Study of drying in two different types of dryers : evaluation of operational parameters and dried material behavior

Orientador: Kil Jin ParkTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia AgricolaResumo: No processo de secagem, a utilização de equipamentos que promovem um incremento nos coeficientes de transferência é de grande interesse. A secagem vibro-fluidizada se baseia na passagem de um fluxo de ar aquecido através do leito do material colocado sobre uma grade distribuidora de ar, aliado ao efeito mecânico da agitação do leito do secador. É utilizada para materiais termolábeis, que requerem tempos de residência curtos, altas taxas de secagem e baixas temperaturas de secagem, tais como: materiais granulares, pastas e pós; tanto para materiais farmacêuticos, biológicos e alimentares. Neste estudo pretendeu-se então, submeter materiais biológicos a um processo de secagem utilizando diversos dispositivos e avaliar o comportamento da secagem, consumo de energia, propriedades do material e extração de componente. Os secadores utilizados foram: secador vibrofluidizado (patente PI 9302443-6 e auxílio FAPESP n°: 00/05543-2) e secador agitador/misturador (patente PI 0506639-5). O processo de secagem foi avaliado com grãos de milho no secador vibrofluidizado e batata e raízes de yacon no secador agitador/misturador. Realizaram-se o levantamento do tempo de residência com análise de imagens e seleção manual; levantamento da perda de carga e do perfil de velocidade no secador vibrofluidizado com sistemas aberto e fechado. A partir dos testes para levantamento da distribuição do tempo de residência, foi desenvolvida uma metodologia para avaliação da quantidade de traçador na massa de produtos com base somente em imagens digitais das amostras. Com isso é possível encontrar valores de tempo de residência sem o uso de práticas manuais e, consequentemente, trabalhosas. Levantamento do tempo de residência foi também realizado no secador agitador/misturador que pode ser utilizado tanto como secador contínuo como secador a batelada. Esse secador permite a aplicação de vácuo e de energia radiante infravermelha durante a secagem. Foi utilizado, ainda, na secagem de batata e raiz de yacon e na avaliação destes recursos tecnológicos. A extração de inulina proveniente das raízes de yacon foi avaliada. A utilização de temperaturas de secagem mais altas resultou em um maior consumo de energia por quilograma de água retirada do produto, enquanto que a aplicação de energia infravermelha durante a secagem reduziu o tempo de secagem e, consequentemente, a energia elétrica gasta. A influência dos parâmetros operacionais de secagem não se mostrou significativa estatisticamente na extração de inulina a partir de raízes secas de yaconAbstract: In the drying process, the use of equipments which promote an increment in the transfer coefficients is of great interest. The vibrofluidized drying is based on the passage of a warm air flow through the bed of the material put on an air distributing grille, allied to the mechanical effect of the agitation of the drying bed. It is used for thermo sensible materials, which request short residence times, high drying taxes and low drying temperatures, such as: granular materials, pastes and powders; so much for pharmaceutical, biological and food materials. In this project it was intended then, to submit biological materials to a drying process using several devices and to evaluate the behavior of the drying, energy consumption, material properties and component extraction. The used dryers were: vibrofluidized dryer (patent PI 9302443-6 and FAPESP financial support n°: 00/05543-2) and agitator/mixer dryer (patent PI 0506639-5). The drying process was evaluated with corn grains in the vibrofluidized dryer and potato and yacon roots in the agitator/mixer dryer. The survey of the residence time with analysis of images and manual selection; the survey of pressure drop and air velocity profile in the vibrofluidized dryer in open and closed systems were also carried out. Starting from the survey of the residence time distribution, a methodology was developed for evaluation of the tracer amount in the mass of products based on only digital images of samples. In this way, it is possible to find residence time without using manual procedures and, consequently, laborious. Survey of the residence time was accomplished also in the agitator/mixer dryer which can be used as continuous dryer as well as batch dryer. This dryer allows vacuum and infrared radiant energy application during drying. It was used, even, in potato and yacon root drying and in the evaluation of these technological devices. The extraction of inulin originated from yacon roots was also evaluated. The use of higher drying temperatures resulted in a larger consumption of energy per kilogram of removed water from product, while the infrared energy application during drying reduced the drying time and, consequently, the consumed electric energy. The influence of drying operational parameters was not statistically significant in the extraction of inulin from dried yacon rootsDoutoradoTecnologia Pós-ColheitaDoutor em Engenharia Agrícol

Blackberry pulp microencapsulation with arrowroot starch and gum arabic mixture by spray drying and freeze drying

The objective of this research work was to obtain blackberry pulp powder (BL, without encapsulating agent) and microencapsulated blackberry pulp (ML, with encapsulating agent :mixture of starch arrowroot and gum arabic (1:1)) obtained by freeze drying and spray drying and evaluate their physico- chemical properties. The yield of blackberry freeze drying process was higher than the value found for spray drying process. The presence of encapsulating agent and drying method used for producing the powders influenced the average particle size, diameter, hygroscopicity, solubility, wettability and anthocyanin content of the powdersPostprint (published version

Effect of incorporation of blackberry particles obtained by freeze drying on physicochemical properties of edible films

This research work aimed to evaluate the physicochemical properties of arrowroot starch films plasticized with glycerol and incorporated in film- forming solution directly (D) and by sprinkling (S) with 0%, 20%, 30%, 40% (mass blackberry solids / biopolymer mass) of blackberry pulp (BL) powder and freeze dried microencapsulated blackberry pulp (ML) using mixture of gum arabic and arrowroot starch (1: 1, mass / mass). Thickness, water solubility and water vapour permeability of the films significantly increased with increasing concentration of blackberry powder. Compared to arrowroot starch film (0%), the surface of films with BL and ML powder became irregular and roughPostprint (published version

PHYSICOCHEMICAL CHARACTERIZATION OF JUSSARA PULP POWDER BY SPRAY-DRYING

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

Active edible films based on arrowroot starch with microparticles of blackberry pulp obtained by freeze-drying for food packaging

This research work evaluated the influence of the type of incorporation and variation in the concentration of blackberry pulp (BL) and microencapsulated blackberry pulp (ML) powders by freeze-drying on the chemical and physical properties of arrowroot starch films. Blackberry powders were added to the film-forming suspension in di erent concentrations, 0%, 20%, 30% and 40% (mass/mass of dry starch) and through two di erent techniques, directly (D) and by sprinkling (S). Scanning electron microscopy (SEM) images revealed that the incorporation of blackberry powder has rendered the surface of the film rough and irregular. Films incorporated with BL and ML powders showed an increase in thickness and water solubility and a decrease in tensile strength in comparison with the film containing 0% powder. The incorporation of blackberry BL and ML powders into films transferred colour, anthocyanins and antioxidant capacity to the resulting films. Films added with blackberry powder by sprinkling were more soluble in water and presented higher antioxidant capacity than films incorporated directly, suggesting great potential as a vehicle for releasing bioactive compounds into foodPostprint (published version

Bioactive edible films based on arrowroot starch incorporated with cranberry powder: microstructure, thermal properties, ascorbic acid content and sensory analysis

The growing global awareness about environmental preservation has stimulated the search for alternatives to replace conventional plastics made from fossil sources. One of the advantages is using polymers from renewable sources, such as starch and gelatin, which, in addition to being biodegradable, may also be edible. The incorporation of cranberry into a polymeric matrix can transfer bioactive composite films, colour and flavour to the film, which are characteristic of this fruit, expanding its application to fruit stripes or colourful coatings for specific foods. In this context, the aim of this work was to evaluate the influence of the incorporation of 0, 5, 15, 25, 35, 45 and 55% (solids mass/biopolymer mass) cranberry powder on the microstructure, thermal properties, ascorbic acid content and sensory analysis of gelatin and arrowroot starch films obtained by casting. Scanning electron microscopy (SEM) images showed that the incorporation of cranberry made the film surface rough and irregular. All films presented an X-ray di raction pattern typical of a semicrystalline material. The glass transition temperature (Tg) decreased when increasing the concentration of cranberry in films. All films with cranberry presented high ascorbic acid content and were well accepted by the tasters when sensory analysis was performedPostprint (published version

Microencapsulation of babassu coconut milk

The objective of this study was to obtain babassu coconut milk powder microencapsulated by spray drying process using gum Arabic as wall material. Coconut milk was extracted by babassu peeling, grinding (with two parts of water), and vacuum filtration. The milk was pasteurized at 85 ºC for 15 minutes and homogenized to break up the fat globules, rendering the milk a uniform consistency. A central composite rotatable design with a range of independent variables was used: inlet air temperature in the dryer (170-220 ºC) and gum Arabic concentration (10-20%, w/w) on the responses: moisture content (0.52-2.39%), hygroscopicity (6.98-9.86 g adsorbed water/100g solids), water activity (0.14-0.58), lipid oxidation (0.012-0.064 meq peroxide/kg oil), and process yield (20.33-30.19%). All variables influenced significantly the responses evaluated. Microencapsulation was optimized for maximum process yield and minimal lipid oxidation. The coconut milk powder obtained at optimum conditions was characterized in terms of morphology, particle size distribution, bulk and absolute density, porosity, and wettability.737744Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Bread preservation with use of edible packaging

We live in a world that usually use plastic bags either to go shopping or to pack the snack for a short trip. However, packaging makes life easier and serves as protection for products such as food. Bread is a common food product that needs packaging in order to be protected at storage and transportation. Therefore, with aim of reducing petroleum derived packagin g consumption it was developed an edible film from potato starch to packeg bread and some quality characteristics like water content, firmness and weight loss were evaluated, showing that edible film can be used as a packagingPostprint (published version

Edible films and coatings formulated with arrowroot starch as a non-conventional starch source for plums packaging

Increasing environmental awareness has promoted an interest in alternative strategies to common plastics obtained from fossil sources, stimulating research on the use of biodegradable and edible films/coatings obtained from renewable sources such as arrowroot starch. This research work aimed to evaluate the use of arrowroot starch on the formation of edible films and coatings. Increasing the concentration of arrowroot starch (from 1% to 5%, mass/mass) in the film produced by casting resulted in increased water vapor permeability (from 2.20 to 3.68 g mm/m2 day kPa), moisture content (3.22% to 7.95%), increased thickness (from 0.029 to 0.101 mm), and decreased solubility in water (from 22.45% to 13.89%). The films were homogeneous, transparent and manageable, with the exception of the film with 1% starch. Film-forming solutions at concentrations of 0%, 2%, and 4% (mass/mass) of arrowroot starch were prepared and applied to plums to evaluate post-harvest behavior when stored at 25 and 5 ¿C for 35 days. The 2% coating adhered well to the plums’ surfaces, was bright and was effective in reducing mass loss and respiratory rate, associated with storage temperature of 5 ¿C. The 4% coating presented an opaque and flocculated appearancePostprint (published version