Articles
THE EFFECT OF STORAGE CONDITIONS ON THE QUALITY OF PEARS “KRYSTALLI” VARIETY
The optimum storage temperature for most varieties of pears is close to -1°C (Hall and Scott, 1964 /4/, 1965 /5/) which is slightly above the normal freezing point of the flesh of pears; the optimum ripening temperature is about 20°C /1/.
Many of the defects of pears are caused by inappropriate storage temperatures and over-long storage /1/.
Controlled atmosphere (C.A.) storage increases the storage life and subsequent shelf-life of many pear and apple varieties /6/.
Blanpied and Smock /2/ in their investigation on the separate effects of O2 and CO2 found high flesh firmness and low storage scald associated with low temperature, low O2 and high CO2 levels.
There is a general agreement that less scald is likely under low O2 storage /7/,/9/,/10/,/12/,/15/,/16/. Scott /13/ reported that raising the CO2 level at high O2 levels increased scald on apples, while raising it at low O2 levels reduced scald.
Brown heart was early considered by Kidd and West /20/ and it has since been reported by others /3/, /8/, /17/, /18/. Thomas /17/ considered internal and invasive aldehyde poisoning to be injuries from high levels of CO2 and also he found that apples under anaerobic conditions accumulated ethyl alcohol, the epidermal tissue browned and this browning moved inward to the core.
He termed such injury "invasive alcohol poisoning" Brown core /15/, core flush /4/, /16/ or core browning /3/ also may be more severe under certain conditions if too much CO2 is present.
For pears gas storage of "Conference" is applied on a commercial scale in England and Holland /19/.
In this work we tried to study the effect of different conditions of temperature and gas mixtures on the quality characteristics of pears of the "Krystalli" variety.
We also used the advantage of C.A. /6/ to try a temperature higher than the recommended one in an attempt to save energy.