Phenolic content and antioxidant activities of white and purple juices manufactured with organically- or conventionally-produced grapes

Effects of Cultural Practices on Total Phenolics and Vitamin C Content of Organic Table Grapes

“…There are studies on grapes showing either a decrease or an increase in the phenolic and vitamin contents. For instance, a higher total phenolic content of organically grown wine grapes (Malusà et al, 2004) and Labrusca varieties (Dani et al, 2007) has been recorded. Dani et al (2007) found that the juice of purple and white organic grapes contained statistically higher amounts of vitamin C. Mulero et al (2010), in contrast, reported no changes in Monastrel grapes.…”

“…For instance, a higher total phenolic content of organically grown wine grapes (Malusà et al, 2004) and Labrusca varieties (Dani et al, 2007) has been recorded. Dani et al (2007) found that the juice of purple and white organic grapes contained statistically higher amounts of vitamin C. Mulero et al (2010), in contrast, reported no changes in Monastrel grapes. However, the total phenolic contents of the cultivars studied here showed comparable results to previous studies, such as that of Kanner et al (1994), who studied the seedless table grapes, and Revilla et al (1995), who studied white and red grapes.…”

Development of new non-dairy beverages from Mediterranean fruit juices fermented with water kefir microorganisms

“…High values of polyphenols generally determine high antioxidant activity (Dani et al, 2007), but this phenomenon may depend on fruit maturity and cultivation practices (Burin et al, 2010). The radical scavenging activity is positively associated to a high content in anthocyans, as registered for pomegranate juice (Gil et al, 2000).…”

Evaluation of physicochemical parameters of grape juices produced in the Serra Gaúcha

“…It is well known that the concentration of polyphenols is greater in purple grape juices than in whites, since that dark colored grapes have higher contents of phenolic compounds and antioxidant capacity [9][10][11][12]. Moreover the technology used for preparing the juice, mainly related with the temperature and time of extraction, regulates the intensity of solubility and diffusion of the compounds, from the skin to the must, and is hence a fundamental influence on the chemical composition of the final product [13][14][15][16][17].…”