Diacetyl and Acetylmethylcarbinol production in the manufacture of unsalted butter
During the ripening of sweet or neutralized sour cream in laboratory and semi-commercial trials there were some irregularities in the effects of various factors on the diacetyl and acetylmethylcarbinol contents of the cream, but generally the contents were increased by an increase in the acidity to which the cream was ripened, by addition of small ·amounts of citric acid to the cream and by agitation (shaking in the laboratory trials and revolving the coils in the semi-commercial trials) during the ripening. In some trials the contents were greatly influenced by the use of certain butter cultures, while in other trials they were not.
In general, as the diacetyl contents increased in the ripening cream the acetylmethylcarbinol contents. also increased, but there were variations from this relationship. The occasional decreases in diacetyl contents often were accompanied by increases in acetylmethylcarbinol contents.
Some of the ripening procedures used with the cream were beneficial from the standpoint of score of the butter under certain holding conditions. These procedures included development of higher acidities in the cream, addition of citric acid to the cream and agitation of the cream during ripening.