Utilização de ultrassom em suco de uva : efeito nas características físico-químicas, análises microbiológicas e estudo sensorial
Nenhuma Miniatura disponível
Data
2018-02-21
Autores
Filgueiras, Bruna Garcia Alves
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
The grape is a fruit that have been conquering space in the consumer’s table. In Brazil, it has excelled for the production and processing of derived products, such as grape juice. The grape juice is full of phenolic compounds, however, it has less quantity than the fruit “in natura”. The pasteurization process is used in the grape juice’s processing as a microbiological inactivation. It can lead to alterations in the sensory and nutritional characteristics, though. The ultrasound technology has been studied as an alternative to microbiological inactivation with fewer losses in the nutritional and sensory quality of the food. However, the introduction of these new technologies not always is accompanied with information to consumers, which may reflect is on the acceptance of the product. On that way, the purpose of this dissertation was evaluate the effect of ultrasound in the physical-chemical, microbiological characteristics and sensory study on the cultivar Isabel’s grape juice. To achieve that, the 20 kHz ultrasound’s sounder was applied with the 90% of the potency in the 3, 6, 9, 12, 15 minutes in the samples. Then, it was analyzed soluble solids, pH, acidity, ash, sugar reducer, turbidity, phenolics, anthocyanins, and activity antioxidant in addition to counting of total mesophiles, molds and yeasts. It was also evaluated a triangular test the sensory acceptance of grape juice submitted to ultrasound. The results obtained were compared with the obtained in the pasteurized juice and in the natural juice. The ultrasound does not modify the juice characteristics, when it comes to pH, acidity, soluble solids, sugar reducer, ash and turbidity. About the color, the ultrasound does not interfere in the a* coordinate, which is relate to color red/green. The sonicated juice had an increasing in the polyphenols, anthocyanins and antioxidant capacity for 15 minutes, which was similar to the result found in the heat treatment at 85 ° C for 15 minutes, generally used in juices. Through the results, it was found that the treatment with ultrasound was effective in the reduction of the mesophiles, molds and yeasts’ population. In the triangular sensory test, the evaluators were not capable of distinguish the sonicated juice from the natural one (p>0,05). In relation to the acceptance test, there was no statistical difference in the overall impression for the pasteurized and sonicated juice samples in the three sessions (p <0.05), being the first session a blind test, the second test with information and the third the test with informational text. The results guarantee that the information about the processing using the ultrasound did not influence in a negative way the acceptance of the grape juice. The ultrasound is a technology that does not modify the natural characteristics of the fruit, because of that it can be used in the processing of the juice. Therefore, the ultrasound applied for a longer period of time was efficient to provide greater nutritional value to the grape juice in relation to the natural one, been as well effective in the conservation of the product.
Descrição
Palavras-chave
Aceitação sensorial , Isabel grape , Uva Isabel , Sonication , Sonicação , Phenolic compounds , Compostos fenólicos , Sensory acceptance , Aceitação sensor