786 



STARCHES OF ZINGIBERACE^. 



Differentiation of Certain Starches of the Genus Zingiber. Continued. 



Histological Chabactekistics. Continued. 

 Size. 

 Z. officinale: From 7.5 to 64^, commonly 44m. 

 Z. officinale var. Jamaica No. 1: From 5 to 45ai, com- 

 monly 30m. 

 Z. officinale var. Jamaica No. 2: From 4 to 42m, com- 

 monly 28m. 

 Z. officinale var. Cochin: From 5 to 40m, commonly 28m. 



PoLARiscopic Properties. 



Figure. 



Z. officinale: Extremely eccentric, very distinct and not 



sharply defined. Usually only 1 or 2 of the 4 lines 



of the figure are visible. 

 Z. officinale var. Jamaica No. 1: Essentially the same 



as in Z. officinale, but less eccentric. 

 Z. officinale var. Jamaica No. 2: Essentially the same 



as in Z. officinale, but less eccentric. 

 Z. officinale var. Cochin: Essentially the same as in Z. 



officinale, but less eccentric. 



Degree of Polarization. 

 Z. officinale: Fair. 



Z. officinale var. Jamaica No. 1: Low. 

 Z. officinale var. Jamaica No. 2: Low, lower than in Z. 



officinale var. Jamaica No. 1. 

 Z. officinale var. Cochin: Low, the same as in Z. officinale 



var. Jamaica No. 2. 



With Selenite. 

 No marked differences. 



Iodine Reactions. 

 Intensity and Color. 

 Z. officinale: Fairly deep; blue-violet. 

 Z. officinale var. Jamaica No. 1: Fairly deep, less than in 



Z. officinale; blue-violet. 

 Z. officinale var. Jamaica No. 2: Fairly deep, less than 



in Z. officinale var. Jamaica No. 1; blue-violet. 

 Z. officinale var. Cochin: Fairly deep, deeper than in 

 Z. officinale; blue-violet. 



Staining Reactions. 

 With Gentian Violet. 

 Z. officinale: Fairly deep. 

 Z. officinale var. Jamaica No. 1: Fairly deep, but less 



than in Z. officinale. 

 Z. officinale var. Jamaica No. 2: Fairly deep, but less 



than in Z. officinale. 

 Z. officinale var. Cochin: Fairly deep, but less than in 



Z. officinale. 



With Safranin. 

 Z. officinale: Light. 

 Z. officinale var. Jamaica No. 1: Light, slightly less than 



in Z. officinale. 

 Z. officinale var. Jamaica No. 2: Light, less than in 



Z. officinale. 



Staining Reactions. Continued. 

 With Safranin. Continued. 

 Z. officinale var. Cochin: Light, slightly less than in 

 Z. officinale. 



Temperature of Gelatinization. 



Z. officinale: 73.3 to 74.4 C, mean 73.85. 



Z. officinale var. Jamaica No. 1: 81.7 to 82.8 C, mean 



82.25. 

 Z. officinale var. Jamaica No. 2: 85.5 to 86.3 C, mean 



85.9. 

 Z. officinale var. Cochin: 89.5 to 90.5 C, mean 90. 



Effects of Various Reagents. 



Reaction with Chloral Hydrate- Iodine. 



Z. officinale: Begins in most in 30 seconds; complete 

 in all in 2 minutes. 



Z. officinale var. Jamaica No. 1: Begins in 1 minute; 

 complete in all in 10 minutes. 



Z. officinale var. Jamaica No. 2: Begins in most in 

 45 seconds; complete in all in 8 minutes. 



Z. officinale var. Cochin: Begins in 2J-^ minutes; com- 

 plete in all in 10 minutes. 



Reaction with Chromic Acid. 

 Z. officinale: Begins in 20 seconds; complete in 2 minutes. 

 Z. officinale var. Jamaica No. 1: Begins in IJ^ minutes; 



complete in 20 minutes. 

 Z. officinale var. Jamaica No. 2: Begins in 2 minutes; 



complete in 13 minutes. 

 Z. officinale var. Cochin: Begins in 2 minutes; complete 



in 11 minutes. 



Reaction with Pyrogallic Acid. 



Z. officinale: Begins in most in 2 minutes; all partially 

 gelatinized in 35 minutes. 



Z. officinale var. Jamaica No. 1: Begins in a few in 2 

 minutes; a few partially gelatinized in 20 minutes. 



Z. officinale var. Jamaica No. 2: Begins in some in 3 min- 

 utes; about half partially gelatinized in 35 minutes. 



Z. officinale var. Cochin: No reaction. 



Reaction icith Ferric Chloride. 

 Z. officinale: Begins in 45 seconds; complete in 5 minutes. 

 Z. officinale var. Jamaica No. 1: Begins in 2}^ minutes; 



partially complete in IJ^ hours. 

 Z. officinale var. Jamaica No. 2: Begins in 3 minutes; 



complete in 45 minutes. 

 Z. officinale var. Cochin: Begins in a few in 3 minutes; 



complete in 55 minutes. 



Reaction with Purdy's Solution. 

 Z. officinale: Begins at once ; complete in 1 J/^ minutes. 

 Z. officinale var. Jamaica No. 1: No reaction after 2 



hours. 

 Z. officinale var. Jamaica No. 2: Begins in some in 15 



minutes; most are affected after 3 hours. 

 Z. officinale var. Cochin: No reaction after 2 hours. 



NOTES ON THE STARCHES OF ZINGIBER. 



The starch of Z. officinale differ.s in histology and in reactions from the specimens of Jamaica 

 ginger which are marketed as Z. officinale; and both of these in turn from Z. officinale var. Cochin. 

 The true Z. officinale is particularly distinguished by the conspicuousness of the nipple-like proximal 

 end, the distinct lamellae, and average greater size. Cochin ginger bears a closer resemblance to 

 Z. officinale than to the Jamaica gingers. In their reactions Z. officimde likewse stands apart, and 

 the Jamaica and Cochin gingers have relationships which, on the whole, are in accord with those 

 of their histologj'. The high temperature of gelatinization of the Jamaica and Cochin gingers is 

 notable (82.25, 85.9, and 90), especially of the latter, which is the highest record of any starch yet 

 examined. The comparatively great resistance shown by the Jamaica and Cochin gingers in com- 

 parison with Z. officinale in the reactions with the chemical reagents is very marked. 



