Plant-based foods are sources of fiber and vitamins, and are rich in bioactive compounds, such as polyphenols and carotenoids. Mixed fruit-juices have been widely consumed as sources of antioxidants and detoxifying compounds and there are different industrialized products available for consumption. However, it is not known if these products have any health benefits. Thus, the objective of this work was to evaluate the stability of bioactive compounds, present in different mixed, industrialized or in natura juices. Two lots of four different brands of industrialized juice and one non-industrialized juice containing a mixture of red fruits were purchased. The batches were homogenized and kept refrigerated for three days after opening, as this is the period indicated by manufacturers for consumption of these products. Aliquots were taken after 0, 6, 12, 24, 36 and 72 hours after the opening of packages to carry out the analyzes of total phenolics, using the Folin-Ciocalteau’s reagent and the antioxidant activity, using the DPPH radical. The samples showed a great variability of type and number of fruits used (from 4 to 9 fruits), which may have caused the difference between total polyphenol contents (30.3-82.2 mg / 100 mL of juice). The juice with higher content of polyphenols contained grape and açai as the main ingredients. Despite the result of polyphenols, all samples showed high antioxidant activity (70-86% inhibition of DPPH). The content of phenolic compounds and the antioxidant activity were stable throughout the storage period in all evaluated juices. It is concluded that there is great variation among the juices available in the market, mainly in relation to the content of phenolic compounds. However, these compounds are stable during storage, ensuring product quality.