Aplicação do ultrassom para conservação de suco misto de laranja com cenoura
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Data
2019-03-18
Autores
Lepaus, Bárbara Morandi
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Universidade Federal do Espírito Santo
Resumo
Ultrasound technology is an alternative to pasteurization juice preservation, aiming at minimizing the nutritional and physical-chemical damages observed during traditional thermal processing. This study aimed to evaluate the effect of ultrasound on the microbiological, physical-chemical and sensorial quality of blend orange-carrot juice. Samples of juices were submitted to pasteurization treatments at 90°C for 30 seconds and 40 kHz ultrasound at times of 5 or 10 minutes at temperatures of 40, 50 or 60°C. Untreated juice samples were considered control. Samples were stored at 7 ± 1 °C for 22 days and over the course of the storage period, the microbiological and physicalchemical analyses were conducted. After the evaluation of the results of these analyses, the treatments with ultrasound at 60°C for 5 and 10 minutes were selected, in addition to the natural juice without treatment and pasteurized, to perform the sensorial analysis. Higher reductions were obtained after ultrasonic treatment at 60°C for 10 minutes for aerobic mesophilic bacteria, molds and yeasts, and coliforms at 35°C. All the conditions maintained pH, titratable total acidity, total soluble solids, total carotenoids, vitamin C, phenolic compounds and antioxidant activity after treatment. Ultrasound treatments increased color parameters and turbidity. During storage, there was a reduction in pH, titratable total acidity, total soluble solids, vitamin C, phenolic compounds, antioxidant activity, and turbidity. It was observed an increase in the content of total carotenoids and in the parameters of color L*, a*, and c*, as well as reduction of hue angle and b*. Ultrasound treatment at 60°C for 5 and 10 minutes delayed the sedimentation process. Optical microscopy showed that increasing the time and temperature of treatment caused more damage to cell structures. In sensory analysis, there was no difference between the notes obtained for sample treated with ultrasound at 60°C for 5 minutes and the pasteurized sample. The ultrasound treatment at 60°C for 5 minutes demonstrated to be promising in the conservation of orange-carrot juice, offering a microbiologically safe juice, maintaining physicalchemical characteristics and obtaining good acceptability by consumers.
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Thermosonication , Quality , Conservation , Termossonicação , Qualidade , Conservação