Studies on the Deterioration and Preserve-ability of Cartons in the Cold Storage

Abstract

Various characteristics of carton boxes filled with AMANATSU-DAIDAI in the cold storage were examined, and the following results were obtained.
I. Factors affecting moisture contents of cartons in the cold storage.
(1) Moisture contents of cartons filled with AMANATSU-DAIDAI, hereafter is named filled-carton, increased more rapidly than that of empty-cartons (Fig. 6).
Relative humidity in the filled-cartons reached 100 percents after the lapse of 2 to 3 hours.
The lower the relative humidity of air in the cold storage room, the greater the difference of moisture contents between filled and empty cartons
(2) Moisture contents of cartons were influenced both by relative humidity and absolute humidity of the air, and the effect of the former was more remarkable.
(3) Moisture contents of empty-cartons increased in proportion to the area of perforation, and that of filled-cartons decreased, inversely, with the perforation (Fig. 8).
(4) Moisture contents of empty-cartons increased with the increse of air velocity in the forcedair cooling, untill the moisture-equilibrium of carton was reached (Fig. 9).
Change in the moisture contents of filled-cartons due to heair velocity could not be observed.
II. Cold storage tests of cartons filled with AMANATSU-DAIDAI were made and the following results were obtained.
(1) The compressive strength of cartons decreased with the lapse of preserving days, and this tendency was remarkable both in the lower part of the loading and in the water-proof cartons (Fig. 10, 11).
Moisture contents of empty-cartons reached to their equlibrium after 43 hours' preserving, whereas that of filled-cartons after 30 days (Fig. 12).
(2) Decay of AMANATSU-DAIDAI was slower at the upper part of the loading and in the water-proof cartons (Fig. 13).
(3) Upper part of the loading in the cold storage room showed lower loss in weight. The loss in weight in the cold storage was 3.5 percents in a month, 7 percents in two months and 14 percents in three months.
Moisture contents of cartons increased when the inner fruit showed higher loss in weight (Fig. 14).
(4) Softening of AMANATSU-DAIDAI in the cold storage was the general tendency regardless of the carton position of the loading.
By using water-proofcartons, the softening of AMANATSU-DAIDAI was reduced (Fig. 15).
(5) Fall of the content of the total sugar and citric acid of AMANATSU-DAIDAI in the cold storage had no clear relation with the position of the loading and the kind of cartons.