STORAGE OF APPLES

Gisborne Herald, Volume LXXIII, Issue 21977, 22 March 1946, Page 4

STORAGE OF APPLES

TEST OF NEW PROCESS

LONGER FIRST-CLASS STATE (P.A.) WELLINGTON, March 22.

Experiments which it is expected will ultimately make apples of first-class quality available to the public all the year round are being carried out by the Department of Scientific and Industrial Research.

At present apples are extremely scarce, if not unobtainable, from November until January. Tlie secret is refrigerated-gas storage, which already has proved successful overseas. The gas used is the carbon dioxide given off by the apples themselves. As the principal product of respiration in its simplest application, the system is merely one of restricted ventilation. Apples are placed in a gaslight chamber until the carbon dioxide builds up. The gas is then maintained at the desired concentration by adjusting the amount of air admitted.

Under this simple system of restricted ventilation carbon diox,de and oxygen together always form 21 per cent of the storage atmosphere. Some varieties of apples, however, require an atmosphere in which carbon dioxide and oxygen amount to less than 21 per cent. In that case the fruit brings the oxygen to the required level by conversion to carbon dioxide the excess of the latter gas absorbed by caustic soda.

In all cases refrigeration is used in conjunction with gas.

To find the appropriate gas mixture for each variety, experiments are first made on a small scale, artificial atmospheres being supplied from gases in cylinders. Further tests are then made under semi-commercial storage conditions in rooms holding 500 cases of apples. The results can be summarised as follows, the first date in each case being that to which the variety can normally be held in cool store, and the second the date to which it can be held in the refrigerated-gas store: Ballarat, end of September, end of Ociober: Washington, mid-June, end of October; Jonathan, early July, early September; Stunner, mid-November, end of February. In all cases the apples have come out of the refrigerated-gas store in firstclass condition. Their subsequent life is longer than that of apples held in cool store.