RESPIRATION OF PEARS 
IN SPECIFIED WRAPS 
MGS. CO, PER KG. PER HR. | ; 
ANJOU BARTLETT 
| 
Chom bese ee. 
ame Pliofilm, FMI-100 
peee« Polyethylene, 150 
EO. 100 150° 200. 0. 50 100 150 
DAYS STORAGE AT 31° F 
U.S. DEPARTMENT OF AGRICULTURE NEG. 1139-54(10) AGRICULTURAL MARKETING SERVICE 
Ficure 5.—Respiration of pears in sealed film and in paper wraps. 
Ripening Capacity and Dessert Quality 
Data on the ripening of Bartlett pears at 65° F. in various kinds 
of sealed film are summarized in table 4. The practice of ripening 
pears in sealed film is fraught with danger of destruction of flavor 
and discoloration of tissue as a result of possible i injurious accumula- 
tion of carbon dioxide and a depletion of oxygen. ‘To establish the 
length of time that the ripening fruit can be held in the sealed films 
at 65° without injury to the fruit, seals were broken after various 
periods of ripening. Carbon dioxide and oxygen concentrations after 
5 days of ripening varied from 3 to 13 percent and from 1.5 to 3.5 
percent respectively for the different films (table 3). These con- 
centrations of CO, and O, for the first 4 to 7 days following removal 
of the pears to the ripening room were not injurious to normal ripen- 
ing provided the previous period of cold storage was not too long 
(t table 4). Rapid ripening of pears is generally desired at most 
terminal markets and can be obtained even with film-sealed fruit by 
immediate perforation of the film. The margin of safety of 4 to 7 
days of ripening under seal should provide “ample time to handle 
pears at wholesale and retail without serious danger to dessert quality. 
Bartlett pears when packed 1 in the conventional manner usually have 
a maximum storage life at 31° F. of 70 to 85 days. Data in table 4 
show that this per iod can be consider whos extended by packaging in any 
of the sealed films used. For instance in 1950, pears in the sealed film 
ripened satisfactorily after 107 days of cold storage, whereas those 
stored this long in the conventional pack never ripened to acceptable 
dessert quality, but remained granular in texture, and developed scald 
and core breakdown before obtaining acceptable dessert quality. 
9 
