The influence of four day/night growing temperature
combinations (18/12, 25/12, 25/22, 30/22 °C) on phenolic acid, flavonol, and
anthocyanin content and their antioxidant activities against peroxyl radicals
(ROO •), superoxide radicals (O2 •-), hydrogen peroxide (H2O2), hydroxyl
radicals (OH •-), and singlet oxygen (1O2,) in fruit juice of ‘Earliglow’ and
‘Kent’ strawberry (Fragaria x ananassa Duch.) were studied. The content of
cyanidin- based anthocyanins, were much lower than pelargonidin-based anthocyanins.
High day/night temperature conditions significantly enhanced p-coumaroylglucose,
dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol
3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin
3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate and
pelargonidin 3-glucoside-succinate content in strawberry juice. Plants grown at
low day and night temperatures (18/12 °C) generally had the lowest anthocyanin
contents. Plants grown at the highest day/night temperatures (30/22 °C)
produced fruit with the most phenolic content as well as antioxidant capacity.
Fruit of ‘