794 



STARCHES OF ZINGIBERACE^. 



Differentiation of Certain Starches of the Genus Curcuma. 



HiBTOLOGiCAi, Characteristics. 

 Conspicuous Forms. 



C. longa: Simple, isolated, frequently irregular- ovoid, 

 often with flattened sides and somewhat abruptly 

 pointed proximal end: triangular with curved base; 

 pyriform, often with flattened sides, shield-shaped, 

 mussel-shell-fihaped, and imperfect quadrilateral 

 when viewed on end, usually narrow elliptical. 



C. petiolata: Same as in C. longa, but more irregular; 

 protuberances more prominent, comers limiting 

 distal end longer; sometimes curved towards the 

 proximal end. 



Hilum — Form, Number, and Position. 

 C. longa: Form very indistinct, round or lenticular spot. 



Position eccentric usually about 0.12 to 0.07 of 



longitudinal axis. 

 C. petiolaUi: Form rather more often visible than in C. 



longa. Position eccentric usually about 0.16 to 0.05 



of longitudinal axis. 



LameUoe — General Characteristics and Number. 



C. longa: Usually not clearly demonstrable, especially 

 near the hilum, rather fine to fairlj' coarse, follow 

 outline of distal margin, probably mcomplete. 32 

 to 40 on larger grains. 



C. petiolata: Rather more distinct, and can be counted 

 over the whole surface in a larger number of grains 

 than in C. longa. 35 to 50 on fmr to large grains. 



Size. 

 C. longa: From 10 to 42/i, commonly 24 by 18;u. 

 C. petiolata: From 9 to 50m, commonly 28 by 20^. 



POLAHISCOPIC PrOPEBTIES. 



Figure. 

 C. longa: Very eccentric, usually indistinct in area in 



which the lines intersect; lines rather broad and 



frequently bent. 

 C. petiolata: lines more often bent than in C. longa. 



Degree of Polarization. 

 C. longa: Fair. Very low or absent at proximal end. 

 C. petidata: Fjur. A little higher than in C. longa, otheiv 

 wise the same. 



Polarization with Sdenite — Qiuidrants and Colors. 

 C. longa: Quadrants not clearly defined, one at proximal 

 end rarely seen, irregular in shape, unequal in size. 

 Colors not quite pure. 



PoLARiscopic Properties. — Continued. 

 Polarization ujithSelenite — Quadrants and Colors. — Cont'd. 

 C. petiolata: Quadrants same as in C. longa except more 



irregular. Colors not quite pure, blue, more often 



pure than in C. longa. 



Iodine Reactions. 

 Intensity and Color. 

 C. longa: Light; dull red- violet. 



C. petiolata: Light, deeper than in C. longa; brighter than 

 in C. longa. 



Staining Reactions. 

 With Gentian Violet. 

 C. longa: Fair. 

 C. petiolata: Fair, slightly deeper than in C. longa. 



With Safranin. 

 C. longa: Fair. 

 C. petiolata: Fair, slightly deeper than in C. longa. 



Temperature op Gelatinization. 

 C. longa: 82 to 83° C, mean 82.5°. 

 C. petiolata: 82 to 83° C, mean 82.5°. 



Effects op Vabiotts Reagents. 

 Reaction with Chloral Hydrate-Iodine. 

 C. longa: Begins at once; complete in 30 seconds. 

 C. petiolata: Begins at once; complete in 40 seconds. 



Reaction with Chromic Acid. 

 C. longa: Begins at once; complete in 10 minutes. 

 C. petiolata: Begins at once; complete in all in 8}^ minutes. 



Reaction with Pyrogallic Acid. 

 C. longa: Begins in a few in 30 seconds; in nearly all in 



30 minutes; incomplete in 60 minutes. 

 C petiolata: Begins in a few in 30 seconds; most are from 



one-third to two-fifths gelatinized in 30 minutes; 



incomplete in an hour. 



Reaction with Ferric Chloride. 

 C. longa: Begins in 30 seconds; complete in 10 minutes. 

 C. petiolata: Begins in a few in 60 seconds; complete in 

 10 minutes. 



Reaction with Purdy's Solution. 

 C. longa: Begins in a few in 30 seconds; complete in 10 



minutes. 

 C. petiolata: Begins in a few in 60 seconds; complete in 

 10 minutes. 



NOTES ON THE STARCHES OF CURCUMA. 

 The Curcuma starches show important histological differences, as instanced in C. petiolata, hav- 

 ing grains more irregular and prominences more marked; the corners limiting the distal end 

 larger and sometimes curved towards the proximal end; the hilum more often visible; the lamellae 

 rather more distinct; and the grains slightly larger, as a whole. In their reactions they show 

 distinct differences, except in the case of heat, ferric chloride, and Purdy's solution. The varia- 

 tions are quite important. 



NOTES ON THE STARCHES OF ZINGIBERACE^. (Charts 332 to 334.) 



Leaving out of consideration the starches of the varieties of Z. officinale, it will be observed that 

 the starches of all three genera are in very close correspondence in their histological characteristics. 

 Those of Z. officinale and H. coronarium are very much alike, the chief differences being in H. cor- 

 onarium in the more marked lamellation; more marked tendency to a decidedly pointed proximal 

 end; the distinct tendency to a hooked proximal end, and to a nodular projection from one side of 

 the grain. In H. coronarium polarization is lower; and there are more or less marked differences in 

 the reactions. In Curcuma, while there is the same type of grain, the grains are more closely allied 

 to Zingiber than to Hedychium and the tendency to a broadening of the distal end is very noticeable. 



