Selenium is an essential micronutrient with significant antioxidant activity promising in mitigating the formation of acrylamide during high-temperature roasting. In this study, green coffee beans pretreated with selenium (Se-coffee) were investigated on their selenium uptake, selenium retention in green and roasted beans, antioxidant activities, and formation of acrylamide during conventional and superheated steam roasting. Comparisons were made with positive (pretreated without selenium) and negative (untreated) controls. The acrylamide formation was significantly inhibited in Se-coffee (108.9-165.3 μg/kg) compared to the positive and negative controls by 73.9% and 52.8%, respectively. The reduction of acrylamide by superheated steam roasting only observed in the untreated coffee beans (negative control) by 32.4% parallel to the increase in its antioxidant activity. Selenium pretreatment significantly increased antioxidant activity of the roasted Se-coffee beans after roasting although soaking pretreatment significantly reduced antioxidant activity in the green beans. Acrylamide reduction in the roasted coffee beans strongly correlated with the change in antioxidant capacities after roasting (∆FRAP, 0.858; ∆DPPH, 0.836). The results indicate that the antioxidant properties of the organic selenium suppressed acrylamide formation during coffee roasting.
Liberica coffee is the most important coffee species grown in Malaysia. However, there is little or no research at all conducted on coffee berries and green coffee beans since the plant itself is a low income crop in Malaysia. Therefore, research on Malaysian Liberica coffee can help to increase the knowledge of coffee farmers and coffee manufacturers in the processing and handling of the coffee. Physical properties of Liberica coffee berries and beans were investigated the current study. The properties investigated include the size, mass, density, coefficient of friction, angle of repose, fracture force and colour. In comparison to Arabica and Robusta coffee, Liberica coffee has the biggest size, mass, true density and fracture force values but were lower in bulk density in both berries and beans. The Liberica berries and beans were found to be orange-ish and yellowish colour respectively. Angle of repose was low and approximately similar in berries and beans while jute fibre gave the highest friction to both Liberica berries and beans.
This study reports the caffeine content in seven locally available coffee. The caffeine was extracted with chloroform and analysed using Fourier Transform Infrared (FTIR). The method reports an average recovery of 101% with the limit of determination established at 0.1%. The absorption band at 1654 cm-1 was used to construct the calibration curve for quantification of caffeine where the regression was fitted with satisfactory linearity. An average of 0.55% of caffeine was detected in the seven coffee products with Arabica coffee demonstrating lower caffeine concentration. The study evidenced that caffeine content in coffee is determined by the coffee types. The caffeine content found in the local coffee products was relatively lower likely due to the solvent types, extraction procedure and analytical method used.
This study was to assess the impact of different colors of coffee fruit (green, yellow and red) on adipogenesis and/or lipolysis using 3T3-L1 adipocytes. Characterization of chemical constituents in different colors of coffee fruit extracts was determined by ESI-Q-TOF-MS. The cytotoxicity of the extracts in 3T3-L1 preadipocytes were evaluated by MTT assay. Oil-red O staining and amount of glycerol released in 3T3-L1 adipocytes were measured for lipid accumulation and lipolysis activity. All coffee fruit extracts displayed similar chromatographic profiles by chlorogenic acid > caffeoylquinic acid > caffeic acid. Different colors of raw coffee fruit possessed inhibitory adipogenesis activity in 3T3-L1 adipocytes, especially CRD decreased lipid accumulation approximately 47%. Furthermore, all extracts except CYF and their major compounds (malic, quinic, and chlorogenic acid) increased glycerol release. Our data suggest that different colors of coffee fruit extract have possessed anti-adipogenic and lipolytic properties and may contribute to the anti-obesity effects.
Coffee has been studied for its health benefits, including prevention of several chronic diseases, such as type 2 diabetes mellitus, cancer, Parkinson's, and liver diseases. Chlorogenic acid (CGA), an important component in coffee beans, was shown to possess antiviral activity against viruses. However, the presence of caffeine in coffee beans may also cause insomnia and stomach irritation, and increase heart rate and respiration rate. These unwanted effects may be reduced by decaffeination of green bean Arabica coffee (GBAC) by treatment with dichloromethane, followed by solid-phase extraction using methanol. In this study, the caffeine and chlorogenic acid (CGA) level in the coffee bean from three different areas in West Java, before and after decaffeination, was determined and validated using HPLC. The results showed that the levels of caffeine were reduced significantly, with an order as follows: Tasikmalaya (2.28% to 0.097% (97 ppm), Pangalengan (1.57% to 0.049% (495 ppm), and Garut (1.45% to 0.00002% (0.2 ppm). The CGA levels in the GBAC were also reduced as follows: Tasikmalaya (0.54% to 0.001% (118 ppm), Pangalengan (0.97% to 0.0047% (388 ppm)), and Garut (0.81% to 0.029% (282 ppm). The decaffeinated samples were then subjected to the H5N1 neuraminidase (NA) binding assay to determine its bioactivity as an anti-influenza agent. The results show that samples from Tasikmalaya, Pangalengan, and Garut possess NA inhibitory activity with IC50 of 69.70, 75.23, and 55.74 μg/mL, respectively. The low level of caffeine with a higher level of CGA correlates with their higher levels of NA inhibitory, as shown in the Garut samples. Therefore, the level of caffeine and CGA influenced the level of NA inhibitory activity. This is supported by the validation of CGA-NA binding interaction via molecular docking and pharmacophore modeling; hence, CGA could potentially serve as a bioactive compound for neuraminidase activity in GBAC.
In order to investigate the role of roasting conditions in antioxidant formation, methanol and hot water extracts from Robusta coffee beans roasted for various lengths of time and at various temperatures were analyzed for total phenolic acid, chlorogenic acid, and caffeine content, as well as for their antioxidant activities using 1,1-diphenyl-2-picryhydrazyl (DPPH), thiobarbituric acid (TBA), and malonaldehyde/gas chromatography (MA/GC) assays. The amount of total phenolics in methanol extracts decreased linearly over the roasting temperature from 63.51 ± 0.77 mg chlorogenic acid equivalent (CAE)/g coffee beans (roasted at 200°C) to 42.56 ± 0.33 mg CAE/g coffee beans (roasted at 240°C). The total chlorogenic acid content decreased when the roasting time was increased from 78.33 ± 1.41 mg/g (green coffee beans) to 4.31 ± 0.23 mg/g (roasted for 16 min at 250°C). All methanol extracts from roasted coffee beans possessed over 90% antioxidant activities in the DPPH assay. The antioxidant activity of methanol extracts ranged from 41.38 ± 1.77% (roasted at 250°C for 10 min) to 98.20 ± 1.49% (roasted at 230°C for 16 min) as tested by the TBA assay. The antioxidant activity of methanol extracts of green coffee beans and roasted coffee beans ranged from 93.01% (green coffee beans) to 98.62 ± 1.32% (roasted at 250°C for 14 min) in the MA/GC assays. All hot water extracts exhibited moderate pro-oxidant activities in TBA and MA/GC assays. The results indicated that roasting conditions of coffee beans play an important role in the formation of antioxidants in brewed coffee, which can be dietary supplements having beneficial effect to human health.