VIEW ARTICLE    DOI: 10.1094/ASBCJ-42-0159

Precipitation of Protein During Mashing: Evaluation of the Role of Calcium, Phosphate, and Mash pH. M. J. Lewis and N. Nelson Wahnon, Department of Food Science and Technology, University of California, Davis 95616. J. Am. Soc. Brew. Chem. 42:0159, 1984.

In a temperature-programmed mash, malt protein first dissolved during the protein rest, then decreased in concentration as the mash temperature approached 70° C. With a technique called grain-out mashing, a precipitate containing about 62% protein was isolated. This accounted for the entire decrease in dissolved protein observed in normal (grain-in) mashes. Addition of calcium significantly affected mash pH, which was not constant during the mash period, but clear evidence of reaction of calcium with malt phosphate could not be gained. Calcium did not react directly with protein or affect protein precipitation, although it somewhat reduced the dissolution of protein from malt particles. Although wort pH, calcium, and phosphate concentration changed during mashing in parallel with protein solution and precipitation, a causal relation among these factors could not be established.

Keywords: Calcium, Mashing, pH, Phosphate, Precipitation, Protein