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 °C) and carbon dioxide [CO2 ] (400, 650 and 950 µmol 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 µmol g-1 FW) were detected in 'Albion' grown at 30 °C and under 950 µmol 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 °C and 950 µmol 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. © 2019 Society of Chemical Industry.

The effectiveness of dietary polyphenols in obesity management: A systematic review and meta-analysis of human clinical trials.

Dietary polyphenols have been postulated to be effective in preventing obesity through various multitargeted mechanisms of weight loss. A meta-analysis of recent clinical trials was carried out to evaluate the effectiveness of polyphenols in obesity management in adults through assessing obesity-related anthropometric measures. Forty-four articles with 40 randomised clinical trials published between 2010 and 2021 met the eligibility trial criteria. Pooled results showed that polyphenols had a statistically significant reduction in body weight, body mass index and waist circumference. No significant lowering effect on body fat percentage was reported. Subgroup analysis suggested that polyphenol intake significantly changed anthropometric parameters in subjects aged <50 years, in Asian populations, in patients with obesity-related health issues, for periods of ≥ 3 months, and at dosages of <220 mg d-1. Overall, dietary polyphenols show promise in the prevention and management of obesity for certain adults.

Bioaccessibility of micronutrients in fresh and frozen strawberry fruits grown under elevated carbon dioxide and temperature.

Strawberry cultivar "San Andreas" was grown under ambient (400 ppm CO2, 25 °C) and elevated (950 ppm CO2, 30 °C) growth conditions. The strawberries were subjected to in vitro gastrointestinal digestion and colonic fermentation to examine the accessibility of polyphenols, vitamin C and folates in fresh and frozen fruits using HPLC-UV analyses. Results revealed that elevated CO2 and higher temperature enhanced the amounts of accessible bioactive compounds in strawberries. Bioaccessibility of pelargonidin-3-glucoside increased from 67% to 88% in strawberries grown under elevated growth. Fresh strawberries grown under ambient growth contained 93.09 ±â€¯6.2 µg/100 g folates and 18.55 ±â€¯0.5 mg/100 g vitamin C as bioaccessible fractions under fed state while, elevated growth enhanced soluble folates and vitamin C up to 188.63 ±â€¯7.5 µg/100 g and 30.48 ±â€¯0.3 mg/100 g, respectively. Fresh strawberries contained higher amounts of accessible micronutrients than frozen strawberries, while increased bile contents in intestinal fluid (fed state) facilitated the release of bioactive compounds to gastrointestinal fluid.