Deficit irrigation strategies enhance health-promoting compounds through the intensification of specific enzymes in early peaches.

Background: Biochemical and enzymatic responses to long-term regulated deficit irrigation (RDI) at harvest, during cold storage and after the retail sale period of 'Flordastar' early peaches were evaluated. Irrigation strategies were Control, and two RDI applied during post-harvest period (RDI1 , severe; RDI2 , moderate), based on different thresholds of maximum daily shrinkage signal intensity (RDI1 , 1.4 to dry; RDI2 , 1.3 to 1.6).

Results: Both RDI provoked stress in the plant. This meant higher antioxidant concentration [averaging 1.30 ± 0.27 g ascorbic acid equivalents (AAE) kg(-1) fresh weight (FW) for control and 1.77 ± 0.35 and 1.50 ± 0.30 g AAE kg(-1) FW for RDI1 and RDI2 , respectively]. Antioxidant levels decreased with storage by polyphenoloxydase action, which increased (from 0.04 ± 0.01 U mg(-1) protein to 0.32 ± 0.08 U mg(-1) protein). Vitamin C was initially higher in RDI samples (44.22 ± 0.05 g total vitamin C kg(-1) FW for control vs. 46.77 ± 0.02 and 46.27 ± 0.03 g total vitamin C kg(-1) FW for RDI1 and RDI2 , respectively).

Conclusion: The way RDI was applied affected bioactive fruit composition, being catalase and dehydroascorbic acid good water stress indicators. RDI strategies can be used as field practice, allowing water savings while enhanced healthy compound content in early peaches.