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The results of a study on the evolution of phenolic compounds, colour and antioxidant activity in two industrial red myrtle liqueurs during storage in bottles under different bottle headspace (constant or increasing) and exposure to light are reported. In the year of the study, the phenolic compounds showed considerable changes even in the liqueurs stored with constant headspace. The anthocyanins in particular, both free and combined, tended to decrease. As expected, the same phenomena were observed in an accelerated form in the product stored in bottles with increasing headspace. The colour, evaluated according to the classic spectrophotometric parameters of intensity and hue, showed marked variability, especially in samples in which headspace was progressively increased. The two liqueurs showed antioxidant capacity values, expressed as mM of Trolox, comparable to those of red wine. They significantly decreased during storage in the bottles with increasing headspace, while values remained almost constant in the others.

In this study the main chemical parameters, ascorbic acid and polyphenol content, and antioxidant activity of two varieties of prunes, dried by high-temperature (85 + 70 degrees C) and low-temperature (60 degrees C) procedures, were monitored during storage. Ascorbic acid content was higher in the prunes dried at 60 degrees C but significantly decreased in both varieties during storage. The different classes of polyphenols analyzed (cinnamates, anthocyanins, flavonols) showed different stabilities during storage. Neochlorogenic acid decreased only in the President variety, whereas chlorogenic acid increased in both varieties; anthocyanins, present only in the President prunes, disappeared in the first months of storage, and the flavonol content fell significantly in both cultivars during the year of the study. Drying temperature significantly affected the polyphenol content, with different effects according to the class of polyphenols. Antioxidant activity showed a significant increase at the end of the storage period and in the President variety was higher in the sample dried at the higher temperature.

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Fadda C., Fenu P.A.M., Usai G., Del Caro A., Diez Y.M., Sanguinetti A.M., Piga A. (2015): Antioxidant activity and sensory changes of strawberry tree fruits during cold storage and shelf life. Czech J. Food Sci., 33: 531-536.The influence of storage time on a range of quality parameters, in vitro antioxidant activity, and the sensory acceptability of fully ripe strawberry tree fruits packaged into polypropylene trays under plastic film was assessed. Fruits were stored at 0°C for 6, 12 or 18 days and then transferred to shelf life at 20°C for 2 days. The parameters most influenced by cold storage and shelf life were firmness, colour, and antioxidant activity. Firmness decreased significantly during storage and colour parameters showed a decrease in saturation. Significant increases in polyphenols and anthocyanins were registered during storage, with a resulting increase in total antioxidant activity. The sensory analysis demonstrated that fruits maintain an acceptable quality level for up to 1 day under shelf life conditions following 18 days of cold storage.

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