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​02 Acids Methods​

​02-01.02 Fat Acidity—General Method

Natural fats are mixtures of esters of fatty acids with glycerol. They are essentially neutral. Unfavorable storage conditions may cause partial hydrolysis of the glycerides. The resultant free fatty acids increase the acidity, which is an indication of deterioration in quality. This method determines total fatty acids in grain and grain products by a general titrimetric procedure.

02-02.02 Fat Acidity—Rapid Method, for Small Grains​

This method determines total fatty acids in small grains by a rapid titrimetric procedure.

02-03.02 Fat Acidity—Rapid Method, for Corn

This method determines total fatty acids in corn by a rapid titrimetric procedure.

02-04.02 Fat Acidity—Colorimetric Method

This method determines total fat acidity acids in grain and flour by colorimetry.

02-31.01 Titratable Acidity

Titratable acidity or acid content (ml) is measured by the amount of 0.1N NaOH (ml) required to neutralize an acid solution. The method is applicable to nonfat dry milk.

02-32.02 Neutralizing Value of Acid-Reacting Materials

To determine the neutralizing value of monocalcium phosphate (monohydrate and anhydrous), sodium acid pyrophosphate, sodium aluminum phosphate (acidic), and other acid-reacting materials used in chemical leavening systems. Chemical neutralizing value is used as a guideline for determining functional neutralizing value in foods and is expressed as parts of sodium bicarbonate that are neutralized by 100 parts of the acid salt. The neutralizing value can be used to calculate the theoretical level of acid required to react completely with the sodium bicarbonate.

02-52.01 Hydrogen-Ion Activity (pH)—Electrometric Method

To determine the hydrogen ion activity (pH) of flour and some bread, cracker, cake, and pastry products that do not release gasses that may change pH, upon suspension in water. The method is not applicable to dough.