Caracterização físico-química e comportamento reológico de sucos

ABSTRACT
The growing interest of the society for fruit and/or vegetable juices and pulps in
several ways is responsible for advances in the beverages market. Fruits and
vegetables are nutritional sources of vitamins, minerals and soluble
carbohydrates, which amount of these components varies from vegetable type
and species. Formulations of blends ready to drink can be used to improve the
nutritional characteristics of certain juices by addition of nutrients supplied by
different fruits and vegetables, such as carrot and orange mix. Carrot is a rich
source of vitamins, and its great content of carotenoids and minerals like
calcium, sodium and potassium, has antioxidant properties that help to prevent
free radicals responsible for cellular aging. Orange juice is an important source
of ascorbic acid, a nutrient also with high antioxidant effect that stimulates the
immunological system. The rheological behavior of juices is strongly affected by
physical and chemical properties, and as a consequence will be dependent of
the fruit or vegetable type, or processing steps used such as enzyme treatment
or pasteurization. The knowledge of the rheological characteristics of juices is
indispensable not only as a quality measure, but also as a fundamental
parameter to be used in projects such as pumping, agitation, tube transport,
evaporation, and so on. This work attempts to the physicochemical
characterization and rheological behavior of different mixtures of carrot and
orange juices. It was evaluated pasteurized and enzyme treated-pasteurized
carrot juice, and pasteurized orange juice. Crude carrot juice was treated with a
mixture of commercial enzymes Pectinex Ultra-SPL (Novozymes), at 1 unit L -1
concentration, applying temperatures of 50-55 °C to the pulp for 1 hour.
Pasteurizing operating conditions were 100 °C for 1 hour. Juices were
evaluated by pH, acidity, density, and contents of ash, reducing and total
sugars, soluble and total solids, pectins fibers and proteins. Statistically
significant modifications were observed for all physicochemical properties
studied for the different treatments applied to the carrot juice, except for total
solids and fiber contents, according to the Duncan test at a significance level of
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