AOAC Official Method 936.08 Ash (Original) of Flour for Phosphated and Self-Rising Flour
Gustafson Method
First Action 1936
Final Action
To 20–25 g test portion sample in metal centrifuge tube [cup 2 in. (5 cm) diameter, 6 in (15 cm) deep], add enough CCl4 to fill tube to within 25 mm of top (ca 250 mL). Centrifuge 5–7 min at 1600 rpm and let centrifuge come to rest slowly. With large tablespoon, carefully skim off flour, which is in compact layer on surface of CCl4, recovering as much flour as possible in 1 spoonful. (Note: One tablespoon is approximately 15 mL. With care, ca 90% of original flour may be recovered.) Let wet flour dry overnight and proceed as in 923.03 (see 32.1.05). (CCl4 may be filtered, distilled, and used again.)
References: JAOAC 19, 82(1936).
Cereal Laboratory Methods (1962) A.A.C.C.
