ARTICLES 609 



and cost of fuel make this process a relatively expensive one. 

 Dried vegetables have been shown over and over again to be 

 deficient in anti-scurvy value ; they are without any appreci- 

 able protective power against scurvy, and, although they may 

 doubtless be used as flavouring, they should never be relied upon 

 as the main source of anti-scorbutic in a diet.^^ On drying, by 

 the most favourable methods, a loss of about 90 per cent, of the 

 original anti-scorbutic value occurs : after about six months 

 no anti-scorbutic value whatever can be detected. When 

 dried vegetables are stored at ordinary temperatures a gradual 

 further deterioration of their slight anti-scorbutic value there- 

 fore takes place. The dried products are best stored in a cool, 

 dry place in a stoppered jar or closed tin, so that no atmo- 

 spheric moisture may be absorbed. 



With regard to canning, direct evidence from the results 

 of experiments by Campbell and Chick * show that a large 

 amount of destruction of anti-scorbutic value is inevitable in 

 the methods commonly employed, and recommended to the 

 public for canning vegetables in Pamphlet No. 34 of the Food 

 Production Department. Controlled experiments showed that 

 by this method cabbage would be exposed in canning for at 

 least an hour and a half to temperatures varying from 90° to 

 100° C. : the corresponding loss of anti-scurvy value was over 

 70 per cent* {cp. Table III). The growth-promoting vitamine 

 (fat-soluble A) had, moreover, been lost, part of it, at least, 

 being found in the liquor surrounding the leaves. 



In the case of runner beans, the canned product must be 

 twice heated in order to ensure sterilisation, thus involving a 

 total period of heating to 100° C. for 2 hours 20 minutes. 

 The loss of anti-scurvy value involved amounted to about 

 90 per cent, of that of the fresh green bean-pods. These 

 authors conclude that the value of canned vegetables, as regards 

 scurvy and growth-promoting properties, must be regarded as 

 negligible. 



With regard to fruits, it is probable that canning and bottling 

 the more acid fruits does not involve so great a loss as in the 

 case of vegetables ; for, in the first place, the fruit is not kept 

 at 100° C. for more than 20 minutes (even in the case of " hard " 

 fruits), and, in the second place, the juice of oranges, lemons, 

 and raspberries is known to be heat stable. The juice of 

 tomatoes is somewhat less stable (see Table IV). A brand of 

 bottled tomatoes tested at the Lister Institute! iii 19^9 had 

 lost about 70 per cent of its original value {i.e. as compared 



* The loss of anti-scurvy value is less than when cabbage is cooked for a 

 corresponding time in open vessels, but most of this heating is done after 

 sealing up the tins. 



t Unpublished experiments by Rhodes and Delf, 1919. 



