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Influence of temperature on berry quality of 'Glen Ample' red raspberry

Remberg, S.F., Sonsteby, A., Wold, A.B., Heide, O.M.
Acta horticulturae 2012 no.926 pp. 705-711
anthocyanins, antioxidant activity, ascorbic acid, environmental factors, pollinating insects, small fruits, temperature, water content
The influence of post-flowering temperature (12, 18, and 24°C) on berry quality of the red raspberry ‘Glen Ample’ was studied under controlled environment conditions. Berry weight decreased throughout the harvesting period at all temperatures, but the decrease was markedly faster at high temperatures. Fruit maturation and harvest were advanced in the order of increasing temperature. The yield levelled off at about 1.6 kg per plant, due to lack of pollinating insects in the phytotron compartments. Because the moisture content increased in parallel with the berry weight, the concentration of a range of bioactive compounds decreased with decreasing temperature and progress of the harvest season when expressed on a fresh weight basis. L-ascorbic acid (vitamin C) increased with decreasing temperature, despite the dilution effect of large berries. Berry antioxidant activity was closely correlated (r=0.958) with total phenolic concentration, predominantly anthocyanins and ellagitannins.