|Krause, Andrea - NC STATE UNIVERSITY|
|Miracle, Robert - NC STATE UNIVERSITY|
|Drake, Mary - NC STATE UNIVERSITY|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 8, 2008
Publication Date: May 19, 2008
Citation: Krause, A., Miracle, R.E., Sanders, T.H., Dean, L.L., Drake, M.A. 2008. The effect of refrigerated and frozen storage on butter flavor and texture. Journal of Dairy Science 91:455-465. Interpretive Summary: Butter is often stored for several months in refrigerated and frozen storage. Deterioration of flavor and texture may occur during this time. This study examined the effect of refrigeration (5°C) and frozen (-20°C) storage on the physical properties and flavor of butter. Sensory changes were monitored through descriptive sensory analysis of flavor, texture, and color by a trained panel using a defined sensory language. Physical changes were monitored by oxidative stability index, peroxide value, free fatty acid value, vane, instrumental color, and oil turbidity. Currently, no specifications exist for butter storage. This study will help to establish guidelines for the industry so they can better market and distribute stored butter.
Technical Abstract: Butter is often stored for extended periods of time; therefore, it is important for manufacturers to know the refrigerated and frozen shelf-life. The objectives of this study were to characterize the effect of refrigerated and frozen storage on the sensory and physical characteristics of butter. Fresh butter was obtained on two occasions from two facilities in 113 g sticks and 4 kg bulk blocks (2 facilities, 2 package forms). Butters were placed into both frozen (-20°C) and refrigerated storage (5°C). Frozen butters were sampled after 0, 6, 12, 15, and 24 mo; refrigerated butters were sampled after 0, 3, 6, 9, 12, 15, and 18 mo. Every 3 mo., oxidative stability index (OSI) and descriptive sensory analysis (texture, flavor, and color) were conducted. Every 6 mo., peroxide value (PV), free fatty acid value (FFA), fatty acid profiles, vane , instrumental color, and oil turbidity were examined. A mixed model analysis of variance was conducted to characterize the effects of storage time, temperature, and package type. Storage time, temperature, and package type impacted butter flavor, OSI, PV, and FFA (p<0.05). Refrigerated butter quarters exhibited refrigerator/stale off-flavors concurrent with increased levels of oxidation (lower oxidative stability and higher PV and FFA) within 6 mo. of refrigerated storage and similar trends were observed for refrigerated bulk butter after 9 mo. Off-flavors were not evident in frozen butters until 12 or 18 mo. for quarters and bulk butters, respectively. Off-flavors in frozen butters were not correlated with instrumental oxidation measurements. Since butter is such a desirable fat source in terms of flavor and textural properties, it is important that manufacturers understand how long their product can be stored before negative attributes develop.