Determination of polyphenols in the coffee production chain
The antioxidant power of polyphenols plays an important role in the stability of many plant products, as there is a correlation between the amount of total polyphenols and resistance to oxidation over time.
Analyzing Polyphenols in Coffee: Why it matters
The analysis carried out on green coffee allow to assess the quality of the product, to evaluate its organoleptic potential and its chemical characteristics. This will allow making the right choices in the following roasting phase and evaluating its conservation over time.
The analysis carried out on the roasted coffee are proper to identify the chemical and organoleptic characteristics of the product and to give a first evaluation of the sensory profile that could be found in the cup. The same analysis can also be carried out on the extracted coffee in order to evaluate the efficiency of the extraction process.
Method
Test type: End Point.
Time testing: 5 minutes.
Analysis sessions with multiple samples are possible up to a maximum of 4 tests for CDR CoffeeLab®.
Sample treatment
Green coffee beans (without parchment) must be finely ground and sieved to obtain a homogeneous powder. Weigh 1 gram of coffee powder into a centrifuge tube and add 5 ml of distilled water. Mix for about 10 minutes and then centrifuge for 5 minutes at 5000 rpm (code 222061).
It is necessary to dilute the sample with the appropriate dilution kit before performing the analysis.
Roasted coffee: the beans must be ground to fine grind and the powder must be as homogeneous as possible.
Weigh 1 gram of coffee powder into a centrifuge tube and add 5 ml of distilled water. Mix for about 10 minutes and then centrifuge for 5 minutes at 5000 rpm (code 222061). It is necessary to dilute the sample with the appropriate dilution kit before performing the analysis.
Espresso: Mix for 5 minutes at 5000 rpm (codice 222061). It’s necessary to dilute the sample with the appropriate dilution kit before performing the analysis.
Test Principle
The polyphenols, in contact with a chromogenic compound in an alcoholic solution, are oxidized and decrease the color of the compound. The decreasing of color, read at 505 nm, is directly proportional to the concentration of polyphenols in the sample, expressed in % gallic acid.
Reagent test Kits
Measuring range
| Analyses | Measuring range | Resolution | Repeatability |
|---|---|---|---|
| Polyphenols espresso | 0.2 - 4 % gallic acid | 0.1 % gallic acid | 0.1 % gallic acid |
| Polyphenols | 0.5 - 8 % gallic acid | 0.01 % gallic acid | 0.21 % gallic acid |
CDR CoffeeLab® the analysis equipment for the world of coffee from origins to roasting
CDR CoffeeLab®
- Complete analysis panel, supplied already configured
- Up to 16 determinations simultaneously
- Possibility of carrying out analyses of the same sample
- Integrated printer
- Full connections (LAN - USB - Bluetooth barcode/QR code reader)