Coffee is a brewed drink prepared from ground roasted coffee beans, which are the seeds of berries from the Coffea plant. Over 2.25 billion cups of coffee are consumed daily and it is one of the world’s most popular beverages.
Among different varieties of genus coffea plants, Arabica and Robusta are the two most economically and commercially important ones. Arabica beans contain lower caffeine content than Robusta beans and Arabica coffee is more favorable than Robusta coffee, Robusta tends to be bitter and have less flavor but better body than Arabica. For these reasons, 75–80% of the coffee produced worldwide is Arabica and around 20% is Robusta. Once ripe, coffee berries are picked, processed, and dried. Then dried coffee beans are roasted to varying degrees and blended to obtain different flavors. Roasted beans are ground and brewed with near boiling water to produce coffee as a beverage. Each year, over 8.8 million tons of coffee is produced worldwide. It is one of the most traded agricultural commodity and ranks second only to petroleum in terms of dollar traded.
In this highly competitive industry quality control is a very important factor. From harvesting through processing, quality control tests are required for every stage of coffee production; for example, to check the moisture content of green beans, monitor degree of roasting, and test for chemical constituents such as caffeine, chlorogenic acids, trigonelline, fat, sucrose and dry matter of the roasted beans, since these determine the quality of coffee as a beverage. Quality analysis and testing provide the assurance for the best final product.
Compared to traditional analytical methods, near-infrared (NIR) spectroscopy has many advantages, including:
- Nondestructive testing: raw materials can be analyzed as-is, without changes or damage
- Simultaneous measurements of multiple components
- Speed: NIR spectroscopy provides real-time analysis – generally less than 10 seconds’ measurement time; it also eliminates sample preparation time
- Easy-to-use: with a calibrated instrument, the end user needs no special skills or spectroscopy knowledge to run the test
- Cost Effectiveness: NIR spectroscopy eliminates the need for consumables such as solvents, columns, and reagents
- Flexibility: portable NIR spectrometers can be used in the field as well as in the lab, and can measure multiple components per analysis
- Approachability: Our NIR spectrometers are user-friendly, providing point-of-need analysis
- Repeatability: NIR spectroscopy eliminates many sources of systemtic error, particularly during sample and test preparation
FT-NIR spectroscopy provides a rapid, nondestructive method for analyzing coffee. Near instantaneous results comparable to traditional lab methods can be obtained across a wide range of parameters. Applications of NIR spectroscopy in coffee production and quality control include:
- Determining the moisture content in raw materials such as green beans
- PLS calibrations can be developed to predict roasting parameters such as weight loss, density, and moisture content of roasted coffee samples
- Used as a quick screening tool, FT-NIR can detect adulterants such as chicory, malts, starch, glucose, and coffee husk
Galaxy Scientific offers offline/inline/atline FT-NIR solutions for the analysis of coffee. Designed with a large 23mm sampling area and additional off-centered mounted spinner accessory, the reflectance capabilities of the QuasIR™ 3000 are ideally suited to coffee analysis. The QuasIR™ 4000 is equipped with both integrating sphere and sample compartment, and can be utilized for offline solids and liquids measurements.