Summary Anthocyanin profiles and radical scavenging activity of Camarosa strawberry jams as affected by two processing methods (conventional/industrial) and storage conditions were evaluated. Industrial strawberry jam produced in a closed system with vacuum preserved the anthocyanin composition (the total content was 35.77 ± 2.56 mg per 100 g) when compared with conventional jam produced in an open system (3.35 ± 0.05 mg per 100 g). However, the radical scavenging activity of conventional jam was lower than that of industrial jam, as EC50 was 52.99 ± 0.94 and 44.33 ± 2.47 mg mL−1, respectively. Two‐way analysis of variance indicated a significant effect of processing method and storage time during 60 days and a significant interaction for all variables except for EC50. Long‐time storage of industrial jams at −8 °C leads to 80% reduction in anthocyanin content without loss of sensorial characteristics, whereas at room temperature the reduction was 98%, and the red colour was replaced by a brownish. Regardless of storage temperature, the radical scavenging activity of jams decreased 50–60% of its initial value.

Pinho C., Soares M.T., Almeida I.F., Aguiar A.A.R.M., Mansilha C., Ferreira I.M.P.L.V.O. (2015): Impact of freezing on flavonoids/radical-scavenging activity of two onion varieties. Czech J. Food Sci., 33: 340-345.Flavonols, anthocyanins, and radical-scavenging activity of two Portuguese onion cultivars (Branca da Póvoa, white; and Vermelha da Póvoa, red) were evaluated simulating domestic freezing conditions (-18°C). Frozen portions of onions with different periods of domestic storage at ambient temperature presented increased flavonoid content when compared with the respective composition before freezing. No significant differences were observed on radicalscavenging activity. Domestic freezing of onion portions extended its shelf life. Thus, domestic freezing can be a good alternative to prevent the loss of unused fresh onions, preserving its antioxidant capacity, since frozen onions can be a useful natural antioxidant source.

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