Dissertação
Ultrassom no tratamento pós-colheita de uvas cultivar Isabel e Cabernet Sauvignon e sua influência na composição dos sucos
Fecha
2012-02-24Registro en:
COMARELLA, Carine Glaucia. ULTRASOUND IN THE POST-HARVEST TREATMENT OF ISABEL
AND CABERNET SAUVIGNON CULTIVAR GRAPES AND ITS
INFLUENCE ON THE COMPOSITION OF JUICES. 2012. 85 f. Dissertação (Mestrado em Ciência e Tecnologia dos Alimentos) - Universidade Federal de Santa Maria, Santa Maria, 2012.
Autor
Comarella, Carine Glaucia
Institución
Resumen
Phenolic compounds in plants have attracted considerable attention during the last
decade due to their contribution to human health in reduce the risk of chronic
diseases. The grape is one of the largest sources of these substances and like other
plants, the synthesis of these compounds is usually associated with defense
responses against stress factors, also called elicitors. More recently, ultrasound has
been studied as possible abiotic elicitors of secondary metabolites due to mechanical
stress and microstreaming induced by acoustic cavitation. Thus, this work aimed
evaluate the application of different power densities (53 and 113 W cm-2) and
exposure times (1, 5 and 10 minutes) to ultrasound in Isabel and Cabernet
Sauvignon grapes about the effects on total polyphenols of juices made from this two
cultivars. The samples were also subjected to the determination of total
anthocyanins, tannins, total soluble solids, total acidity, pH and sensory
evaluation. The Isabel cultivar showed more significant results in response to
ultrasound, an increase of up to 83% in the levels of total polyphenols of juice, as
well as significant increase in the content of total anthocyanins and tannins. These
results were also accompanied by an increase in total soluble solids and total acidity
of the juices. The application of ultrasound emphasized color, odor and taste of the
Isabel grape juice, and the sonicated treatments were preferred by tasters. About
Cabernet Sauvignon cultivar, it only showed a little variation in the most
parameters. Power density and exposure time to ultrasound influenced the most of
parameters evaluated in juices regarding to degree of response to
sonication. Treatment with 5 and 10 min of exposure to ultrasound and power density
of 113 W cm-2, is the combination that proved more effective for the elicitation of
phenolic compounds by activation of plant secondary metabolism, improving the
quality of the Isabel grape juice.