Effects of Germplasm Origin and Fruit Character on Volatile

Chapter 7

Downloaded by CORNELL UNIV on May 22, 2017 | http://pubs.acs.org Publication Date (Web): March 18, 2010 | doi: 10.1021/bk-2010-1035.ch007

Effects of Germplasm Origin and Fruit Character on Volatile Composition of Peaches and Nectarines Yiju Wang,a,b Feng Chen,c Jinbao Fang,d Chunxiang Yang,a Jianbo Zhao,e Quan Jiang,e and Shaohua Lif,* aInstitute

of Botany, The Chinese Academy of Sciences, Beijing 100093, P.R. China bGraduate School of Chinese Academy of Sciences, Beijing 100049, P.R. China cDepartment of Food Science and Human Nutrition, Clemson University, Clemson, SC 29634, USA dZhengzhou Fruit Institute, The Chinese Academy of Agriculture Sciences, Zhengzhou 450009, P.R. China eInstitute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Science, Beijing 100093, P.R. China fWuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan 430074, P.R. China *Corresponding author. Telephone: +86-27-87510599. Fax: +86-27-87510251. E-mail: [email protected].

Ninety-five volatile chemicals in peaches and nectarines with different fruit characters representing different germplasm origins were investigated using HS-SPME-GC-MS. The result showed that the composition and content of volatiles depended on germplasm origins and fruit characters. Chinese bred cultivars obtained from Chinese local and foreign cultivars and Japanese cultivars had significantly higher contents of total volatiles and esters than Chinese local cultivars. White-flesh flat peaches had the highest contents of total volatiles and esters, which were significantly higher than those of other groups with different fruit characters. Terpenoids in white-flesh flat peaches was significantly higher than that in white-flesh nectarines. Ten cultivars including ‘Yutian’, ‘Ruipan 3’, ‘Yangzhou 124 © 2010 American Chemical Society Qian and Rimando; Flavor and Health Benefits of Small Fruits ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

Pantao’, ‘Beijing 5’, ‘Fenglu’, ‘Kanto 5’, ‘Okitsu’, ‘Charme’, ‘Babygold 5’ and ‘Babygold 6’ with high contents of lactones, terpenoids and total volatiles are considered the desirable cultivars that can be used for further breeding.


Introduction It is well known that peaches and nectarines are native to China where peaches have been cultivated for at least 3000 years, and nectarines for over 2000 years. Peach tree was introduced into Europe at the beginning of the Roman era and then into the United States during the 19th century. With a long history of cultivation and extensive geographical distribution, there are a rich germplasm resources of peaches and nectarines in China and all over the world. However, regardless of the significant development of novel cultivars and increase of fruit production, many peaches and nectarines are often criticized about their undesirable qualities, which were affected by size, external color, texture (e.g., firmness), and contents of sugars, acids, as well as aromas. As one of the essential indices of fruit quality, aroma-impact flavors of peaches and nectarines have been intensively studied, resulting in the identification of more than 110 volatile compounds (1–11), which include C6 compounds, alcohols, aldehydes, esters, terpenoids, ketones and lactones. Among the lactones, particularly γ- and δ-decalactones, have been reported to be the major contributors to the peach aroma, while other volatiles such as C6 aldehydes, alcohols and terpenoids, also made a certain degree of contribution (12–15). Moreover, intensive investigations have focused on the aroma evolution of peach and nectarine during ripening (3, 7, 8, 12, 15, 16) and cold storage (9, 17). It is well known that the composition and content of volatile aromas have significant changes during the maturation. For example, in immature fruits, C6 compounds are the initial major aroma contributors, but their levels decrease drastically while those of lactones, benzaldehyde and linalool increase significantly during maturation (5, 12). Several studies have also investigated the effect of culturing techniques and managements on composition and content of volatiles, which could be changed by orchard management, such as fertilization (18), storage (19), climate or microclimate conditions such as sun light (20), and postharvest treatment (4, 7, 21, 22). Volatile composition is also cultivar dependent. Engel et al. concluded that nectarines contained significantly higher amounts of δ-decalactone than peaches (5, 13). Robertson et al. reported that white-flesh peaches contained more linalool than yellow-flesh cultivars (23). Headspace solid-phase microextraction (HS-SPME) was a sampling technique based on sorption of analytes on a polymeric material that is coated on a silica fiber. It has been widely used for the analyses of volatile and semi-volatile compounds of food and fruits (11, 24–30) since its introduction by Zhang and Pawliszyn in 1993 (31). The HS-SPME technique has the following advantages: low cost, small amount of sample required, no solvent contamination, short time of extraction, simplicity, high selectivity and sensibility (32). The HP-SPME 96 Qian and Rimando; Flavor and Health Benefits of Small Fruits ACS Symposium Series; American Chemical Society: Washington, DC, 2010.


method involves two steps: the partitioning of the analytes between the coating material and the sample; and the thermal desorption of the analytes into gas chromatograph (28). In this study, HP-SPME combined with gas chromatography-mass spectrometry (GC-MS) was applied to study the characteristic volatiles of peaches and nectarines at the germplasm level. This study mainly focused on comparing the aroma composition and content among the germplasm resources, which include Chinese local cultivars and a number of cultivars from other countries in order to acquire information for future breeding efforts aiming at enhancing fruit quality via effects on aroma.

Materials and Methods Plant Materials A total of 95 peach (Prunus persica L. Batsch) cultivars were used to study the aroma composition and content (Table 1). All the samples were collected from the Germplasm Repository for peach in the Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Science, in 2007. The trees, grafted on a wild P. persica rootstock, were planted in 3 m apart within rows and 5 m apart between rows in the spring of 1996. They were trained to ‘Y’ training systems and pruned by the long pruning method in winter (33). The same orchard managements, such as fertilization and irrigation were applied in the whole orchard. The fruits were picked from three trees of each cultivar when the green color of the fruit skin has almost disappeared. At the same time, the ground color of white-fleshed peaches turned milk white, whilst the ground color of yellow-fleshed peaches turned yellow or orange. All the fruits were picked from the southern or western crown about 1.5-2 m high from the ground of the tree at maturity. The fruit samples were taken to the laboratory immediately after harvest, washed by deionized water and surface-dried with gauze. Then three slices were taken from different orientations of each fruit. Three fruits were used for one composite sample per tree, and considered as one replication resulting in three replications for every cultivar. Samples were ground to a powder in liquid nitrogen and stored at -40°C until analysis.

Isolation and Concentration of Volatiles For headspace sampling, SPME fibers coated with poly-dimethylsiloxanedivinylbenzene (65 µm, PDMS/DVB) (Supelco Co., Bellefonte, PA, USA) were used by optimization of the method carried out in a previous work (24). The fiber was activated according to the manufacturer’s instructions. The SPME method was used for the isolation and concentration of volatiles. For each extraction, 2 g of the pulp powder, 40 µL 3-octanol (0.814 mg L-1, added as an internal standard), 0.6 g NaCl and 0.4 g CaCl2 (added to increase partitioning of volatiles from the 97 Qian and Rimando; Flavor and Health Benefits of Small Fruits ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

liquid into the gas phase and to restrain the enzyme activity, respectively) (34, 35) were placed in a 4 mL capped vial. The vial was placed in a 45°C water bath with a consistent magnetic stirring when the SPME fiber was exposed to the headspace of the sample to adsorb the volatile analytes for 30 min. The fiber was then introduced into the GC injector port for desorption at 220°C for 2 min in the splitless mode. Linear retention index (LRI) were calculated by using n-alkane standards (C5-C40) based on the method of Ceva-Antunes, et al. (36).


Table 1. Peach and nectarine cultivars are listed according to their origins. The number in parenthesis following the cultivar indicates the accession number. Populations

Characters WF

Cla

Cb

CF

J

b

Taxa Baimangpantao (1)

WP

Baifentao (2), Baiyintao (3), Cuixiangtao (4), Jinhongtao (5), Linbai 4 (6), Qingmaozibaihuatao (7), Xiaobaihua (8)

YP

Huanglu (9), Zaoshenghuangjin (10)

WF

Ruipan 4 (11), Ruipan 5 (12)

WP

Baihuatao (13), Ji 2102 (14), Lvhua 7 (15), Qiuxiangmi (16), Wanshuomi (17), Xinbaihua (18), Yulu (19), Yutian (20), Zaobaimi (21)

YP

Chengyan (22), Jinshiji (23), Wanshiji (24)

WF

Ruipan 3 (25), Yangzhou124 Pantao (26)

WP

Beijing 5 (27), Fenglu (28), Huayu (29), Jingyu (30), Qinxuan 2 (31), Wanhongmi (32), Xiahui 6 (33), Yihongshuimi (34), Zaoyu (35)

YP

Guihuang (36), Qiukui (37), Yanfeng (38)

WN

Ruiguang 2 (39), Ruiguang 7 (40), Ruiguang 27 (41)

YN

81-26-4 (42), 90-8-18 (43), 94-6-19 (44)

WP

Hakuto (45), Nippon Suimitsu (46), Okayama 500 (47), Shin Musume (48), To Hakuho (49)

YP

Ban Ougon (50), Kanto 5 (51), Myojo (52)

YN

Okitsu (53)

WP

Charme (54), Chimarrita (55), Corol (56), Fuzalode (57), J7 (58), NJ250 (59), NJ257 (60), P6 (61) Continued on next page.

98 Qian and Rimando; Flavor and Health Benefits of Small Fruits ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

Table 1. (Continued). Peach and nectarine cultivars are listed according to their origins. The number in parenthesis following the cultivar indicates the accession number. Populations


AE

Characters

Taxa

YP

Androreda (62), Babygold 5 (63), Babygold 6 (64), Babygold 9 (65), Bulgaria 2(66), Caullinan (67), Dixon (68), Early Crawford (69), Emilia (70), Fortuna (71), Fuzador (72), Glohaven (73), Harbrita (74), Havis (75), Loring (76), Mcneely (77), NJC47 (78), NJC77 (79), NJC237 (80), Norman (81), Redtop (82), Riogrand (83), Shasta (84), Vivian (85)

YN

Flavortop (86), French Nectarine (87), Great Diamond (88), Legrand (89), NJN78 (90), Nectared 4 (91), Nectared 6 (92), P1 (93), Tasiva (94), Vega (95)

a

Cl Chinese local cultivars; Cb pure Chinese original bred cultivars; CF China × foreign cultivars; J Japanese cultivars; AE American and European cultivars b WF= white-flesh flat peaches; WP= white-flesh peaches; YP= yellow-flesh peaches; WN= white-flesh nectarines; YN= yellow-flesh nectarines

GC-MS Conditions The volatile constituents were analyzed by an Agilent (Palo Alto, CA) 5975 mass selective detector coupled to an Agilent 7890 gas chromatograph, equipped with a 30 m × 0.25 mm ×1.0 µm HP-5 MS (5% phenyl-polymethylsiloxane) capillary column. Helium was used as the carrier gas at a linear velocity of 1.0 mL/min. The injector temperature was kept at 220°C and the detector at 280°C. The oven temperature was programmed from 40°C (2 min), increasing at 3°C /min to 150°C (2 min), then increasing at 10 °C /min to 220 °C, and then held for 2 min by optimizing the method used in the previous investigations (2, 25). Mass spectra were recorded in the electron impact (EI) ionization mode at 70 eV. The quadrupole mass detector, ion source and transfer line temperatures were set at 150, 230 and 350°C, respectively. Mass spectra were scanned in the range of m/z 30-350 amu at 1 s intervals. Identification of volatile compounds was achieved by comparing the mass spectra of our collected standards and those of the data system library (NIST 05) and linear retention index.

Statistical Analysis All the cultivars were classified according to two methods: 10 Chinese local (Cl), 14 pure Chinese bred (Cb, cultivars obtained from the cross between two Chinese local cultivars), 20 China × foreign (CF, Chinese bred cultivars containing blood of foreign cultivars), 9 Japanese (J) and 42 American and European cultivars (AE) according to origins; 5 white-flesh flat peaches (WF), 38 white-flesh peaches (WP), 35 yellow-flesh peaches (YP), 3 white-flesh nectarines (WN) and 8 yellow99 Qian and Rimando; Flavor and Health Benefits of Small Fruits ACS Symposium Series; American Chemical Society: Washington, DC, 2010.

flesh nectarines (YN) according to the color of fruit flesh, the fruit shape and with or without hair on the fruit surface (Table 1). Data for each cultivar were averages of three replications. A one-way ANOVA analysis was used to determine significant differences of volatiles contents between groups.

Results and Discussion


Identification of Volatiles Seventy-five volatile compounds were identified and relatively quantified. Some volatiles were only found in a few cultivars in this study (Table 2). Those compounds included 5 C6 compounds, 8 esters, 13 aldehydes, 8 lactones, 17 terpenoids, 4 ketones, 13 alcohols and 7 other compounds including some carbonyl compounds.

Table 2. Volatiles detected in fruits of all 95 peaches and nectarines C6 compounds

Lactones

LRIb

Compoundsa

Codes

Hexanal

C1

802

2-Hexenal

C2

847

(Z)-3-Hexen-1-ol

C3

851

(E)-2-Hexen-1-ol

C4

862

1-Hexanol

C5

870

γ-Hexalactone

L1

1051

γ-Heptalactone

L2

1151

γ-Octalactone

L3

1255

γ-Nonalactone

L4

1359

6-Amyl-α-pyrone

L5

1454

γ-Decalactone

L6

1464

δ-Decalactone

L7

1490

δ-Dodecalactone

L8

1680

Continued on next page.


Table 2. (Continued). Volatiles detected in fruits of all 95 peaches and nectarines


Aldehydes

Esters

Terpenoids

LRIb

Compoundsa

Codes

Pentanal

A1

697

(E)-2-Pentenal

A2

752

Heptanal

A3

902

Benzaldehyde

A4

955

Octanal

A5

1003

Benzeneacetaldehyde

A6

1039

(E)-2-Octenal

A7

1056

Nonanal

A8

1103

(E)-2-Nonenal

A9

1158

Decanal

A10

1204

(E)-2-Decenal

A11

1238

2,4-Decadienal

A12

1314

Undecanal

A13

1362

Butyl acetate

E1

812

(Z)-3-Hexenyl acetate

E2

1009

Hexyl acetate

E3

1016

2-Hexenyl acetate

E4

1018

Methyl 2-methylpentanoate

E5

1220

3-Hydroxy-2,4,4-trimethylpentyl 2-methylpropanoate

E6

1346

Diisobutyl phthalate

E7

1872

Dibutyl phthalate

E8

1969

D-Limonene

T1

1024

cis-Linalool Oxide

T2

1086

Linalool

T3

1099

Oxoisophorone

T4

1140

(3E)-5-Ethyl-6-methyl-3-hepten-2-one

T5

1145

Epoxylinalol

T6

1166

α-Terpineol

T7

1186

p-Menth-1-en-9-al

T8

1212

α-Citral

T9

1270





Alcohols

Ketones

Compoundsa

Codes

LRIb

(E)-Theaspirane

T10

1309

α -Damascenone

T11

1380

α, α-Dihydro-á-ionone

T12

1433

4-(2,6,6-Trimethyl-cyclohex-1-enyl)-butan-2-ol

T13

1441

Geranyl acetone

T14

1451

2,6-Ditert-butylquinone

T15

1460

α -Ionone

T16

1481

Nerolidol

T17

1747

1-Penten-3-ol

B1

684

Isoamylol

B2

730

1-Pentanol

B3

768

1-Octen-3-ol

B4

980

2-Ethyl-1-hexanol

B5

1030

5-Methyl-5-nonanol

B6

1121

3-Methyl-3-nonanol

B7

1138

6-Tridecanol

B8

1317

4-Tridecanol

B9

1339

10-Dodecyn-1-ol

B10

1446

6-Pentadecanol

B11

1519

4-Pentadecanol

B12

1549

1-Hexadecanol

B13

1594

1-Penten-3-one

K1

684

Cyclohexanone

K2

895

1-Octen-3-one

K3

978

6-Methyl-5-hepten-2-one

K4

988





Others

LRIb

Compoundsa

Codes

2-Pentyl-furan

O1

991

Butylated hydroxytoluene

O2

1511

2,4-Di-tert-butylphenol

O3

1514

Hexadecane

O4

1600

Heptadecane

O5

1700

3,5-Di-tert-butyl-4-hydroxybenzaldehyde

O6

1767

Nonadecane

O7

1900

a

Identities confirmed by comparing mass spectra and retention time with those of authentic standards. b Linear retention index calculated using a series of n- alkane.

Table 3. Average contents of major compounds and the groups of volatiles (µgkg-1 FW equivalent of 3-octanol) in different origins of peach and nectarine cultivars Cla

J

AE

128.0±14.4bb 145.6±18.3ab 190.0±16.2a

132.2±7.1b

175.9±9.2ab

C2

31.9±9.1

32.2±5.9

38.9±7.1

30.9±5.7

20.5±2.8

C3

20.3±5.2b

38.7±8.7a

38.6±4.9a

29.4±5.0ab

21.3±2.0b

C4

8.3±2.1ab

10.8±1.8ab

12.3±1.8a

9.4±1.2ab

6.6±0.6b

C5

18.9±5.1ab

30.9±5.8ab

33.3±6.0a

27.1±4.4ab

17.9±1.7b

L1

25.0±9.4

23.6±6.3

25.3±4.1

24.2±2.4

22.3±2.0

L5

16.0±4.7b

18.2±4.0b

23.2±6.4ab

42.6±13.4a

21.6±4.4ab

L6

94.0±23.3b

128.0±29.9ab 121.6±27.0ab 201.8±43.2a

L7

37.8±9.0b

52.5±11.8b

50.2±11.2b

87.3±17.9a

37.1±6.8b

A3

7.1±1.4ab

5.8±0.9b

8.2±1.0ab

5.7±1.1b

10.8±1.1a

A4

19.4±2.3

19.1±2.1

26.1±2.1

23.6±6.2

27.0±1.4

A5

9.5±2.3b

6. 8±1.3b

12.1±1.9ab

6.1±1.2b

19.1±1.9a

A7

28.4±3.9bc

26.3±3.4c

37.7±1.9ab

29.5±3.8abc

39.2±2.1a

A8

13.9±1.4c

15.4±0.9bc

20.3±1.2ab

15.8±1.5bc

21.9±1.4a

E1

17.7±1.9

18.5±3.3

22. 9±3.1

14.6±2.5

22.0±1.8

E2

34.5±4.9b

45.8±7.9ab

62.5±6.2a

50.7±7.4ab

61.4±3.7a

E3

5.2±0.9

6.4±1.0

7.7±1.2

6.0±1.1

8.9±1.4

C1c

Cb

CF

96.3±17.6b




Table 3. (Continued). Average contents of major compounds and the groups of volatiles (µgkg-1 FW equivalent of 3-octanol) in different origins of peach and nectarine cultivars Cla

Cb

CF

J

AE

E4

4.8±1.4

5.8±0.9

6.4±1.2

5.5±1.0

7.2±1.0

T3

19.5±9.8

11.5±2.9

23.8±6.5

21.3±9.5

35.3±5.7

T7

3.7±1.1b

3.9±0.5b

4.4±0.6b

4.1±0.8b

9.9±1.3a

T8

10.6±4.6ab

7.33±2.5b

11.7±2.8ab

8.3±1.8b

25.0±4.9a

T14

9.4±1.5

10.0±0.8

11.3±1.1

9.7±1.1

9.6±0.7

T16

6.6±1.2bc

11.5±1.4a

10.8±1.7ab

9.2±1.683abc 5.1±0.6c

K4

8.9±1.3

10.4±0.7

11.3±1.1

11.9±1.7

9.3±0.5

O1

7.0±0.9b

6.7±0.7b

11.8±1.7a

7.3±0.9b

11.4±0.5a

O2

29.4±10.1b

51.4±8.5a

43.2±5.2ab

40.2±9.3ab

25.2±3.8b

C6s

205.5±24.4b 258.2±38.9ab 313.2±30.9a

229.0±18.6ab 242.0±13.5ab

C6s % of TVd

26.80%

22.90%

Lactones

199.6±46.2b 245.0±51.1ab 230.7±47.3ab 381.1±76.9a

195.5±31.0b

Lactones% of TV

26.00%

Aldehydes

28.10%

30.70%

26.70%

26.10%

22.70%

38.10%

21.10%

103.1±12.7b 97.6±10.5b

130.0±9.8ab

96.3±13.3b

151.6±8.6a

Aldehydes% of TV

13.40%

10.60%

12.80%

9.60%

16.30%

Esters

64.5±8.7b

86.3±13.2ab

107.4±10.2a

89.0±10.9ab

103.7±5.7a

Esters% of TV

8.40%

9.40%

10.50%

8.90%

11.20%

Terpenoids

76.8±12.2

70.8±7.2

87.9±8.8

71.4±13.4

116.9±11.5

Terpenoids% of TV

10.00%

7.70%

8.60%

7.10%

12.60%

Alcohols

55.7±7.4b

67.2±5.1ab

67.7±4.3ab

76.9±12.0a

57.2±3.1b

Alcohols% of TV

7.30%

7.30%

6.60%

7.70%

6.20%

Ketones

12.9±1.9

14.3±0.9

15.1±1.5

15.2±2.1

14.3±0.9

Ketones% of TV

1.70%

1.60%

1.50%

1.50%

1.50%

Others

49.6±12.5b

79.0±10.7a

66.4±5.9ab

64.3±10.3ab

46.3±4.3b



Table 3. (Continued). Average contents of major compounds and the groups of volatiles (µgkg-1 FW equivalent of 3-octanol) in different origins of peach and nectarine cultivars Cla

Cb

CF

J

AE

Others% of TV

6.50%

8.60%

6.50%

6.40%

5.00%

Total

767.7±57.0b 918.4±55.3ab 1018.5±68.7a 1000.3±70.7a 927.5±34.1ab


a

Cl Chinese local cultivars; Cb pure Chinese original bred cultivars; CF China×foreign cultivars; J Japanese cultivars; AE American and European cultivars. b The different small letters indicate significant differences between populations (P

Effects of Germplasm Origin and Fruit Character on Volatile

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