Abstract The effect of irradiation through UV-C on the content of phenolic compounds, antioxidant activity, color, and texture profile was evaluated in Bordô variety grapes. Grapes were subjected to stress by irradiation at time of 0.5, 1.0, 4.0, 10 and 30 min that correspond at doses of 0.1, 0.3, 1.0, 2.4, and 7.2 kJ m-2, respectively. The total phenolic and anthocyanins content, antioxidant activity, color and texture of the grapes were evaluated after storage at 22 ºC for 24 and 48 h. In general, samples irradiated did not show an increase in total phenolic content, anthocyanin compounds and antioxidant activity. Hue and Chroma values indicated that the color of grapes did not change when irradiated. Texture profile analysis suggested that UV-C treatment delayed grapes softening.

Resumo Foi estudada a desidratação osmótica do kiwi, utilizando soluções osmóticas de sacarose a 45, 55 e 65 °Brix. Durante o tempo de desidratação, houve diminuição da umidade livre, da atividade da água e ganho de soluto pelo fruto. Observou-se um período inicial de secagem, em que as taxas de perda de água foram maiores. A diminuição da atividade da água foi maior quando o produto esteve imerso na solução a 65 °Brix. O teor de umidade de equilíbrio estimado pelo modelo de Peleg diminuiu significativamente com o aumento da concentração da solução osmótica e os valores de difusividade de água estiveram na faixa entre 1,5 × 10-9 a 1,9 × 10-9 m2 s-1. As pressões osmóticas das soluções também foram preditas.

Abstract Osmotic dehydration of kiwi was evaluated using 45, 55 and 65 °Brix sucrose solutions. Free moisture, water activity and solutes gain decreased in fruit during the process. Water loss rates were higher in the beginning of drying. Water activity decrease was higher when the product was in 65 °Brix solution. The equilibrium moisture content estimated by the Peleg model decreased significantly with increasing concentration of the osmotic solution, and the diffusivity values of water loss were in the range from 1.5 × 10-9 to 1.9 × 10-9 m2 s-1. The osmotic pressures of the solutions were also predicted.

ABSTRACT The inactivation of peroxidase and polyphenol oxidase and the degradation of phenolic compounds, anthocyanins, and antioxidant activity in blackberry were investigated during blanching in water at 80-90 °C, and in steam, from 0 to 10 minutes. The enzyme kinetics indicated the presence of two isoenzymes with different thermal stability, following two-phase model, in which the reaction rate constant increased with increasing temperature for both the heat labile and heat resistant component. The phenolic compounds also followed a biphasic pattern, indicating a more heat resistant fraction, and the rate constants increased with increasing temperature. For the antioxidant activity and anthocyanins, the first order kinetic model (R2>0.982) indicated an increase in degradation rate constants with temperature, from 0.050 to 0.137min-1 for DPPH, 0.085 to 0.285min-1 for ABTS, and 0.017 to 0.052 min-1 for anthocyanins.

RESUMO O yacon é uma raiz que contém compostos com atividade antioxidante e prebiótica. Este estudo teve como objetivo avaliar as características físicas, químicas e prebióticas das micropartículas de yacon encapsuladas por atomização. A partir do extrato do yacon foram obtidas as soluções de retido e permeado usando a separação por ultrafiltração (UF) com membranas de 10 e 30 kDa. O permeado foi misturado com goma arábica em concentrações de 10 e 15% e encapsulado por atomização a temperaturas de 140 e 160 °C. As micropartículas obtidas tiveram valores de solubilidade maiores que 90%, enquanto que a higroscopicidade diminuiu com o aumento da concentração de goma e da temperatura de secagem. A microscopia eletrônica mostrou uma forte tendência à aglomeração de partículas menores em torno das maiores, principalmente a 140 ºC. Em relação à cor, o parâmetro L* mostrou que a secagem a 160 ºC produziu amostras mais escuras, e os parâmetros a* e b* indicaram que todas as amostras tiveram coloração amarelo esverdeado. A concentração de inulina diminuiu durante a secagem, enquanto que os conteúdos de glicose e de frutose aumentaram devido às reações de termólise, o que levou à degradação das cadeias de inulina. As dispersões permeadas e retidas provenientes da separação de UF apresentaram atividade prebiótica, enquanto que somente o pó encapsulado proveniente da membrana de 30 kDa foi metabolizado pelo Lactobacillus acidophilus, apresentando escores de atividade sem diferença significativa em relação à da glicose.

ABSTRACT Yacon root is a functional food which contains antioxidants and prebiotics compounds. This study aimed to evaluate the physical, chemical and prebiotic characteristics of a yacon extract powder obtained by ultrafiltration (UF) with membranes of 10 and 30 kDa and encapsulation of the resulting permeate by spray drying. Drying air temperatures of 140 and 160 ºC and concentrations of gum arabic of 10 and 15% were tested. The samples had solubility values greater than 90% while the hygroscopicity decreased with increasing gum concentration and drying temperature. Electron microscopy showed a strong tendency to agglomeration of smaller particles around the larger ones, mainly at a temperature of 140 ºC. Regarding color, the parameter L* showed that drying at 160 ºC produced darker samples and the parameters a* and b* indicated that all samples were greenish yellow. The concentration of inulin decreased during drying, whereas the levels of glucose and fructose increased due to the thermolysis reaction, which led to degradation of inulin chains at drying temperature. The permeates and retentates from the UF membranes had prebiotic activity, while only the encapsulated product from UF-30 membrane, metabolized by Lactobacillus acidophilus LA-5(r), presented activity scores without significant difference to that of glucose.

ABSTRACT This study aimed to evaluate the influence of the drying air temperature (140 and 160°C) and the concentration of encapsulating agents gum Arabic and polydextrose (10 and 15%) on the physicochemical characteristics of the red cabbage extract obtained through extraction in acidulated water and drying using a spray dryer. The anthocyanin retention, antioxidant activity, water activity, solubility, color and microstructure of the final product were analyzed. Results showed that increase in the temperature did not cause significant changes in the anthocyanin quantity and antioxidant activity. The microscopic analysis revealed that for both the encapsulating agents, the absence of fissures and porosity in the particle surfaces produced powder with high solubility in water. The principal component analyses showed a strong correlation between the anthocyanin content and the antioxidant activity (r = 0.82) and luminosity (r = 0.81).

RESUMOAs raízes de yacon contém inulina, o qual possui propriedade prebiótica e pode ser usado como substituto de sacarose ou gordura. Entretanto, a inulina é solúvel em água. As perdas desse nutriente durante o branqueamento são causadas, principalmente, por difusão ou lixiviação, o qual pode ser diminuído se as condições de tempo e temperatura são corretamente empregadas. Objetivou-se neste trabalho, foi estudar a lixiviação, durante o branqueamento em água quente em diferentes condições de tempo e temperatura, dos açúcares inulina, glicose e frutose presentes na raiz do yacon. As amostras foram previamente limpas, descascadas e cortadas na forma geométrica de disco de 1,75 ± 0,35 milímetros de espessura. Os resultados indicaram que o tempo e a temperatura foram significativos na dissolução dos açúcares. As menores perdas de inulina ocorreram à temperaturas e tempos menores que 60 ºC e 3 minutos, respectivamente, enquanto que as menores perdas de glicose e frutose, para todas as temperaturas, foram obtidas para tempos menores que 3 e 5 minutos, respectivamente.

ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching under different time/temperature conditions. The samples were cleaned and peeled and cut into geometric forms of 1.75 ± 0.35 mm thick disks. A complete factorial experimental design was used, and the treatments of the samples were compared using the Tukey test. The results indicated that the time and temperature were significant in the dissolution of the sugars. The lowest inulin losses occurred at temperatures and times lower than 60 ºC and 3 minutes. For all temperatures, the lowest glucose and fructose losses were obtained at time lower than 3 and 5 minutes, respectively.

The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration.

Fructooligosaccharides (FOS) are food ingredients applied due to combination of prebiotic benefits and interesting technological properties, being used as a sugar substitute. The knowledge of their physicochemical characteristics is important for predicting the stability of the food products where they are added. For this reason, a saccharides powder extracted from yacon (Smallanthus sonchifolius) roots by membrane technology and freeze-dried was investigated. Color, water activity (aw), microstructure by Scanning Electron Microscopy coupled to Energy- dispersive X-ray Spectroscopy (SEM-EDS) and crystallinity by X-ray diffraction were evaluated. The obtained product, containing 19.75% FOS, 36.66% glucose and 43.59% fructose (w/w) was a whitish granulated powder, with aw of 0.284 and CIELAB color coordinates L*, a* and b* of 76.25±1.19, -1.03±0.09 and 1.02±0.03, respectively. It was highly hygroscopic and with agglomeration tendency, confirmed by the formation of bridges between particles on the SEM images. No peaks were identified at X-ray diffractograms, indicating its amorphous characteristics, but sample high hygrospicity and formation of a rigid mass might have hampered a trustable X-ray analysis.

As propriedades funcionais tecnológicas do amido nativo e modificado (hidrólise ácida) de pinhão (Araucaria angustifólia) foram comparadas às propriedades do amido nativo e ácido hidrolisado de milho. As espécies de amido foram hidrolisadas (3.2 mol.L-1 HCl, 44 ºC, 6 horas) e avaliadas, antes e após a reação de hidrólise, de acordo com as análises de formação, fusão e termorreversão do gel, retrogradação (em um período de 30 dias, com medidas a cada 3 dias), estabilidade ao congelamento e descongelamento (após 6 ciclos de congelamento e descongelamento), poder de inchamento e índice de solubilidade. Os resultados obtidos demonstraram que o amido de pinhão apresenta menor tendência à retrogradação quando comparado ao amido de milho, tanto para a forma nativa quanto na modificada, após períodos similares de armazenamento. O amido nativo de pinhão (APN), quando submetido a sucessivos ciclos de congelamento e descongelamento, apresentou menor sinérese do que o amido de milho nativo (AMN). Nas temperaturas de 25, 50 e 70 ºC, a solubilidade do APN foi menor do que a obtida pelo AMN. Entretanto, para a forma modificada, o amido de pinhão apresentou maior solubilidade (p < 0,05) do que o amido de milho. Através dos resultados, pode-se afirmar que o tratamento ácido modificado realizado no amido de pinhão foi efetivo para a produção de um potencial substituto de gordura, propriedade que deve ser testada e analisada em estudos futuros.

Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine) starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours) and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days), paste freezing and thawing stability (after six freezing and thawing cycles), swelling power, and solubility. The results of light transmittance (%) of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation) than that obtained for corn starches after similar storage period. Native pinhão starch (NPS) presented lower syneresis than native corn starch (NCS) when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS), this property was significantly higher (p < 0.05) when compared to that of acid-thinned corn starch (ACS). From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

O efeito da embalagem em atmosferas modificadas sobre os insetos Sitophilus spp. nos grãos de milho orgânico foi estudado. Os grãos de milho foram empacotados em cinco atmosferas iniciais diferentes de 20% de O2, ou 20, 40, 60, 80% de CO2 com balanço de N2. As embalagens foram armazenadas por 30 dias a 26ºC. As concentrações de CO2 e O2 foram monitoradas dentro das embalagens durante o armazenamento. As análises de teor de umidade, acidez e pH foram também realizados no primeiro e trigésimo dia. Os resultados mostraram que no quinto, décimo quinto e trigésimo dia de estocagem não foram encontrados diferenças significativas nas porcentagens de insetos mortos quando CO2 foi usado. Os resultados relativos à progênie indicaram que no quinto dia o número de insetos emergentes foi menor a 20, 60 e 80% CO2. A completa inibição dos insetos foi atingida com 30 dias de exposição em atmosferas de CO2.

The effect of modified atmosphere packaging on the mortality of Sitophilus spp. in organic maize grain was studied. Maize grains were packed with five different atmospheres consisting of 20% O2, or 20, 40, 60, 80% CO2 with remaining N2. The packages were stored for 30 days at 26°C. CO2 and O2 concentrations were monitored inside the packages during the storage. The moisture content, titratable acidity and pH were analysed on the first and thirtieth day. At 5, 15 and 30 days of storage no significant differences were observed in the percentages of dead insects when CO2 was used. The results of progeny indicated that from the fifth day the number of emerging insects was low at 20, 60 and 80% CO2. Complete inhibition of the insects was achieved with 30 days of exposure in CO2 atmospheres.

The aim of this work was to produce crystallized fruit from watermelon rind. The following procedure was developed: the outer peel was removed; the material was sliced into 7 mm cubes, blanched for, 0, 5 and 10 minutes, and then treated with 10% sodium chloride solution. This product was treated with solutions of sucrose (30 to 72 °Brix), and dried in a hot air dryer at different temperatures (40, 60 and 80 °C). Products were then analyzed by a sensory panel. The experimental design used was randomized blocks and the results were analyzed by the Tukey's test. The best acceptance of the sensory panel was for the product obtained by 5 minutes blanching followed by drying at 60 °C, whose intensity values for appearance, flavor and gummosis were between 6 and 7.

El presente trabajo tuvo como objetivo el aprovechamiento de las cascaras de sandía en la elaboración de productos cristalizados. Para esto fue eliminada la cutícula verde externa de la cascara, cortadas en forma de cubo de aproximadamente 7 mm de lado, escaldado con agua en su temperatura de ebullición utilizando 0, 5 ó 10 minutos y dejados inmersos en una solución de cloruro de sodio. Posteriormente fueron sometidas a concentraciones crecientes de soluciones de sacarosa (30 a 72 °Brix) y deshidratadas en un secador a diferentes temperaturas (40, 60 y 80 °C). Los diferentes tratamientos fueron evaluados por un panel sensorial. El diseño experimental empleado fue el de bloques completos aleatorios y los resultados del análisis sensorial fueron evaluados por la prueba de comparación de medias de Tukey. Fue constatado que el tratamiento con mayor aceptabilidad, por parte del panel sensorial, fue la que había sido sometida a un escaldado de 5 minutos y deshidratado a 60 °C, cuyos valores de intensidad para la apariencia, sabor y gomosidad estuvieron entre 6 y 7.

A elaboração e o armazenamento de pães crus congelados têm se mostrado vantajosos para os pontos de venda e para o consumidor final. O primeiro, pela redução da perda e menor exigência de espaço físico e mão-de-obra especializada, e o segundo, por disponibilizar pães sempre frescos. O presente trabalho objetivou verificar a influência do armazenamento sobre a viabilidade das células de levedura em massas congeladas de pão francês. Para tanto, as massas foram elaboradas seguindo a metodologia de massa direta: os ingredientes (pré-mistura para pão francês, fermento fresco e água) foram misturados até o desenvolvimento completo do glúten; então foi dividida em porções de 60g e modelada. O congelamento foi realizado em ultracongelador a -32°C, e o armazenamento foi feito em câmaras com temperaturas de -18°C e -40°C. Para a estimativa de vida de prateleira, analisou-se a cinética da redução da viabilidade das leveduras. Esse teste foi realizado em placas de Petri contendo meio Sabouraud acrescido de cloranfenicol 0,2% a 28°C durante cinco dias. A cinética de redução das células de levedura seguiu uma reação de primeira ordem, cujas constantes de velocidades foram 0,027 dias-1 (R²=0,931) e 0,026 dias-¹ (R²=0,938) para as temperaturas de -18°C e -40°C, respectivamente. Para ambas as temperaturas, a redução em 50% da população de leveduras se deu em aproximadamente 25 dias.

The preparation and storage of frozen bread has proved to be advantageous for the market and to the final consumer. First because of loss reduction and need for smaller physical storage space and workforce, second because it provides always fresh bread. This study aimed to investigate the influence of storage on the viability of yeast cells in frozen French bread. In order to that, frozen French breads were prepared by the direct-dough method: the ingredients (premix for French bread, fresh yeast and water) were mixed until the dough was fully developed and then divided into portions of 60g and moulded. Freezing was held in ultra freezer at -32°C and the storage was made in chambers at temperatures of -18oC and -40°C. To estimate the shelf life, the study of reduction of leavening cells viability in frozen French bread dough was analyzed. This test was performed in Petri dishes containing Sabouraud agar with chloramphenicol 0.2% at 28°C during 5 days. The kinetics of reduction of leavening cells viability followed a first-order reaction, which rate constants were 0.027 days-1 (R²=0.931) and 0.026 day-¹ (R²=0.938) for -18°C and -40°C temperatures, respectively. For both temperatures, the 50% reduction in the number of leaven occurred in approximately 25 days.

O coeficiente de difusão efetivo do óleo essencial de cravo-da-índia em CO2 líquido subcrítico foi estimado. O equipamento experimental usado foi um extrator de leito fixo. O leito fixo foi formado por cravo-da-índia moído (mesh -32 + 65) e compactado, sendo assim considerado como um meio sólido. O coeficiente de difusão efetivo foi estimado pelo ajuste do perfil de concentração experimental à equação de balanço de massa em estado transiente, para difusão unidirecional em um meio sólido. A dependência do coeficiente de difusão com a concentração de óleo no sólido, foi descrita por uma função exponencial. O coeficiente de difusão determinado variou de 3,64 a 5,22x10-10m2/s. Os erros médios relativos foram menores do que 3,1%.

The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65) and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%.