A STUDY OF SWEET POTATO VARIETIES. 



21 



Table 4. — Results of chemical anali/ses of samples of four varieties of siceet 

 potatoes canned at intervals of 10 days during curing and storage. 



Sample. 



Big-Stem Jersey: 



Freshly dug 



After curing 10 days . 

 After storage — 



10 days 



20 days 



Nancy Hall: 



Freshly dug 



After curing 10 days. 

 After storage— 



10 days 



20 days 



Southern Queen: 



Freshly dug 



After curing 10 days. 

 After storage — 



10 days 



20 days 



Porto Rico: 



Freshly dug 



After curing 10 days. 

 After storage — 



10 days 



20 days 



Constitutents (per cent). 



Mois- 

 ture. 



72.63 

 71.51 



71.23 

 70.40 



66.80 



64.60 

 65.11 



71.09 

 68.62 



68.55 

 68.57 



70.03 

 69.15 



68.78 

 68.20 



Dry 

 weight. 



Sugar content (calculated 

 as invert). 



Reducing! TvT„j,re- 

 (beforein-! ^°^^t 

 version). I ^^^cmg. 



27.37 

 28.49 



28.77 

 29.60 



33.20 

 33.20 



35.40 

 34.89 



28.91 

 31.38 



31.45 

 31.43 



29.97 

 30.85 



31.22 

 31.80 



6.50 

 5.65 



6.03 

 6.11 



9.17 

 9.76 



10.57 

 10.38 



7.67 

 8.18 



8.39 

 6.75 



2.15 

 4.15 



4.59 



4.51 



1.89 

 4.23 



4.51 

 4.65 



1.38 

 3.74 



3.02 

 3.70 



1.83 



4.88 



5.34 



4.88 



Total. 



8.65 



10.62 

 10.62 



11.06 

 13.99 



15.08 

 15.03 



9.05 

 11.92 



12.10 

 12.09 



8.58 

 13.78 



13.63 



13.74 



Total 

 polysac- 

 charids 



(calcu- 

 lated as 

 starch). 



10. 85 

 10.31 



10.. 39 

 10.36 



11.02 

 8.51 



9.21 

 9.14 



10.64 

 9.53 



10.14 

 9.06 



11.06 

 7.65 



8.44 

 9.13 



Dextrin. 



0.41 



.46. 



.32 

 4.78 



5. IS 

 5. 11 



.17 

 1.33 



4.73 



3.78- 





 3.92 



3.88. 

 3.66 



From Table 4 it will be seen that the moisture content of the 

 canned product is highest in the lots canned immedia'tely after 

 digging, those- canned at the end of the storage period of 20 

 days showing a loss of from 1.6 to 2.5 per cent. The total 

 sugar content increases in the succeeding tests and the total 

 polysaccharids, calculated as starch, decrease, but these changes seem 

 insufficient to account for the enormous change in plasticity. 



The dextrin content of the samples is of interest. In the Big-Stem 

 Jersey none was found in the material canned from freshly dug 

 potatoes, and only a relatively small amount in any of the lots canned 

 subsequently^ In the Nancy Hali there was a small amount of dex- 

 trin in the material from the freshly dug potatoes and this quantity 

 greatly increased in the material from the cured and f rorn the stored 

 potatoes. The Southern Queen showed a small dextrin content in 

 the lot from the freshly dug roots, a larger amount in material cured 

 for 10 days, though less than is formed in the corresponding lots of 

 Nancy Hall and Porto Eico, and a considerable amount in the lots 

 from stored potatoes. The figures for the Porto Rico are similar 

 to those for the Nancy Hall except that no dextrin is found in ma- 

 terial from the freshly dug potatoes and the figures in the succeeding 

 lots are somewhat lower. From qualitative tests made in connection 

 with these studies but not recorded here it seems almost certain that 



