaluate the effect of the independent variables of inlet air temperature (140 °C to 200 °C), carrier agent concentration - CAC (0.5 to 2 g carrier agent/g jussara pulp solids) and the proportions of MS:WPC or MS:SPI (5 to 30 g WPC or SPI/100 g carrier agent) on the following responses for powders formulated with MS:WPC and MS:SPI, respectively: moisture content (0.3% to 1.4% and 0.6% to 1.2%), solubility (78.0% to 92.9% and 78.9% to 83.8%), retention of total anthocyanins (49.2% to 82.9% and 34.1% to 96.9%), encapsulation efficiency (98.5% to 99.7% and 98.5% to 99.5%), hue angle (9.1 to 44.0 and 3.7 to 42.6), chroma (10.0 to 15.3 and 9.2 to 14.3) and process yield (33.2% to 55.5% and 49.9% to 78.5%). The inlet air temperature 170 °C, CAC of 1.25 and 2 g/g jussara pulp solids and proportion of MS:WPC or MS:SPI of 17.5 and 30 g/100 g were recommended as the selected conditions. Resumo O objetivo deste trabalho foi otimizar a secagem por atomização da polpa de juçara, utilizando-se misturas de amido modificado (AM), concentrado proteico de soro de leite (CPL) ou isolado proteico de soja (IPS), como agentes carreadores. Dois delineamentos compostos centrais rotacionais foram realizados para avaliar o efeito das variáveis independentes: temperatura do ar de entrada (140 °C a 200 °C), concentração de agente carreador ‒ CAC (0,5 a 2 g de carreador/g de sólidos de polpa juçara) e proporções de AM:CPL ou AM:IPS (5 a 30 g de CPL ou IPS/100 g carreador) sobre as seguintes respostas para pós formulados com AM:CPL e AM:IPS, respectivamente: teor de umidade (0,3% a 1,4% e 0,6% a 1,2%), solubilidade (78,0% a 92,9% e 78,9% a 83,8%), retenção de antocianinas totais (49,2% a 82,9% e 34,1% a 96,9%), eficiência de encapsulação (98,5% a 99,7% e 98,5 a 99,5%), ângulo de tonalidade (9,1 a 44,0 e 3,7 a 42,6), croma (10,0 a 15,3 e 9,2 a 14,3) e rendimento do processo (33,2% a 55,5% e 49,9% a 78,5%). A temperatura do ar de entrada de 170 °C, CAC de 1,25 e 2, e a proporção de AM:CPL ou AM:IPS de 17,5 e 30 foram recomendadas como condições selecionadas.

The aims of this study were to assess the turmeric oleoresin microencapsulation by freeze-drying with modified starch/gelatin and to evaluate its stability during storage at different temperatures and light. Encapsulated turmeric oleoresin w stored at −20, 25 and 60C, in the absence of light, and at 25C in the presence of light, and analyzed over a period of 6 weeks for curcumin and total phenolic contents and color. The different concentrations of wall material showed no significant effect on the curcumin retention. The best conditions for microencapsulation of turmeric oleoresin were: wall material composed of 30 g/100 g of modified starch + 1 g/100 g gelatin and mechanical homogenization. Encapsulated material was more stable during storage at −20C and less stable at 25C in the presence of light. Practical Applications Turmeric oleoresin, obtained by organic solvent extraction of turmeric (Curcuma longa L.), is a brownish-orange oily liquid used as a flavoring agent and a food color. However, despite the natural antioxidants content, turmeric oleoresin is sensitive to light, heat and oxygen. Furthermore, the oleoresins are immiscible in the aqueous medium, which makes difficult its use in food matrices. Encapsulation can solve some of these problems increasing stability and solubility of turmeric oleoresin. Use of freeze-drying on the encapsulation may be interesting as the low temperature of the process can minimize adverse chemical changes and transform the physical characteristics of turmeric oleoresin without providing significant losses related to bioactive compounds.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:30:32Z No. of bitstreams: 0 Made available in DSpace on 2014-05-27T11:30:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-09-01 Polyols are widely used as sugar substitutes and provide texture to foods. Guar gum has many applications in food industry such as increasing product viscosity and improving texture. Knowledge of rheological properties of gum/polyol systems is important to permit replacing sugar while maintaining product texture. In this work, rheological properties of 0.1, 0.5 and 1 g/100 g guar solutions containing 10 and 40 g/100 g of maltitol, sorbitol, or xylitol were studied. The behavior of these mixtures was evaluated by steady and oscillatory shear measurements, and after a freezing/thawing cycle. Apparent viscosity of guar solutions increased with addition of polyols and with the increase in their concentrations, except for 40 g/100 g sorbitol addition to 1 g/100 g guar gum, in which the apparent viscosity decreased. Addition of polyols also increased the dynamic moduli of the systems. In mixtures of guar with 40 g/100 g polyol, the phase angle (δ) was below unity, but was dependent on frequency, which is characteristic of concentrated solutions with a certain degree of structuring. FTIR spectroscopy was studied to provide information on possible interactions between guar gum and polyols. Analyses carried out after freezing/thawing showed no changes in the viscoelastic behavior of the solutions. © 2013 Elsevier Ltd. Departamento de Engenharia e Tecnologia de Alimentos Universidade Estadual Paulista, São José do Rio Preto, 15054-000 Departamento de Física Universidade Estadual Paulista, São José do Rio Preto, 15054-000 Departamento de Engenharia e Tecnologia de Alimentos Universidade Estadual Paulista, São José do Rio Preto, 15054-000 Departamento de Física Universidade Estadual Paulista, São José do Rio Preto, 15054-000

Made available in DSpace on 2018-12-11T17:32:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01. Added 1 bitstream(s) on 2021-07-15T15:04:19Z : No. of bitstreams: 1 S0104-14282017000100062.pdf: 1507797 bytes, checksum: 0f250800c93a12ba76c353686dc378a8 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study aimed at characterizing the soy protein isolate and high-methoxyl pectin biopolymers individually, and the complexes formed by both at different proportions and pHs in order to find the most suitable pH and biopolymer ratios to food application as stabilizers. The biopolymers were evaluated through solubility, charges, turbidimetry, and optical microscopy analyses; the systems with the pair of biopolymers were analyzed through turbidimetry and optical microscopy. High-methoxyl pectin showed high solubility at all pHs investigated. The soy protein isolate showed low solubility at pH 4.5, which is close to its isoelectric point, and complete solubility at pH 11.0. The formation of complexes suggested an attractive interaction between the biopolymers, with high absorbance reading values and images of complexes from optical microscopy. These complexes were present in systems with pHs below the soy protein isolate's isoelectric point, with positive charges; the high-methoxyl pectin, however, had negative ones. Laboratory of Physical Measures Department of Food Engineering and Technology Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Laboratory of Physical Measures Department of Food Engineering and Technology Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP FAPESP: 2013/10842-9 FAPESP: 2014/02910-7 FAPESP: 2014/08520-6

Food products with low water activity, dried, or frozen, are usually stored at non-equilibrium states, in which long-term stability cannot be assured. Changes in the storage conditions, including temperature and relative humidity, as well as internal diffusion of water and other compounds may affect the glass transition of foods, leading to deleterious effects on the product quality. The objective of this chapter is reviewing the main storage conditions that influence the glass transition of food materials, focusing on low-moisture and frozen products, in addition to discussing different approaches to applying in search of enhancing product stability and increasing shelf-life of foods.

This study was carried out to evaluate the effects of different mixtures of carrier agents (CA) (modified starch-MS plus whey protein concentrate-WPC or soy protein isolate-SPI) on the characteristics of microcapsules containing spray-dried jussara pulp powder. Four treatments, 30 %CAC+17.5 %MS:WPC, 17.5 %CAC+30 %MS:WPC, 30 %CAC+17.5 %MS:SPI and 17.5 %CAC+30 %MS:SPI, were evaluated, where CAC=carrier agent concentration (g carrier/g jussara pulp solids) and the proportions MS:WPC and MS:SPI indicate the grams of protein (WPC or SPI) per 100g of carrier. The solubility of the particles was not affected by the wall material, attaining average values of 78 %. The concentration of 30 %CAC+17.5 %MS:WPC improved the bulk density and moisture content. WPC and SPI were shown to be good alternative secondary wall materials for jussara pulp, together with MS.

Sorption mechanisms of pineapple powders produced by vibro-fluidized drying (VFD), spray drying (SD), freeze drying (FD) or vacuum drying (VD) were interpreted through enthalpy/entropy variations with respect to equilibrium moisture content (EMC) at 20, 30, 40 and 50 °C and water activity (aw) between 0.059 and 0.907. Powders from SD and VFD were more hygroscopic and integral properties indicated higher stability at changing aw compared to powders from VD and FD. Powders showed an enthalpy driven zone with equal isokinetic temperature (TB1 = 499.0 ± 4.8 K) due to their same composition, and an entropy controlled zone with different isokinetic temperature, TB2 (VD: 116.0 ± 40.6 K; FD: 118.3 ± 24.1 K; SD: 95.8 ± 23.4 K; VFD: 81.8 ± 6.3 K), caused by different microstructures resulting from different drying methods. Powders from SD and VFD presented larger entropic zones that shifted the minimum integral entropy to higher aw, improving storage stability.

Data on pressure drop were obtained in stainless steel, sanitary fittings and valves during laminar and turbulent flow of egg yolk, coffee extract, blackberry juice and concentrated milk, which were selected as typical liquid food products. The rheological properties of these fluids were obtained from previously published studies and the power-law model provided the best description of the rheological behavior of these liquids. Friction losses were measured in fully and partially open butterfly, seat, no-return and ball valves, bends, tees and unions. Values of loss coefficients (kf) were calculated and correlated as a function of the generalized Reynolds number by the two-k method. The model adjustment was satisfactory, being better in the laminar flow range (0.884 ≤ r2 ≤ 0.999) than in the turbulent one (0.751 ≤ r2 ≤ 0.989). In order to test the adequacy of the results that are needed to predict loss coefficients during flow of liquid food products, measurements were carried out during the flow of orange juice in the same temperature range at which the correlations were obtained. The flow of coffee extract and egg yolk at different temperatures than those of the correlations were also analyzed. Comparison between experimental and predicted loss coefficients showed very good agreement.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:25:28Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:36:09Z : No. of bitstreams: 1 2-s2.0-78951484849.pdf: 404054 bytes, checksum: 04465b40b5ceaa5ba836d2e70aa4e929 (MD5) Made available in DSpace on 2014-05-27T11:25:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-15 The sugarcane juice is a relatively low-cost agricultural resource, abundant in South Asia, Central America and Brazil, with vast applications in producing ethanol biofuel. In that way, a good knowledge of the rheological properties of this raw material is of crucial importance when designing and optimizing unit operations involved in its processing. In this work, the rheological behavior of untreated (USCJ, 17.9 °Brix), clarified (CSCJ, 18.2 °Brix) and mixed (MSCJ, 18.0 °Brix) sugarcane juices was studied at the temperature range from 277K to 373K, using a cone-and-plate viscometer. These fluids were found to present a Newtonian behavior and their flow curves were well-fitted by the viscosity Newtonian model. Viscosity values lied within the range 5.0×10 -3Pas to 0.04×10 -3Pas in the considered temperature interval. The dependence of the viscosity on the temperature was also successfully modeled through an Arrhenius-type equation. In addition to the dynamic viscosity, experimental values of pressure loss in tube flow were used to calculate friction factors. The good agreement between predicted and measured values confirmed the reliability of the proposed equations for describing the flow behavior of the clarified and untreated sugarcane juices. © 2010 Elsevier B.V. Universidade do Estado de São Paulo (UNESP) Departamento de Tecnologia e Engenharia de Alimentos, CEP 15054-000 São José do Rio Preto, SP COSAN S.A. Indústria e Comércio Bairro Água da Aldeia s/n Unidade Taruma, Polo Regional de Assis, CEP 19820-000 Tarumão, SP Universidade Federal de Viçosa (UFV) Departamento de Tecnologia de Alimentos, CEP 36571-000 Viçosa, MG Universidade do Estado de São Paulo (UNESP) Departamento de Tecnologia e Engenharia de Alimentos, CEP 15054-000 São José do Rio Preto, SP

Water sorption isotherms for vacuum-dried persimmon pulp (PP) powder were determined in the temperature range of 20–50C, and the effects of maltodextrin (MD) or gum arabic (GA) addition on the water sorption behavior of the dried powders were analyzed. Several models were evaluated to fit the experimental data and the Guggenheim-Anderson-de Boer model was selected as the most adequate to describe the observed behavior. Addition of encapsulants affected the isotherms: at the same water activity, PP powder with added GA (PP + GA) or MD (PP + MD) presented lower equilibrium water content than pure PP and were less affected by temperature variations. Samples of PP + MD presented lower equilibrium moisture content than those of PP + GA. The isosteric heats of sorption of pulp powders with encapsulants were higher (less negative) than those of PP, suggesting that there are more active polar sites in PP than in pulp powder containing encapsulants. PRACTICAL APPLICATIONS The choice of persimmon to carry out this work was due to the large persimmon production available in Brazil; moreover, persimmon pulp is rich in vitamin C, vitamin A and iron, as well as in phenolic compounds. Drying of fruit pulps with high sugar content presents technical difficulties because the hygroscopicity and thermoplasticity of the resulting powders when exposed to high temperature and relative humidity. For this reason, addition of high-molar-mass biopolymers, such as maltodextrin or gum arabic, is a strategy to aid drying and to improve storage stability. Knowledge of water sorption isotherms and net isosteric heats of sorption is important to various food processing operations, including drying, storage and packaging. They are useful in calculating time and energy consumptions during drying, modeling moisture changes during storage and predicting shelf life of food products.

Suspensions formed by saturated sucrose solutions were analyzed at different temperatures (0 ≤ T ≤ 65C) and with different added fractions (0.005 ≤ φ ≤ 0.40) of known size sucrose crystals (0.163 ≤ dp ≤ 1.26 mm). Saturated sucrose solutions, taken as the suspension dispersant mean, were rheologically characterized using a concentric-cylinder rheometer and showed Newtonian behavior. The crystal suspensions were rheologically evaluated by using a mixer-type rheometer constituting an anchor impeller coupled to a rotational rheometer, also known as a mixer-type rheometer. The studied crystal suspensions also showed Newtonian behavior. Theoretical and semiempirical models were used to describe the correlation between suspension relative viscosity and crystal volumetric fraction. The best results were obtained using the Krieger and Dougherty, and the Mooney model, resulting in values of intrinsic viscosity, (η), and maximum packing fraction, φm, compatible with data reported for coarse concentrated suspensions of nonspherical particles. PRACTICAL APPLICATIONS Rheological follow-up of dynamic systems may be useful for a wide variety of applications where there is a manifest interest in studying the rheological evolution of a medium under controlled conditions. In crystallization processes, nucleation and growth of crystals modify the system rheological properties that, when measured during the process, make possible the determination of processing rates in function of operational conditions. Viscosity is important in the work of crystallizers because of its influence in heattransfer rates. Knowledge of viscosity allows sizing of pumps, pipes and also calculation of the necessary torque for crystallizers in order to prevent super sizing of equipment. Fluid viscosity is also fundamental in the characterization of flow as well as in modeling mass and heat transfer processes involved in several unit operations used in food industry.

Physicochemical and structural properties of grapefruit juice powder were studied as affected by water activity. Powdered juice was obtained by freeze-drying and equilibrated at different water vapor pressure atmospheres in order to give samples with water activity in the range of 0-084 The mechanical properties of the powder were measured by confined compression tests and the compressed samples, which presented uniform surface and thickness, were subjected to color analysis The maximum force attained during the compression tests and the color coordinates could be quantified with good reproducibility. The results were related to water activity and to glass transition temperature The occurrence of mechanical changes in the powder was shown to precede significant color changes with increasing water activity. Considering the susceptibility to stickiness, the stability limit was observed at T-T(g) approximate to 2 degrees C, with a high degree of mechanical changes being detected at T-Tg 16 degrees C, whereas for significant color changes this critical temperature difference was around 32 degrees C, Authors thank the Ministerio de Educacion y Ciencia and the Fondo Europeo de Desarrollo Regional (FEDER) for the financial support throughout the projects AGL2002-01793 and AGL 200505994. Vania R. N. Tells acknowledges the support of the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) as an external grant (Proc. BEX 4452/06-2).

En este trabajo fueron determinados experimentalmente el calor específico, conductividad térmica, difusividad térmica y densidad del jugo de lulo en el rango de contenido de agua de 0.55 a 0.90 (p/p en base húmeda) y en temperaturas variando de 4 a 78.6 °C. La conductividad térmica y el calor específico fueron obtenidos utilizando el mismo aparato - una célula constituida de dos cilindros concéntricos - operando en estado estacionario y no- estacionario, respectivamente. La difusividad térmica fue obtenida a través del método de Dickerson y la densidad determinada por picnometria. Tanto la temperatura como el contenido de agua presentaron una fuerte influencia en los datos experimentales de las propiedades termofísicas del jugo de lulo. Los resultados obtenidos fueron utilizados para obtener modelos matemáticos y predecir estas propiedades en función de la concentración y la temperatura.Neste trabalho, foram determinados experimentalmente o calor específico, a condutividade térmica, difusividade térmica e densidade de suco de lulo na faixa de conteúdo de água entre 0,55 e 0,90 (p/p em base úmida) e em temperaturas entre 4 e 78,6 °C. A condutividade térmica e o calor específico foram obtidos utilizando-se o mesmo equipamento - uma célula constituída de dois cilindros concêntricos - operando em estado estacionário e não estacionário, respectivamente. A difusividade térmica foi obtida através do método de Dickerson e a densidade determinada por picnometria. Tanto a temperatura como o conteúdo de água apresentaram grande influência nos dados experimentais das propriedades termofísicas do suco de lulo. Os resultados obtidos foram utilizados na obtenção de modelos matemáticos para predizer estas propriedades em função da concentração e temperatura.

To design equipment for biofuel production and an optimizing process for heating, settling, and filtration of industrial sugar cane juices, the thermophysical properties must be known. Since the thermophysical properties of biological materials are strongly dependent upon chemical composition and temperature, composition- and temperature-based models provide a means of estimating these properties. In this work, the thermophysical properties of untreated sugar cane juice (USCJ), mixed sugar cane juice (MSCJ), and clarified sugar cane juice (CSCJ) were determined at a temperature range of (277.4 to 373.4) K. Simple polynomial models as a function of temperature were fitted to the experimental data, showing good agreement. Thermal conductivity and heat capacity varied from (0.475 to 0.493) W·m−1·K−1 and (3601.8 to 3802.9) J·kg−1·K−1, respectively. Density varied from (1044.5 to 1189.5) kg·m−3.

Datos de humedad de equilibrio de polvo de pulpa de lulo (PL) con y sin aditivos - 58% de maltodextrina (MD) o 58% de goma Arábiga (GA) - fueran determinados en las temperaturas de 20, 30, 40 y 50 °C utilizando el método estático gravimétrico para un rango de actividades de agua entre 0.06 y 0.90. Las isotermas presentaran formato sigmoidal del tipo III, y el modelo de Guggenhein-Anderson-de Boer (GAB) fue ajustado satisfactoriamente a los datos experimentales de humedad de equilibrio en función de la actividad de agua. La adición de encapsulantes afecto las isotermas de tal manera que en la misma actividad de agua, las muestras PL + GA y PL + MD presentaron un menor contenido de humedad de equilibrio y no fueron afectadas por la variación de temperatura. Los calores isostéricos de sorción de las pulpas en polvo con encapsulantes fueron mayores (menos negativos) con relación a las pulpas de lulo en polvo, sugiriendo la existencia de sitios polares más activos en el producto sin adición de GA o MD. Una relación exponencial empírica fue utilizada para describir la dependencia del calor de sorción con el contenido de humedad del material.Dados de umidade de equilíbrio de polpa de lulo em pó (PL) com e sem aditivos - 58% de maltodextrina (MD) ou 58% de goma Arábica (GA) - foram determinados nas temperaturas de 20, 30, 40 e 50 °C, utilizando-se o método estático gravimétrico numa faixa de atividade de água de 0,06 a 0,90. As isotermas apresentaram formato sigmoidal do tipo III e o modelo de Guggenhein-Anderson-de Boer (GAB) ajustou satisfatoriamente os dados experimentais de umidade de equilíbrio em função da atividade de água. A adição de encapsulantes afetou as isotermas de tal maneira que na mesma atividade de água, as amostras PL + GA y PL + MD apresentaram um menor conteúdo de umidade de equilíbrio e não foram afetadas pela variação de temperatura. Os calores isostéricos de sorção das polpas em pó com encapsulantes foram maiores (menos negativos) em relação à polpa de lulo em pó, sugerindo a existência de sítios polares mais ativos no produto sem adição de GA ou MD. Uma relação exponencial empírica foi utilizada para descrever a dependência do calor de sorção com o conteúdo de umidade do material.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:53:11Z No. of bitstreams: 0 Made available in DSpace on 2013-08-22T18:53:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-01 Made available in DSpace on 2013-09-30T19:44:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:11:44Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T15:11:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-01 Dados de umidade de equilíbrio de polpa de lulo em pó (PL) com e sem aditivos - 58% de maltodextrina (MD) ou 58% de goma Arábica (GA) - foram determinados nas temperaturas de 20, 30, 40 e 50 °C, utilizando-se o método estático gravimétrico numa faixa de atividade de água de 0,06 a 0,90. As isotermas apresentaram formato sigmoidal do tipo III e o modelo de Guggenhein-Anderson-de Boer (GAB) ajustou satisfatoriamente os dados experimentais de umidade de equilíbrio em função da atividade de água. A adição de encapsulantes afetou as isotermas de tal maneira que na mesma atividade de água, as amostras PL + GA y PL + MD apresentaram um menor conteúdo de umidade de equilíbrio e não foram afetadas pela variação de temperatura. Os calores isostéricos de sorção das polpas em pó com encapsulantes foram maiores (menos negativos) em relação à polpa de lulo em pó, sugerindo a existência de sítios polares mais ativos no produto sem adição de GA ou MD. Uma relação exponencial empírica foi utilizada para descrever a dependência do calor de sorção com o conteúdo de umidade do material. Datos de humedad de equilibrio de polvo de pulpa de lulo (PL) con y sin aditivos - 58% de maltodextrina (MD) o 58% de goma Arábiga (GA) - fueran determinados en las temperaturas de 20, 30, 40 y 50 °C utilizando el método estático gravimétrico para un rango de actividades de agua entre 0.06 y 0.90. Las isotermas presentaran formato sigmoidal del tipo III, y el modelo de Guggenhein-Anderson-de Boer (GAB) fue ajustado satisfactoriamente a los datos experimentales de humedad de equilibrio en función de la actividad de agua. La adición de encapsulantes afecto las isotermas de tal manera que en la misma actividad de agua, las muestras PL + GA y PL + MD presentaron un menor contenido de humedad de equilibrio y no fueron afectadas por la variación de temperatura. Los calores isostéricos de sorción de las pulpas en polvo con encapsulantes fueron mayores (menos negativos) con relación a las pulpas de lulo en polvo, sugiriendo la existencia de sitios polares más activos en el producto sin adición de GA o MD. Una relación exponencial empírica fue utilizada para describir la dependencia del calor de sorción con el contenido de humedad del material. Universidad Nacional de Colombia Departamento de Física e Química Universidade Estadual Paulista Departamento de Engenharia e Tecnologia de Alimentos Universidade de São Paulo Engenharia de Alimentos Universidade Estadual Paulista Departamento de Engenharia e Tecnologia de Alimentos

The purpose of this work was to determine some physicochemical characteristics of collagen fibers and collagen powder obtained from bovine hides as potential raw materials for production of films with improved mechanical properties. These materials are collagen in its crude form, without the hydrolysis reaction that leads to gelatin production. The following analyses were carried out: proximate composition, amino acid composition, solubility in water, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), size distribution and moisture sorption isotherms. The collagen fibers and collagen powder showed practically the same protein content, and the only differences between them, apart from the particle shape and size, were in their solubility in water, which was probably partly due to differences in particle size. Due to their similar composition but different physical properties, collagen fibers and collagen powder were shown to be suitable for the production of biocomposite films where the powder is the basis of the film matrix and the fibers act as filler, exerting a reinforcement effect. Films with the protein content supplied by 50% collagen powder and 50% collagen fibers could be produced with the film thickness fixed at 180 μm and subjective evaluations suggested that the fibers remained completely involved in the filmogenic matrix.

To design equipment for food processing and estimate process times for refrigerating, freezing, heating, or drying of foods, the thermophysical properties must be known. Since the thermophysical properties of foods are strongly dependent upon chemical composition and temperature, composition and temperature based models provide a means of estimating these properties. In this work, the thermophysical properties of lemon juice were determined at a water mass fraction of (0.381 to 0.900) and a temperature of (273.45 to 353.75) K. Density and thermal conductivity varied from (962.3 to 1282.8) kg·m−3 and (0.344 to 0.624) W·m−2·K−1, respectively. Heat capacity and thermal diffusivity varied from (2446.5 to 4060.1) J·kg−1·K−1 and (0.1160·10−6 to 0.1785·10−6) m2·s−1, respectively. Simple polynomial functions were fitted to the experimental data, and good agreements were obtained. In the tested range, water content showed greater influence on the thermophysical properties.

The purpose of this work was to investigate the viscoelastic properties of aqueous suspensions of crude collagen powder extracted from bovine hides and nonsubmitted to the hydrolysis reaction that leads to gelatin. The studied variables included the collagen concentration and the addition of xanthan gum or maltodextrin at varied concentrations during heating/cooling of the mixtures. Differential scanning calorimetry thermograms showed that the addition of polysaccharides decreased the endothermic peak areas observed at the denaturation temperature of collagen. The rheological properties of the pure collagen suspensions were highly dependent on concentration: 4% and 6% collagen suspensions presented a great increase in the storage modulus after heating/cooling, whereas for concentrations of 8% and 10% G′ decreased during heating and did not recover its original value after heating/cooling. The frequency sweeps showed that the thermal treatment was responsible by the strengthening of the interactions that formed the polymer network. Addition of 0.1% xanthan gum to collagen suspensions increased the gel strength, especially after heating/cooling of the system, whereas increasing gum concentration to 0.3% resulted in a weaker gel, which could indicate thermodynamic incompatibility between the biopolymers. Mixtures of collagen and maltodextrin resulted in more fluid structures than those obtained with pure collagen at the same collagen concentration and the range of temperatures in which these mixtures behaved as a gel decreased with increasing concentrations of both collagen and maltodextrin, suggesting incompatibilities between the biopolymers.

Physicochemical and structural properties of grapefruit juice powder were investigated as affected by the addition of maltodextrins of two dextrose equivalent (DE) and gum arabic. Freeze-dried powdered juices were equilibrated at different vapor pressure atmospheres, giving samples with water activity between zero and 0.84. The mechanical properties of the powders were assessed by confined compression, and the compressed samples were subjected to color analysis. The maximum force attained during the compression and the color coordinates were related to water activity and glass transition temperature, and a single value of ΔT = T − Tg could be taken as the critical limit to the safe storage of the powders, regardless of their composition. The results indicated that from the perspective of the time at which deleterious changes would take place in powders stored at certain ambient conditions and exposed to certain rate of water uptake, the collapse of the powder would precede browning development.

The rise in boiling point of blackberry juice was experimentally measured at soluble solids concentrations in the range of 9.4 to 58.4°Brix and pressures between 4.9 × 103 and 9.0 × 104 Pa (abs.). Different approaches to representing experimental data, including the Duhring's rule, a model similar to Antoine equation and other empirical models proposed in the literature were tested. In the range of 9.4 to 33.6°Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 39.1°Brix. Experimental data could be best predicted by adjusting an empirical model, which consists of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration.

High temperatures and long drying times used in hot air drying can negatively affect the nutritional quality of the final product. It is generally observed that, if ascorbic acid is well retained, other components are also well retained. Hence, ascorbic acid can be taken as an index of nutrient quality of foods. The interest in dried tomato has increased since its use as ingredients for pizza and various vegetable and spicy dishes has became popular. Tomatoes are usually dried in slices or halves, after seeds and parenchyma removal with a resulting large amount of wastes and an important nutrient loss. The objective of this work was to investigate the effects of drying temperatures on ascorbic acid degradation kinetics in caustic-peeled whole tomatoes (with or without osmotic pre-treatment) and in halved and drained tomatoes. The degradation rates were dependent on samples treatment before drying, as well as on drying temperature. Lower degradation rates were observed in osmotically pre-treated whole tomatoes, whereas higher degradation rates occurred in halved tomatoes. Increasing drying temperature led to higher degradation rates.

Data on pressure drop were obtained in stainless steel, sanitary fittings and valves during laminar and turbulent flow of aqueous suspensions of sucrose and bentonite. The rheological properties of these suspensions were determined and the Bingham model provided the best fitting with the experimental data. Friction losses were measured in fully- and partially-open butterfly and plug valves, bends and union. Values of loss coefficients (kf) were calculated and correlated as functions of the classical Reynolds number and the Reynolds number proposed by Govier and Aziz (1972) for viscoplastic fluids. The two-k method and a new proposed model presented the best adjustments for the Govier and Aziz Reynolds number, and Hedstrom and classical Reynolds numbers, respectively. On a obtenu des donnees sur la perte de charge dans des ajustages et des vannes sanitaires en acier inoxydable pour l'ecoulement laminaire et turbulent de suspensions aqueuses de sucrose et bentonite. Les proprietes rheologiques de ces suspensions ont ete determinees, et le modele de Bingham fournit le meilleur calage des donnees experimentales. Les pertes de friction ont ete mesurees dans des vannes a papillon et a opercule pleinement et partiellement ouvertes, les coudes et les raccords. Les valeurs des coefficients de pertes (kf) ont ete calculees et correlees en fonction du nombre de Reynolds classique et du nombre de Reynolds propose par Govier et Aziz (1972) pour des fluides viscoelastiques. La methode des deux k et un nouveau modele propose presentent les meilleurs ajustements pour le nombre de Reynolds de Govier et Aziz, et les nombres de Reynolds d'Hedstrom et classique, respectivement.

Moisture equilibrium data of pineapple pulp (PP) powders with and without additives – 18% maltodextrin (MD) or 18% gum Arabic (GA) – were determined at 20, 30, 40 and 50 °C by using the static gravimetric method in a water activity range of 0.06–0.90. The obtained isotherms were sigmoid, typical type III, and the Guggenhein–Anderson–de Boer (GAB) model was fitted to the experimental data of equilibrium moisture content versus water activity. Addition of additives was shown to affect the isotherms in such a way that, at the same water activity, samples PP + GA and PP + MD presented lower equilibrium moisture content and were not so affected by varying temperature. The net isosteric heats of sorption of pulp powders with additives were higher (less negative) than those of pineapple pulp powders, suggesting that there are more active polar sites in the product without addition of GA or MD. An empirical exponential relationship could describe the heat of sorption dependence on the material moisture content.

Pressure drop and minimum fluidization velocity were experimentally studied in a vibro-fluidized bed of inert particles subjected to different vibration intensities during drying of soursop pulp. Maltodextrin was added to the pulp in order to prevent stickiness between particles and the consequent bed collapse. Pulps were initially concentrated, resulting in pastes with different soluble solids content, and a constant fraction of maltodextrin was guaranteed in the final pulp samples. The pulp rheological behavior as affected by temperature and total soluble solids content, including maltodextrin, was evaluated and the effect of pulp apparent viscosity on pressure drop and minimum vibro-fluidization velocity were investigated. Two types of inert particles – 3.6 mm glass beads and 3 mm Teflon cylinders (length and diameter) – were tested and, due to lower pressure drop presented by Teflon cylinders during operation of the dry vibro-fluidized bed, these particles were adopted for pulp drying process. Increasing pulp apparent viscosity caused a considerable increase in the vibro-fluidized bed pressure drop during pulp drying and, as a consequence resulted in a larger value of minimum vibro-fluidization velocity. On the other hand, the negative effect of increasing apparent viscosity could be attenuated by increasing the fluidized bed vibration intensity, which could prevent stickiness between particles.

Pressure drop and minimum fluidization velocity were experimentally studied in a vibro-fluidized bed of inert particles subjected to different vibration intensities during drying of guava pulp. Maltodextrin was added to the pulp in order to prevent stickiness between particles and the consequent bed collapse. Pulps were initially concentrated, resulting in pastes with different soluble solids content, and a constant fraction of maltodextrin was guaranteed in the final pulp samples. The pulp rheological behavior as affected by temperature and total soluble solids content, including maltodextrin, was evaluated and the effect of pulp apparent viscosity on pressure drop and minimum vibro-fluidization velocity were investigated. Two types of inert particles – 3.6 mm glass beads and 3 mm Teflon cylinders – were tested and, due to lower pressure drop presented by Teflon cylinders during operation of the dry vibro-fluidized bed, these particles were adopted for pulp drying process. Increasing pulp apparent viscosity caused a considerable increase in the vibro-fluidized bed pressure drop during pulp drying and, as a consequence resulted in a larger value of minimum vibro-fluidization velocity. On the other hand, the negative effect of increasing apparent viscosity could be attenuated by increasing the fluidized bed vibration intensity, which could prevent stickiness between particles.

The rise in boiling point of grapefruit juice was experimentally measured at soluble solids concentrations in the range of 9.3�60.6 °Brix and pressures between °6.0 × 10 3 and 9.0 × 104 Pa. Different approaches to represent experimental data, including the Duhring's rule, the Antoine equation and empirical models proposed in the literature were tested. In the range of 9.3�29.0 °Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 29.0 °Brix. Experimental data could be best predicted by adjusting an empirical model, which consisted of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration. The rise in boiling point of grapefruit juice was experimentally measured at soluble solids concentrations in the range of 9.3�60.6 °Brix and pressures between °6.0 × 10 3 and 9.0 × 104 Pa. Different approaches to represent experimental data, including the Duhring's rule, the Antoine equation and empirical models proposed in the literature were tested. In the range of 9.3�29.0 °Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 29.0 °Brix. Experimental data could be best predicted by adjusting an empirical model, which consisted of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration. The rise in boiling point of grapefruit juice was experimentally measured at soluble solids concentrations in the range of 9.3�60.6 °Brix and pressures between °6.0 × 10 3 and 9.0 × 104 Pa. Different approaches to represent experimental data, including the Duhring's rule, the Antoine equation and empirical models proposed in the literature were tested. In the range of 9.3�29.0 °Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 29.0 °Brix. Experimental data could be best predicted by adjusting an empirical model, which consisted of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration.

Degradation kinetics of food constituents may be related to the matrix molecular mobility by glass transition temperature. Our objective was to test this approach to describe ascorbic acid degradation during drying of persimmons in an automatically controlled tray dryer with temperatures (40 to 70°C) and air velocities (0.8 to 2.0 m/s) varying according a second order central composite design. The Williams-Landel-Ferry model was satisfactorily adjusted to degradation curves for both control strategies adopted—constant air temperature and temperature fixed inside the fruit. Degradation rates were higher at higher drying temperatures, independent of the necessary time to attain the desired moisture content.

Experimental viscosity values of sucrose, glucose, and fructose aqueous solutions in a large range of temperatures (0 to 85°C) and concentrations (10 to 60% w/w) that might be encountered in food processes were obtained in order to contribute to extending the available database of food properties. The temperature dependence of viscosity could be adequately described by the Arrhenius model, and the activation energy was well represented by a unique function of the solute volume fraction, valid for sucrose, glucose, and fructose solutions.

The freezing point depression of mango and papaya pulps was measured by using a simple apparatus, consisting of two major sections: a freezing vessel and a data acquisition system. The thermal conductivity of both pulps as a function of frozen water fraction and temperature was also investigated by using a coaxial dual-cylinder apparatus. Thermal conductivity above the initial freezing point was well fitted by polynomial equations. Below the freezing point, the thermal conductivity was strongly affected by both the frozen water fraction and temperature. Simple equations in terms of frozen water fraction and temperature could be fitted to the experimental data of freezing point depression and thermal conductivity.

The objective of this work was to study the spray drying of jussara pulp using ternary mixtures of gum Arabic (GA) and modified starch (MS) together with either whey protein concentrate (WPC) or soy protein isolate (SPI), as the carrier agents. Two experimental mixture designs and triangular response surfaces were used to evaluate the effects of the mixtures on the responses for powders formulated with GA:MS:WPC and GA:MS:SPI, respectively. The spray drying process was selected for each carrier agent mixture, aiming to maximum the process yield (PY), solubility (S), retention of total anthocyanins (RTA) and encapsulation efficiency (EE). It was shown that the ternary formulations showed higher PY, S and RTA than the pure and binary formulations, as well as good results for EE and a low moisture content, showing that the use of GA and MS together with either WPC or SPI provide better microencapsulation of the jussara pulp.

RESUMO Proteinas e polissacarideos estao presentes em conjunto em muitos tipos de sistemas alimenticios e ambos contribuem para a estrutura, textura e estabilidade atraves de seu comportamento espessante ou gelificante ou de sua atividade de superficie. Misturas de proteinas e polissacarideos sao interessantes, pois o comportamento reologico das misturas pode diferir bastante do comportamento dos compostos puros. Alem disso, a aplicacao de ultrassom de alta intensidade com o objetivo de alterar propriedades funcionais dos biopolimeros tambem vem sendo estudada. O objetivo do trabalho foi avaliar a interacao eletrostatica do par concentrado proteico de soro de leite e pectina de alto teor de metoxilacao em funcao da razao proteina:polissacarideo com e sem a aplicacao de ultrassom, buscando identificar as microestruturas formadas por meio de reologia, microscopia otica e avaliacao visual no pH 3,5. O modelo Lei da Potencia ajustou-se bem aos dados (R 2 =0,9) e o par apresentou comportamento pseudoplastico (n

RESUMO A elaboracao do suco de uva em po representa uma alternativa interessante no sentido de melhorar a conservacao do produto, sendo a producao de sucos de frutas em po uma aplicacao de crescente interesse industrial. O produto seco apresenta um aumento da sua vida util e maior disponibilidade, porem, o processo de atomizacao e dificultado devido ao comportamento pegajoso que as frutas exibem quando submetidas as variacoes de umidade e temperatura. E de grande importância para a industria melhorar o desempenho do processo de secagem por atomizacao, a fim de obter produtos com melhores caracteristicas, bem como aumentar o rendimento. Uma alternativa para otimizar o processo e adicionar agentes carreadores, que tambem possuem a funcao de encapsulantes. O objetivo deste trabalho foi avaliar a estabilidade e qualidade de sucos de uva em po obtidos atraves spray drying, utilizando combinacoes de maltodextrina (MD) com proteina isolada de soja (SPI) ou proteina concentrada de soro de leite (WPC) como agentes carreadores, visando a protecao das antocianinas e obtencao de um produto com boa estabilidade. A amostra SPI 1, apos 90 dias de exposicao a luz, apresentou maior retencao de antocianinas, com perda de apenas 28 % do conteudo inicial, com menor ganho de umidade e menor variacao na coloracao do suco em po. A utilizacao desses agentes carreadores resultou em pos mais estaveis ao armazenamento, sendo promissores como encapsulantes.

RESUMO O presente trabalho teve como objetivo a obtencao de microcapsulas de betalainas obtidas do extrato de beterraba pelo processo de spray drying. Foram produzidas particulas utilizando diferentes tipos de agentes carreadores: maltodextrina 10DE (Md) e amido de milho modificado (Am) adicionadas do extrato de beterraba, resultando em um grupo de quatro amostras: Am80Md20[15], Am80Md20[35], Am50Md50[15], Am50Md50[35], que foram analisadas quanto ao tamanho das particulas, aos parâmetros de cor (L, C e h), alem de rendimento e umidade. O rendimento do processo variou entre 51 e 82% enquanto os valores de umidade foram inferiores a 2%. A concentracao e a proporcao Am:Md causaram um efeito negativo no valores de C, ou seja, quanto maior a concentracao e a proporcao Am:Md, menor o valor C obtido. Em relacao ao parâmetro L, os valores apresentaram diferenca significativa entre as amostras, o que nao foi observado para h. As amostras com maior concentracao total de carreadores resultaram em particulas maiores, o que esta relacionado ao aumento da viscosidade da mistura a ser seca.

Pseudoternary phase diagrams, at 25 °C, were constructed for the systems soy bean oil (SBO)/surfactant/water, with single anionic sodium bis(2-ethylhexyl)sulfosuccinate (AOT), nonionic monoolein (MO) and mixtures of these surfactants, showing the isotropic phase of W/O microemulsions (MEs). The area of ME formation in the phase diagrams was shown to be dependent of the relative amount of surfactants, being larger for MO:AOT equals to 2:1. Rheological and dynamic light scattering (DLS) studies indicated that the viscosity of the isotropic ME phase exhibited two different behaviors depending on composition. The viscosity of “dry” MEs initially decreased with increasing amount of water following a dilution line in the phase diagram, i.e., a constant surfactant:SBO percentage ratio. As the water content increased the relative viscosity attained a minimum and then increased. This minimum could be related to the transition between two ME regions, L2 and L 2 ′ , having different characteristics. DLS measurements confirm the existence of ordinary W/O ME droplets in the L2 region and suggest the existence of another structure in the L 2 ′ region. The size of the MEs droplets in L2 phase ranges from 3.6 to 16.5 nm, depending on composition of SBO, surfactant and water. Small angle X-ray scattering (SAXS) also indicates the existence of structures with different characteristics, for the SAXS curves exhibit a typical micelle asymmetrical peak at low scattering vector q for MEs in L2 but a symmetrical correlation peak at higher q vector in L 2 ′ .

Density, heat capacity and thermal conductivity of liquid egg products, such as egg white, egg yolk, whole egg and various white and yolk blends, were determined as affected by temperature and water content ranging from 273 to 311 K and 51.8 to 88.2% (mass), respectively. Polynomial models fitted the experimental data very well, showing a linear relationship both for temperature and water content.