Films Tested 
Pears were packaged in Phiofilms 120P6, 120P4, 75FF, 80 FM1, 
100 FM1, 80HP and 100HP;; cellophane 300 LSAT; ead polyethylene 
100 and 150. Golden Delicious apples, in the earlier work of 1945-49, 
were packaged in cellophanes 450 MSAT, 300 MSAT, 300 LSAT: 
Pliofilms 120P6, 120P4, and 75FF. In 1951-52 the newer Pliofilms 
80 FM1, 80 HP, and 100 HP were used along with polyethylene 150. 
In most instances these films were used in the form of sealed box 
Jiners: when film perforation was tried, four 44g inch openings per 
liner were made. <A fresh supply of the various kinds of film was 
obtained from the manufacturer each year a particular film was 
under study. 
Analytical Procedures 
Carbon dioxide and oxygen in the test packages of pears and apples 
were determined with a portable Hayes gas analyzer and a Beckman 
Model D instrument, respectively. ‘Firmness w was measured with a 
Magness-Taylor pressure tester using a 4, inch and %¢ inch plunger 
for pears and apples, respectively, on 3 ‘paired sur faces of 20 fruits. 
Loss in weight was obtained by weighing the unwrapped fruit before 
and after treatment. Soluble pectin was determined (as percentage 
of calcium pectate) in 100 gm. of fresh tissue macerated in a Waring 
Blender according to unpublished methods of U. S. Department of 
Agriculture laboratories at Wenatchee, Wash. Respiration values 
were obtained by absorption of the CO, from tared fruits in standard 
NaOH, precipitation of the carbonate with BaCl,, and titration with 
0.3N HC1; they are expressed as milligrams of CO, per kilogram of 
fruit per hour. Aeration during absorption was at the rate of 30 
liters per hour of CO.-free air. 
Storage. Ripening. and Dessert Quality 
The apples and pears under study were stored at 31° F. and 85 
percent relative humidity and ripened at 65° F. in a relative humidity 
of 85 percent. Visual inspection was made for color change, scald, 
and core breakdown in pears, and appearance, condition, and storage 
quality of apples. Measurements of firmness, soluble pectins, and 
respiration were made on pears and apples and determinations of 
weight loss were made on apples. Dessert quality (texture and flavor) 
was Judged by a taste panel of 4 people. 
BARTLETT PEARS 
Storage Physiology, Atmospheres, and Appearance 
Many of the data from a study of 10 different kinds of films over 
a period of 5 years on 4 varieties of pears are condensed; some per- 
taining to the older types of films are omitted. The primary group- 
ing of ‘the data is by variety. 
The soluble pectin content, firmness, and loss in weight are recog- 
nized guides for the storage condition of pears. Data in table 2 show 
6 
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