10 BULLETIISr 1041, V. S. DEPAKTMElSrT OF AGRICULTURE. 



ization was apparent to the taste or sight, and the results in general 

 were satisfactory. Comparison of this material with that canned 

 immediately after digging showed it to be far superior in quality, 

 due to the first lot being overprocessed, and a marked difference in 

 the consistency was noted. As before stated, those potatoes canned 

 early in the season were firm and fairly dry, but in these the con- 

 sistency was much less firm, and in such varieties as the Nancy Hall, 

 Porto Rico, and Southern Queen the material was very soft and 

 moist. The work of the earlier investigators upon the transforma- 

 tions in the starch of the sweet potato during storage suggested the 

 possible cause of this difference in the consistency of freshly dug 

 and of stored potatoes, but it was necessary to postpone investiga- 

 tions of this problem until some later date. All canned potatoes not 

 already opened were stored for later comparisons. 



WORK IN 1919. 



The work of 1918 showed that sweet potatoes undergo changes 

 in storage which greatly alter the firmness of the canned product 

 and also that these changes differ with varieties. Since a rather com- 

 plete record was secured upon the potatoes canned immediately after 

 digging, it was thought advisable to get also a complete record of 

 their canning qualities after the usual curing and storage.^ For this 

 purpose 38 varieties and strains were provided. They were dug on 

 October 1, put into open slatted- crates, and placed at once in the 

 curing rooms. Here the temperature was maintained at about 85° F. 

 for 10 days. At the end of this time they were transferred to the 

 storage room, where the temperature ranged from 55° to 65° F., and 

 were held there until used. The canning tests were made November 

 19 to 21. 



The procedure of handling was about the same as that followed 

 during the latter part of the preceding season. The potatoes were 

 washed, cooked in flowing steam for 30 to 40 minutes, peeled rapidly 

 by hand, and passed directly through a food grinder into No. 2 

 plain sanitary cans. Sealing was done immediately, and the tem- 

 perature of the material averaged 70° to 80° C. The processing was 

 carried out at once, one lot of each variety being given the inter- 

 mittent treatment in boiling water (1| hours on each of three suc- 

 cessive days) and the other being processed in the steam retort at 

 116° C. for 45 minutes. At the end of the processing periods all 

 cans were removed and cooled in air. 



Only slight differences in quality could be noted in the material 

 processed according to the two methods mentioned, it being judged 



■ For Information upon curing and storing sweet potatoes, see Farmers' Bulletin 970, 

 entitled " Sweet-Potato Storage." 



