Impact of elevated carbon dioxide and temperature on strawberry polyphenols

BACKGROUND The strawberry cultivars 'Albion' and 'San Andreas' ('SA') were grown under various combinations of day temperature (25 and 30 degrees C) and carbon dioxide [CO2] (400, 650 and 950 mu mol mol(-1)) conditions. The influence of different growth combinations on the polyphenol, flavonoid, anthocyanin, antioxidant, and individual phenolic compound content of fresh strawberry fruits was studied. The content of individual phenolic compounds of fresh strawberry fruits was quantified using high-performance liquid chromatography - ultraviolet (HPLC-UV). RESULTS Elevated [CO2] and higher temperature caused significant increases in total polyphenol, flavonoid, anthocyanin and antioxidants in both strawberry cultivars when compared with plants grown under ambient conditions. Results of HPLC-UV analysis also revealed that individual phenolic compounds of fruits were also increased with increasing [CO2] and temperature. However, the responses were significantly altered by the interaction of elevated [CO2] and higher temperature. The individual and interaction effects of [CO2] and temperature were also significantly cultivar dependent. The largest amounts of flavonoid (482 +/- 68 mg kg(-1) FW) and antioxidant (19.0 +/- 2.1 mu mol g(-1) FW) were detected in 'Albion' grown at 30 degrees C and under 950 mu mol mol(-1), and total polyphenol (3350 +/- 104 mg GAE kg(-1) FW) and anthocyanin (332 +/- 16 mg kg(-1) FW) in 'San Andreas' grown at 25 degrees C and 950 mu mol mol(-1). CONCLUSION Strawberry fruit was rich with polyphenols and antioxidants when grown under elevated [CO2] and higher temperature. There were also interactions between [CO2] and temperature affecting the fruits' content. An increase in the polyphenol and antioxidant content in strawberry fruits would be highly beneficial to human health. (c) 2019 Society of Chemical Industry