Estimating the Solid Fat Content of Chocolate and Butter Products

Estimating the Solid Fat Content of TA no.85 Chocolate and Butter Products 2008.8 Using DSC to investigate of the taste of edible fats

1. Introduction late, high-cacao chocolate (with a cocoa content of The safety and quality of food products are ana- 86%) and creamy chocolate. lyzed from various perspectives. Fat, one of the main Measurements were performed using a DSC6220 constituents of food products, has a low melting differential scanning calorimeter. The heating rate temperature and many crystal forms. Factors such as was 10℃/min and the temperature range was -50 to changes in crystal formation when fat is melted and 60℃. The sample weighed 5mg and was measured in the extent of solid fat at room temperature deter- an open aluminum pan. mine characteristics such as hardness or fluidity. Manufacturing and storage environment are impor- 2.1.2 Measurement results tant considerations in creating fat-based foods with Figure 1 shows the DSC curves for all samples. The the desired crystal form or solid fat content. To creamy chocolate showed endothermic peaks at evaluate these characteristics, Differential Scanning around 10℃ and 28℃. Melting started at a lower Calorimeters (DSC) is used to measure the melting temperature than the other types of chocolate. This temperature of fats. means that the majority of the fat is melted at room In this brief, chocolate, butter and margarine are temperature (around 25℃) and explains the distinc- measured as examples of food products whose main tive soft texture of creamy chocolate. constituent is fat. On the other hand, the milk chocolate and high-cocoa chocolate had melting peak temperatures 2. Measurements and Results of around 33℃ and 34℃, respectively. This means 2.1 DSC measurements of chocolate that the majority of the fat melts above room tem- Chocolate is a fat-based food product with crys- perature. These types of chocolate are hard when tallized cocoa butter from cacao beans as its main placed in the mouth and then gradually melt. constituent. There are 6 known types of crystal 2.0 生チョコレート 31.0mJ/mg polymorphs (Type I to VI) of cocoa butter. The 0.0

10.4℃ higher the number, the more thermally stable the ミルクチョコレート 69.2mJ/mg -2.0 structure is. By analyzing the crystal polymorphs of 27.6℃ 高カカオチョコレート cocoa butter, product characteristics such as heat -4.0 58.0mJ/mg

resistance, storage stability and texture can be de- -6.0

termined, which makes it possible to manufacture DSC / mW 33.2℃ -8.0 high-quality products. -10.0

2.1.2 Measurement conditions -12.0

Samples were commercially-available milk choco- 34.0℃ -14.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 Temp / ℃ Figure 1 DSC curves for Chocolate (1st Run)

It is known that cooling conditions change the Figure 3 shows the DSC curve for creamy choco- crystal structure of melted cocoa butter. The 3 types late and the integral curve for melting. A 2-stage of chocolate were cooled to -50℃ at 10℃/min to integral curve corresponding to the melting peaks crystallize them. Figure 2 shows the DSC curves of was obtained. The melting integral is considered 2nd heating for the 3 types of chocolate. equivalent to SFC so the proportion of melted fat at By comparing the 1st and 2nd heating curves, it can any temperature can be obtained from the melting be seen that the melting temperature of all samples integral curve. lowered and that a portion of the chocolate was still 2.00 melted at room temperature. This indicates that 100 melting chocolate once greatly changes the melting 1.00 temperature. 80 0.00 31.0mJ/mg 60 4.00 生チョコレート -1.00 28.0mJ/mg

DSC / mW 40 固体脂量 / % 2.00 28.2℃ -2.00

13.2℃ 52.8mJ/mg ミルクチョコレート 20 0.00 -3.00

0 -2.00 -4.00 DSC / mW 高カカオチョコレート 18.1℃ 37.3mJ/mg -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 Temp / ℃ -4.00 Figure 3 The DSC curve and the Melting integral curve for Creamy Chocolate (1st heating) -6.00

19.5℃ -8.00 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 Figure 4 shows the melting integral curves for the Temp / ℃ Figure 2 DSC curves for Chocolate (2nd heating) 3 types of chocolate. It can be seen that the proportion of solid fat in the creamy and milk chocolate gradually decreased from the minus temperature Solid Fat Content (SFC) is another method to range. On the other hand, the proportion of solid fat evaluate fat and is generally performed using pulse in the high-cocoa chocolate did not change very nuclear magnetic resonance (pulse NMR). This much up to room temperature but started to de- method is important for evaluating the softness and crease rapidly from around 30℃. 15.00 snappiness of fat. 100 14.00 Using DSC to investigate the integral curve for 13.00 melting is an easy way to perform an evaluation 12.00 80 comparable to SFC curve created by pulse NMR. 11.00 ▲ 高カカオチョコレート 10.00 60 9.00 ● ミルクチョコレート

DSC mW 8.00 40 固体脂量 / % ◆ 生チョコレート 7.00 6.00 20 5.00

4.00 0 3.00 -20.00 0.00 20.00 40.00 Temp / ℃ Figure 4 Melting integral curves for Chocolate (1st heating)

2.2 DSC Measurement of Butter and Margarine 5.0 Butter is made by separating fat content in raw milk バター

バター1/3 and then churning it to harden it and its principal 0.0 constituent is saturated fatty acid. On the other hand, margarine is made by emulsi- マーガリン -5.0 fying plant or animal fat and its principal constituent is unsaturated fatty acid. While butter and margarine DSC / mW -10.0 have different hardness and cooking purposes, their fat and water contents are roughly equal. Recently, fat-based food products that combine the good -15.0 points of both products have been released. -20.0 -40.0 -20.0 0.0 20.0 40.0 2.2.1 Measurement conditions Temp / ℃ Three samples were measured: commer- Figure 5 DSC curves for Butter, Margarine and 1/3 fat butter cially-available butter, margarine and 1/3 fat butter. Measurements were performed using a DSC6220 Overall, the 1/3 fat butter DSC curve was the differential scanning calorimeter. The heating rate same as the curve for margarine. However, the peak was 10℃/min and the temperature range was -50 to at 15℃ that appeared in the butter results was also 50℃. The samples weighed 5mg and were measured detected here. (See Figure 6) in an allogene-treated aluminum sealed pan. 3.00 2.1.2 Measurement results バター Figure 5 shows the DSC curves for butter, mar- 2.00 garine and 1/3 fat butter. Between 0 and -5℃, an 1.00 endothermic peak appeared due to the melting of water. Fat melting peaks for butter were detected as 0.00 バター1/3 endothermic peaks at -25℃, 15℃ and 30℃. For DSC / mW margarine, peaks appeared at -25℃ and 30℃ but, -1.00 unlike butter, a peak was not found at 15℃. This マーガリン data indicates that the peak at 15℃ is the saturated -2.00 fatty acid peak because butter is the only sample -3.00 that contains it. 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 Temp / ℃

Figure 6 Enlarged View of DSC curves for Butter, Margarine and 1/3 fat butter

The solid fat content of butter and margarine was 3. Conclusion also investigated. Figure 7 shows the results of the The solid fat content of fat-based food products melting integral curve from the DSC curves. was investigated by using DSC to measure the fat melting peaks and then obtaining integral curves. 120 -24.0 Pulse NMR is usually used to investigate solid fat -26.0 100 content but DSC can easily measure it from the -28.0 minus temperature range. -30.0 80 Furthermore, this method is useful for product -32.0 60 development and quality evaluations because data -34.0 can also be obtained about the crystal structure of DSC mW -36.0 40 固体脂量 / % measurement samples with different melting behav- -38.0 ▲ バター iors or thermal histories. 20 -40.0 ● マーガリン

-42.0 ◆ バター1/3 0 -44.0

-20 -40.0 -20.0 0.0 20.0 40.0 Temp / ℃ Figure 7 Melting integral curves for Butter, Margarine and 1/3 fat butter

For all 3 measurement samples, melting caused solid fat content to decrease starting from around -25℃. By around 0℃, solid fat content was only 20% for margarine and 1/3 fat butter. Furthermore, the data shows that the solid fat content of the 1/3 fat butter decreased more rapidly than the margarine in the minus temperature range, despite the fact that it contains butter, which resists decreases in solid fat content. This data shows that its solid fat content is already low when refrigerated so it is soft and ready to use when it is removed from the refrigerator. By using DSC to understand the relationship of fat melting and solid fat content, it is possible to investigate characteristics such as creaminess and spread ability.