22 STARCHES. 



(18) Sago Starch. 



Sago starch is obtained from the stem of the sago palm, Metro- 

 xylon Sagu, Rottb. and allied trees. 



The form of the grains of sago starch varies according as they are 

 simple or compound. Simple grains are oval, rounded, etc. ; but 

 the compound grains have a very remarkable shape. Each of these 

 usually consists of a large grain to which 1, 2 or 3 small ones are 

 attached. The large grain is conical or muller-shaped, and 

 frequently bears one or two projections, to the flat ends of which 

 the smaller grains have been attached ; sometimes these two flat 

 surfaces meet to form an angle. 



The largest grains measure 50 to 65/x, in length, the smallest 

 10 to 20/A. The hilum is very distinct, linear, transverse or oblique, 

 sometimes stellate and usually surrounded by distinct striae. 



Commercial sago starch often contains debris of vegetable 

 tissue, etc., left in it by the imperfect washing it has undergone. 

 Sclerenchymatous cells, hairs and crystals may thus be found in it. 



(19) Pearl Sago. 



Genuine or East Indian sago (pearl sago) is largely prepared in 

 Singapore from sago starch. 



The starch is converted into sago by beating it whilst moist, as 

 described under tapioca. Several varieties occur in commerce, 

 differing in source and appearance. 



Pearl sago, when examined under the microscope, exhibits starch 

 grains in various stages of transformation, induced by the heat to 

 which they have been subjected. Some of them have preserved 

 their original shape and can be easily identified. Many are more 

 or less altered ; in some the central portion has been gelatinised 

 and is transparent and homogeneous ; others have swollen to an 

 unrecognisable gelatinous mass. 



