Division 6.1 Measurement by polarimeter

United Kingdom

Starch content (%) = \frac{2 000 (P - P')}{{[α]}_{20°}^{D}}

Total optical rotation in angle degrees

Optical rotation in angle degrees of the substances soluble in 40 % (V/V) ethanol

{[α]}_{20°}^{D}

Specific optical rotation of pure starch. The numerical values conventionally accepted for this factor are the following:

+185,9^o:	rice starch
+185,7^o:	potato starch
+184,6^o:	maize starch
+182,7^o:	wheat starch
+181,5^o:	barley starch
+181,3^o:	oat starch
+184,0^o:	other types of starch and starch mixtures in compound feed