W. A. Davis, A. J. Daish and G. C. Sawyer 317 



From Polarisation data, (a) Citric acid. 



Change of rotation of B in 200 mm. tube caused by inversion 



= 0-274° + (2 X 0-064°) = 0-402°. 



„, f , 0-402 500 2000 500 100 „ .. „ , 



% of saccharose = ^^^^ ^^^^^ ^^.^^^ ■ — ■ ygj:^^ = 6-48 %. 



(b) Inverlase. Change of rotation of B 



= 0-274° + (2 X 0-071°) = 0-416°. 

 .". % of saccharose (as in («)) = 6-70 %. 

 Apparent Dextrose and Laevulose. 



Reduction of 25 cc. B {= 15 cc. A) = 0-2210 grm. 

 Reduction due to pentoses in 25 cc. B 



1 5 

 = i^ X 0-0201 X 1-017 X 2-65t = 0-0163 CuO. 

 50 ' 



.'. Reduction due to hexoses = 0*2047 grm. CuO. 

 Grms. pentose in 100 cc. B 



IK 



= ix^x 0-0201 X 1-017 = 0-0245 grm. 

 50 '^ 



Rotation of pentose in B in 200 mm. tube. 

 If arabinose= 102-2 :< 200 x 0-0245 = 0-050°. 

 If xylose = 18-8 x 200 x 0-0245 = 0-009°. 

 Now the concentration of saccharose in 100 cc. B 



- m ^ '''■'' '' Joo ^ 5 < io - '■'''' g^-- 



Rotation due to saccharose in B (200 mm. tube) 



_ 66-44 X 200 X 0-24 17 , 



- ^^ = 0-d^l . 



.'. Rotation due to hexoses in B, 

 calculating pentoses as arabinose = 0-274 — 0-050 — 0-321° = — 0-097°, 

 xylose = 0-274 - 0-009 - 0-321° = - 0-056°. 



* The factor 1-744 represents the change of rotation in a 200 mm. tube caused by 

 the inversion of a 1 per cent, solution of saccharose. 



f Assuming the pentoses to be a mixture of equal quantities of arabinose and xylose 

 and using the tables given by Daish [1014] for the reducing power of the pentoses. The 

 value 0-0163 fomid is slightly higher than the residual reduction 0-0130 after fermentation, 

 which is due to the pentoses. 



