Desidratação de cuxá em leito de espuma: avaliação da cinética de secagem e da qualidade do produto em pó
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Data
2017-05-09
Autores
Cavalcante Neto, Adeval Alexandre [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A vinagreira (Hibiscus sabdariffa L) é uma hortaliça não convencional de uso expressivo em todo o mundo, apesar disso, suas folhas geralmente são ignoradas e descartadas. No Brasil, a importância da planta é decorrente da utilização das folhas na alimentação humana e seu maior consumo é verificado no Maranhão, sendo o principal ingrediente do “cuxá”, comida típica desse Estado. No entanto, a alta perecibilidade do alimento não permite a sua comercialização e/ou consumo para outras regiões do país. Assim, o desenvolvimento de técnicas de conservação, como a secagem, tornam-se fundamentais para o aumento da vida útil do produto. Neste sentido, objetivou-se avaliar o processo de secagem em leito de espuma (foam mat drying) do cuxá e caracterizar os pós de cuxá formados, com o intuito de obter um novo produto com qualidade nutricional, contribuindo com indústrias regionais de pequeno porte e com diminuição de perdas pós-colheita da vinagreira. A secagem foi conduzida em três temperaturas (60 ºC, 70 ºC e 80 ºC) e duas concentrações de agentes espumantes (5 g de Emustab/100 g de cuxá e 10 g de Albumina/100 g de cuxá), selecionadas a partir de testes com todas as combinações entre as proporções de 0 (controle), 5, 7,5 e 10 g de Albumina /100 g de cuxá e 0 (controle), 5, 7,5 e 10 g de Emustab /100 g de cuxá. Os critérios de seleção para a escolha das concentrações de agentes espumantes foram baseados na densidade (kg/m3), overrun, estabilidade e cor das espumas. A vida útil dos pós de cuxá com 10 g de Albumina/100 g de cuxá nos tempos 0, 10, 20, 40 e 60 dias foi avaliada em três temperaturas de armazenamento (5 ºC, 25 ºC e 35 ºC). Verificou-se que as espumas apresentaram elevados coeficientes de difusão (Def), o que proporcionou tempos curtos de secagem e pós de cuxá com baixas umidades e atividade de água. A aplicação de modelos de cinética de secagem demonstrou que o modelo de Page foi o que melhor representou a desidratação das espumas de cuxá em ambas concentrações testadas. Os pós com 5 g de Emustab/100 g de cuxá apresentaram coloração mais próxima à do cuxá in natura e não houve efeito da temperatura de secagem sobre este parâmetro. A retenção de compostos fenólicos foi maior na secagem em temperatura de 60 ºC e concentração de 10 g de Albumina/100 g de cuxá (74,2%) e menor na concentração de 5 g de Emustab/100 g de cuxá e temperatura de 80 ºC (69,8%). O cuxá em pó se manteve microbiologicamente seguro durante o tempo de armazenamento, com aw máxima de 0,292. Durante o armazenamento, o modelo cinético de ordem zero apresentou o melhor ajuste aos dados experimentais para a degradação da clorofila. Os parâmetros cinéticos Ea= 4,9 kcal.mol-1 e Q10 de 1,1, estabelecidos no teste acelerado de vida de prateleira, permitiram estimar em 64 dias a vida de prateleira para o produto armazenado à temperatura ambiente (25 °C) e 57 dias na temperatura acelerada (35 ºC).
Roselle (Hibiscus sabdariffa L.) is an unconventional vegetable of expressive use throughout the world, yet its leaves are usually ignored and discarded. In Brazil, the importance of the plant is due to the use of leaves in human consumption and its greatest consumption is verified in Maranhão, being the main ingredient of cuxá, typical food of this State. However, the high perishability of the food does not allow its commercialization and/or consumption to other regions of the country, so the conservation techniques development such as drying, become essential to increase the shelf life of the product. In this sense, the objective was to evaluate the foam mat drying process of cuxá and to characterize their powders in order to obtain a new product with nutritional quality, contributing to the small food industries development and reduction of postharvest losses of Roselle. Drying was conducted at three temperatures (60 ° C, 70 ° C and 80 ° C) and two concentrations of foaming agents (5 g Emustab /100 g cuxá and 10 g Albumin /100 g cuxá), selected from tests with all combinations Between the proportions of 0 (control), 5, 7.5 and 10 g of Albumin /100 g of cuxá and 0 (control), 5, 7,5 and 10 g of Emustab /100 g of cuxá. The selection criteria for the choice of foaming concentrations were based on the density (kg / m3), overrun, stability and color of the foams. The shelf life of powders with 10 g of albumin / 100 g of cuxá after 0, 10, 20, 40 and 60 days were evaluated at three storage temperatures (5 ºC, 25 ºC and 35 ºC). It was verified that the foams presented high diffusion coefficients (Def), which provided short drying times and cuxá powders with low humidity and water activity. The application of drying kinetic models showed that the Page model was the one that best represented the dehydration of cuxá foams at both concentrations tested. The powders with 5 g of Emustab / 100 g of cuxá presented staining closer to the cuxá in natura and there was no effect of the drying temperature on this parameter. The retention of phenolic compounds was higher in drying at 60 ºC and 10 g of Albumin / 100 g of cuxá (74.2%) and lower in the concentration of 5 g of Emustab /100 g of cuxá and temperature of 80 ºC (69.8%). The cuxá powder remained microbiologically safe during the storage time, with maximum aw of 0.292. The zero order kinetic model presented good fit to the experimental data for chlorophyll degradation during the storage period. The kinetic parameters Ea = 4.9 kcal.mol-1 and Q10 of 1.1, established in the accelerated test, allowed to estimate the shelf life, which was 64 days at room temperature (25 ° C) and 57 days at temperature (35 ° C).
Roselle (Hibiscus sabdariffa L.) is an unconventional vegetable of expressive use throughout the world, yet its leaves are usually ignored and discarded. In Brazil, the importance of the plant is due to the use of leaves in human consumption and its greatest consumption is verified in Maranhão, being the main ingredient of cuxá, typical food of this State. However, the high perishability of the food does not allow its commercialization and/or consumption to other regions of the country, so the conservation techniques development such as drying, become essential to increase the shelf life of the product. In this sense, the objective was to evaluate the foam mat drying process of cuxá and to characterize their powders in order to obtain a new product with nutritional quality, contributing to the small food industries development and reduction of postharvest losses of Roselle. Drying was conducted at three temperatures (60 ° C, 70 ° C and 80 ° C) and two concentrations of foaming agents (5 g Emustab /100 g cuxá and 10 g Albumin /100 g cuxá), selected from tests with all combinations Between the proportions of 0 (control), 5, 7.5 and 10 g of Albumin /100 g of cuxá and 0 (control), 5, 7,5 and 10 g of Emustab /100 g of cuxá. The selection criteria for the choice of foaming concentrations were based on the density (kg / m3), overrun, stability and color of the foams. The shelf life of powders with 10 g of albumin / 100 g of cuxá after 0, 10, 20, 40 and 60 days were evaluated at three storage temperatures (5 ºC, 25 ºC and 35 ºC). It was verified that the foams presented high diffusion coefficients (Def), which provided short drying times and cuxá powders with low humidity and water activity. The application of drying kinetic models showed that the Page model was the one that best represented the dehydration of cuxá foams at both concentrations tested. The powders with 5 g of Emustab / 100 g of cuxá presented staining closer to the cuxá in natura and there was no effect of the drying temperature on this parameter. The retention of phenolic compounds was higher in drying at 60 ºC and 10 g of Albumin / 100 g of cuxá (74.2%) and lower in the concentration of 5 g of Emustab /100 g of cuxá and temperature of 80 ºC (69.8%). The cuxá powder remained microbiologically safe during the storage time, with maximum aw of 0.292. The zero order kinetic model presented good fit to the experimental data for chlorophyll degradation during the storage period. The kinetic parameters Ea = 4.9 kcal.mol-1 and Q10 of 1.1, established in the accelerated test, allowed to estimate the shelf life, which was 64 days at room temperature (25 ° C) and 57 days at temperature (35 ° C).
Descrição
Palavras-chave
Vinagreira, Compostos fenólicos, Clorofila total, Emustab, Albumina, Vida útil