Elevating the Quality of Arabica Coffee Beans with Synchrotron Light Technology

          Currently, the market value of coffee around the world still tends to increase every year Even though Thailand can grow and produce both Arabica and Robusta coffee beans, however, the current amount of coffee production is still unable to compete with leading coffee exporting countries in the world market such as Brazil, Ethiopia, and Vietnam due to the limitation in planting areas in the country.

Therefore, an important factor in promoting the Thai coffee industry is to improve the quality of Thai coffee by creating the identity of Thai coffee, such as promoting the production of special coffee (Specialty coffee), which is high-quality coffee. It smells and tastes good. And it received high scores from tasting by Associations of Specialty Coffee both national and international coffee experts.

The good quality of coffee depends on many factors. It is important from the type of coffee, how we take care and produce the coffee, harvesting, processing coffee, the technique of roasting up to how to make coffee. Nevertheless, the standard of coffee quality will be evaluated based on tasting (Cupping score) by the experts who were trained in terms of tasting and smelling coffee. Nevertheless, scientific analysis techniques have begun to be used to assess the quality of coffee, such as studying the composition of smell compounds in coffee using gas chromatography techniques and using high-performance liquid chromatography techniques to study the important substances within coffee beans.

Dr. Nichada Jiannaikun, Beamline Scientist at Synchrotron Light Research Institute (Public Organization) or SLRI, has applied the analysis technique based on synchrotron light to analyze the quality of coffee beans (green beans) or raw coffee beans that have not been roasted. She used Arabica coffee beans that have been processed or dried with different processes such as dry process, wet process, honey process, and the Low temperature and Low humidity (LTLH process) developed by Preeda Coffee Roasting Factory, Lampang Province.

The researchers used synchrotron light combined with Fourier transform infrared spectroscopy which can provide information about the main biochemical components contained in coffee beans including caffeine, fatty esters, Chlorogenic acid and carbohydrate components, and etc. Such substances within coffee beans will be developed into smell and flavor substances when roasted. From the results of the examination (Figure 1), it was found that coffee substances prepared by the dry process had the highest composition of fatty esters. As for the caffeine component, it was found that the amount did not vary in each drying process. When looking at the carbohydrate composition, it was seen that the wash process will have a higher amount of carbohydrates than other processes. As for chlorogenic acid, there is a lot of it in coffee beans that are dried using LTLH Process. This information reveals that the process of preparing coffee substances is different. Therefore, it affects the smell and taste of coffee which is unique to each drying process when roasting coffee substances.

In addition, the research team also conducted a comparative study of the microstructures within coffee bean samples that were dried using four different processes using the X-ray Tomography technique. The results of the analysis (Figure 2) showed that coffee beans prepared by using LTLH Process, developed by Preeda Coffee Roastery, will have a consistent structure within the coffee beans and has the lowest air cavities within the coffee beans, or it has the highest coffee content, compared to coffee substances prepared with other processes.

The research team took coffee beans prepared by LTLH Process to study and monitor the microstructural changes within the coffee beans that occur during roasting. The X-ray tomographic imaging technique (Figure 3) compares the internal characteristics of coffee beans (before roasting) with coffee beans at temperatures 100, 120, 140, 160, 190, 195, 200, and 204 degrees Celsius (at the end of roasting). The structure of coffee beans roasted at various temperatures will be useful for coffee developers to find the right roasting style or roasting profile for coffee beans to produce a good smell and flavor.

The structure of coffee beans that have been roasted at various temperatures will be useful for those who are coffee developers in order to find suitable conditions in roasting that will produce coffee with good smell and taste.

The knowledge that we have gained from this study can be recommended or suggested to agriculturists and coffee business entrepreneurs to improve the process related to coffee bean production to gain the most effective quality leading to the elevation of the competitiveness of agriculturists who plant Thai coffee beans. And it will enable Thailand to export Thai coffee beans to worldwide market with high price. This will sustainably result in an increase in coffee beans farmers' income.

Article by: Dr. Nichada Jiannaikun, Beamline Scientist, Synchrotron Light Research Institute (Public Organization)

Complier: Corporate Communications Section

Translation: International Relations Officer

 

Figure 1. Utilization of synchrotron light combined with infrared spectroscopy to analyze differences in the biochemical composition of coffee beans prepared in different ways, including the dry process method, shown with a red symbol, the method of washing with water (Wet process) is shown with a blue symbol. Semi-dry, semi-wet method (Honey process) shown with a green symbol, and the drying method at low temperature and humidity (LTLH process) developed by Preeda Coffee Roastery shown with a blue symbol. The left side of the data shows a clear separation into distinct groups. The image on the right shows the different biochemical components within coffee beans prepared from different processes.

Figure 2. It displays three-dimensional photographs of coffee beans using the X-ray Tomography technique which can be used to examine the microstructure or look at the distribution of pores within the coffee beans. The picture below is a comparison of the pores within the coffee beans. The green portion represents the air cavity inside the seed. The black part shows the coffee beans. It can be seen that coffee substances prepared by drying at low temperature and humidity (LTLH) minimizes the formation of cavities in coffee beans.

Figure 3. The image of cut coffee beans obtained by using X-ray Tomography, comparing coffee beans before roasting (coffee substance) and coffee beans at various temperatures. During roasting at 100, 120, 140, 160, 180, 190, 195, 200 and 204 degrees Celsius, it is seen that the pores within the coffee beans increase both in size and quantity, starting at a temperature of 140 degrees Celsius and the cracks that form increase and expand. (Note: The coffee beans photographed are different coffee beans in the roaster.)