Quality of red raspberry Rubus idaeus L. cultivars after storage in controlled and normal atmospheres

Abstract

Five raspberry cultivars ‘Glen Ample’, ‘Glen Lyon’, ‘Malling Admiral’, ‘Malling Orion’ and ‘Veten’, were grown in the south-eastern part of Norway. The potential for the fresh market after different storage treatments was evaluated, by measuring respiration rates, physical and chemical properties and decay. Emphasis was laid on postharvest changes of nutritionally valuable components. Principal component analysis showed that cultivars originating from the same source i.e. cultivars developed at the Scottish Crop Research Institute (‘Glen Ample'and ‘Glen Lyon’), and cultivars from East Malling (‘Malling Admiral’ and ‘Malling Orion’) and the Norwegian cultivar ‘Veten’ were grouped according to their physical and chemical characteristics. ‘Glen Ample’ and ‘Glen Lyon’ showed a good potential for the fresh market. Storage in controlled atmospheres (10% O2+15% CO2, 10% O2+31% CO2) suppressed rotting significantly. Berry colour was darker, and pigment levels increased during 7 days storage in normal atmospheres. Raspberry cultivars with a lighter red colour with less blue like ‘Malling Admiral’ and ‘Glen Lyon’ kept a better colour compared with a darker and more bluish cultivar like ‘Veten’. Measurements of the optical density in the berry juice were highly correlated with total anthocyanin content. Total and soluble solids were unchanged after storage, and titratable acids decreased. The cultivars ‘Glen Ample’, ‘Glen Lyon’ and ‘Malling Orion’ had higher levels of l-ascorbic acid, which were unchanged or slightly increased after one-week storage period.