Efeito do pré-tratamento osmótico com sacarose e cloreto de sódio sobre a secagem convectiva de abóbora
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Data
2008-03-01
Autores
Borin, Isabella [UNESP]
Frascareli, Elen Cristina [UNESP]
Mauro, Maria Aparecida [UNESP]
Kimura, Mieko [UNESP]
Título da Revista
ISSN da Revista
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Editor
Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Resumo
O objetivo deste trabalho foi avaliar os efeitos de pré-tratamentos osmóticos sobre a cinética de secagem de fatias de abóbora (Cucurbita moschata) e sobre características sensoriais do produto seco, utilizando sacarose e NaCl como solutos. Condições de pré-tratamento foram selecionadas com base na relação perda de água/ganho de solutos e na limitação de conteúdo de sal no produto final. Amostras tratadas nas condições selecionadas (50% de sacarose; 47% de sacarose e 3% de NaCl; 40% de sacarose; 37% de sacarose e 3% de NaCl, p/p, 1 hora) e amostras não tratadas foram secas com ar aquecido a 70 °C, 2 m/s. A cinética de secagem foi descrita pela Segunda Lei de Fick. Coeficientes de difusão efetivos de água foram determinados considerando-se a espessura inicial e a espessura média das fatias durante a secagem. As difusividades determinadas em amostras tratadas e não tratadas resultaram próximas quando a espessura média foi utilizada. Amostras tratadas apresentaram taxas de secagem maiores que amostras sem tratamento, mostrando que os pré-tratamentos melhoraram a eficiência do processo. Os tratamentos também melhoram a cor e a aparência geral das fatias secas, em relação às amostras sem tratamento.
The objective of this work was to evaluate the effects of osmotic pre-treatments on the air-drying kinetics of sliced pumpkin (Cucurbita moschata) and on the sensory quality of the dried pumpkin, using sucrose and NaCl as solutes. Pre-treatment conditions in osmotic solutions were selected based on the water loss/solute gain ratio and on the final salt content. Pre-treated samples in the selected conditions (50% sucrose; 47% sucrose and 3% NaCl; 40% sucrose; 37% sucrose and 3% NaCl, w/w, 1 hour) and non-treated samples were dried at 70 °C, 2 m/s. The drying kinetics was described according to Fick's Second Law. Effective diffusion coefficients were determined considering the initial thickness and the average thickness of the slices during air-drying. The effective water diffusivities of pre-treated and non-treated samples were similar when average thickness was used. Drying rates of the treated samples were higher than those of the non-treated samples, showing that the pre-treatments enhanced the efficiency of convective drying. The color and the general appearance of the dried pumpkin were improved by the previous treatments in comparison to the non-treated samples.
The objective of this work was to evaluate the effects of osmotic pre-treatments on the air-drying kinetics of sliced pumpkin (Cucurbita moschata) and on the sensory quality of the dried pumpkin, using sucrose and NaCl as solutes. Pre-treatment conditions in osmotic solutions were selected based on the water loss/solute gain ratio and on the final salt content. Pre-treated samples in the selected conditions (50% sucrose; 47% sucrose and 3% NaCl; 40% sucrose; 37% sucrose and 3% NaCl, w/w, 1 hour) and non-treated samples were dried at 70 °C, 2 m/s. The drying kinetics was described according to Fick's Second Law. Effective diffusion coefficients were determined considering the initial thickness and the average thickness of the slices during air-drying. The effective water diffusivities of pre-treated and non-treated samples were similar when average thickness was used. Drying rates of the treated samples were higher than those of the non-treated samples, showing that the pre-treatments enhanced the efficiency of convective drying. The color and the general appearance of the dried pumpkin were improved by the previous treatments in comparison to the non-treated samples.
Descrição
Palavras-chave
Sucrose, sodium chloride, Pumpkin, Osmotic dehydration, Drying kinetics, effective diffusion coefficients, Sacarose, cloreto de sódio, Abóbora, Desidratação osmótica, Cinética de secagem, coeficientes efetivos de difusão
Como citar
Food Science and Technology (Campinas). Sociedade Brasileira de Ciência e Tecnologia de Alimentos, v. 28, n. 1, p. 39-50, 2008.