STORAGE OF APPLES

Evening Post, Volume CIX, Issue 119, 22 May 1930, Page 22

STORAGE OF APPLES

CARBON DIOXIDE

SYSTEM OF PROMISE

(From "The Post's" Ropresontatlvo.) LONDON, 27th March. - In the month of March, writes a correspondent of "The Times,' 1 the'supplies of home-grown apples on tho 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 oeady and regular marketing of tho fruit. In England the only apples .that arc stored in large quantities are Bramley's Seedling, and these come on to the markets during March. Tor some weeks thero have been aniplo supplies of these Bramlnys from cold storage chambers; in addition, there have been' supplies from the novel gas stores of-a Knnfc grower, and .it. is interesting to compare thu condition of the fruits stored in theso different wavH. .

The Bramley Seedlings from the cold chambers have probably been kept at 32deg-S4deg 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, may give the skins a wet appearance—yet iii ; 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 tho day they were gathered. , As the storage temperature has been higher, no water condensation occurs. So far as this particular variety is concerned there can be ny doubt that the apples store rather boiler in the gas store than in the refrigerated chambers.

A gas store is ojio hi 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 15 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 15 per cent, of carbon dioxide there is the 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 15 per cent. The temperature of the store-is also a contributory factor to good storage. At, say, 32cjeg F. or 34deg F., for instance, Bramley applesj when stored in gas-stores, give trouble through internal, breakdown, and, in consequence, is/not recommended. At 41deg F. no such .-breakdownoccurs, and from a practical point of view this is the most convenient temperature to maintain. A gas store, then, is a chamber in which the temperature can be maintained at 41deg 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 low 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 6u tho markets confirm the xesultsof 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 chango.