20 CIRCULAR 713, U. S. DEPARTMENT OF AGRICULTURE 



Peas 



Peas were kept in a bushel hamper in a 24° F. room for 50 hours. 

 The hamper was papered over the sides and bottom. On removal 

 from the freezing room many pods over the top and next to the 

 sides of the hamper were found frozen. After 24 hours at 60 ° no 

 evidence of freezing injury was found. 



A few pods not in a container were placed at 24° F. and left for 

 24 hours. When thawed out at 40° the pods were found to be soft 

 and water-soaked; the shelled-out peas were generally water- 

 soaked and darker green than unfrozen ones. Numerous whitish 

 spots were noted, but these were on the pods and evidently were 

 due to the drying out of bruised or rubbed areas and not to 

 freezing. 



Peppers 



Peppers were held in a bushel basket in a 24° F. room for 24 

 hours ; the basket was papered over the sides and bottom. After 6 

 hours at 60 s freezing injury was spotty. Some specimens showed 

 no injury; in others the entire outer wall was soft, water-soaked, 

 and darker colored than that of unfrozen ones. There was no 

 browning of any part of the peppers. This same lot was returned 

 to a temperature of 24° for 48 hours more. At the end of that 

 time all the peppers were found frozen and, after they had thawed 

 out, a few around the outside of the basket showed browning of 

 cores and seeds, as well as water soaking. Such peppers were soft 

 and worthless. 



Potatoes 

 market observations 5 



The symptoms of freezing injury in potatoes vary, depending 

 upon the kind of tissues killed, the amount of tissue involved, and 

 the consistency and color of the affected regions. Which of the 

 symptom complexes will develop depends upon whether the injury 

 is due to (1) long exposure to temperatures just below the freezing 

 point, (2) moderately long exposure to very low temperatures, 

 (3) moderately short exposure to temperatures just at the freezing 

 point, or (4) short exposure to temperatures far below the freez- 

 ing point. In the first two cases, almost all the tissues may be 

 killed and both external and internal symptoms may appear 

 shortly after thawing. In the last two cases only the most sus- 

 ceptible tissues are killed and no external symptoms are apparent 

 for weeks or months. Short exposures generally produce slight 

 injury of the net or ring type or a combination of these ; longer 

 exposures the blotch type, often in combination with the net and 

 ring types. The restricted or limited type of injury is known as 

 freezing or frost necrosis. 



Before thawing, frozen potato tissue no longer possesses the 

 crispness of the normal tissue. It is abnormally firm, looks dull, 

 and does not cut readily or with snap. This is due to the presence 



5 Adapted from Link. G. K. K., and Ramsey, G. B. market diseases op fruits 

 axd vegetables : potatoes. U. S. Dept. Ast. Misc. Pub. 98, 63 pp., illus. 1932. 

 (See pp. 18 and 19.) 



