Rafael Augustus de Oliveira

Influence of Process Conditions on the Physicochemical Properties of Pequi Powder Produced by Spray Drying

Microencapsulation of extract pequi pulp by spray drying, using Arabic gum as a microencapsulating agent, was studied. Tween 80 was used as a secondary emulsifier. A factorial design was conducted with the following independent variables: inlet air temperature (140 to 200°C), surfactant concentration Tween 80 (0 to 5%), and microencapsulating agent concentration (10 to 20%) on the responses; moisture content (0.3 to 1.9%), hygroscopicity (10.7 to 14.3 g adsorved water/100 g solids), process yield (25.8 to 56.1%), water activity (0.07 to 0.17), vitamin C (113.0 to 306.6 mg ascorbic acid/g pequi solids), and carotenoids content (10.9 to 74.3 mg carotenoids/g pequi solids). Only powder moisture content, hygroscopicity, water activity, and vitamin C content were statistically influenced by independent variables. Spray drying was optimized for maximum vitamin C and carotenoids content and minimal water content and hygroscopicity. Powder obtained under optimum conditions was characterized as to particle morphology, bulk, absolute density, and particle size distribution.

Determinação da difusividade efetiva de raiz de chicória

Inulin is a fructooligosacharide found in diverse agricultural products, amongst them garlic, banana, Jerusalem artichoke and chicory root. Inulin generally is used in developed countries, as a substitute of sugar and/or fat due to its characteristics of fitting as functional and dietary food. Chicory root is usually used as source and raw material for commercial extration of inulin. The experiments consisted on drying sliced chicory roots based on a factorial experimental design in a convective dryer whose alows the air to pass perpendicularly through the tray. Effective diffusivity (dependent variable) has been determined for each experimental combination of independent variables (air temperature and velocity). The data curves have been fitted by the solution of the second Fick law and Pages model. Effective difusivity varied from 3.51 x 10-10 m2 s-1 to 1.036 x 10-10 m2 s-1. It is concluded that, for the range of studied values, air temperature is the only statistically significant variable. So, a first order mathematical model was obtained, representing effective diffusivity behavior as function of air temperature. The best drying condition was correspondent to the trial using the highest drying air temperature.

Influence of different combinations of wall materials on the microencapsulation of jussara pulp (Euterpe edulis) by spray drying.

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.

Otimização da prensagem de grãos de girassol e sua caracterização

The continuous screw pressing of oilseeds is noted for its speed, case of handling and for its low cost installation and support, adapting perfectly to small agricultural communities. However, in terms of efficiency, the traditional solvent extraction still has a higher yield. Attempting to improve the screw pressing technique, some researchers had observed that some variables had an influence on oil yield, such as grain moisture content, grain temperature and some construction aspects of the press. In relation to the initial raw material preparation, studies reveal the possibility of finding optimal values of the moisture content and temperature. In this work, the influence of temperature and moisture content on oil yield was evaluated. For the experimental range of values chosen, among the effects studied, the moisture content and the interaction between moisture and temperature were significant, affecting in a negative way the oil yield, to 95% of confidence. The biggest value of oil yield was reached with the moisture content between 8 to 8.5% and the temperatures between 47.8 to 60 oC. The oil obtained by pressing presented characteristics similar to those of commercial sunflower oil.

Nocturnal thermal comfort in facilities for growing swines

Em grande parte das granjas de suinos no Brasil, os sistemas para climatizacao do ambiente funcionam com acionamento manual. Para os periodos matutino e noturno, esta pratica nao e adequada, uma vez que, nestes periodos, em geral, nao ha funcionarios disponiveis para o acionamento destes sistemas. Por meio deste trabalho, objetivou-se comparar o perfil bioclimatico de duas instalacoes construtivamente diferentes entre si e com o ambiente externo, considerando o periodo de 18 as 6h, durante a primavera, a fim de verificar que as condicoes de conforto termico da noite e da madrugada podem apresentar-se fora do desejado para suinos em crescimento, e que, por esta razao, a climatizacao deve ser realizada tambem nestes periodos. Foram analisados a temperatura de bulbo seco, a umidade relativa do ar, o Indice de Temperatura e Umidade e a entalpia nos galpoes e no ambiente externo as instalacoes. Nas condicoes estudadas, foi possivel concluir que o galpao construtivamente adequado estudado mostrou ser menos influenciado pelo ambiente externo, propiciando conforto termico mais adequado para os suinos em crescimento. Mais estudos devem ser realizados para que se verifique a necessidade de acionamento automatico de equipamentos de climatizacao durante a noite e a madrugada.

Microencapsulation of pequi pulp by spray drying: use of modified starches as encapsulating agent

O objetivo deste trabalho foi avaliar a microencapsulacao de polpa de pequi por spray drying. Um delineamento composto central rotacional foi utilizado para avaliar o efeito das variaveis independentes: temperatura do ar de entrada, concentracao de surfactante e concentracao de amido modificado sobre o rendimento do processo e as caracteristicas do produto microencapsulado. A selecao da melhor condicao de processo foi baseada na obtencao de um produto com maior teor de vitamina C e de carotenoides. Todos os pos produzidos mostraram teores de umidade inferiores a 2%. Os valores experimentais de higroscopicidade, rendimento de secagem, atividade de agua, vitamina C e carotenoides totais dos pos variaram de 7,96 a 10,67 g de agua adsorvida/ 100 g solidos, 24,34 a 49,80%, 0,13 a 0,30, 145,78 a 292,11 mg de acido ascorbico/g de solidos de pequi e 15,51 a 123,42 mg de carotenoides/g de solidos de pequi, respectivamente. Temperatura de ar de entrada de 140°C, concentracao de surfactante de 2,5% e concentracao de amido modificado de 22,5% foram recomendadas como sendo a condicao selecionada. Atraves da microscopia eletronica de varredura, observou-se que a maioria das particulas apresentou formato esferico e superficie lisa.

Spray drying of babassu coconut milk using different carrier agents

ABSTRACT The objective of this work was to optimize the spray drying of babassu coconut milk, an oil-in-water emulsion extracted from babassu kernels, using maltodextrin 10DE and modified starch as the carrier agents. Two central composite rotatable designs were used to verify the effect of the inlet air temperature and carrier agent concentration on process performance (process yield and outlet air temperature) and the physicochemical properties of the powder (moisture content, water activity, hygroscopicity, and lipid oxidation). Powders obtained under optimized conditions (25% maltodextrin concentration and 188°C, and a modified starch concentration of 20% and 170°C) were evaluated according to their morphology, particle size distribution, bulk and absolute densities, porosity, wettability, and thermal analysis.

Transferência de massa e secagem em leitos vibrofluidizados: uma revisão

Development of processing technology and equipments requires new methods and better quality of the processed product. In the continuous drying process, utilization of equipments that promotes an increment in the transfer coefficients becomes of the major interest. The use of vibrational energy has been recommended to the dispersed materials. Such method is based on the use of vibrational energy applied to disperse media. Thus, a literature review on the mass transfer and drying in vibro-fluidized beds was carried out, showing experimental results and mathematical modeling.

Effect of incorporation of blackberry particles on the physicochemical properties of edible films of arrowroot starch

ABSTRACT This research work evaluated the physicochemical properties of arrowroot starch films plasticized with glycerol and incorporated directly and by sprinkling with 0, 20, 30, and 40% (blackberry solids mass/biopolymer mass) blackberry particles obtained by spray drying. The films were characterized by thickness, color, water activity, moisture content, water solubility, water vapor permeability, mechanical properties, anthocyanins content, and antioxidant properties. Films incorporated with blackberry particles showed an increase in thickness, water solubility, water vapor permeability, and elongation at break as well as decrease tensile strength compared to the control film. The incorporation of blackberry particles to films transferred bioactive compounds and antioxidant capacity, as well as color to resulting films.

Bioactive films of arrowroot starch and blackberry pulp: Physical, mechanical and barrier properties and stability to pH and sterilization

The influence of the incorporation of blackberry pulp on properties of arrowroot starch films has been studied. The blackberry pulp transferred bioactive compounds, antioxidant capacity and color to arrowroot starch films. Increasing the concentration of blackberry pulp (from 0 to 40%, mass/mass of dry starch) in the film resulted in increased thickness (from 0.065 to 0.133 mm), increased elongation (from 3.18 to 13.59%), decreased tensile strength (from 22.71 to 3.97 MPa), increased water vapor permeability (from 3.62 to 4.60 g.mm/m2.day.kPa) and solubility in water (from 14.18 to 25.46%). The films were stable to different media, maintaining the same initial diameter dimensions after immersion in acidic, neutral and alkaline solutions, but their color intensity was reduced, probably due to the release of anthocyanins to the solutions. The films with blackberry pulp presented darkness after sterilization process.