FKUITS AND FRUIT JUICES. 



49 



either the direct or the invert reading at room temperature and the 

 percentage of reducing sugar, owing to the variable amounts of cane 

 sugar, but the invert polarization is in a general way indicative of the 

 amount of total sugars. The approximate percentage of levulose in 

 excess of dextrose may be figured from the polarization at 86 U by 

 multiplying the degrees of levorotation by 0.42 in case the normal 

 weight has been used for the polarizations. 



TABLE 13. Polarization of fruits and fruit juices. 



A. L. Winton, Conn. Expt, Stat. Report, 1899, Pt. II. p. 127. 



A number of the fresh fruits were fermented to determine whether 

 any nonfermentable optically active bodies were present. It was found 

 that in all cases the nonfermentable matter was inappreciable and that 

 with a 10 per cent solution the polarization after fermentation was 

 never more than three or four tenths of a degree either to the right or 

 the left. 



Alt'ohol precipitate. The alcohol precipitate consists largely of 

 pectin bodies, and the determination is valued only for the estimation 



17673 No. 6602 4 



