Here, we present a new approach using high-performance anion-exchange (HPAE) chromatography with pulsed amperometric detection (PAD) (HPAE-PAD) for the determination of carbohydrates in extracts from instant coffee and green coffee beans. This should be of interest to food scientists working on determining the quality and flavor of coffee.
Coffee carbohydrates, which constitute at least 50% of the dry weight of raw coffee beans, contribute to the flavor of coffee as they undergo complex changes during the roasting process. In addition, carbohydrates act as aroma binders, foam stabilizers, and impart viscosity to the coffee beverage. And, lastly, carbohydrates are also good tracers for assessing the authenticity of instant coffee.
Application Note 280: Carbohydrate in Coffee: AOAC Method 995.13 vs a New Fast Ion Chromatography Method, (downloadable PDF) compares two methods: the AOAC Method 995.13 and a fast method using our carbohydrate analysis column (Thermo Scientific Dionex CarboPac SA10 Carbohydrate column). The former method has a longer run time (80 minutes) compared to the fast method (10 minutes). For certain sugars that may be difficult to resolve with the official method, minor modifications are suggested. The fast method, proposed for analyzing coffee carbohydrates, resolves 7 of the 11 coffee carbohydrates in 8 minutes and needs only the addition of deionized water for continuous operation.
Both methods have high precision and acceptable recovery for the carbohydrates in instant and green coffee extracts. In addition, disposable gold working electrodes provide consistently high detector response for both methods, assuring greater instrument-to-instrument and lab-to-lab reproducibility. In summary, both the AOAC official method 995.13 and the fast method are sensitive, accurate, reliable, and differ primarily in their total analysis time and peak resolutions for coffee carbohydrate determinations.
The ion chromatography system used is our Thermo Scientific Dionex ICS-5000 or ICS-3000 IC system.
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