How Important is Solids in Fat and Cream?

In the global dairy industry, cream is important not only as a final product but also as a raw ingredient for a range of other consumer dairy products such as coffee creamer, sour cream, ice cream, butter, and several others. It is most often produced by the separation of butterfat from unhomogenized milk and is categorized, or graded, based on its butterfat content. This content usually ranges from about 18% for light cream to over 36% for heavy cream. Due to the high value of butterfat, accurate analysis fat is crucial for dairy manufacturers who process cream. Solids analysis is another critical quality control metric since it has a strong impact on the overall quality, grade, taste, and texture.

The SMART 6™–ORACLE™ is a combination system with the ability to rapidly determine fat and solids. In this system, the dual-frequency drying (iPower) of the SMART 6 is coupled with the breakthrough NMR technology of the ORACLE. The dual-frequency drying enables precise and rapid determination of solids in both liquid and powdered cream samples. The ORACLE is a rapid time-domain NMR (TD-NMR) instrument encompassing sophisticated technology that enables the fat in food products to be directly determined.

The ORACLE has the potential to completely isolate the detection of fat even in complex sample matrices, thereby eliminating the need for method development. On the whole, the paired system provides precise, rapid, and accurate total fat and solids in cream.

A collection of 11 distinctive cream samples (inclusive of two certified reference materials (CRMs) were acquired and analyzed to demonstrate the potential of the SMART 6–ORACLE to determine the fat and solids content in cream.

Key System Benefits

• No need for method development — each system comes with single pre-installed method
• Precise — better repeatability when compared to wet chemical extraction techniques
• Rapid — analysis can be performed within 5 minutes
• Stable — eliminates the need for recalibration or calibration maintenance
• Accurate — extensively validated with CRMs for various dairy matrices, including powdered and liquid cream
• AOAC-approved methodology — AOAC PVM 1:2004 for coupled SMART solids analysis with TD-NMR fat analysis in dairy products

Samples

Nine distinctive light and heavy cream samples were commercially acquired and outsourced to an accredited laboratory for reference testing (each in duplicate) of fat (Roese-Gottlieb, AOAC 920.111ⁱⁱ) and solids (oven drying, AOAC 990.20ⁱ). Moreover, two CRM cream samples (MP-0211 and R-0434) were acquired from Muva Kempten (Kempten, Germany).

CRMs are food samples that have already been subjected to extensive component testing (with the help of accredited wet chemistry reference methods) as part of multi-lab collaborative analyses. Generally, it is customary to submit CRM samples to over 10 accredited laboratories, selected based on previous results demonstrating their proficiency for testing a given sample matrix. This renders CRMs best-suited for evaluating the precision and accuracy of component analysis methods. They are commercially available from various vendors, such as Muva Kempten, ERM, NIST, LGC, Actalia Cecalait, and others.

Sample Preparation and Analysis

Analysis of the cream samples was performed after equilibrating to room temperature.ⁱⁱⁱ Every single cream aliquot was gently and slowly inverted 5 to 10 times to ensure proper mixing before the analysis (care should be taken to prevent shaking, as this could lead to agglomeration of fat).

Samples were pre-dried in the SMART 6 before being prepped and introduced into the ORACLE for the analysis of fat. Analysis of each obtained cream sample was performed in triplicate.

Note: For optimal results, cream samples (specifically unhomogenized cream) should be acquired and analyzed as closely as possible to the production date. If the sample container is observed to include considerable amounts of solids, it could be challenging to obtain a representative sample, even after tempering.

Figure 1. SMART 6 – ORACLE moisture/solids and fat system

Results

Table 1 illustrates the precision and accuracy of the ORACLE for powdered and liquid cream CRM samples, where the average of five ORACLE replicates have been compared with certified values. It can be observed that the deviations of the ORACLE evaluation from the certified values are within the uncertainties (standard deviation) of the certified values, showing that the ORACLE is reliable for determining the fat content in both types of samples.

Table 1. Certified reference materials (CRMs) on ORACLE

Tables 2 and 3 illustrate the precision and accuracy of the SMART 6–ORACLE for the outsourced cream samples. It can be observed from Table 2 that the deviation between the SMART 6 and the Oven results was in the range of 0%–0.12% for solids, and the deviation between the ORACLE and the Roese-Gottlieb results was in the range of 0%–0.10% for fat.

Table 2. Accuracy of SMART 6–ORACLE

Table 3 illustrates that the standard deviations were in the range of 0.01%–0.08% for fat using the ORACLE and 0.01%–0.15% for solids using the SMART 6. These results demonstrate the reliability of SMART 6–ORACLE in matching prevalent reference chemistry results for a broad array (ca. 9%–44% fat) of liquid cream samples.

Table 3. Precision of SMART 6–ORACLE

References

i. AOAC Official Methods of Analysis, 990.20.

ii. AOAC Official Methods of Analysis, 920.111.

iii. If deemed necessary (e.g. solids observed), cream should be tempered in a water bath at 38 ± 1 °C according to AOAC Official Method of Analysis 995.19 (“Fat in Cream”).

This information has been sourced, reviewed and adapted from materials provided by CEM Corporation.

For more information on this source, please visit CEM Corporation.