The Alkalinity of Milk Ash and its Relation to the Detection of Neutralizers in Dry Milks. I. Dry Skim Milk

Abstract

Summary The ash alkalinity of 16 samples of unneutralized dry sweet cream buttermilk ranged from 55.0 to 112.0 and averaged 78.0, expressed as milliliters 0.10 normal hydrochloric acid required to titrate the ash from 100 grams of the sample. The ash alkalinity of 90 commercial samples of dry buttermilk ranged from 110 to 673 and averaged 238. The ash alkalinity of dry buttermilk from Holstein milk was considerably greater than that of dry buttermilk from Guernsey and Jersey milk. The addition of relatively small amounts of either Absorbex M, calcium hydroxide, magnesium oxide or sodium hydroxide to buttermilk before drying caused measurable increases in the ash alkalinity of the dried product. The increases produced by the various compounds were of the same order when they were added in equivalent amounts. The addition of sodium bicarbonate to cream produced increases in the ash alkalinity of the buttermilk churned from the cream which were comparable to the increase produced by the addition of the same amount of this neutralizer directly to buttermilk. Even though the increases in ash alkalinity produced by the addition of neutralizer in amounts sufficient to reduce the titratable acidity of buttermilk or cream 0.01 to 0.03 per cent were measurable, they were usually not great enough to make the ash alkalinity of the dried buttermilk appear abnormal as compared with the range of values obtained on samples of unneutralized dry buttermilk. This was due largely to the fact that the original unneutralized buttermilk used in these experiments was quite low in ash alkalinity.