What are the methods of postharvest heat treatment of fruits?

Heat treatment methods include hot water, hot steam, hot air, strong hot air and hot ash burying, but hot water and hot air are mainly used for commerce. Hot air is treated with saturated steam at 38 ~ 46℃,12h ~ 4d; The hot water treatment is 43 ~ 63℃ for several seconds to 2 hours. Hot water treatment includes hot water soaking (43 ~ 53℃, several minutes to 2h) and hot water spraying (48 ~ 63℃, 10 ~ 25s).

Hot air heat transfer is slow and takes a long time, but the treatment temperature is low, so the thermal damage caused by hot air is very small. The hot water treatment time is short, which is convenient for operation and water temperature control. Hot water spraying also has the function of disinfecting and cleaning fruits. However, hot water treatment is easy to cause thermal damage, and short-term high temperature can reduce thermal damage. Commercially, the cost of hot water treatment is 10% of that of traditional hot air treatment. The temperature and time of heat treatment depend on the kind, size, maturity, cultivation conditions and growth conditions of fruits. Heat treatment has been applied to commercial production in some countries.