264 ASCORBIC ACID 



in Europe and the United States of America have been included. Rose hips 

 (species of which have been found to contain more than 1000 mg. of ascor- 

 bic acid per 100 g.) have, however, been used in the diet in the form of 

 sirup, and some Asiatic plants are of considerable interest in view of their 

 reputed high vitamin C content. All fully mature nuts are negligible sources 

 of the vitamin and have therefore been omitted from Table V. 



1. Storage of Untreated Foods 



Post-harvest storage may have a significant effect on the antiscorbutic 

 value of the raw fruit or vegetable. The degree to which the vitamin is 

 affected is associated with the time and temperature of storage, the extent 

 to which the cellular tissue may be damaged after harvesting, the structure 

 of the fruit or vegetable, and the presence or absence of ascorbic acid oxidase 

 in the tissue. Hard fruit, such as pears and apples and citrus fruit, retain 

 their vitamin C content over normal periods of storage, provided that the 

 temperature is not allowed to rise unduly. Most soft berry fruits, however, 

 especially when fully or overripe, show a rapid deterioration in quality 

 after harvesting, and this is associated with a corresponding fall in ascorbic 

 acid content. Firm berries such as gooseberries, however, can be kept for 

 several days at room temperature without any appreciable change in vi- 

 tamin C content. With root vegetables, long-term storage is to be antici- 

 pated and, in such cases, a progressive fall in vitamin C content is to be 

 expected (Table VI). Green vegetables, on account of wilting, can be held 

 at room temperature for a maximum of only a few days after harvesting. 

 The tightly packed leaves in a head of cabbage will show a negligible loss 

 of vitamin, even when wilted, whereas the loose leaves of spinach show a 

 rapid loss under similar conditions. Low-temperature storage in all cases 

 slows down the rate at which the ascorbic acid content is decreased. 



6 B. K. Watt and A. L. Merrill, U.S. Dept. Agr., Agr. Handh. 8 (1950). 



7 H. E. Munsell, L. 0. Williams, L. P. Guild, C. B. Troescher, G. Nightingale, and 

 R. S. Harris, Food Research 15, 16 (1950). 



8 H. E. Munsell, L. O. Williams, L. P. Guild, C. B. Troescher, G. Nightingale, and 

 R. S. Harris, Food Research 15, 34 (1950). 



9 H. E. Munsell, L. O. Williams, L. P. Guild, C. B. Troescher, G. Nightingale, L. T. 

 Kelley, and R. S. Harris, Food Research 15, 263 (1950). 



10 H. E. Munsell, L. O. WilHams, L. P. Guild, C. B. Troescher, and R. S. Harris, 



Food Research 15, 355 (1950). 

 " H. E. Munsell, L. O. Williams, L. P. Guild, L. T. Kelley, A. .M. McNally, and 



R. S. Harris, Fo(M Research 15, 379 (1950). 

 12 H. E. Munsell, L. O. Williams, L. P. Guild, L. T. Kelley, and R. S. Harris, Food 



Research 15, 421 (1950). 

 " H. E. Munsell, L. O. Williams, L. P. Guild, L. T. Kelley, A. M. McNally, and 



R. S. Harris, Food Research 15, 439 (1950). 

 " Wu,L.Woot-Tsuen,R.K.Pecot,andB.K. Watt, U.S. Dept. Agr., Agr. Handh. 34 



(1952). 



