Relation Between Thermal Properties of Butter and Its Hardness

The heat capacity of commercial and experimental butter as a function o temperature was measured in an electrical input calorimeter. Hardness of the samples was measured either as seetility and viscosity at 10 C, or as lubrieity value at 22 C. Plots of the heat capacity curves of commercial butter showed major phase changes eentering at -24, -11, 5, 12, 20, and 30 C. Curves for experimental butter were similar, except that the peak at --24 C was mi.~sing. Comparison to curves for butteroil ~howed that the changes at -24 and -11 C were associated with tile aqueous phase of batter. The change at-11 C rel)resents the melting of a salt soluti(m, the ex:lct melting point being related to the salt coutent of tile butter. Summer butter v,miai,md more liquid fat between -8 and 12 W, a.nd was less ;,,(:tile and less vis('(m~' Liquid fat <.ontents at 10 C were 41%: iu the sunimer lind 35% in the winter. Pril/ting' reduced butter hardness, hut did n(>t affect the liquid I':lt content. Exi)erimellta.1 butter made a(~c(>Ming to the winter method or by vat proeessing of the cream was s(lfter, and had hig'her liquid fat contents, especially lit 20 ('. t:Oml)etition has stimulated ~,,mc nielnbers of the l)airy Industry to t)ecome (,)ncerned with iml)rovin ~' the appeal of I)utter t,, the consumer. The flavor of butter is cmMdered one of its strong selling points, but the protection of this flavor :requires cm~stnnt refrigeration. ]{iehl (1]) eonlpared the sprcadabilities of butters and lllargtlriiles ;111(] found the l'~tter m(n'e aceepL:lble at horn<, refrigeration temper;ilure (about 7 (:). Thus, there is a need for ~tn(ls'in ~' the filetors related t() butter hard-YIPNS.