Background

Strawberry cultivars ‘Albion’ and ‘San Andreas’ were grown under various combinations of day temperature (25 and 30 °C) and carbon dioxide [CO₂] (400, 650 and 950 μmoL/moL) conditions. The influence of different growth combinations on polyphenol, flavonoid, anthocyanin, antioxidant and individual phenolic compound contents of fresh strawberry fruits were studied. The contents of individual phenolic compounds of fresh strawberry fruits were quantified by using HPLC‐UV system.

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 growth conditions. Results of HPLC‐UV analysis also revealed that individual phenolic compounds of fruits were also increased by increased [CO₂] and temperature. However, the responses were significantly altered by the interaction of elevated [CO₂] and higher temperature. In addition, the individual and interaction effects of [CO₂] and temperature were significantly cultivar dependent. The greatest amounts of flavonoid (482±68 mg/kg FW) and antioxidant (19.0±2.1 μmoL/g FW) were detected in ‘Albion’ grown under 30 °C and 950 μmoL/moL, and total polyphenol (3350±104 mg GAE/kg FW) and anthocyanin (332±16 mg/kg FW) in ‘San Andreas’ grown at 25 °C and 950 μmoL/moL.

Conclusion

Strawberry fruits were rich with polyphenols and antioxidants when they were grown under elevated [CO₂], higher temperature and their interactions. The increase contents of polyphenols and antioxidants of strawberry fruits will be highly beneficial to human health.