Table 3 Concentration of volatile compounds identified in raw and cooked black rice varying with milling degrees

Aldehydes

12

Hexanal

***

20.9 ± 0.0c

12.6 ± 0.2b

10.1 ± 0.0a

**

8.8 ± 0.0b

8.3 ± 0.3b

5.9 ± 0.2a

29

Octanal

**

15.1 ± 0.1c

12.0 ± 0.8b

9.9 ± 0.5a

**

19.9 ± 1.1c

13.4 ± 0.4b

9.0 ± 0.4a

32

(E)-2-heptenal

***

8.8 ± 0.6c

7.2 ± 0.2b

5.2 ± 0.0a

n.d.

n.d.

n.d.

37

Nonanal

***

299.7 ± 6.7c

271.4 ± 3.5bc

215.4 ± 0.2a

**

117.3 ± 2.2c

97.3 ± 4.1b

69.6 ± 4.6a

42

(E)-2-octenal

**

32.8 ± 0.1c

31.8 ± 0.9b

26.7 ± 1.9a

***

9.9 ± 0.1c

7.6 ± 0.2b

4.9 ± 0.2a

47

2-Furaldehyde

n.d.

n.d.

n.d.

**

10.2 ± 0.1b

5.9 ± 0.6a

5.3 ± 0.2a

49

Decanal

11.7 ± 0.3

11.4 ± 0.2

10.9 ± 0.0

*

14.8 ± 1.4c

9.6 ± 0.3b

8.0 ± 0.6a

50

Benzaldehyde

***

82.5 ± 0.0c

56.5 ± 0.1b

41.7 ± 0.4a

*

157.1 ± 3.0b

145.0 ± 12.3ab

121.1 ± 3.9a

51

2-Nonenal

***

1.6 ± 0.0c

1.5 ± 0.0b

1.3 ± 0.1a

*

1.7 ± 0.1b

1.2 ± 0.1a

1.0 ± 0.0a

56

2,6,6-Trimethyl-1-cyclohexene-1-carbaldehyde

n.d.

n.d.

n.d.

***

10.9 ± 0.4b

10.1 ± 0.2b

4.7 ± 0.2a

57

Phenylacetaldehyde

n.d.

n.d.

n.d.

**

23.5 ± 0.6c

15.9 ± 2.8b

6.5 ± 0.1a

58

2-Butyl-2-octenal

n.d.

n.d.

n.d.

*

5.5 ± 1.0b

3.0 ± 0.0a

1.3 ± 0.1a

72

Pentadecanal

**

15.0 ± 0.1c

12.1 ± 0.7b

9.5 ± 0.4a

***

88.3 ± 3.7c

76.6 ± 0.8b

34.6 ± 0.5a

96

4-Hydroxy-3-methoxybenzaldehyde(vanillin)

n.d.

n.d.

n.d.

***

78.4 ± 2.5c

37.4 ± 2.0b

20.9 ± 0.2a

Ketone

1

Acetone

**

33.7 ± 1.3c

28.2 ± 0.5b

21.3 ± 0.3a

***

13.4 ± 0.4c

6.3 ± 0.0b

3.5 ± 0.2a

20

2-Heptanone

***

23.6 ± 1.7c

16.7 ± 1.1b

10.6 ± 0.1a

*

22.9 ± 1.9c

18.1 ± 0.9b

13.5 ± 0.1a

28

2-Octanone

***

8.8 ± 0.6c

6.3 ± 0.1b

4.4 ± 0.2a

**

18.5 ± 0.9c

11.2 ± 0.3b

6.3 ± 0.3a

31

2,5-Octanedione

n.d.

n.d.

n.d.

**

14.9 ± 0.3c

11.2 ± 0.6b

8.3 ± 0.2a

34

6-Methyl-5-hepten-2-one

***

53.8 ± 0.4c

41.9 ± 2.5b

28.9 ± 1.2a

*

26.2 ± 4.6b

16.5 ± 1.6a

12.7 ± 0.7a

36

2-Nonanone

n.d.

n.d.

n.d.

*

1.1 ± 0.0c

0.9 ± 0.0b

0.8 ± 0.1a

39

3-Octen-2-one

n.d.

n.d.

n.d.

***

0.9 ± 0.0b

0.7 ± 0.1a

48

2-Decanone

**

7.8 ± 0.5b

7.3 ± 0.1b

5.5 ± 0.0a

**

4.3 ± 0.2b

4.2 ± 0.1b

2.7 ± 0.2a

54

6-Methyl-3,5-heptadien-2-one

n.d.

n.d.

n.d.

**

26.4 ± 1.3b

27.0 ± 2.3b

10.0 ± 0.3a

63

(5E)-6,10-dimethyl-5,9-undecadien-2-one

n.d.

n.d.

n.d.

**

29.1 ± 0.1b

19.3 ± 1.0a

20.7 ± 1.8a

64

Geranyl acetone

***

9.4 ± 0.1c

7.5 ± 0.0b

4.7 ± 0.2a

n.d.

n.d.

n.d.

71

2-Pentadecanone

n.d.

n.d.

n.d.

**

136.8 ± 3.9c

98.2 ± 17.2b

49.4 ± 1.0a

74

5-Pentyl-2(5H)-furanone

n.d.

n.d.

n.d.

**

5.6 ± 0.3c

4.5 ± 0.1b

3.4 ± 0.3a

77

6,10,14-Trimethyl-2-pentadecanone

n.d.

n.d.

n.d.

**

3.7 ± 0.4c

1.4 ± 0.0b

0.5 ± 0.0a

78

Hexahydrofarnesyl acetone

***

9.6 ± 0.0c

7.6 ± 0.0b

6.6 ± 0.1a

n.d.

n.d.

n.d.

85

3-Ethyl-4-methyl-1 h-pyrrole-2,5-dione

***

3.6 ± 0.1c

2.5 ± 0.0b

1.3 ± 0.0a

n.d.

n.d.

n.d.

89

4,4,7a-Trimethyl-5,6,7,7a-tetrahydro-1-benzofuran-2(4H)-one

***

2.9 ± 0.1c

2.2 ± 0.0b

1.3 ± 0.0a

n.d.

n.d.

n.d.

99

7,9-Bis(2-methyl-2-propanyl)-1-oxaspiro[4.5]deca-6,9-diene-2,8-dione

***

5.0 ± 0.2c

4.5 ± 0.2b

2.7 ± 0.1a

n.d.

n.d.

n.d.

Alcohols

3

Ethanol

***

83.7 ± 1.4c

70.3 ± 0.4b

22.4 ± 0.3a

n.d.

n.d.

n.d.

18

1-Methoxy-2-propanol

*

35.6 ± 0.6b

43.2 ± 3.1c

15.9 ± 1.5a

n.d.

n.d.

n.d.

27

1-Pentanol

***

30.3 ± 2.1c

19.3 ± 1.3b

6.6 ± 0.8a

n.d.

n.d.

n.d.

35

1-Hexanol

***

286.7 ± 15.6c

190.5 ± 6.5b

56.8 ± 0.5a

***

56.4 ± 0.6c

29.9 ± 0.1b

22.4 ± 0.5a

46

1-Octen-3-ol

***

73.9 ± 3.4c

46.8 ± 2.1b

26.4 ± 0.1a

**

115.2 ± 6.2c

90.1 ± 5.1b

45.4 ± 0.1a

53

1-Octanol

***

21.7 ± 0.4c

16.4 ± 1.0b

9.1 ± 0.1a

n.d.

n.d.

n.d.

59

1-Nonanol

***

12.5 ± 0.2c

8.0 ± 0.1b

4.4 ± 0.2a

n.d.

n.d.

n.d.

88⁺

2,2′-[1,2-Ethanediylbis(oxy)]diethanol

***

0.5 ± 0.0a

0.8 ± 0.1b

n.d.

n.d.

n.d.

n.d.

Acids and esters

45

Acetic acid

***

18.4 ± 1.3c

12.3 ± 0.4b

3.4 ± 0.3a

n.d.

n.d.

n.d.

52

Ethyl nonanoate

***

31.2 ± 1.5c

27.2 ± 0.2b

21.9 ± 0.7a

n.d.

n.d.

n.d.

60

3-Methylbutanoic acid

***

7.3 ± 0.5c

4.5 ± 0.4b

0.8 ± 0.0a

n.d.

n.d.

n.d.

62

Hexanoic acid

***

42.8 ± 0.4c

22.7 ± 2.5b

7.4 ± 0.9a

**

69.3 ± 0.1c

57.0 ± 2.3b

40.5 ± 1.2a

68

2-Ethylhexanoic acid

***

27.7 ± 0.3c

23.5 ± 0.7b

3.8 ± 0.4a

n.d.

n.d.

n.d.

70

Methyl myristate

***

5.7 ± 0.3c

3.1 ± 0.2b

0.7 ± 0.0a

n.d.

n.d.

n.d.

73

Octanoic acid

**

39.8 ± 0.3c

21.7 ± 3.4b

5.2 ± 1.1a

n.d.

n.d.

n.d.

75

Dibutyl (2Z)-2-butenedioate

n.d.

n.d.

n.d.

**

13.4 ± 0.1c

11.3 ± 0.4b

9.4 ± 0.4a

79

Nonanoic acid

*

100.5 ± 7.4c

61.0 ± 4.1b

20.6 ± 5.9a

**

6.6 ± 0.1c

5.6 ± 0.1b

5.2 ± 0.1a

82

Methyl palmitate

***

53.5 ± 0.2c

28.3 ± 1.5b

7.1 ± 0.2a

**

4.8 ± 0.4b

2.0 ± 0.1a

1.8 ± 0.2a

83

Butyl myristate

**

6.3 ± 0.3b

6.1 ± 0.5b

2.5 ± 0.6a

n.d.

n.d.

n.d.

84

Ethyl palmitate

***

3.5 ± 0.2c

1.0 ± 0.0b

0.8 ± 0.0a

n.d.

n.d.

n.d.

86

Decanoic acid

***

3.0 ± 0.1c

0.8 ± 0.1b

0.2 ± 0.0a

***

5.7 ± 0.2c

3.2 ± 0.1b

2.2 ± 0.1a

92

Methyl (9Z)-9-octadecenoate

***

7.0 ± 0.5c

2.9 ± 0.0b

0.9 ± 0.1a

**

0.1 ± 0.0b

0.1 ± 0.0b

0.0 ± 0.0a

93

Benzoic acid

***

27.0 ± 1.5c

12.6 ± 0.3b

3.0 ± 0.5a

n.d.

n.d.

n.d.

94

Methyl (9Z,12Z)-9,12-octadecadienoate

***

23.0 ± 1.5c

13.0 ± 0.4b

2.3 ± 0.2a

n.d.

n.d.

n.d.

101

Palmitic acid

***

3.4 ± 0.2c

1.6 ± 0.1b

0.5 ± 0.1a

n.d.

n.d.

n.d.

Alkanes

4

Decane

***

0.8 ± 0.0c

0.7 ± 0.0b

0.2 ± 0.0a

n.d.

n.d.

n.d.

7

2-Methyldecane

***

9.5 ± 0.1c

4.5 ± 0.0b

2.0 ± 0.3a

n.d.

n.d.

n.d.

8

5-Ethyl-2,2,3-trimethylheptane

***

6.3 ± 0.1c

3.3 ± 0.0b

1.5 ± 0.2a

n.d.

n.d.

n.d.

9

3,7-Dimethylnonane

***

4.1 ± 0.0c

2.3 ± 0.0b

1.0 ± 0.2a

n.d.

n.d.

n.d.

10

3-Methyldecane

***

7.1 ± 0.4c

3.9 ± 0.0b

1.8 ± 0.3a

n.d.

n.d.

n.d.

11

3,7-Dimethyldecane

***

7.0 ± 0.5c

4.3 ± 0.0b

2.0 ± 0.4a

n.d.

n.d.

n.d.

13

Undecane

**

4.4 ± 0.3b

4.8 ± 0.7b

1.9 ± 0.2a

**

5.1 ± 0.1b

3.5 ± 0.1a

3.8 ± 0.4a

21

Dodecane

***

4.1 ± 0.1c

4.3 ± 0.0b

2.5 ± 0.0a

**

7.9 ± 0.4c

6.3 ± 0.5b

4.2 ± 0.1a

25

Tricyclo[5.2.1.0^2,6]decane

n.d.

n.d.

n.d.

23.8 ± 1.2

15.6 ± 0.5

10.1 ± 0.8

30

Tridecane

***

1.5 ± 0.1b

1.9 ± 0.0c

1.0 ± 0.0a

*

4.1 ± 0.2c

3.3 ± 0.3b

2.6 ± 0.1a

38

Tetradecane

***

4.6 ± 0.3b

5.7 ± 0.0c

2.8 ± 0.0a

**

10.6 ± 0.1c

8.2 ± 0.4b

6.7 ± 0.6a

55

Hexadecane

***

5.3 ± 0.4c

3.8 ± 0.2b

2.2 ± 0.2a

n.d.

n.d.

n.d.

76

Heneicosane

***

1.1 ± 0.0c

0.5 ± 0.0b

0.2 ± 0.0a

n.d.

n.d.

n.d.

100

1,4,7,10,13,16-Hexaoxacyclooctadecane

***

8.1 ± 0.1b

12.6 ± 0.0c

6.5 ± 0.1a

n.d.

n.d.

n.d.

Olefins

24

1-Dodecene

***

9.5 ± 0.0c

8.7 ± 0.3b

5.0 ± 0.3a

n.d.

n.d.

n.d.

40

3-Ethyl-2-methyl-1,3-hexadiene

n.d.

n.d.

n.d.

**

3.3 ± 0.3b

2.1 ± 0.1a

1.7 ± 0.1a

43

(Z)-4-Tetradecene

***

9.2 ± 0.1c

7.1 ± 0.1b

5.1 ± 0.0a

n.d.

n.d.

n.d.

44

1-Tetradecene

***

1.3 ± 0.0a

2.7 ± 0.2b

1.2 ± 0.1a

**

8.0 ± 0.7c

5.7 ± 0.3b

3.3 ± 0.0a

66⁺

(4Z,8Z)-Tricyclo[10.2.1.02,11]pentadeca-4,8-diene

***

24.5 ± 1.2a

67.2 ± 4.6b

28.4 ± 4.2a

n.d.

n.d.

n.d.

95⁺

Decanamide

63.2 ± 1.0c

27.7 ± 2.9b

15.4 ± 1.9a

n.d.

n.d.

n.d.

Additional compounds

2

Methyl acetate

***

7.1 ± 0.0c

4.0 ± 0.2b

1.9 ± 0.3a

n.d.

n.d.

n.d.

5⁺

Acetonitrile

*

21.0 ± 0.9c

26.2 ± 2.1b

7.9 ± 1.0a

n.d.

n.d.

n.d.

6⁺

Chloroform

***

48.2 ± 0.9c

36.8 ± 1.4b

15.9 ± 0.6a

n.d.

n.d.

n.d.

14

Ethylbenzene

***

33.2 ± 0.4c

30.1 ± 2.5b

13.8 ± 0.6a

*

33.6 ± 1.7b

31.0 ± 0.2ab

27.7 ± 1.6a

15

2-Butylfuran

***

3.1 ± 0.0c

1.9 ± 0.2b

0.5 ± 0.1a

***

16.5 ± 0.1c

10.8 ± 0.3b

5.8 ± 0.0a

16

p-Xylene

***

24.0 ± 0.3b

23.1 ± 0.6b

5.5 ± 0.3a

*

176.5 ± 8.9c

144.1 ± 12.2b

113.9 ± 3.7a

17

m-Xylene

***

20.8 ± 1.0c

25.4 ± 2.2b

6.3 ± 0.3a

**

201.6 ± 5.8c

142.3 ± 7.1b

102.6 ± 8.7a

19

o-Xylene

***

54.5 ± 0.2b

50.3 ± 3.7b

12.8 ± 0.5a

**

214.1 ± 3.3c

191.5 ± 3.8b

168.4 ± 8.4a

22

Propylbenzene

n.d.

n.d.

n.d.

1.7 ± 0.0

1.5 ± 0.2

1.3 ± 0.0

23

2-Pentylfuran

***

20.6 ± 0.4c

14.4 ± 1.0b

4.2 ± 0.1a

**

145.0 ± 3.3b

90.6 ± 1.2a

69.5 ± 12.2a

26

Styrene

***

487.2 ± 11.7c

363.1 ± 29.9b

208.0 ± 12.1a

***

90.4 ± 0.2c

76.7 ± 0.2b

70.9 ± 0.5a

33

Isopropenylbenzene

n.d.

n.d.

n.d.

**

6.7 ± 0.4c

4.8 ± 0.3b

3.5 ± 0.0a

41

2-Heptylfuran

***

4.8 ± 0.0c

4.2 ± 0.5b

3.4 ± 0.8a

n.d.

n.d.

n.d.

61

Calamenene

***

35.4 ± 2.5c

23.8 ± 2.1b

8.3 ± 0.2a

n.d.

n.d.

n.d.

65

Guaiacol

***

33.8 ± 2.5c

31.1 ± 0.2b

11.8 ± 0.2a

**

397.4 ± 33.8c

311.2 ± 15.7b

185.3 ± 0.9a

67⁺

4-Methyl-2,6-bis(2-methyl-2-propanyl)phenol

***

6291.6 ± 190.9c

5872.3 ± 153.9b

2878.5 ± 1.0a

*

19.4 ± 1.0b

15.4 ± 0.4a

15.0 ± 0.8a

69

Diethylene glycol

***

178.1 ± 0.9c

11.7 ± 0.9b

6.0 ± 1.5a

n.d.

n.d.

n.d.

80

2-Sec-butylphenol

n.d.

n.d.

n.d.

t.r.

t.r.

t.r.

81

2-Methoxy-4-vinylphenol

n.d.

n.d.

n.d.

**

42.4 ± 1.7c

32.5 ± 0.8b

26.2 ± 0.3a

87⁺

2,4-Bis(2-methyl-2-propanyl)phenol

***

33.1 ± 0.2b

68.7 ± 0.5c

30.2 ± 1.2a

n.d.

n.d.

n.d.

90

4-Vinylphenol

**

12.5 ± 0.6c

10.4 ± 0.7b

8.1 ± 0.0a

**

920.8 ± 49.4c

572.9 ± 18.5b

447.0 ± 35.7a

91

1H-indole

***

15.3 ± 0.4c

12.1 ± 0.4b

4.0 ± 0.0a

**

500.7 ± 25.2c

402.4 ± 34.2b

212.8 ± 6.9a

97⁺

Dibutyl phthalate

**

2349.2 ± 25.6c

1790.7 ± 201.7b

1087.6 ± 54.4a

n.d.

n.d.

n.d.