Heat treatment : a natural way to inhibit postharvest diseases in rockmelon
McDonal K.L.; Anowaral B.; Morris S.C. and McConchie R.M.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.103
2004
บทคัดย่อ
Heat treatment : a natural way to inhibit postharvest diseases in rockmelon
The export of rockmelons from
Australia to neighbouring countries has increased over the past few years. However, the rate of decay is high due to postharvest diseases such as
Fusarium spp.,
Alternaria spp. and
Colletotrichum spp., if there fruits are not treated with chemical fungicides. We examined the use of hot water fruit dipping as an organic way of preventing postharvest diseases.
In studies conducted, we found that by dipping rackmelons in 50, 55, 60 and 65°C water for one minute, disease development was dramatically inhibited at all temperatures in comparison to the control (22°C). A one minute exposure to 60°C was the optimum temperature, resulting in 97% of fruit being disease free after 3 weeks storage at 5°C (simulated export conditions for Australia) compared to only 7% when dipped in 22°C. An increase in peroxidase activity and enhanced lignification of the cell walls on the rind were correlated with the hot water dipping effect. The levels of peroxidase were increased ten-fold when exposed to 60°C heat in comparison to the control (22°C). Both the extent of lignification and the increase in peroxidase activity correlated with the increase in temperature. Importantly, the taste and physical appearance of the melon was not altered in response to the high temperatures.