Chocolate & Cocoa

The cocoa market is comprised of cocoa processors and chocolate manufacturers. Cocoa Processors are involved with the processing of cocoa beans into the various products that are used to make chocolate. Chocolate manufacturers take these products and turn them into chocolate. Some companies both process cocoa beans and manufacture chocolate.

Chocolate is derived from the cocoa bean. Cocoa beans are roasted in an oven and undergo a winnowing process, where the shells are removed. The resulting de-shelled bean is a product called nibs. The nibs are ground into cocoa liquor, which at slightly elevated temperatures is a thick liquid. Two potential processes can be undertaken with the cocoa liquor. In one process, the cocoa liquor is pressed into cocoa butter and pressed cake. The pressed cake can be ground into cocoa powder. In the other process, sugar and cocoa butter are added to the cocoa liquor to produce chocolate.

At every step in the process, there is a necessity to make analytical measurements. Several methods are used during the process including, near infrared (NIR) analysis, image analysis and wet chemistry analysis. Incoming cocoa beans can be analyzed for moisture to determine the quality. Moisture can be measured during the roasting process to determine when the process is complete. The nibs can be analyzed for moisture and oil content to predict the quality of the resulting cocoa liquor. The cocoa liquor can be analyzed for fat and moisture to determine the quality. Cocoa liquor is sold based on its fat content. After the cocoa liquor is pressed, the resulting cocoa butter can be analyzed for free fatty acids and iodine value. These properties relate to the melting characteristics of the butter. The other by-product of the pressing of cocoa liquor, cocoa powder, can be analyzed for moisture and fat. Cocoa butter is routinely sold based on its fat content.

Chocolate can be analyzed for fat, moisture, and sugar. Chocolate is typically sold based on its fat content, so this is a critical analysis point. Also, by adding cocoa butter, the fat content of the chocolate is raised. Cocoa butter is quite expensive, so anything that can be done to control the addition of this critical component will provide economic benefit to the plant. Sugar analysis is important to control the amount of sugar added to the chocolate.

One way to analyze moisture, fat, sugar, free fatty acids, and iodine value is by using various primary methods. Primary methods to analyze moisture include a 16 hour vacuum oven method or a moisture balance. Both methods use loss on drying to measure moisture content. The drawback to the vacuum oven method is that the testing time is 16 hours, meaning this test will have no impact on real time process control. The moisture balance can analyze a sample in approximately 15 minutes, but it is almost 2-3 times less accurate than a vacuum oven.

Fat is typically analyzed using a Soxhlet extraction method. This complex method usually takes several hours and requires the use of hazardous chemicals. Sugar can be analyzed using HPLC. Free fatty acids and iodine value are analyzed by titrations. These methods are time consuming and require chemicals.

The Unity SpectraStar 2400 provides a NIR solution for improving the analytical testing methods at the cocoa processing or chocolate manufacturing plant. NIR is a fast, safe, and reliable technology that will analyze at all critical points throughout the process. NIR is a secondary technique and is calibrated by analyzing a set of known samples. The SpectraStar 2400 can be used to analyze cocoa beans and nibs for moisture. Cocoa liquor can be analyzed for fat and moisture. Cocoa butter can be analyzed for free fatty acids and iodine value. Cocoa powder can be analyzed for moisture and fat. Chocolate can be analyzed for fat, moisture, and sugar. The analysis time of the SpectraStar is approximately 30 seconds per sample. This speed can provide real time results that can be used to directly impact the process.

The performance of the SpectraStar is approximately equivalent to the performance of the wet chemistry method used to calibrate it. Moisture performance is typically on the order of 0.1% and fat performance is typically 0.2%.

Predicted vs. Actual Plot of Calibration for Fat in Chocolate

The SpectraStar 2400 can be used to analyze at all of the critical points throughout the cocoa process. With an analysis time of approximately 30 seconds, the SpectraStar 2400 provides real-time results that can be used to control the process. Controlling the process at all of these critical points will improve product quality, reduce re-work, and improve cycle time, providing a huge positive economic benefit for the plant.

Chocolate & Cocoa