COMMERCIAL STORAGE OF FRUITS AND VEGETABLES 7 



a temperature of 35° F. These figures are based on experimental 

 determinations of the rate of respiration at various temperatures; 

 some of the data are from the tables given by Magness et al. (13, 15), 

 and the remainder from data reported by Haller et al. (8). The 

 figures for Bartlett pears are based on the maximum values given 

 by Magness (15). The figures given in this table have been obtained 

 by assuming that the heat of respiration is produced by oxidation of 

 a hexose sugar, and can be calculated from the rate of production 

 of carbon dioxide which has been determined experimentally; very 

 few calorimetric measurements of heat production by fruits and 

 vegetables have been made, and this assumption seems to be the 

 best available basis for calculating heat production at any given 

 temperature. 



Table 2. — Approximate amounts of heat of respiration and sensible heat to oe 

 removed from certain fruits in cooling them from 60°, 70°, or 80° to 35° F. 

 in a room at 32° F., when cooling takes place in 3, 4, 5, 6, 8, or 10 days 



[Heat expressed in B.t.u. per ton of fruit] 



Kind of fruit 



Initial 

 tempera- 

 ture (°R) 



Heat of respiration during— 



Sensible 



3 days 



4 days 



5 days 



6 days 



8 days 



10 days 



heat 1 



Apples: 



f 80 

 \ 70 

 I 60 

 f 80 

 { 70 



60 

 f 80 



70 

 { 60 

 f 80 

 \ 70 

 I 60 

 f 70 

 \ 60 

 f 80 

 { 70 

 I 60 



80 

 { 70 

 I 60 



8,000 

 7,000 

 6,000 



12, 000 

 10, 000 



8,000 



13, 000 

 10, 000 



7,000 

 16, 000 

 13, 000 

 10, 000 

 16, 000 

 13, 000 



30, 000 



24, 000 

 19, 000 

 38, 000 



31, 000 



25, 000 



11, 000 



9,000 

 8,000 



16, 000 

 13, 000 

 11, 000 

 18, 000 

 13, 000 

 10, 000 

 22, 000 



17, 000 

 13, 000 

 22, 000 

 17, 000 

 39, 000 

 32, 000 

 26, 000 

 51, 000 

 42, 000 

 34, 000 



14, 000 

 12, 000 

 10, 000 

 20, 000 

 17, 000 

 13, 000 

 22, 000 

 17, 000 

 12, 000 

 27, 000 

 21,000 

 16, 000 

 27, 000 

 22, 000 

 49, 000 

 40, 000 

 32, 000 

 64, 000 

 52, 000 

 42, 000 



16, 000 

 14, 000 

 12, 000 



24, 000 

 20, 000 

 16,000 

 26, 000 

 20, 000 

 14, 000 



32, 000 



25, 000 

 19, 000 



33, 000 



26, 000 

 59, 000 

 49, 000 

 39, 000 

 77, 000 

 63, 000 

 51,000 



22, 000 

 19, 000 

 16, 000 

 32, 000 

 26, 000 

 21, 000 

 35, 000 

 26, 000 

 19, 000 



43, 000 



34, 000 

 25, 000 



44, 000 



35, 000 

 79, 000 

 65, 000 

 51, 000 



102, 000 

 84, 000 

 68, 000 



27, 000 



23, 000 

 20, 000 

 40, 000 

 33, 000 

 27, 000 

 44, 000 

 33, 000 



24, 000 

 54, 000 



42, 000 

 32, 000 

 54, 000 



43, 000 

 99, 000 

 81, 000 

 64, 000 



128, 000 

 104, 000 

 84, 000 



80, 000 

 62, 000 



Grimes Golden... 



Peaches: 



Elberta 



44,000 

 80, 000 

 62,000 

 44, 000 

 80, 000 

 62, 000 



Carman 



44, 000 

 80, 000 

 62, 000 



Pears: 



Bartlett 



44, 000 

 61,000 



Strawberries: 



Chesapeake 



Howard 17 



43, 000 

 83, 000 

 64, 000 

 46, 000 

 83, 000 

 64, 000 

 46, 000 



1 For any one kind of fruit at a given temperature these figures are assumed to be the same for all cooling 

 periods included in the table. 



The assumption has also been made, although it is known to be 

 only approximately correct, that the rate of temperature drop at 

 any given time during cooling is proportional to the difference 

 between room temperature and fruit temperature at that time. With 

 this assumption as a basis, the temperature and thus the rate of 

 respiration at any time during the cooling period, as well as the total 

 heat produced during the whole cooling period, have been cal- 

 culated. 2 



As a result of these calculations it has been found that the heat 

 produced by the respiration of fruit while it cools is directly pro- 

 portional to the length of the cooling period. The figures for cool- 

 ing periods of 3, 4, 5, 6, and 8 days are therefore set at 3, 4, 5, 6, 



2 The authors wish to acknowledge the valuable assistance given by W. V. Hukill, of 

 the Bureau of Agricultural Engineering, in the making of the calculations and in the 

 preparation of this statement on the production of heat by fruits and vegetables. 



