STORAGE OF APPLES.

Otago Daily Times, Issue 21019, 7 May 1930, Page 19

STORAGE OF APPLES.

THE “ GAS ” SYSTEM. (From Oob Own Correspondent.) ■LONDON, March 27. In the month of March (writes a correspondent of The Times) tlxc supplies of Home-grown apples on the market begin to dwindle somewhat and men with apples in storage realise that the time has arrived for the opening of the stores and for a steady and regular marhetipfr of the fruit. In England the only apples that are stored in large quantities are Bramley’s Seedling, and these .come on to the markets during March For some weeks there have been ample supplies of these Bramleys from cold storage chambers; in addition there have been supplies from the novel gas stores of a Kent grower, and it is interesting to compare the condition of the fruits stored in these different ways. The Bramloy Seedlings from the cold chambers have probably been kept at 3234 degrees Fahrenheit for nearly six months, yet their condition is firm and hard. The apples may perhaps have lost that, deep, bright green lustre of the fresh ■ fruit and have yellowed considerably; water condensation, too, maj’ give the skins a wet appearance—yet in spite of this the specimens are good and find ready buyers. The apples from the “gas” stores are still a deep green in colour and almost as fresh as on the day they were gathered. As the storage temperature has been higher, no water condensation oegurs. So far as this particular variety is concerned there can bo no doubt that the apples store rather better in the gas store than in the refrigerated chambers. A gas store is one in which the atmosphere contains more carbon dioxide than occurs in air. This carbon dioxide is given off by the apples, and if the stores are gas-proof the percentage steadily increases. At concentrations of 10 per cent, to 13 per cent, of carbon dioxide a retarding effect on the ripening of the fruit occurs, thus rendering it possible to store fruit in this way. At concentrations in excess of 13 per cent, of carbon dioxide there is a danger of actual poisoning of the fruits by asphyxiation, so it. is necessary to regulate the supply of carbon dioxide to guard against concentrations in excess of 13 per cent. The temperature of the store is also a contributory factor to good storage. At, say, 32 degrees F. or 34 degrees F., for instance, Bramley apples, when stored in gas stores, give trouble through internal breakdown, and in consequence is not recommended. At 41 degrees F. no such breakdown! occurs, and from a practical point of view this

is the most- convenient temperature to maintain. A gas store, then, a chamber in which the 'can be maintained at 41. degrees F., and is gas-, proof, so that the atmosphere may be controlled to contain from 10 per cent.’ to 15 per cent, of carbon dioxide and 10 per cent, of oxygen,: the remainder being inert nitrogen. " In the experiments conducted at the law-temperature station .at Cambridge it was found that Bramleys kept their dark green colour, after storage in such a .store for 39 weeks, while those kept in refrigerated chambers had “yellowed ”, in 24 weeks. The Bramleys now appearing oh the markets confirm the results of these experiments and show that this method of storage is a very practical proposition. It might be pointed out. that the apples on removal from the gas stores to air remain quite firm, perfect in appearance and flavour. If kept for a time they ripen normally. The storage has simply retarded maturity and induced no further change.