Keywords: DSC, fat, butter, fractionation
TA506
Abstract
The fat and water content of butter styles varies slightly throughout the world, yielding different taste and performance, such as spreadability. The mixture of fats melt at various temperatures and melting fractions are important performance indicators of the butters. Differential scanning calorimetry is a heat flow technique that can be used to measure the melting fractions of butter, acting as a useful tool in formulation and screening.
Butter is a complex material containing a mixture of fat molecules, the majority of which are triglycerides. The different triglycerides will melt at different temperatures. Stearins, for example, will melt above 35 °C while Oleins will melt below 15 °C [1]. The melting fractions of butter significantly impact performance and behavior. For example, low-melting fractions lead to easier spreadability straight from the refrigerator, whereas high melting fractions are ideal for lamination in baking [2].
Differential scanning calorimetry (DSC) has been shown to be an effective tool in detecting melt fractions of butter and in screening effects of formulation changes [3] [4]. Differences in water and fat content have been measured, offering a way to determine the impacts of formulation on performance and tune butter recipes for end-use optimization. This note will demonstrate using DSC to investigate four samples of two styles of commercially available butters.
Commercially available samples of four salted butters were used for this work: two brands of American style butter and two brands of European style butter (Irish and French). Table 1 shows the sample designations, style of butter, and typical fat and water content ranges for the butter style.
DSC was run on a TA Instruments™ Discovery™ 2500 Differential Scanning Calorimeter (Figure 1). Sample sizes of 20 mg were loaded into TZero™ Hermetic Pans. The pan rims were wiped clean prior to crimping the lids. Samples were then run in heat-cool-heat experiments at 10 °C/min from -40 to 40 °C.
Table 1. Sample type tested and their typical fat and water content
| Sample Name | Butter Style | Fat Content (%) | Water Content (%) |
|---|---|---|---|
| A | American | 80 | 16-17.5 |
| B | American | 80 | 16-17.5 |
| C | Irish | 82 | 14-16 |
| D | French | 82-84 | 14-16 |
The butter samples showed different melt patterns on the first heat of the DSC experiments, as shown in Figure 2. These melt fraction patterns will be arbitrarily designated as 1, 2, and 3. The sharp peak at the low melt fraction is due to the shortchain and polyunsaturated fatty acids that show more uniform melting characteristics. Fractions 2 and 3 melt at temperatures approaching, and exceeding, room temperature. The heterogeneous nature of food fats, coupled with their tendency to form polymorphs causes these higher temperature melt fractions to show broad, irregular melting peaks. The peak temperatures at which the melt fractions occurred are listed in Table 2.
Table 2. Fraction melt temperatures for butter samples
| Sample Name | Fraction 1 Melt (°C) | Fraction 2 Melt (°C) | Fraction 3 Melt (°C) |
|---|---|---|---|
| A | -21.92 | 2.61 | 32.42 |
| B | -23.14 | 2.12 | 33.29 |
| C | -21.59 | 10.61 | 30.81 |
| D | -22.13 | 2.16 | 32.84 |
The large endotherm near -6 °C is due to the water content of the butter. This is supported during cooling, which shows the characteristic “lean” or “loop” due to self-heating during nucleation.
When comparing the two types of European butters, there were some slight differences in the thermograms at Melt Fractions 1, with the primary differences being in Melt Fractions 2 and 3. (Figure 4a.) Comparing the American butters in Figure 4b, however, showed notable difference in the first melt fraction.
The milk and processing of the two American butter samples occurred in different parts of the country, with significant differences in climate. Sample B is from a dryer climate than the other samples. The first melt fraction of Sample B, from the dry climate, is shifted significantly to the left of the other three. Climate, heat stress, and seasonal fluctuations affect milk production and its protein and fat distribution and must be accounted for to ensure consistency with flavor and texture.
Differential scanning calorimetry can be used to assess, screen, and probe melting fractions of dairy products, such as butter. The mixture of fat content yields different melting fractions that impact performance and behavior of the product. The temperature at which the various fats melt will influence spreadability, taste, and mouthfeel. DSC identifies various melt fractions as a function of melting temperature and detects differences that may with the climate of where the milk was produced.
Related Resources
References
- X. Si, H. Zhu, P. Zhu, Y. Wang, X. Pang, N. Ju, J. Lv and S. Zhang, “Triacylglycerol composition and thermodynamic profiles of fractions from dry fractionation of anhydrous milk fat,” Journal of Food Composition and Analysis, vol. 115, 2023.
- A. Jones, S. Zhang, C. Akoh and S. Martini, “Effect of anhydrous milk fat fraction addition to butter on water loss reduction,” International Dairy Journal, vol. 141, 2023.
- R. Gonzalez-Ortega, Y. V. Rajagukguk, G. Ferrentino, K. Morozova and M. Scampicchio, “Detection of butter adulteration with palm stearin and coconut oil by,” Food Control, vol. 157, 2024.
- J. Tomaszewska-Gras, “Detection of butter adulteration with water using differential,” J Therm Anal Calorim, vol. 108, pp. 433-438, 2012.
Acknowledgement
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This paper was written by Samuel Redstone, Ph.D.
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