Nothing Special   »   [go: up one dir, main page]
Scribd Logo
Upload

Welcome to Scribd!

  • 2K views

    AOAC 922.06 Grasa en Harinas

    Uploaded by

    Compras Fisicoquimico

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    AOAC 922.06 Grasa en Harinas

    Uploaded by

    Compras Fisicoquimico
    2K views1 page

    Original Title

    AOAC 922.06 Grasa en harinas

    Copyright

    © © All Rights Reserved

    Available Formats

    PDF, TXT or read online from Scribd

    Did you find this document useful?

    Is this content inappropriate?

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    2K views1 page

    AOAC 922.06 Grasa en Harinas

    Uploaded by

    Compras Fisicoquimico

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 1

    32.1.

    14
    AOAC Official Method 922.06
    Fat in Flour
    Acid Hydrolysis Method
    First Action 1922
    Final Action
    Place 2 g test portion in 50 mL beaker, add 2 mL alcohol, and stir
    to moisten all particles to prevent lumping on addition of acid. Add
    10 mL HCl (25 + 11), mix well, set beaker in H2O bath held at
    70–80°C, and stir at frequent intervals during 30–40 min. Add
    10 mL alcohol and cool.
    Transfer mixture to Mojonnier fat-extraction apparatus. Rinse
    beaker into extraction tube with 25 mL ether, added in 3 portions;
    stopper flask (with glass, cork, Neoprene, or other synthetic rubber
    stopper not affected by solvents) and shake vigorously 1 min. Add
    25 mL redistilled petroleum ether (bp <60°C) and again shake vigor-
    ously 1 min. Let stand until upper liquid is practically clear, or cen-
    trifuge 20 min at ca 600 rpm.
    Draw off as much as possible of ether-fat solution through filter
    consisting of cotton pledget packed just firmly enough in funnel
    stem to let ether pass freely into weighed 125 mL beaker–flask con-
    taining porcelain chips or broken glass. Before weighing
    beaker–flask, dry it and similar flask as counterpoise in oven at
    100°C; then let stand in air to constant weight.
    Re-extract liquid remaining in tube twice, each time with only
    15 mL of each ether. Shake well on addition of each ether. Draw off
    clear ether solutions through filter into same flask as before and wash
    tip of spigot, funnel, and end of funnel stem with few mL of mixture of
    the 2 ethers in equal volumes, free from suspended H2O. Evaporate
    ethers slowly on steam bath; then dry fat in oven at 100°C to constant
    weight (ca 90 min). Remove flask and counterpoise from oven, let
    stand in air to constant weight (ca 30 min), and weigh. (Owing to size
    of flask and nature of material, there is less error by cooling in air than
    by cooling in desiccator.) Correct this weight by blank determination
    on reagents used. Report as percent fat by acid hydrolysis.
    References: JAOAC 6, 508(1922); 9, 41, 429(1926).

    © 2000 AOAC INTERNATIONAL

    You might also like