Polifenóis totais e avaliação sensorial de suco de uvas Isabel tratadas com ultrassom

Abstract

ResumoO suco de uva no Brasil é um produto amplamente consumido por suas características sensoriais e nutricionais; porém, tratamentos durante o seu processamento podem ocasionar perdas de compostos fenólicos importantes na definição dessas características. O ultrassom é apontado como um possível elicitor desses compostos, visto que o estresse mecânico provocado por cavitação acústica e microagitação estimula respostas de defesa na planta que levam à síntese dessas substâncias. Neste estudo, diferentes densidades de potência (53 e 113 W.cm -2 ) e tempos de exposição (1, 5 e 10 minutos) de ultrassom foram aplicados em uvas Isabel e seu efeito sobre o conteúdo de polifenóis totais e o aspecto sensorial dos sucos foi avaliado. O ultrassom causou um acréscimo de até 83% no teor de polifenóis totais, melhorando também as características sensoriais dos sucos, tendo sido estes os preferidos pelos provadores. Palavras-chave:Ultrassom; Elicitor; Fitoalexinas; Polifenóis; Suco; Uva. SummaryGrape juice in Brazil is a product widely consumed for their sensory and nutritional characteristics, however, treatments during processing can cause loss of phenolic compounds important in defining these characteristics. Ultrasound is cited as a possible elicitor of these compounds, since the mechanical stress caused by acoustic cavitation and microstreaming stimulates the plant defense responses that lead to synthesis of these substances. In this study, different power densities (53 and 113 W.cm -2 ) and exposure times (1, 5 and 10 minutes) of ultrasound were applied in Isabel grapes and its effect on the total polyphenols content and sensory aspect of the juices was evaluated. The ultrasound caused an increase of up to 83% in total polyphenols content, improving the sensory characteristics of juices, being chosen as preferred by the tasters.

Ultrasound in the postharvest treatment of grapes: impact on the extractability and phenolic composition of juice and wine

“…These same biological effects may be involved, according to the authors, in the increased content of phenolic compounds (SALES; RESURRECCION, 2010) and trans-resveratrol (RUDOLF; RESURRECCION, 2005; SALES; RESURRECCION, 2009) in peanuts received sonication. Comarella et al (2012) in their study on the effects of US application in grapes suggested that an 83% increase in phenolic compounds in the juice were due to the elicitor effect of US. Hasan and Baek (2013) also demonstrated that application of US in grapes led to trans-resveratrol accumulation in the fruit peel.…”

“…Juice was prepared from the 'Isabella' cultivar using the meth Comarella et al (2012). The grapes were washed and crushed, then placed in heated in a water bath (for 15 min, at 85 °C) for juice extraction.…”

“…Thereafter, the w juice was put in flasks to be heated to 50 °C for partial desulphurization. Th Juice was prepared from the 'Isabella' cultivar using the method described and modified by Comarella et al (2012). The grapes were washed and crushed, then placed in 500 ml amber glass bottles to be heated in a water bath (for 15 min, at 85 °C) for juice extraction.…”

“…Previous studies have shown that postharvest application of US increased the content of phenolic substances in peanuts (RUDOLF; RESURRECCION, 2005;SALES;RESURRECCION, 2009) and romaine lettuce (YU et al, 2016). Few studies on grapes have demonstrated the effect of US in increasing resveratrol production in the fruit BAEK, 2013), as well as the enrichment of the juice and other phenolic substances (HASAN et al, 2014;COMARELLA et al, 2012).…”

Biochemical characterization of irradiated soybean and nutritional and sensory evaluation of water-soluble soybean extract

“…The growing demand of the population for healthy foods has boosted research aimed at developing new technologies designed to improve or maintain the nutritional value of a food without losses in sensory quality, in addition to providing a safe product for consumers with minimal generation of environmentally harmful waste [5]. Thermal treatments are the most commonly used methods to extend the shelf life of beverages, eliminating microorganisms and inactivating enzymes.…”