Abstract Yellow mombin juice was microencapsulated by spray drying. Optimum operating conditions were selected from the outcomes of tests carried out according to a central composite rotatable design, using air inlet temperature (90 to 190 °C), feed flow rate (0.20 to 1.00 L/h) and 15 DE maltodextrin concentration (10 to 30%) as the independent variables, while powder moisture content, water activity, hygroscopicity, total carotenoids retention, and process yield as the responses. As expected, water activity, moisture content and yield of samples were significantly reduced by spray drying. The powder prepared under optimum conditions, whose reconstituted nectar was the most appreciated by panelists in sensory analysis, was partially characterized in terms of physicochemical properties. It exhibited an apparent density of 0.59 g/mL and a solubility of 81.49%. Particles generally occurred in clusters and exhibited spherical shape and smooth surface. The antioxidant activity was shown to be weak to intermediate.

Resumo A beterraba vermelha é altamente nutritiva e pode ser preservada pela secagem, a fim de evitar desperdícios, aproveitar os excedentes das culturas e agregar valor durante a entressafra. O objetivo deste estudo foi avaliar os efeitos dos pré-tratamentos de desidratação osmótica (DO) e ultrassom (US) na qualidade nutricional e nas características sensoriais de chips de beterraba desidratados. A cinética de perda de umidade durante DO e US foi prevista pelo ajuste dos dados experimentais com modelos de camada fina. Foram determinados parâmetros físico-químicos (umidade, proteína, lipídio, carboidrato, energia, cinzas, sódio e nitrato) e propriedades sensoriais (ordem de preferência afetiva e teste de aceitação). As correlações entre os tratamentos e a aceitabilidade sensorial avaliada pelas percepções do consumidor foram realizadas aplicando técnicas quimiométricas não supervisionadas (Análise de Componentes Principais e Análise de Agrupamento Hierárquico). O modelo exponencial de dois termos forneceu melhor ajuste para os dados experimentais de secagem. O tratamento US promoveu maior taxa de secagem e menores valores de lipídios, cinzas e energia, enquanto o processo DO resultou em maiores valores de cinzas e sódio. A análise multivariada revelou que os tratamentos US e DO melhoraram as propriedades sensoriais dos chips de beterraba. US foi o pré-tratamento mais eficiente para a produção de chips de beterraba, em razão da redução significativa no tempo de secagem e do nível intermediário de preferência sensorial.

Abstract Red beet (or beetroot) is highly nutritious and can be preserved by drying, in order to avoid wastage, to take advantage of crop surpluses, and to add value during the off-season. The objective of this study was to evaluate the effects of osmotic dehydration (OD) and ultrasound (US) pre-treatments on the nutritional quality and sensory characteristics of dried beetroot chips. The kinetics of moisture loss during OD and US were predicted by fitting the experimental data with thin-layer models. The physicochemical parameters (moisture, protein, lipid, carbohydrate, energy, ash, sodium and nitrate) and sensory properties (affective preference-ordering and acceptance test) were determined. Correlations between the treatments and the sensory acceptability evaluated by consumer’s perceptions were performed by applying unsupervised chemometric techniques (Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA)). The two-term exponential model provided the best fit for the experimental drying data. The US treatment promoted a higher drying rate and lower lipid, ash and energy values, while the OD process resulted in higher ash and sodium values. Multivariate analysis revealed that the US and OD treatments improved the sensory properties of the beetroot chips. The US was more efficient pre-treatment for producing beet chips due to its leads a significant reduction on drying time and intermediate level of sensory preference.

The technology for the production of restructured fruit with high contents of fruit pulp using hydrocolloids as binding agents has not been fully developed. This study evaluated the effect of mixtures of sodium alginate, low methoxy pectin, and gelatin on the characteristics of yellow mombin (Spondias mombin L.) fruit gels. The results of the central composite design showed that the models obtained, except for those of water activity and soluble solids, were predictive. Gelatin was the most important factor affecting firmness, pH, and the color parameters of the structured fruit pulp.

Este trabalho avaliou o efeito de misturas de alginato, pectina de baixa metoxilação e gelatina nas características de géis de P. cincinnata, contendo polpa com alto teor de sólidos solúveis (50 °Brix). Os resultados do planejamento experimental central composto mostraram que os modelos obtidos, exceto para a atividade de água e pH, foram preditivos. A gelatina foi o mais importante fator de influência na firmeza e nos parâmetros de cor, sendo que altas concentrações desse hidrocoloide, combinadas com concentrações de alginato e pectina superiores a 1,3% e 1,26%, respectivamente, podem ser utilizadas para obter um produto amarelo claro com firmeza superior a 1,2 kg.

This study evaluated the effect of mixtures of alginate, low methoxy pectin and gelatin on characteristics of P. cincinnata fruit gels, containing pulp with high soluble solids content (50 °Brix). The results of a central composite design showed that the models obtained, except for water activity and pH, were predictive. Gelatin was an important factor affecting firmness and colour parameters since higher concentrations of this hydrocolloid, combined with alginate concentrations greater than 1.3% and pectin quantity up to 1.26%, could be used to obtain clear yellow products with firmness greater that 1.2 kg.

O objetivo deste trabalho foi avaliar a desidratação osmótica da batata-doce (Ipomoea batatas) utilizando soluções hipertônicas de sacarose e/ou NaCl, em três concentrações diferentes a 40 °C. As perdas de água mais elevadas foram obtidas quando se utilizou a mistura de sacarose e NaCl. A adição do NaCl às soluções osmóticas aumenta a força motriz do processo. Verifica-se que o processo de desidratação osmótica é principalmente influenciado pela mudança da concentração de NaCl, mas o efeito positivo da interação do sal com a sacarose também determinou a diminuição do ganho de sólidos quando os solutos estavam em concentrações máximas. As cinéticas de transferência de massa foram modeladas de acordo com as Equações de Peleg, de Fick e de Page, e apresentaram bons ajustes aos dados experimentais. A Equação de Peleg e o modelo da Page apresentaram os melhores ajustes e mostraram uma excelente capacidade de predição para dados de ganho de sólidos e de perda de água. A difusividade efetiva foi determinada utilizando-se a Segunda Lei de Fick aplicada à geometria de placa plana, encontrando valores de 3,82 x 10-11 a 7,46 x 10-11 m²/s para a perda de água, e de 1,18 x 10-10 a 3,38 x 10-11 m²/s para o ganho de sólidos.

The aim of this work was to evaluate the osmotic dehydration of sweet potato (Ipomoea batatas) using hypertonic sucrose solutions, with or without NaCl, at three different concentrations, at 40 °C. Highest water losses were obtained when the mixture of sucrose and NaCl was used. The addition of NaCl to osmotic solutions increases the driving force of the process and it is verified that the osmotic dehydration process is mainly influenced by changes in NaCl concentration, but the positive effect of the salt-sucrose interaction on soluble solids also determined the decrease of solid gain when solutes were at maximum concentrations. Mass transfer kinetics were modeled according to Peleg, Fick and Page's equations, which presented good fittings of the experimental data. Peleg's equation and Page's model presented the best fitting and showed excellent predictive capacity for water loss and salt gain data. The effective diffusivity determined using Fick's Second Law applied to slice geometry was found to be in the range from 3.82 x 10-11 to 7.46 x 10-11 m²/s for water loss and from 1.18 x 10-10 to 3.38 x 10-11 m²/s for solid gain.