Avaliação da desidratação de mamão utilizando métodos combinados
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Data
2012-02-06
Autores
Garcia, Carolina Castilho [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Com o intuito de agregar valor a frutas nacionais desidratadas, os efeitos de pré-tratamentos sobre a secagem de mamão Formosa foram avaliados. Para tanto, foram utilizados previamente à secagem convectiva o branqueamento, a desidratação osmótica (DO) e a aplicação de coberturas comestíveis na superfície das frutas frescas e osmoticamente desidratadas. Com base em um planejamento fatorial, verificou-se que a DO das fatias de mamão frescas e branqueadas em solução de sacarose a 50% p/p adicionadas de 1% p/p de lactato de cálcio e 0,1 M de ácido lático por 120 min e 105 min, respectivamente, foram as condições que ocasionaram redução na atividade de água das amostras e pequenas variações em sua cor. A cinética de DO das frutas frescas e branqueadas mostrou que o branqueamento resultou em maiores coeficientes de difusão da água e dos solutos. Melhores ajustes para as difusividades das fatias de fruta foram verificados considerando-as como placas infinitas. Os resultados evidenciaram grande atividade de invertase no mamão, o qual se apresentou como uma fonte potencial para a extração da referida enzima. As isotermas de sorção de fatias frescas, branqueadas e desidratadas osmoticamente de mamão Formosa mostraram que mais energia foi necessária para a remoção da água das amostras osmoticamente tratadas e que a dessorção das frutas branqueadas exigiu menor quantidade de energia. O branqueamento danificou a estrutura celular dos mamões resultando em maiores coeficientes de difusão da água que as frutas frescas durante a secagem. A desidratação osmótica dos mamões e a cobertura aplicada na superfície das frutas também resultaram em maiores coeficientes de difusão da água em relação às amostras frescas. A cobertura exerceu efeito protetor...
Aiming to add value to national dehydrated fruits, the effects of pre-treatments on convective drying of papaya of Formosa cultivar were investigated. Blanching, osmotic dehydration (OD) and edible coating application at the surface of fresh and osmotically dehydrated fruits were evaluated. Based on a factorial design, it was verified that OD of fresh and blanched papayas sucrose solutions at 50% w/w added with 1% w/w of calcium lactate and 0,1 M of lactic acid for 120 and 105 min, respectively, were the conditions resulting in decreased water activity and small color changes. OD kinetics of fresh and blanched fruits showed that blanching resulted in higher water and solutes diffusion coefficients. The best adjustments for the fruit diffusivities were obtained considering them as infinite slabs. The results revealed the great invertase activity in papaya which presented as a potential source for the referred enzyme extraction. Sorption isotherms of fresh, blanched and osmo-treated papayas showed that more energy was necessary to remove water from osmotically dehydrated samples and the dessorption of blanched fruits needed lower quantity of energy. Blanching damaged the cellular structure of papaya resulting in higher moisture diffusivities than the fresh fruits during drying. Osmotic dehydration and the coating applied at the surface of the fruits also resulted in higher moisture diffusion coefficients in relation to the fresh samples. Coating presented a protective effect on carotenoids content of the samples when applied at fresh fruits surface. Retention of vitamin C of fresh coated fruits was higher than the non-coated fresh and blanched papayas. Osmotic treatment did not have a protective effect on nutritional compounds of papayas, resulting in dried fruits with reduced vitamin C content
Aiming to add value to national dehydrated fruits, the effects of pre-treatments on convective drying of papaya of Formosa cultivar were investigated. Blanching, osmotic dehydration (OD) and edible coating application at the surface of fresh and osmotically dehydrated fruits were evaluated. Based on a factorial design, it was verified that OD of fresh and blanched papayas sucrose solutions at 50% w/w added with 1% w/w of calcium lactate and 0,1 M of lactic acid for 120 and 105 min, respectively, were the conditions resulting in decreased water activity and small color changes. OD kinetics of fresh and blanched fruits showed that blanching resulted in higher water and solutes diffusion coefficients. The best adjustments for the fruit diffusivities were obtained considering them as infinite slabs. The results revealed the great invertase activity in papaya which presented as a potential source for the referred enzyme extraction. Sorption isotherms of fresh, blanched and osmo-treated papayas showed that more energy was necessary to remove water from osmotically dehydrated samples and the dessorption of blanched fruits needed lower quantity of energy. Blanching damaged the cellular structure of papaya resulting in higher moisture diffusivities than the fresh fruits during drying. Osmotic dehydration and the coating applied at the surface of the fruits also resulted in higher moisture diffusion coefficients in relation to the fresh samples. Coating presented a protective effect on carotenoids content of the samples when applied at fresh fruits surface. Retention of vitamin C of fresh coated fruits was higher than the non-coated fresh and blanched papayas. Osmotic treatment did not have a protective effect on nutritional compounds of papayas, resulting in dried fruits with reduced vitamin C content
Descrição
Palavras-chave
Alimentos - Desidratação, Frutas - Industria, Mamã - Desidratação, Desidratação osmótica, Papaya of Formosa cultivar - Drying, Osmotic dehydration
Como citar
GARCIA, Carolina Castilho. Avaliação da desidratação de mamão utilizando métodos combinados. 2012. 173 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2012.