Hyperbaric Pressures Enhance Antioxidant Enzyme Activity and Suppress Grey Mould in Débora Tomato Fruits

ABSTRACT Hyperbaric pressures have been shown to be an efficient technique to inhibit physiological mechanisms of ripening, microbiological development and senescence in vegetables, prolonging their shelf life. However, scarce information is available regarding the effect of hyperbaric pressures on the control of postharvest diseases. This study aimed to evaluate the effect of hyperbaric pressures of 100 (control), 200, 400, 600 and 800 kPa on growth in vitro and in vivo of grey mould ( Botrytis cinerea ), as well as the effects on the synthesis of bioactive compounds and defence‐ and antioxidant‐related enzymatic activity of cv. Débora tomatoes. We evaluated mycelial growth and germination of conidia in vitro, the incidence and severity of grey mould in vivo, lycopene content, total phenolic compounds, and the activity of defence and antioxidant enzymes. The higher hyperbaric pressures inhibited mycelial growth and conidial germination. Tomatoes stored at 800 kPa for 3 days presented a lower incidence and severity of grey mould than the control. In addition, tomatoes showed a reduction in lycopene synthesis, indicating delayed fruit ripening. They also showed a higher content of phenolic compounds and greater activity of defence enzymes phenylalanine ammonia‐lyase (PAL), β‐1,3‐glucanase (GLU) and catalase (CAT). This study demonstrated that hyperbaric pressures at 600 and 800 kPa at room temperature for 3 days retarded grey mould growth in Débora tomatoes and showed the potential of hyperbaric pressures in the control and induction of disease resistance in postharvest conservation.