-
Figure 1. Protein and fat concentration of coffee beans (g/100 g). (a) & (b), protein concentration; (c) & (d), fat concentration. Blue represents Arabica beans, orange represents Robusta beans. 1, medium light; 2, medium; 3, medium dark; 4, dark.
-
Figure 2. Organic acid and CACs concentration of coffee beans (g/100 g). (a) & (b), organic acid concentration; (c) & (d), CACs concentration. Blue represents Arabica beans, Orange represents Robusta beans. 1, medium light; 2, medium; 3, medium dark; 4, dark.
-
Figure 3. Total amount of VCs of different coffee beans. Blue represents Arabica beans, Orange represents Robusta beans. 1, medium light; 2, medium; 3, medium dark; 4, dark.
-
Figure 4. Discriminant results of coffee beans.
-
Production area/region Species Roasting degree Medium light Medium Medium dark Dark Brazil/Espirito Santo Arabica Robusta India/Karnataka Arabica Robusta Indonesia/Sumatra Arabica Robusta Uganda/Elgon Arabica Robusta Vietnam/Lam Dong Arabica Robusta Table 1. Dat for 40 coffee beans used in the study.
-
Parameters Organic acids CACs Speed 0.3 mL/min 1.0 mL/min Column temperature 40 °C 30 °C Wavelength 210 nm 327 nm Moving Phase Methanol (A)-0.1% phosphoric acid solution (B) Elution program 0.00~20.00 min:
10%A-90%B0.00~20.00 min:
20%A-80%B20.01~25.00 min: 100%A 20.01~45.00 min:
35%A-65%B25.01~35.00 min: 10%A-90%B 45.01~55.00 min:
40%A-60%B55.01~60.00 min:
20%A-80%BTable 2. Chromatographic parameters for organic acid and CACs determination.
-
Parameters Value Incubation temperature 60 °C Incubation duration 30 min Injection volume 5000 μL Injection speed 125 μL/s Injector temperature 200 °C Injection time 45 s Trapping temperature 40 °C Trapping duration 50 s Split 10 mL/min Final temperature 250 °C Initial temperature 50 °C (20 s) Temperature program 1 °C/s−80 °C (20 s) 3 °C/s−250 °C (40 s) Acquisition duration 167 s Fid temperature 260 °C FID gain 12 Table 3. E-nose parameters for VCs determination.
-
Sample Protein Fat Brazil-A-1 14.85 ± 0.07jkl 6.3 ± 0.28cdefghijk Brazil-A-2 15 ± 0.14ijk 5.85 ± 0.49fghijklm Brazil-A-3 15.25 ± 0.07ij 6.7 ± 0.14bcdefghi Brazil-A-4 15.75 ± 0.07i 7.95 ± 0.49b India-A-1 14.6 ± 0.14jklm 5.15 ± 0.49jklmno India-A-2 14.7 ± 0.42jklm 5.6 ± 0.42hijklmn India-A-3 14.6 ± 0.28jklm 5.6 ± 0.28hijklmn India-A-4 15.05 ± 0.07ijk 7.15 ± 0.07bcdefg Indonesia-A-1 13.35 ± 0.07op 4.5 ± 0.57mno Indonesia-A-2 13.6 ± 0nop 6.2 ± 0.14defghijkl Indonesia-A-3 14.15 ± 0.21lmn 6.8 ± 0.42bcdefgh Indonesia-A-4 14.5 ± 0.14jklm 7.6 ± 0.14bcd Uganda-A-1 12.55 ± 0.07q 5.3 ± 0.57ijklmno Uganda-A-2 12.85 ± 0.07pq 6.75 ± 0.92bcdefghi Uganda-A-3 13.1 ± 0.14pq 7.95 ± 0.64b Uganda-A-4 13.15 ± 0.07pq 10.05 ± 0.35a Vietnam-A-1 14.07 ± 0.21mno 6.35 ± 0.52cdefghijk Vietnam-A-2 14.45 ± 0.25klm 7.36 ± 0.36bcde Vietnam-A-3 14.69 ± 0.13jklm 7.74 ± 0.06bc Vietnam-A-4 14.85 ± 0.07jkl 9.46 ± 0.35a Brazil-R-1 17.78 ± 0.3efg 4.07 ± 0.3o Brazil-R-2 18.36 ± 0.19def 5 ± 0.21jklmno Brazil-R-3 18.8 ± 0.15cd 4.87 ± 0.33klmno Brazil-R-4 18.93 ± 0.05bcd 5.84 ± 0.21fghijklm India-R-1 19.04 ± 0.08bcd 4.85 ± 0.02lmno India-R-2 19.52 ± 0.02abc 5.3 ± 0.24ijklmno India-R-3 19.66 ± 0.01ab 5.92 ± 0.07efghijklm India-R-4 19.86 ± 0.1a 6.19 ± 0.25defghijkl Indonesia-R-1 17.02 ± 0.12h 4.33 ± 0.16no Indonesia-R-2 17.34 ± 0.37gh 5.72 ± 0.33ghijklmn Indonesia-R-3 17.57 ± 0.19gh 5.99 ± 0.21efghijklm Indonesia-R-4 18.37 ± 14def 5.99 ± 7.1efghijklm Uganda-R-1 17.44 ± 0.09gh 6.15 ± 0.17defghijkl Uganda-R-2 17.68 ± 0.03fgh 5.49 ± 0.3hijklmno Uganda-R-3 17.82 ± 0.35efg 6.45 ± 0.47cdefghij Uganda-R-4 18.48 ± 0.17de 6.39 ± 0.01cdefghij Vietnam-R-1 18.47 ± 0.17de 5.52 ± 0.28hijklmno Vietnam-R-2 19.39 ± 0.07abc 5.57 ± 0.35hijklmn Vietnam-R-3 19.45 ± 0.24abc 6.02 ± 0.14efghijkl Vietnam-R-4 19.94 ± 0.16a 7.32 ± 0.09bcdef *A: Arabica bean; R: Robusta bean
1: medium light; 2: medium; 3: medium dark; 4: dark
Letter code: samples with the same letter code are not significantly different (p < 0.05)Table 4. Protein and fat concentration of each coffee bean (g/100 g).
-
Sample Organic acids Chlorogenic acids compounds Tartaric
acidMalic
acidCitric
acidSuccinic
acidFumaric
acidTotal Neochlorogenic
acidChlorogenic
acidCryptochlorogenic
acidIsochlorogenic
acid AIsochlorogenic
acid BIsochlorogenic
acid CTotal Brazil-A-1 3.48 ± 0.24 0.46 ± 0.15 0.44 ± 0.06 1.37 ± 0.27 0 ± 0 5.75 ± 0.71ghijklmn 0.45 ± 0.02 0.97 ± 0.08 0.58 ± 0.07 0.03 ± 0.01 0.06 ± 0.02 0.06 ± 0.01 2.16 ± 0.2de Brazil-A-2 3.44 ± 0.23 0.48 ± 0.11 0.64 ± 0.06 2.13 ± 0.28 0 ± 0 6.67 ± 0.21cdefg 0.33 ± 0 0.67 ± 0.02 0.38 ± 0.02 0.02 ± 0 0.03 ± 0 0.03 ± 0 1.45 ± 0.01fghi Brazil-A-3 3.97 ± 0.13 0.53 ± 0.06 0.69 ± 0.06 2.49 ± 0.29 0 ± 0 7.67 ± 0.04bcd 0.22 ± 0 0.41 ± 0.01 0.28 ± 0.02 0 ± 0 0.02 ± 0.01 0.02 ± 0 0.94 ± 0.04jkl Brazil-A-4 4.18 ± 0.23 0.64 ± 0.05 1.04 ± 0.07 1.94 ± 0.11 0 ± 0 7.8 ± 0.36bc 0.13 ± 0 0.22 ± 0.01 0.15 ± 0.01 0 ± 0 0 ± 0 0 ± 0 0.5 ± 0.02nop India-A-1 2.61 ± 0.25 0.52 ± 0.04 0.49 ± 0.04 1.59 ± 0.05 0 ± 0 5.2 ± 0.12hijklmnop 0.71 ± 0.1 1.42 ± 0.04 0.85 ± 0.07 0.05 ± 0.01 0.08 ± 0.01 0.08 ± 0.01 3.19 ± 0.24ab India-A-2 3.58 ± 0.11 0.55 ± 0.06 0.8 ± 0.04 0.49 ± 0.09 0 ± 0 5.41 ± 0.3ghijklmnop 0.38 ± 0.05 0.74 ± 0.07 0.48 ± 0.1 0.02 ± 0 0.03 ± 0.01 0.03 ± 0 1.68 ± 0.23fgh India-A-3 3.62 ± 0.05 0.73 ± 0.07 1.01 ± 0.11 2.77 ± 0.01 0 ± 0 8.13 ± 0.25b 0.27 ± 0.02 0.49 ± 0.02 0.32 ± 0.02 0.01 ± 0 0.02 ± 0 0.02 ± 0 1.13 ± 0.07ijk India-A-4 3.75 ± 0.06 0.81 ± 0.1 2.6 ± 0.07 2.77 ± 0.25 0 ± 0 9.93 ± 0.49a 0.15 ± 0 0.27 ± 0.01 0.19 ± 0.02 0 ± 0 0.01 ± 0.01 0 ± 0.01 0.62 ± 0.03lmnop Indonesia-A-1 2.9 ± 0.28 0.33 ± 0.01 1.08 ± 0.06 1.03 ± 0.05 0 ± 0.01 5.33 ± 0.39ghijklmnop 0.67 ± 0.02 1.51 ± 0.08 0.81 ± 0.02 0.05 ± 0.01 0.09 ± 0.01 0.09 ± 0.01 3.22 ± 0.14a Indonesia-A-2 3.53 ± 0.17 0.59 ± 0.08 1.05 ± 0.06 1.11 ± 0.07 0.02 ± 0.01 6.29 ± 0.27defghij 0.5 ± 0.01 1.11 ± 0.02 0.65 ± 0.07 0.03 ± 0.01 0.06 ± 0.01 0.05 ± 0 2.41 ± 0.12cd Indonesia-A-3 3.9 ± 0.16 0.51 ± 0.04 0.71 ± 0.15 1.47 ± 0.04 0 ± 0 6.57 ± 0.38cdefgh 0.31 ± 0.01 0.58 ± 0.01 0.36 ± 0.01 0.01 ± 0 0.03 ± 0 0.03 ± 0 1.32 ± 0.04hij Indonesia-A-4 4.87 ± 0.23 0.73 ± 0.07 1.01 ± 0.04 1.19 ± 0.06 0 ± 0 7.8 ± 0.39bc 0.15 ± 0 0.25 ± 0.01 0.17 ± 0 0 ± 0 0 ± 0.01 0 ± 0.01 0.58 ± 0.01lmnop Uganda-A-1 2.92 ± 0.19 0.57 ± 0.11 1.47 ± 0.24 1.52 ± 0.24 0 ± 0.01 6.48 ± 0.78cdefghi 0.6 ± 0 1.28 ± 0 0.74 ± 0 0.04 ± 0 0.07 ± 0 0.07 ± 0 2.79 ± 0.02bc Uganda-A-2 3.07 ± 0.11 0.55 ± 0.15 1.81 ± 0.23 2.2 ± 0.16 0.01 ± 0.01 7.62 ± 0.64bcde 0.4 ± 0.01 0.86 ± 0.04 0.49 ± 0.01 0.02 ± 0 0.04 ± 0 0.04 ± 0 1.85 ± 0.07ef Uganda-A-3 3.47 ± 0.08 0.55 ± 0.15 2.04 ± 0.13 2.5 ± 0.22 0.01 ± 0.01 8.56 ± 0.4ab 0.26 ± 0.01 0.51 ± 0 0.32 ± 0 0.02 ± 0 0.02 ± 0 0.02 ± 0 1.14 ± 0.02ijk Uganda-A-4 3.57 ± 0.11 0.48 ± 0.1 0.61 ± 0.04 1.7 ± 0.14 0.02 ± 0 6.38 ± 0.38cdefghij 0.14 ± 0.01 0.24 ± 0.02 0.17 ± 0.01 0 ± 0 0 ± 0 0 ± 0 0.56 ± 0.04lmnop Vietnam-A-1 1.28 ± 0.11 0.32 ± 0.05 1.55 ± 0.13 2.21 ± 0.18 0.01 ± 0 5.36 ± 0.46ghijklmnop 0.48 ± 0.04 1.18 ± 0.08 0.59 ± 0.02 0.04 ± 0 0.08 ± 0.01 0.08 ± 0 2.45 ± 0.15cd Vietnam-A-2 1.46 ± 0.05 0.3 ± 0.04 1.27 ± 0.08 3.1 ± 0.01 0.02 ± 0 6.14 ± 0.09fghijkl 0.29 ± 0.01 0.65 ± 0.02 0.38 ± 0.04 0.02 ± 0 0.03 ± 0 0.04 ± 0.01 1.41 ± 0.08ghi Vietnam-A-3 1.73 ± 0.06 0.25 ± 0.03 1 ± 0.01 3.2 ± 0.07 0.01 ± 0.01 6.19 ± 0.18efghijk 0.17 ± 0.01 0.35 ± 0.02 0.23 ± 0.04 0.01 ± 0 0.02 ± 0 0.02 ± 0 0.8 ± 0.07klmno Vietnam-A-4 1.97 ± 0.1 1.11 ± 0.04 0.79 ± 0.03 3.41 ± 0.04 0.03 ± 0.01 7.3 ± 0.21bcdef 0.11 ± 0.02 0.19 ± 0.02 0.13 ± 0.02 0 ± 0 0 ± 0 0 ± 0 0.42 ± 0.06op Brazil-R-1 2.19 ± 0.12 0.1 ± 0.01 0.39 ± 0.03 0.14 ± 0.02 0 ± 0.01 2.83 ± 0.18s 0.65 ± 0.04 1.43 ± 0.04 0.8 ± 0.02 0.05 ± 0 0.09 ± 0 0.09 ± 0.01 3.11 ± 0.11ab Brazil-R-2 2.66 ± 0.38 0.39 ± 0.04 0.27 ± 0.04 0 ± 0 0.01 ± 0.01 3.33 ± 0.37rs 0.39 ± 0.03 0.78 ± 0.05 0.48 ± 0.02 0.03 ± 0 0.04 ± 0 0.04 ± 0 1.75 ± 0.1efg Brazil-R-3 3.04 ± 0.1 0.73 ± 0.07 0.16 ± 0.04 0.41 ± 0.02 0 ± 0 4.33 ± 0.24nopqr 0.16 ± 0 0.29 ± 0.01 0.2 ± 0.01 0 ± 0 0 ± 0.01 0 ± 0.01 0.66 ± 0.01lmnop Brazil-R-4 3.8 ± 0.25 0.3 ± 0.04 0.09 ± 0.02 0.38 ± 0 0 ± 0 4.58 ± 0.27mnopqr 0.08 ± 0.01 0.13 ± 0.01 0.09 ± 0.01 0 ± 0 0 ± 0 0 ± 0 0.29 ± 0.03p India-R-1 3.06 ± 0.21 0.28 ± 0.04 0.28 ± 0.05 0 ± 0 0 ± 0 3.62 ± 0.3qrs 0.5 ± 0.01 0.99 ± 0.03 0.63 ± 0.04 0.06 ± 0.02 0.1 ± 0 0.09 ± 0 2.36 ± 0.1d India-R-2 3.44 ± 0.19 0.85 ± 0.09 0.23 ± 0.03 0 ± 0 0 ± 0 4.52 ± 0.24mnopqr 0.29 ± 0 0.57 ± 0.04 0.36 ± 0.02 0.02 ± 0.01 0.04 ± 0 0.04 ± 0 1.33 ± 0.08hij India-R-3 3.15 ± 0.21 1.01 ± 0.03 0.22 ± 0.01 0.4 ± 0.03 0.02 ± 0.01 4.8 ± 0.15klmnopq 0.21 ± 0 0.39 ± 0.03 0.26 ± 0.01 0.01 ± 0 0.03 ± 0.01 0.02 ± 0 0.92 ± 0.06jklm India-R-4 3.87 ± 0.19 1.26 ± 0.14 0.26 ± 0.06 0.5 ± 0.04 0.02 ± 0 5.91 ± 0.43fghijklm 0.12 ± 0.01 0.21 ± 0.01 0.14 ± 0 0.01 ± 0 0.01 ± 0 0.01 ± 0 0.51 ± 0.03mnop Indonesia-R-1 2.74 ± 0.22 0.32 ± 0.03 0.68 ± 0.05 0.34 ± 0.06 0.01 ± 0.01 4.09 ± 0.37pqrs 0.5 ± 0.02 0.99 ± 0.02 0.62 ± 0.02 0.05 ± 0 0.09 ± 0 0.09 ± 0.01 2.32 ± 0.08d Indonesia-R-2 3.14 ± 0.15 0.43 ± 0.02 0.47 ± 0.07 0.23 ± 0 0.01 ± 0.01 4.27 ± 0.21opqr 0.33 ± 0.01 0.68 ± 0.05 0.45 ± 0.06 0.03 ± 0.01 0.08 ± 0.01 0.05 ± 0.01 1.63 ± 0.14fgh Indonesia-R-3 3.63 ± 0.11 0.47 ± 0.01 0.29 ± 0.02 0.33 ± 0.02 0.01 ± 0.01 4.73 ± 0.15lmnopqr 0.14 ± 0.02 0.25 ± 0.02 0.16 ± 0.01 0.01 ± 0 0.01 ± 0 0.01 ± 0 0.58 ± 0.05lmnop Indonesia-R-4 3.66 ± 3.78 0.16 ± 0.48 0.22 ± 0.6 0.38 ± 1.44 0.01 ± 0.004 4.43 ± 0.37nopqr 0.1 ± 0.3 0.17 ± 0.577 0.12 ± 0.353 0 ± 0.011 0 ± 0.024 0 ± 0.024 0.4 ± 1.289op Uganda-R-1 3.27 ± 0.15 0.31 ± 0.04 0.54 ± 0.06 0.25 ± 0.04 0.01 ± 0 4.38 ± 0.29nopqr 0.5 ± 0.01 1.08 ± 0.05 0.67 ± 0.07 0.05 ± 0.01 0.08 ± 0.01 0.08 ± 0 2.46 ± 0.15cd Uganda-R-2 3.52 ± 0.2 0.25 ± 0.13 0.45 ± 0.04 0.3 ± 0.02 0.02 ± 0 4.53 ± 0.06mnopqr 0.39 ± 0.03 0.77 ± 0.06 0.5 ± 0.06 0.03 ± 0.01 0.05 ± 0.01 0.05 ± 0 1.78 ± 0.18efg Uganda-R-3 3.9 ± 0.33 0.16 ± 0.01 0.11 ± 0.01 0.37 ± 0.08 0.02 ± 0 4.56 ± 0.41mnopqr 0.1 ± 0.12 0.35 ± 0.02 0.27 ± 0.06 0 ± 0 0.02 ± 0 0.01 ± 0.01 0.76 ± 0.05klmno Uganda-R-4 4.01 ± 0.17 0.25 ± 0.13 0.11 ± 0.01 0.41 ± 0.03 0.02 ± 0.01 4.8 ± 0.07klmnopq 0.07 ± 0.02 0.15 ± 0.01 0.1 ± 0.01 0 ± 0 0 ± 0 0 ± 0 0.32 ± 0.03p Vietnam-R-1 3.96 ± 0.08 0.16 ± 0.08 0.46 ± 0.07 0.38 ± 0.04 0 ± 0 4.96 ± 0.1jklmnopq 0.7 ± 0.02 1.42 ± 0.05 0.88 ± 0.05 0.08 ± 0 0.15 ± 0.01 0.14 ± 0 3.36 ± 0.14a Vietnam-R-2 3.94 ± 0.21 0.5 ± 0.04 0.2 ± 0 0.48 ± 0.04 0.01 ± 0.01 5.13 ± 0.13ijklmnop 0.3 ± 0.01 0.54 ± 0.01 0.37 ± 0.02 0.02 ± 0 0.08 ± 0 0 ± 0 1.31 ± 0.04hij Vietnam-R-3 4.69 ± 0.14 0.81 ± 0.13 0.19 ± 0.02 0.5 ± 0.06 0 ± 0 6.19 ± 0.35efghijk 0.2 ± 0 0.36 ± 0 0.24 ± 0 0.01 ± 0 0.02 ± 0 0.01 ± 0.01 0.85 ± 0.02klmn Vietnam-R-4 4.92 ± 0.12 0.5 ± 0.01 0.14 ± 0.01 0 ± 0 0 ± 0 5.56 ± 0.13ghijklmno 0.07 ± 0 0.12 ± 0 0.08 ± 0 0 ± 0 0 ± 0 0 ± 0 0.28 ± 0.01p *A: Arabica bean; R: Robusta bean;
1: medium light, 2: medium, 3: medium dark; 4: dark;
Letter code: Samples with the same letter code are not significantly different (P < 0.05).Table 5. Organic acids and CACs concentration of each coffee bean (g/100 g).
-
Index PC1 PC2 PC3 Protein −0.39 0.613 −0.162 Fat 0.489 0.249 0.501 Total organic acids 0.501 −0.097 −0.806 Total CACs 0.272 −0.74 0.118 Total VCs 0.532 −0.066 0.241 RVC (%) 60.1 26.5 6.6 Cumulative RVC (%) 93.1 Table 6. Loading table of each index of coffee bean
Figures
(4)
Tables
(6)