Caffeine Level In Coffee Mixtures

Coffee level in coffee mixtures

Introduction

Caffeine is an alkaloid present in a large number of plants, such as tea leaves, cocoa grains, Guaraná berries and of course, coffee beans.

This substance has acquired great importance over time due to its wide use in the food and pharmaceutical industry, appearing as a stimulating substance in soft drinks, or even in combination with other active ingredients in medicines. The color study of coffee beans is one of the most important parts for determining its amount of caffeine.

Within food science this study of color is one of the most important factors when deciding the quality of food. According to the color of a product, the degree of acidity or maturation, the level of processing (cooked or raw, roasted or natural …), quality, etc.

For this study, techniques such as colorimetry or spectroscopy are usually used. In both techniques the wavelength that absorbs the product is measured and depending on this parameter, the color of the food (colorimetry) is determined, or other factors that depend on the color, such as the level of caffeine of a coffee according toYour tums.

Color analysis is the parameter with the greatest influence on industries to determine roasting degrees in coffee beans. These have an external color which can present different shades depending on the tuo.

The lower the degree of roasted, and therefore clearer is the grain, the higher level of caffeine will the coffee have because it loses less qualities because it is less exposed to the defendant.

Goal

• Determine the level of caffeine (color) in coffee mixtures using molecular absorption spectroscopy.
• Make a calibrated line (absorbance against concentration) to calculate the amount of caffeine of the samples.
• Check the relationship between the "concentration" of caffeine and coffee color. What we intend to do in our experiment is to determine the color of coffee by measuring the reflection of light or thanks to the visual inspection, for this we will need to compare the toast with ad hoc color patterns. MATERIALS:

Material and instrumentation chemical reagents

• Balance – distilled water
• Thermostatized water bath – HCl 0.01 m
• STIDET – ANHIDRO SODIUM CARBONATE (NA2CO3)
• Embullition to reflux – dichloromethane (CH2CL2)
• Cellulose fold filter – Coffee pattern
• 100 ml and 25 ml aggroid flask
• 100 ml erlenmeyer flask
• 10 ml pipette
• Decantation funnel
• Rotavapor

Process

For the quantification of the caffeine present in a food, the first thing we will do will be to separate, through traditional solid-liquid and liquid-liquid extraction systems, the active substance, which we will later carry out its quantification by spectrophotometry.

Solid-liquid extraction: weigh about 300 mg of coffee (sample) and add it to 200 ml of distilled water that we have to boil at reflux for 15 minutes.

Once we have it, we will filter the hot solution and add 5 g of Na2CO3, and we will have to take it to the total solution.

Liquid-liquid extraction: We will let the solution cool and then pass it to a decantation funnel on what we will add 15 ml of CH2CL2. For a few minutes we have to shake it gently. This procedure will be carried out twice. After having managed to separate the two phases, what we will do will be to opt and collect the organic fractions on which we will add little in little Na2SO4 so that it absorbs the water.

We will pass to an erlenmeyer flask the solution achieved, and then place on the rotavapor and to be able to evaporate all the water and therefore the total dryness.

When we have eliminated the entire CH2CL2, it is put in the same flask, 50 ml of distilled water and shake it to achieve a solution. Next, we will roll it in a 100ml reforated flask. Finally, 10 ml of this solution are extracted, and 1 ml of the HCl 0 solution is added.01 m and rings with distilled water up to 25 ml.

Once the caffeine is extracted we must quantify. For this we have to prepare solutions to different concentrations to determine the maximum wavelength (230 Nm).

Then an interpolation is carried out at 280 nm to obtain the concentration of our sample.

Finally the corresponding calculations are made to obtain the % of caffeine of our sample.

Calculations

After the preparation of solutions with different concentrations of caffeine, we must represent them in a graph according to their respective absorbances. In this graph we must also indicate the absorbance of our extract measured to the maximum wavelength and indicate the equation of the line referring to the graph →

Y = a · x + b;Where we must replace and (absorbance of the problem sample) to be able to find the X value (concentration of the caffeine measured in PPM).

Once the concentration of caffeine has been found, we must express that value in mg of caffeine per 100 mg of food, for which we must take into account that we have used 100 ml of extract volume, of which we have used 10 ml of sample in sample in25 ml of solution to carry out the analysis.

Molecular spectroscopy (principle):

Study of electromagnetic interactions with matter by measuring its absorption depending on the wavelength that is applied to the sample.

Because the sample absorbs those radiation, its absorption is varying depending on the nature of the sample in question. These variations depending on their wavelength is known as absorption spectrum.

It is a very useful technique/ tool that allows us to determine the concentration of caffeine in coffee (in our case) and be able to quantify. For this we perform an ultraviolet spectroscopy.

conclusion

By carrying out this practice, we have been able to understand how the classification of color levels in coffee grains based on their roasted by measuring the reflection of the light in these, relating the toast level of the toast of thecoffee beans with the level of caffeine concentration in these.