Changes in Coffee Silver Skin Removal

Changes in Coffee Silver Skin Removal - Focusing on the analysis of fragrance substances of roasted coffee beans

By: Jeong, Yu Hyeon

The Journal of Korea Coffee & Culture Study (Dec. 2022)
Dankook University
Department of Culture and Arts | Department of Coffee 

The purpose of this study is to present and discuss the results by comparing and analyzing silver skin extract, general coffee extract, and silver skin removal coffee extract. To this end, this study collected silver skin using Coffee Bean Grinder (Patent No. 10-2252891), and for general coffee and silver skin removal coffee, a total of 70 g was used twice, 35 g each, to obtain the extract of 500 ml required for the experiment. But due to the nature of the silver skin, it is large in volume and light in weight, so 17 g was extracted and 300 ml of extract was used as the minimum amount. The experimental tool used for this study was the GC-MS device (Agilent 5977A MSD, 7890B GC), and Heracles II Neo was used as the equipment for the electronic nose experiment. The scent ingredient analysis program used a D program produced by Convenient Food Information Co., Ltd. This tool is a flavor analysis system developed based on 'Ordour Thresholds’. The main findings are as follows.

First, as a result of the Silver Skin extract analysis, the substance with the highest OVA (odour activity value) value was (2)-2-noneral, followed by isovaleraldehyde, 3,5-cocoa pyrazine, Hexanol, (e,z)-2, and 4-decadienal. Specifically, the silver skin extract contained a fragrance substance representing fatty green waxy cucumber melon, ethereal aldehydic chocolate peach fatty, cocoa, chocolate, nutty, fresh green fatty aldehydic grass leafy fruity sweaty, orange sweet fresh citrus fatty green. The biggest proportion of eight groups that have the largest proportion of the top eight groups and surface area.

The comparative analysis results of general coffee and silver skin remoral coffee are as follows. General coffee extract (e) - β - damascenone acounted for 64.38% and contained woody, floral, herbal, green and fruity with spicy tobacco. The (e) - β - damascenone accounted for 70.6% of the daily buskin removal coffee. The fragrance substance was the same as (e)- β -damascenone of the general coffee extract, but accounted for a larger proportion of 6.22%. Half-coffee extract (e) - β - damascenone accounted for 64.38% and contained woody, floral, herbal, green and fruity with spicy tobacco.

According to a comparative analysis of the scent of silver skin, regular coffee, and silver skin, silver skin has a low smell of 2, 3 pentanedione (butter), 4-vinylquoicol (smoke), and furural (caramel) commonly found in beans, while there are many substances such as nonen eggs, nucleic acid eggs, decadienals, and isovaleraldehyde. Therefore, the scent is completely different, but their role was not revealed much in the analysis of scents including silver skin. It is judged that it cannot play a leading role due to the relatively small content of the silver skin and the amount of fragrance substances.