Summary There is an increased interest in the consumption of fruits containing high phenolic concentrations such as berry fruits. Attractive colour of berries plays a vital role for consumer acceptance. The aim of this work was to evaluate colour parameters (a*, b*, L*), phenolic content and sensory changes of blueberry, elderberry and blackcurrant (BC) pasteurised commercial juices during accelerate storage. Initial phenolic concentration was 3.21, 10.06, 10.72 g GAE L−1 for blueberry, elderberry and BC, respectively. Moreover, phenolic concentration of all juices decreased by approximately 40% throughout the first 30 days. Blueberry exhibited a substantial decrease in a* (40%) in the first 30 days, while elderberry presented a gradual decrease and BC only presented a slight decrease (7%) at the end of storage. Colour preferences decreased when storage time increased. However, when consumers were informed that ‘the juices are a rich source of phenolics, which contribute to reducing risk of suffering chronic diseases’, a high level of purchase intention was obtained.

BACKGROUND: Berry fruits stand out for their high contents of anthocyanins responsible for their red-purple color. The region of Patagonia, Argentina, is a significant cultivar region of these fruits. Due to berries' very short shelf-life, it is interesting the development of dehydrated products that can be stored at room temperature and still be a source of bioactive components and natural colorants. OBJECTIVE: The objective of this work was to evaluate the effect of freeze-drying process and storage at 38 • C on the levels of bioactive compounds and color, in lyophilized products based on blueberry, blackcurrant, elderberry and maqui berry pulps from the El Bolsón area, Río Negro, Argentina. METHODS: Fruit pulps with addition of encapsulating agents (Maltodextrin/Arabic gum) were freeze-dried and evaluated for the content of monomeric anthocyanins, total polyphenols, antioxidant capacity, color (CIELab parameters) and physical characteristics. RESULTS: The obtained freeze-dried powders showed high levels of retention of bioactive compounds, yielding between 68.2 and 99.6% of retention of polyphenols and anthocyanins depending on the fruit. Color parameters were also stable after freeze-drying and during 60 days of storage at 38 • C. CONCLUSIONS: The obtained stable powder ingredients based on berries from Patagonia can be used as a source of bioactive compounds and pigments.

BACKGROUND: Fruits like blackcurrant, blueberry and maqui berry stand out for their high content of anthocyanins that give products an attractive red colour, in addition to their rich composition of other polyphenols and vitamins. Comprehensive understanding of thermal properties of foods and quantitative changes in quality attributes are necessary for the proper design of thermal processes. OBJECTIVE:The aim of the present study was to evaluate the kinetics of monomeric anthocyanin (MAcy) and colour degradation due to thermal processing of pulps of blackcurrant, blueberry and maqui berry produced in El Bolsón, Argentina. METHODS: Anthocyanins content was measured with pH-differential method. CIELab parameters were obtained with a Minolta Spectrophotometer, total phenolics were determined by Folin-Ciocalteu method. MAcy degradation and evolution of colour parameter a* were fitted to a first-order model. RESULTS: Activation energies for anthocyanins losses were between 81 and 94 kJ/mol, and for the deterioration of colour between 85 and 89 kJ/mol. In the case of deterioration of anthocyanins, maqui berry presented the highest values of half-life times especially at 90 • C. In the case of colour, blackcurrant showed greater stability showing average colour degradation half-life times between 5 and 11 times higher than those of anthocyanins loss. CONCLUSIONS: Kinetic parameters calculated for different berry juices can be used to design a thermal treatment to obtain a high retention of colour and bioactive compounds.