Thyme oil vapour and modified atmosphere packaging reduce anthracnose incidence and maintain fruit quality in avocado

BACKGROUND Postharvest application of prochloraz fungicide is commercially practiced to control anthracnose, a postharvest disease in avocado. Increasing consumer concern regarding food safety and demand for organically produced fruits make it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry. RESULTS A combination of modified atmosphere packaging (MAP; approximate to 8% CO2, 2% O-2) plus thyme oil (TO) was evaluated on the incidence and severity of anthracnose, physiological disorders (grey pulp, vascular browning), fruit quality parameters (L*, h degrees, firmness, weight loss) and sensory parameters (taste, texture, flavour and overall acceptance), phenylalanine ammonia-lyase (PAL) enzyme activity, total phenolic compounds, flavonoid contents and antioxidant activity in avocados (Fuerte' and Hass' cultivars) held at 10 degrees C cold storage for 18days and thereafter, ripened at 25 degrees C for 5-10days. Stand-alone MAP, commercial treatment (prochloraz 0.05%) and untreated (control) fruit were included for comparison. MAP+TO treatment significantly (P<0.05) reduced the incidence and severity of anthracnose, grey pulp, vascular browning, weight loss and loss of fruit firmness, and showed acceptable taste, flavour, texture and higher overall acceptance, increased PAL activity, total phenolic compounds, flavonoid contents and antioxidant activity, after ripening at 25 degrees C followed by cold storage at 10 degrees C. CONCLUSION This investigation recommends MAP+TO combination treatment as a suitable alternative to the currently adopted prochloraz application. (c) 2013 Society of Chemical Industry