본 연구는 커피부산물의 화장품 소재로서의 활용가능성을 평가하기 위해 커피부산물을 유기 용매인 n-hexane을 이용하여 60(±10)°C에서 24시간동안 교반하며 추출하여 실험을 수행하였다. B16F10 melanoma cell line과 RAW264.7 macrophage cell line에서의 커피박 추출물의 세포독성을 water solubletetrazolium salt-1 assay로 평가하였다. 또한 free radical 소거능을 측정하기 위해 DPPH 법을 사용하여 항산화를 평가하였으며, 항균력 검색을 위해 Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Candida albicans를 이용하였다. 실험결과 B16F10 murine melanoma cells에서 커피부산물 추출물을 처리한 군은 0.125 ~ 2 μl/ml 농도에서, RAW 264.7 macrophage cells 에서는 0.125부터 0.5 μl/ml 농도에서 세포독성을 나타내지 않았다. 항산화 실험 결과 커피박 추출물은 농도 의존적인 DPPH radical 소거능을 보였다. 또한 커피박 추출물의 항균 효능을 측정하기 위해 Paper disc법을 이용하였으며 그 결과 Straphylococcus epidermidis, Straphylococcus aureus, Escherichia coli, Candida albicans에서 각각 11.3±0.4, 12.±0.7, 12.0±0.0, 0.0±0.0 mm의 clear zone을 나타내었다. 이러한 결과는 커피박 추출물의 화장품 소재로서의 가치를 제안할 수 있다.

In this study, to cope with the renewable portfolio standard system, a thermochemical process was applied to coffee residues. After the basic thermal characteristics analysis, it was judged that the gasification process could be applied because the volatile matter in coffee residues was high. The temperature and equivalent air ratio were set by using the data and the gasification characteristics with varying equivalent ratios were evaluated. Also, the experiments were conducted in a downdraft fixed bed reactor which was easy to operate and generates less tar. The best experimental results at equivalent ratio of 0.3 were obtained with syngas composition, lower heating value of product gas, gas yield, and tar yield of 16.94%, 1,410 kcal/Nm3, 2.04 Nm3/kg and 33.33 mg/L respectively. Also, cold gas efficiency and carbon conversion rate as the most important indicators of gasifier performance were 63.83% and 88.59% respectively. Comparing the gasification characteristics with sawdust in the same reactor, the value of coffee residue was higher in the cold gas efficiency but the amount of tar was higher. However, we could apply the gasification technology to coffee residues if we carried out studies to improve the gasification efficiency and to reduce the amount of tar. Furthermore, we take into consideration the fact that the supply of coffee residues was insufficient to use as a single feedstock and the consequent necessity to study the means of using it with other available fuel materials.

Converting biomass to biocrude oil has been extensively studied worldwide as a renewable energy technology and a solution to global warming caused by overuse of fossil fuels because it is a carbon neutral fuel that originates from biomass and, thus, could help prevent climate change. Fast pyrolysis is an effective technology for producing biocrude-oil, and woody biomass is usually used as feedstock. Although many studies have been performed with this feedstock, high production cost and low higher heating value (HHV) have frequently reported as challenging barriers to commercialization. Thus, coffee ground residue was selected as an alternative feedstock to overcome this barrier due to its higher HHV than other biomasses, as well as an expected improvement in the recycling rate of organic waste from many coffee shops. A kinetic study on the thermal decomposition reaction of ground coffee residue was carried out previously to investigate pyrolysis characteristics by thermogravimetric analysis, and its kinetic parameters were studied using two calculation models. A bubbling-fluidized-bed reactor was used for fast pyrolysis and the yield and characteristics of the biocrudeoil from ground coffee residue were investigated at reaction temperatures of 400-600°C. The activation energy of the decomposition reaction was calculated separately to be 41.57 kJ/mol and 44.01-350.20 kJ/mol with the above two methods. The highest biocrude-oil content was about 51.7wt% at 550°C.

Quality characteristics of Yanggaeng prepared with water extract (CRE) and powder (CRP) of roasted coffee ground (CR) were investigated. Total polyphenol content and DPPH raidcal scavenging ability of water extract of CRE were 13.52 g/mL and 78.75%, respectively. The pH ranges of Yanggaeng prepared with CRE (CREY) and CRP (CRPY) were 7.10~7.29 and 6.95~7.15, respectively. The DPPH radical scavenging activities of CREY containing 0.1~1.0% CRE showed 8.77~43.10% and CRPY containing 0.1~1.0% CRP showed 5.28~14.92%. The total polyphenol contents and DPPH radical scavenging activity of CREY and CRPY increased significantly with increasing CRE and CRP concentrations (p<0.05). Sensory evaluation which includes taste, flavor, texture, and overall acceptability of CREY and CRPY were higher than that of control. The overall acceptability showed the highest levels in Yanggaeng containing 0.5% CRE and containing 0.3% CRP. These results indicate the potential use of roasted coffee ground residue as a valuable resource for development of side menu in coffee restaurants.