Cinética de liofilização/reidratação e avaliação sensorial de uva itália e tangerina processadas
The fruitculture is responsible for more than 40% of Brazilian agricultural production. Food dehydration is an operation that contributes to the increase of the shelf life’s food and the decrease of its water activity. Among these operations, freeze drying has been highlighted, since the products ar...
| Autor principal: | Silva, Felipe Rodolfo Pereira da |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2020
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/12637 |
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| Resumo: |
The fruitculture is responsible for more than 40% of Brazilian agricultural production. Food dehydration is an operation that contributes to the increase of the shelf life’s food and the decrease of its water activity. Among these operations, freeze drying has been highlighted, since the products are not submitted to high temperatures. Often, prior to the use of dehydrated products, rehydration is performed. Food rehydration is a complex unit operation aimed at restoring the characteristics of the in natura product by immersing the dehydrated product in a liquid medium. The sensory analysis allows the complete characterization of the foods, being the hedonic scale test one of the most used. The objective of this work was to model the freeze drying and the rehydration of tangerines and grapes and to sensory evaluate the dehydrated fruits. Freeze drying was performed with frozen fruits in a conventional freezer (T ≈ -18 ° C) for 24 h in Labconco Free Zone 6 equipment at a pressure of 70 Pa and heating at 60 ° C for 48 h. Rehydration was performed in triplicate in water at 25 ° C for 24 h. The fruits were periodically weighed along the freeze drying and rehydration operations and the experimental data were adjusted to Fick's law, allowing the calculation of the effective coefficient of water diffusion; and to nine empirical/semi-empirical models. The sensory evaluation of freeze dried fruits (buds or whole berries) was performed with 117 untrained tasters aged between 18 and 65 years, in two academies in the city of Medianeira - PR, being evaluated the attributes color, flavor, aroma, texture, overall impression and the buy intention; as well as the relation of the consumption of this type of food with the scholarity, the income, the consumption of in natura and dehydrated fruits. In order to evaluate the acceptance of the dehydrated fruits, a hedonic scale of nine points was used and the judges were questioned about their intention to buy the food. Fick's law satisfactorily represented the experimental data on dehydration and rehydration of the grapes (R2 > 0.97, P < 10 %, SE close to zero), being that the water diffusion coefficients during the operations were, respectively, 2.14∙10-6 and 6.33∙10-6 m2∙s-1 For the tangerines these coefficients were 1.01∙10-6 and 3.15∙10-6 m2∙s-1 for freeze drying and rehydration, respectively. Among the empirical/semi-empirical models, Page was the one that better represented the freeze drying of the grapes, the Two Terms, was the one that better represented the freeze drying of the tangerines; while the Modified Handerson and Pabis model was the one that better adjusted the rehydration of both fruits. Approximately 65 % of the grades were between the "slightly liked" and "highly liked" hedonic terms for all evaluated attributes for both fruits. The texture of dehydrated fruits presented an average grade higher than 7.0. The color of the tangerines also presented average grade higher than 7.0, but this result was not reached by the grapes, due to the rupture in the barks. For the other evaluated items the average grades were higher than 6.5. The results showed that there is a market for innovative products, such as freeze dried grapes and tangerines. |
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