The contents of sugars, organic acids, total phenolic content, and the antioxidant activity were quantified in the flesh of red beet from conventional (CON), integrated (INT), organic (ORG), biodynamic (BD), and control farming systems using established methods. Significant differences were measured for malic acid, total phenolic content (TPC), and total antioxidant activity, where malic acid content ranged from 2.39 g kg(-1) FW (control) to 1.63 g kg(-1) FW (CON, ORG, and INT). The highest TPC was measured in BD and control samples (0.677 and 0.672 mg GAE g(-1), respectively), and the lowest in CON samples (0.511 mg GAE g(-1)). Antioxidant activity was positively correlated with TPC (r(2) = 0.6187) and ranged from 0.823 mu M TE g(-1) FW to 1.270 mu M TE g(-1) FW in CON and BD samples, respectively, whereas total sugar content ranged from 21.03 g kg(-1) FW (CON) to 31.58 g kg(-1) FW (BD). The importance of sugars, organic acids, phenols, and antioxidants for human health, as well as for plant resilience and health, gained from this explorative study, is discussed and put into perspective.
