Influence of Elevated Polyunsaturated Fatty Acids on Processing and Physical Properties of Butter

Abstract

Milk fat containing varied percents of linoleic acid (from 1.8 to 28.0% of the fatty acids) from feeding cows a protected lipid supplement and by blending conventional and polyunsaturated milk fats was used to make experimental butters by churning and by the continuous Votator system. Measurements were made of the hardness of the butters by disk and cone penetrometers, of melting characteristics of the milk fats by dilatometry, of butters by nuclear magnetic resonance, and of oiling off properties at 10 and 20C. The higher the linoleic content of the milk fat, the softer the butter. Comparison at similar linoleic percents of butters made from milk fat as produced and those from blends of conventional and polyunsaturated milk fat showed that products from blends were harder, had a wider temperature range at which they were plastic, and were less susceptible to oiling off at 20C. Below 12C butter made by the continuous Votator system was appreciably harder than that by churning, but at higher temperatures hardness of the two butters was similar. The results indicate possibilities for improving the spreadability of butter by manipulating the composition and physical properties of milk fat by feeding cows protected lipid supplement.