• Food Science and Preservation
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• v.22 no.2
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• pp.182-189
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• 2015

Four different kinds of coffee beans (CS, Colombia supremo; EY, Ethiopia yirgacheffee; IM, Indonesia mandheling; and IMM, India monsooned malabar) were roasted at 200 and $250^{\circ}C$ for 10, 15, and 20 min. To determine the optimum roasting conditions, various components of the coffee beans such as pyrazines produced during the roasting, and their antioxidant and antidiabetic effects were analyzed. The different roasting condition did not affect on the concentration of caffeine. However, the amount of 5-caffeoylquinic acid and the total phenolics decreased significantly, at a greater temperature and a longer roasting time. The greatest amount of pyrazines was produced from the IMM however, the amount of pyrazines decreased rapidly at $250^{\circ}C$ according to increasing in roasting time. The DPPH free radical scavenging activity was mostly 80% more effective than that of BHT and ${\alpha}$-tocopherol activities at the same concentration. In the case of the FRAP assay, the reducing power of the coffee slightly decreased at a greater temperature pand longer time. While the inhibitory effect on ${\alpha}$-glucosidase was negligible, the activity decreased by more than 80% when the coffee beans were roasted at $250^{\circ}C$ for 20 min. The inhibitory effect on ${\alpha}$-amylase showed similar results. Taken together, the optimum roasting conditions were determined to be $200^{\circ}C$ and 15 min, which provided the best physiological activity and nutty and chocolatey aromas from the pyrazine of coffee.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.4
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• pp.365-377
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• 2017

The objective of this study was to investigate the sensory quality characteristics of coffee under various processing and roasting conditions of green beans. Colombia green bean samples were obtained from three processing methods: natural, pulped-natural, and washed methods. The green beans were roasted differently according to Agtron number: light (Agrton #65), medium (Agtron #55), and dark (Agtron #45). Moisture content, density, color value, pH, and total dissolved solid contents (TDS) were measured, and quantitative descriptive analysis (QDA) with 23 sensory attributes was performed for nine coffee samples. Hunter L values were significantly elevated with the degree of processing but reduced with roasting intensity. The pH values of the nine coffee samples were 5.6~6.2 and significantly increased with intensity of roasting. TDS decreased with an increase in processing and increased with roasting intensity. QDA results show that smoky aroma and nutty and chocolate flavor significantly increased while fruit and floral aroma decreased with intensity of processing. The attributes of brownness, oily surface, smoky aroma, bitter and burnt flavor, and greasy and heavy mouthfeel significantly increased while fruity and floral aroma, black tea, sour and umami flavor, pureness, and softness decreased as roasting intensity increased. Principle component analysis showed the overall significant relationships between 23 sensory attributes and nine coffee samples under different processing and roasting conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.487-496
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• 2013

Green coffee beans (CB, Indonesian Mandheling) were fermented with three kinds of mushrooms (Phellinus linteus, PL; Hericium erinaceum, HE; Ganoderma lucidum, GL) or two kinds of mycelia from molds (Monascus purpureus, MP; Monascus ruber, MR) using solid-state culture to enhance physiological activity. After the roasting of fermented green coffee beans, roasted coffees were extracted with a hot-water decoction or 95% ethanol reflux. Yields from hot water extracts (HW, 17.7~25.3%) were higher than those from ethanolic extracts (EE, 9.5~12.2%). Hot-water extracts of roasted coffees from green coffee beans fermented with two molds (MP-CB-HW and MR-CB-HW) showed higher total polyphenols, flavonoids, and DPPH free radical scavenging activity than roasted coffees from non-fermented (CB-HW) or fermented green coffee beans with the three mycelia from mushrooms. MR-CB-HW also had the most potent macrophage stimulating and mitogenic activity (1.32 and 1.40-fold of CB-HW, respectively). In addition, MP-CB-EE and MR-CB-EE did not show any cytotoxicity to the RAW 264.7 cell at a concentration of $100{\mu}g/mL$, and these extracts significantly inhibited nitric oxide (NO) production from the LPS-stimulated RAW 264.7 cell line (38.6 and 37.0% of the LPS-treated group). Meanwhile, the chlorogenic acid concentrations of MP-CB-HW or MR-CB-HW highly increased (to 76.21 or $76.73{\mu}g/mL$, respectively), but caffeine concentrations were not affected by solid-state fermentation. In conclusion, the physiological activities of roasted coffees were enhanced by the solid-state culture of green coffee beans with M. purpureus or M. ruber, suggesting that these roasted coffees could possibly serve industrial applications as functional coffee beverages.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.383-390
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• 2017

Regarding the facts that fat, which is easily oxidized, is one of the major responsible factors affecting the quality of aroma, and polyphenol compounds including chlorogenic acid (CGA) contribute the anti-oxidative activities to coffee, we investigated fat oxidation, conversion of CGA, and changes of anti-oxidative activities according to the degree of roasting and storage of 60 days. We found that the amount of extractable fat by diethyl ether is increased as the coffee beans are roasted longer. Furthermore, the acidity values of the fat are increased from $8.91{\pm}0.16$ to $17.81{\pm}0.11$, and $10.37{\pm}0.27$ to $17.93{\pm}0.09$ in the medium and dark roasted coffee beans, respectively, while it is increased from $4.47{\pm}0.11$ to $11.89{\pm}0.18$ in the green coffee bean after 60 days. The CGA contents in the coffee beans were decreased from $310{\pm}8.2$ to $282{\pm}11.2$, then to $58{\pm}0.0mg$ in 10 gr of the green, medium and dark beans, respectively, and were not changed significantly during the storage period. However, the anti-oxidative activities measured by 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging assays were not significantly different among the green, medium, and dark coffee beans during the storage period. Furthermore, antioxidant reactive element-luciferase assay showed that biological anti-oxidative activities were increased as coffee beans were more roasted and stored longer. As the total polyphenolic contents in the beans were significantly decreased by roasting, the results suggests that other molecules, such as, Maillard reaction products might play substantial role in anti-oxidative activity and influence cup quality of coffee.

• Food Science and Preservation
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• v.22 no.5
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• pp.690-698
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• 2015

Effects of roasting on physical (weight, volume, density and color) and chemical properties (total phenol, caffeine, chlorogenic acid and antioxidant properties) of three Arabica coffee beans (Brazil Bourbon, Indonesia Mandheling and Kenya Tatu) were investigated. A steady weight loss, volume increase, and bean density decrease were observed during the roasting process. The $L^*$, $a^*$, and $b^*$ values tended to decrease as the roasting temperature and time increased. Caffeine level was approximately 0.73% in green beans, and increased to 40-67% for darker roasts. Green beans contained the highest chlorogenic acid content, which decreased as the roasting temperature and time increased. The light- and medium-roasted coffee showed the highest total phenolol contents. The antioxidant activities were measured using DPPH and ABTS. The light-roasted coffee beans showed the highest antioxidant activities, and an approximately 36-51% loss in antioxidant activity was observed after further roasting. The flavor patterns of roasted coffee beans were analyzed using an electronic nose system based on gas chromatography. This analysis demonstrated that an electronic nose system can be applied to identify the green bean variety and the degree of roasting.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1706-1719
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• 2020

The objective of this study was to optimize the conditions for enhancing the antioxidant properties of sword bean (Canavalia gladiata) as a coffee substitute in two processing methods, roasting and grinding. The optimum conditions for removing off-flavor of the bean and maximizing functionality and efficiency were light roasting and cryogenic grinding (< 53 ㎛). In these conditions, extraction yield was 16.75%, total phenolic content (TPC) was 69.82 ± 0.35 mg gallic acid equivalents/g, and total flavonoid content (TFC) was 168.81 ± 1.64 mg quercetin equivalents/100 g. The antioxidant properties were 77.58 ± 0.27% for DPPH radical scavenging activity and 58.02 ± 0.76 mg Trolox equivalents/g for ABTS radical scavenging activity. The values for TFC and ABTS radical scavenging activity were significantly higher (p < 0.05) than in other conditions, and TPC and DPPH radical scavenging activity were second highest in lightly roasted beans, following raw beans. HS-SPME/GC-MS analysis confirmed that the amino acids and carbohydrates, which are the main components of sword bean, were condensed into other volatile flavor compounds, such as derivatives of furan, pyrazine, and pyrrole during roasting. Roasted and cryogenically ground (cryo-ground) sword beans showed higher functionality in terms of TFC, DPPH, and ABTS radical scavenging activities compared to those of coffee. Overall results showed that light roasting and cryogenic grinding are the most suitable processing conditions for enhancing the bioactivity of sword beans.

• Korean journal of food and cookery science
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• v.27 no.1
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• pp.85-99
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• 2011

Grinding is an indispensible step in preparation of espresso coffee. The purpose of this study was to evaluate physicochemical and sensory characteristics of espresso according to the grinding grades of coffee beans. Specifically, physicochemical characteristics according to the grinding grades of coffee beans were tested based on foam index, persistence of foam, total solids, concentration, extraction yield, pH, viscosity, total soluble solid content and density. With regard to sensory characteristics, QDA were carried out by 10 trained panels. Persistence of foam, total solids, concentration, extraction, pH and viscosity in physicochemical test showed significant differences among the three categories of the samples. In other words, the finer the size of particles was, the higher value was, at the p=0.001 value. Meanwhile, the value of foam index and total soluble solid content to the grinding grades was the highest in 'fine', at the p=0.001 value. Tiger-skin effect in crema, an important attribute for excellent espresso coffee, was perceived by all of the panels in 'fine'. Also, intensity of flavor was perceived as to the strongest in 'fine'. Moreover, 'fine' had the sweetness to balance the acids and bitters. In conclusion, according to the grinding grades, it was identified that there were differences in the physicochemical and sensory characteristics. Furthermore, when the size of particles was 'fine', it brought to the most positive result.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.255-261
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• 2013

This study investigated changes in the physicochemical characteristics and coffee flavors of coffee beans under different roasting conditions. Four different kinds of roasted coffees were analyzed using a headspace gas chromatographic technique. The moisture content and total acidity of roasted coffee decreased whereas the pH and weight loss (%) increased, as coffee beans were roasted at higher temperatures. The Hunter's color values of the roasted coffee (indicating L (lightness) and b (yellowness)) decreased as the roasting temperature of the coffee beans increased, but a (redness) value only increased with light roasting. We also noted that the color of the Arabica coffee was darker than that of the Robusta coffee. The aroma compounds, acetaldehyde, acetone, 2-methylfuran, 2-methylbutanol, 2-methylpyrazine, furfural, 2-propanone, furfuryl alcohol, 2,5-dimethylpyrazine and furfuryl acetate were mainly analyzed. A sensory evaluation of all light-roasted coffees had flavor and sourness and those of all medium-roasted coffees had heaviness and finishness.

• Food Science and Preservation
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• v.18 no.2
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• pp.178-183
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• 2011

The consumer awareness concerning coffee beverages has increased in Korea. The objective of this study was to optimize the roasting conditions of coffee bean for consumer's attribute. The optimal roasting conditions for Colombian coffee beans were analyzed by using a central composite design with a quadratic polynomial model by response surface methodology (RSM). The experimental conditions for coffee bean roasting were $194.82^{\circ}C{\sim}250.00^{\circ}C$ and 7.93~22.07 minutes. The responses of sensory attributes. physicochemical and physical properties were analyzed with RSM. The width. length and height of green beans increased when the beans were roasted. The higher degree of roasting gave the higher pH and solid contents but the lower total acidity and total phenolic compounds. In sensory tests, the roasting temperature and time had a significant effect on the flavor score. The optimum roasting condition of Colombian coffee bean predicted for maximizing the length, width, solid contents, total phenolic compounds and flavor score were 20 minutes at $225^{\circ}C$ by RSM.

• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.178-185
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• 2016

This study was designed to develop and to qualify a coffee alternative beverage using a mixture of coffee beans and roasted black beans (Rhynchosia nulubilis). Therefore, the total isoflavone content (TIC), total phenol content (TPC), antioxidant activity, anti-inflammatory activity, NFATc1 (Nuclear factor of activated T-cells c1) expression in RANKL (receptor activator of nuclear factor kappa-B ligand)-stimulated RAW264.7 cells and sensory evaluation were measured for 5 different Cb (coffee bean)-RoS (roasted seomoktae) mixture extracts (Cb100RoS0, Cb75RoS25, Cb50RoS50, Cb25RoS75, and Cb0RoS100). Cb0RoS100 had the highest TIC ($516.83{\pm}36.61mg/100g$) and TPC ($18.11{\pm}1.77mg$ TAE/100 g) along with the highest antioxidant activity as measured by DPPH radical scavenging activity ($73.55{\pm}8.11%$) and ABTS radical scavenging activity ($63.27{\pm}7.27%$). Also, Cb0RoS100 showed the highest anti-inflammatory activity as measured by NO production ($13.57{\pm}2.21{\mu}M$) and PGE2 production ($3.25{\pm}0.21ng/mL$). The more the RoS ratio was increased in the mixtures of Cb-RoS, the more the NFATc1 protein expression was decreased in RANKL-stimulated RAW264.7 cells. In case of sensory evaluation, Cb50RoS50 had the highest scores for flavor, delicate flavor and overall quality, which were similar to those in Cb alone (Cb100RoS0). We suggest that the use of RoS replacement instead of Cb in/as a coffee alternative beverage may help to reduce the risk of caffeine-related bone loss and/or bone disease by effectively blocking NFATc1 expression in RANKL-stimulated RAW264.7 cells compared with Cb alone.