AOAC Official Method 932.04 Diastatic Activity of Flour
First Action 1932
Final Action
A. Reagent
Acetate buffer solution.—pH 4.6–4.8. Dilute 3 mL CH3COOH and 4.1 g anhydrous NaCH3COO to 1 L with H2O.
B. Determination
(Total maltose after diastasis 1 h.) Place 5 g test portion and 5 mL ignited quartz sand in 100 or 125 mL Erlenmeyer, and mix by rotating flask. Add 46mLacetate buffer solution, and again mix by rotating flask until all test portion is suspended. Bring flask and all ingredients individually to 30°C before mixing. Digest 1 h at 30°C, preferably in temperature-controlled H2O bath, rotating flask every 15 min. After 1 h add 2 mL H2SO4 (1.79 ± 0.025M, ca 1 + 9), and mix thoroughly. Add 2mL12% Na2WO4×2H2Osolution (w/v), mix, and let stand 1–2 min. Filter through paper (Whatman No. 4, or equivalent), discarding first 8 or 10 drops. Proceed as in 939.03C(a) (see 32.1.20).
