Volatile Compounds from Vegetative Tobacco and Wheat Obtained by

9 Volatile Compounds from Vegetative Tobacco and Wheat Obtained by Steam Distillation and Headspace Trapping 1

2

1

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R. A. Andersen , Thomas R. Hamilton-Kemp , P. D. Fleming , and D. F. Hildebrand

Downloaded by UNIV OF PITTSBURGH on March 10, 2015 | http://pubs.acs.org Publication Date: August 25, 1986 | doi: 10.1021/bk-1986-0317.ch009

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Agricultural Research Service, U.S. Department of Agriculture, and Department of Agronomy, University of Kentucky, Lexington, KY 40546 Department of Horticulture, University of Kentucky, Lexington, ΚY 40546 Department of Agronomy, University of Kentucky, Lexington, ΚY 40546

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I d e n t i f i c a t i o n and quantitative analyses of 25 com pounds in steam d i s t i l l a t e s of burley tobacco s t a l k were accomplished. Compounds included twelve C C compounds that were probable fatty acid oxida tion products and 13 compounds >C that varied in origin. The l a t t e r included oxidation products of fatty acids, a C prenyl pyrophosphate metabolite, and biodégradation products of carotenoids and chlorophyll. About 1/3 of the distillate mass was accounted f o r . Burley tobacco s t a l k headspace volat i l e s were also studied. When compared to the steam distillate, the headspace contained greater concentrations of sesquiterpenoids but lower concentrations of C and C aldehydes and alcohols. V o l a t i l e s in steam d i s t i l l a t e s of tobacco s t a l k were not quantitat i v e l y different in a fungal resistant and a fungal sensitive variety of tobacco. Y i e l d comparisons were made of headspace v o l a t i l e s from tobacco and wheat. Studies were also begun on the e f f e c t s of fatty acid oxidation i n h i b i t o r s on y i e l d s of tobacco and wheat steam d i s t i l l a t e s . 6

9

9

10

6

9

There have been r e l a t i v e l y few reports on the occurrence and biogenesis of v o l a t i l e compounds in v e g e t a t i v e tobacco. Investigators have reported on these constituents in air-cured burley tobacco leaf (_l-4). Burton et a l . (4) showed that the composition of some v o l a t i l e components in burley leaf at harvest changed during a i r curing. Several investigators reported on v o l a t i l e s in flue-cured tobacco leaf in terms of composition (3, _5, 6) and i t s changes during curing (6). V o l a t i l e compounds emitted from the leaves and stems of a g r i c u l t u r a l crops during growth may affect plant host-parasite interactions that determine s u s c e p t i b i l i t y or resistance to fungal infections and insect damage (£-9). The purpose of t h i s i n v e s t i g a t i o n was to characterize v o l a t i l e s and study their biogenesis in s t a l k of burley tobacco and wheat during active growth. A comparision was made of v o l a t i l e compounds obtained by steam d i s t i l l a t i o n and headspace 0097-6156/ 86/0317-0099$06.00/0 © 1986 American Chemical Society In Biogeneration of Aromas; Parliment, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

100

BIOGENERATION O F A R O M A S

t r a p p i n g techniques Buttery et a l . (7).

that

were

similar

to

those

described

by

Experimental


Reagents Chemical compounds for comparisons of mass spectra and GC r e t e n t i o n times were obtained from commercial sources. Pentadecanal was synthesized as before (10). Neophytadiene and solanone were obtained from H. Burton, University of Kentucky. Reagent-grade hexane was r e d i s t i l l e d on a Vigreaux column. Water was deionized, passed through activated charcoal and d i s t i l l e d . Tenax GC adsorbent (60-80 mesh) was obtained from A l l t e c h Assoc. Inc. Plant materials Burley tobaccos (Nicotiana tabacurn L. cv KY 14 and cv KY 17 ) were grown at various times in the s o i l floor of a greenhouse. Recommended c u l t u r a l and f e r t i l i z a t i o n practices were followed (11). A randomized complete block experimental design (12 ) with four replications was used for comparison of v o l a t i l e yields between the two c u l t i v a r s . Plants were harvested at 7, 13, and 14 weeks after transplant, and leaves (including stems) were removed from stalks. Stalks were used either fresh for headspace v o l a t i l e d e t e r m i n a t i o n s , or they were immediately frozen at -20 C f o r the i s o l a t i o n of v o l a t i l e s by simultaneous steam distillation-hexane extraction. Fresh leaves (including stems) were used for headspace v o l a t i l e determinations. Wheat (Triticum aestivum L. cv Arthur 71) was field-grown and harvested when plants were 40-50 cm in height in May, or was grown in f l a t s under greenhouse conditions and harvested 2 weeks after emergence. Field-grown whole plants were immediately frozen and stored at -20 C prior to simultaneous steam distillation-hexane extractions. Field-grown stems were used frozen for headspace determination. Fresh greenhouse-grown plants were used for headspace v o l a t i l e determinations. Isolation of v o l a t i l e compounds by simultaneous steam distillation-hexane extraction (SDE) Frozen burley tobacco stalks (1-4 kg) were cut perpendicular to the main axis into 0.5-cra sections and placed in a 12-L flask with 4 L of d i s t i l l e d water. The flask contents were steam d i s t i l l e d for 4 h in a continuous extraction apparatus of the type described by Likens and Nickerson (13) and modified in a manner similar to that described by Buttery et a l . (14 ). Forty ml of hexane was used as the extractant and the additional condenser in the steam side arm was maintained at -4 C. The apparatus was operated at a reduced pressure (200 mm of Hg) with contents b o i l i n g at 65°C. After d i s t i l l a t i o n , the hexane solution was separated from the water layer and concentrated to a 1-ml volume in a microdistillation apparatus. When preparative GC separation and a n a l y s i s was c a r r i e d out, the hexane concentrates from SDE equivalent to 9 kg of tobacco stalk were combined and reduced to an 80-ul volume in the same manner. Isolation of v o l a t i l e compounds by headspace trapping on Tenax A diagram of the glass-Teflon Tenax trap is shown in Figure 1. The

In Biogeneration of Aromas; Parliment, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

9.

ANDERSEN ET AL.

Volatile Compounds

from

Vegetative Tobacco and

Wheat

101


1.5-g Tenax plug (16 χ 1 cm) was held in a glass tube by hexane-washed glass wool. The Tenax was activated before use by washing J. with 200 ml hexane and then preheating J. 2 h in the glass tube at 250°C in a stream of p u r i f i e d nitrogen. P l a n t samples used in the apparatus were: fresh burley tobacco stalk (1 kg) cut perpendicular to the main axis into 8-cm sections; fresh burley tobacco whole leaf (100 g or 1 kg); and wheat leaves plus stems or stems alone (250 g). P u r i f i e d a i r or p u r i f i e d nitrogen was used as the entrainment (sweep) gas at a flow rate of 500 ml/min for 20 h; a s l i g h t pressure drop was maintained at the system e x i t . Hexane (50 ml) was used to desorb T e n a x - a d s o r bed components; the hexane s o l u t i o n was then concentrated to 1 ml in a m i c r o d i s t i l l a t i o n apparatus. This solution was used d i r e c t l y for c a p i l l a r y GC or GC-MS analysis. P r e p a r a t i v e GC fractionation of tobacco s t a l k SDE samples I d e n t i f i c a t i o n of v o l a t i l e s in SDE equivalent to 9 kg s t a l k m a t e r i a l was c a r r i e d out by preliminary GC separation into fractions on temperature-programmed packed 20% methyl s i l i c o n e as previously described (15). These fractions were stored at -20 C u n t i l analyzed by c a p i l l a r y GC or GC-MS. C a p i l l a r y GC and GC-MS analyses A Hewlett-Packard 5880A GC was used with a 60 m χ 0.32 mm Supelcowax 10 or 30 m χ 0.25 mm Carbowax 20M fused s i l i c a c a p i l l a r y column for c a p i l l a r y GC analyses. The following conditions were used: operation in s p l i t l e s s mode; He c a r r i e r linear velocity 31 cm/sec; column temperature held 1 min isothermal and then programmed from 60 C to 220°C at 3°/min and held at 220°C for 30 min. Kovats i n d i c e s were calculated for separated components r e l a t i v e to hydrocarbon standards (16). Yields of t o t a l v o l a t i l e o i l s in SDE and in Tenax-trapped headspace eluates were estimated by GC results using octadecane as the internal or external standard. Preparative GC fractions of tobacco stalk that were condensed in U-tubes were dissolved in acetone. An aliquot of the combined acetone solutions that contained pentadecane as internal standard was analyzed by GC-MS using a Hewlett-Packard Model 5985A instrument and as p r e v i o u s l y d e s c r i b e d (15), but with the c a p i l l a r y GC column conditions described in this subsection. In a d d i t i o n to e l e c t r o n impact MS, chemical ionization MS were obtained with methane. The i d e n t i f i c a t i o n of compounds was confirmed by matching EI- and CI-MS data and by co-chromatography of plant components with authentic compounds. Fatty acid determinations The r e l a t i v e amounts of i n d i v i d u a l hydrolyzable fatty acids in 100 mg samples of freeze-dried tobacco s t a l k harvested 7 weeks after transplant and in wheat harvested at the 40- to 50-cm height plant stage were determined as fatty acid methyl esters by GC-FID (17). Fatty acid oxidation i n h i b i t o r studies Each of the following solutions was used in place of 4L of d i s t i l l e d water during the i s o l a t i o n of v o l a t i l e s by SDE from 1 kg tobacco (KY 14) stalk harvested 7 weeks after transplant: 10 mM SnCl adjusted to pH 9


102

BIOGENERATION OF AROMAS

5.0 with d i l u t e NaOH; 1 M NaCl; or 10 mM a c e t y l s a l i c y l i c a c i d . A control run was made using 4 L of d i s t i l l e d water. Each of the following solutions was used in place of 4L of d i s t i l l e d water during the i s o l a t i o n of v o l a t i l e s by SDE from 250 g of wheat (whole plant): 100 juM phenidone; 100 pH nordihydroguaiaretic acid; or 100 uM a c e t y l s a l i c y l i c a c i d . A control run was made using 4 L of d i s t i l l e d water. The solution containing the wheat was homogenized at high speed in a Waring blendor for 30 sec just before the d i s t i l l a t i o n procedure was begun.


Results and Discussion Tobacco stalk v o l a t i l e s isolated by SDE Total v o l a t i l e o i l s obtained by SDE of tobacco stalk harvested 7 weeks after transplant contained >80 detectable components on c a p i l l a r y GC columns coated with Carbowax-type l i q u i d phase. Yields of t o t a l v o l a t i l e o i l s were about 1 jig/g of stalk on a wet weight basis. The reported s t i m u l a t i o n of fungal spore germination by v o l a t i l e compounds i d e n t i f i e d from plant sources (8) and the influence of host plant-emitted v o l a t i l e s in the s u s c e p t i b i l i t y to fungal i n f e c t i o n 09) l e d us to compare v o l a t i l e s from stalks of two genetic v a r i e t i e s of tobacco. These d i f f e r e d in r e s i s t ance to black shank, a common disease of tobacco caused by Phytophthera p a r a s i t i c a . Resistant- and non-resistant tobacco plant samples yielded no s i g n i f i c a n t quantitative differences in the 35 largest peaks. I d e n t i f i c a t i o n of v o l a t i l e compounds in SDE of KY 14 tobacco stalk The i d e n t i f i c a t i o n and q u a n t i t a t i o n of 25 v o l a t i l e compounds in tobacco s t a l k which comprised about 30% of the t o t a l v o l a t i l e o i l i s o l a t e d was f a c i l i t a t e d by a 2-dimensional GC approach. In this technique, there was a preliminary preparative GC separation of t o t a l SDE v o l a t i l e s from 9 kg s t a l k into about 25 fractions on a r e l a t i v e l y non-polar column followed by c a p i l l a r y GC and CG-MS analysis of X single or 2-3 combined fractions on a s t r o n g l y p o l a r column. Q u a n t i t a t i v e results of individual components were based on tobacco s t a l k samples that were harvested from a single plot and steam d i s t i l l e d in one d i s t i l l a t i o n run. I d e n t i f i c a t i o n and q u a n t i t a t i v e e s t i m a t i o n s of v o l a t i l e compounds in SDE samples of KY 14 tabacco stalk were carried out (Table I ) . Many 6- and 9-carbon v o l a t i l e aldehydes and alcohols in p l a n t tissue are believed to form from the oxidation of unsaturated f a t t y acids such as l i n o l e i c and l i n o l e n i c acids mediated by lipoxygenase, hydroperoxide cleavage enzyme systems, cis 3:trans 2-enal isomerase enzymes and aldehyde dehydrogenases (18-20 ). Monoterpenes such as 1,8-cineole in plants may be synthesized from neryl or geranyl pyrophosphate (21). Diterpenes may derive from geranylgeranyl pyrophosphate (21), but J. is also possible that neophytadiene from tobacco s t a l k may have formed from a breakdown of chlorophyll during the i s o l a t i o n as proposed in F i g u r e 2. A l i p h a t i c aldehydes such as pentadecanal are believed to form v i a -oxidation of fatty acids. The proposed oxidation of palmitic acid to pentadecanal is shown in Figure 2. Compounds such as 13-carbon solanone, jB-ionone and geranylacetone may form as carotenoid oxidation products. A possible mechanism of formation of ^-ionone is given ifi Figure 2.



9. ANDERSEN ET AL.

Volatile Compounds

from

Vegetative Tobacco and Wheat

F i g u r e 1. A p p a r a t u s f o r c o l l e c t i o n components.

o f headspace

°C-, jb- O R Ï-C A R O T E N E /R

PALMITIC CH (CH ) 3

2

ACID 1 4

COOH

oc O X I D A T I O N •

• CH (CH ) 3

2

1 3

CHO

n-PENT^DECANAL

CHLOROPHYLL ESTERASE

PHfTYLiCgoHagO- )-PORPHYRIN( M g )

7>

• PHYTOL-

CH2

NEOPHYTADIENE

F i g u r e 2. P o s s i b l e pathways o f f o r m a t i o n f o r j P - i o n o n e , p e n t a d e c a n a l and n e o p h y t a d i e n e .


103

104



Table I .

Compounds in Steam Distillâte-Hexane E x t r a c t o f V e g e t a t i v e Tobacco S t a l k

Compound i d e n t i t y by c a p i l l a r y GC/GC-MS ( E I + C I ) and GC cochromatography —hexanal hexanoic a c i d t r a n s 2-hexenal 2-ethylhexan-l-ol trans 2-octen-l-ol octan-l-ol VC9 nonanal Compound s H t r a n s 2-nonenal c i s 3-nonen-l-ol t r a n s , c i s 2,6-nonadienal trans c i s 2,6-nonadien-l-ol _ _ c i s , c i s 3,6-nonadien-l-ol '—1,8-cineole

/^|"-f >

naphthalene n-decanal t r a n s 2-decanal t r a n s , t r a n s 2,4-decadienal 2-methylnaphthalene 1-methylnaphthalene solanone

% of total oil 2.18 1.79 0.86 0.97 0.78 0.25 2.32 5.75 1.51 4.38 0.09 0.63 0.10

0.28 1.56 0.25 0.34 0.35 0.02 0.41

Possible precursor fatty acid

C

p

r

10 pyro-

e

n

y

l

phosphate fatty acid

carotenoid

C

> 9 Compound s

1.64

geranylacetone

0.16

tetradecanal pentadecanal neophytadiene

0.09 2.00 1.24

fatty acid palmitic acid chlorophyll or p h y t o l



9. ANDERSEN ET AL.

Volatile Compounds

from


105

Tobacco stalk headspace v o l a t i l e s isolated by Tenax traps Tobacco stalk headspace v o l a t i l e s eluted from Tenax contained at least 70 components on 60m χ 0.32mm GC columns coated with Carbowax-type l i q u i d phase, which is comparable in number to that found in SDE samples. However, there were differences in the c a p i l l a r y GC profiles. Peaks corresponding to 6- and 9-carbon aldehydes and a l c o h o l s in the headspace p r o f i l e s were absent. Presumably, oxidative conversion of fatty acids to v o l a t i l e aldehydes and a l c o h o l s occurred to a l e s s e r extent during c o l l e c t i o n of headspace v o l a t i l e s . However, our results to date are not complete enough to quantitatively compare the i n d i v i d u a l v o l a t i l e compounds obtained by these 2 methods. Identifications were made f o r several compounds; these are indicated on the c a p i l l a r y GC t o t a l ion chromâtοgram obtained during an i d e n t i f i c a t i o n run in the GC-MS system (Figure 3). In addition, 2 sesquiterpenoids were present at scan numbers 784 and 836 ( F i g u r e 3 ) , but t h e i r s p e c i f i c structure has not been determined. There is evidence f o r the presence of several straight chain, saturated hydrocarbons including undecane in the headspace. The o r i g i n of the sesquiterpenoid caryophyllene is thought to be f a r n e s y l pyrophosphate ( 2 ^ ) , and the other unidentified sesquiterpenoids are also presumed to have the same precursor. Speculation about the o r i g i n of 3-octanone(scan 344) must include fatty acid oxidation and also the p o s s i b i l i t y that oxidation of Tenax-absorbed components such as alcohols may occur during the 20-h a i r entrainment period. Other studies are planned that w i l l compare the results of headspace analyses of tobacco stalk conducted with nitrogen versus a i r as entrainment gases. The presence of methyl s a l i c y l a t e is of considerable interest to us, e s p e c i a l l y since we have some evidence that mite resistance in strawberry p l a n t s is associated with high l e v e l s of methyl s a l i c y l a t e in v o l a t i l e i s o l a t e s obtained by SDE and headspace trapping (22). Comparisons of yields of t o t a l headspace v o l a t i l e s from vegetative tissues of tobacco and wheat Quantitative estimates of headspace t o t a l v o l a t i l e y i e l d s are summarized in Table I I . Table I I .

Yields of Total Headspace V o l a t i l e s from Vegetative Plant Materials

Yield, Sample Plant material Sweep Weeks description gas weight, kg growth ( ) ng/g tobacco (KY 14 burley) 10 stalk air 1 7 71 air stalk 14 1 112 leaf air 1 13 980 leaf air 0.1 14 wheat (Arthur 71) 365 air whole plant 0.25 2 444 whole plant 0.25 N ? 2597 stems 8 > 0.25 ir [a)In greenhouse was f i e l d grown (b) Wheat stem asample a

(b



106


These findings represent preliminary information obtained from a survey of several factors investigated for their e f f e c t s on y i e l d s of headspace v o l a t i l e s . The factors were plant age, plant part, plant genetics (genus, species, v a r i e t y ) , growth conditions, sweep gas and weight of sample. Yields from tobacco leaf were greater than from tobacco stalk; y i e l d s from wheat plant were greater than from tobacco l e a f . Nitrogen and a i r were both e f f e c t i v e for entrainment of v o l a t i l e s , and, in the case of wheat, the y i e l d s of t o t a l v o l a t i l e s did not d i f f e r by more than 25%. Fatty acids as precursors of v o l a t i l e s in steam d i s t i l l a t e - ^ hexane extracts of tobacco and wheat Relative abundances of s p e c i f i c fatty acids in hydrolysates of 2 v a r i e t i e s of burley tobacco s t a l k and 1 variety of wheat (whole plant including leaves and stems) are given in Table I I I . Table I I I .

Fatty acid palmitic palmitoleic oleic linoleic linolenic

Relative Abundances of Fatty Acids in Plant Samples

//Carbons : //double bond s 16:0 16:1 18:1 18:2 18:3

Total hydrolyzable fatty acids^ % Tobacco Wheal Tobacco (Arthur71) (KY14)stalk (KY17)stalk 8.5 29.9 31.6 — — 24.8 1.8 3.9 2.9 14.4 40.8 39.6 50.4 23.7 24.2

There were r e l a t i v e l y small v a r i e t a l differences in content between the 2 tobacco stalk materials , but there were large differences between the tobacco stalks and wheat. Our previous results (15) on the composition of wheat SDE v o l a t i l e s are shown in Table IV. These results support a direct precursor-product relationship between a fatty acid and a s p e c i f i c steam d i s t i l l e d v o l a t i l e compound, because hexanal and trans 2-nonenal (which presumably originate from their l i n o l e i c acid precursor C18:2) account for a larger proportion of the t o t a l o i l from steam d i s t i l l a t e s of tobacco s t a l k than is the case for wheat plants ( c f . Table I and Table IV). On the other hand, trans 2-hexenal and the sum of nonadien-aldehydes and alcohols (which presumably originate from l i n o l e n i c acid C18:3) account for a larger proportion of the o i l of wheat than of tobacco s t a l k . Several s t u d i e s showed that chemical agents can i n h i b i t lipoxygenase and cycloxygenase-mediated changes of fatty acid substrates. For example, Tappel et a l . (23) and Takahama (24) determined that lipoxygenase-catalyzed oxidation of l i n o l e i c acid was i n h i b i t e d by v a r i o u s antioxidants such as catechol, nordihydroguaiaretic acid and quercetin. Recently Josephson et a l . (25) showed that formation of carbonyl-containing compounds and alcohols that characterize the fresh f i s h aroma of emerald shiners was inhibited when f i s h were s a c r i f i c e d and immediately t r e a t e d with i n h i b i t o r s of cyclooxygenase and lipoxygenase, respectively. Also Blackwell and Flower (26) showed that phenidone was a potent i n h i b i t o r of lipoxygenase and cyclooxygenase in v i t r o .


9. ANDERSEN ET AL.

T a b l e IV.

Volatile Compounds

from


107

Compounds in Steam D i s t i l l a t e - H e x a n e E x t r a c t o f Wheat Plants


U )

Compound i d e n t i t y by c a p i l l a r y GC/GS-MS ( E I ) , GC cochromatography and IR in some cases

% of

hexanal t r a n s 2-hexenal hexan-l-ol trans 2-hexen-l-ol heptanal trans 2-heptenal heptan-l-ol trans 2-octenal octan-l-ol nonanal t r a n s 2-nonenal t r a n s , c i s 2,6-nonadienal nonan-l-ol trans 2-nonen-l-ol c i s 3-nonen-l-ol trans, c i s 2,6-nonadien-l-ol c i s , c i s 3,6-nonadien-l-ol decanal t r a n s 2-decenal JB-ionone benzaldehyde unidentified (a) Reproduced a f t e r a d a p t a t i o n w i t h p e r m i s s i o n (b) From f r o z e n wheat p l a n t s 40-50 cm in macerated p r i o r t o d i s t i l l a t i o n ( c ) t r i n d i c a t e s l e s s than 0.5%

1.3 11.1 0.6 1.7

oil

C

b

)

tr 0.5 0.5 9.9 2.2 7.7 tr 1.2 2.5 5.6 5.0 0.5 tr 3.6 tr 43.9 from r e f e r e n c e 15 height t h a t were

S t u d i e s were c a r r i e d o u t w i t h tobacco and wheat t o determine the e f f e c t s o f known i n h i b i t o r s o f l i p o x y g e n a s e and c y c l o o x y g e n a s e on t h e y i e l d s o f v o l a t i l e o i l s in SDE ( T a b l e V ) . A l t h o u g h t h e r e is c o n s i d e r a b l e e v i d e n c e t h a t l i p o x y g e n a s e is important in h i g h e r p l a n t m e t a b o l i s m , J. is n o t c e r t a i n whether cyclooxygenase p l a y s a s i m i l a r r o l e (18-20, 27 ). I n t h e case o f v o l a t i l e s from tobacco s t a l k , s m a l l i n c r e a s e s were observed which may have r e s u l t e d f r o m t h e h i g h e r ionic s t r e n g t h of the solutions. We d e c i d e d t o t r y o t h e r s p e c i f i c agents u s i n g homogenized plant t i s s u e , reasoning t h a t h o m o g e n i z a t i o n would r e l e a s e more n a t i v e enzymes and would a l l o w maximum exposure of endogenous p l a n t s u b s t r a t e s t o t h e i n h i b i t o r s . Wheat was used because J. c o u l d be homogenized more e a s i l y than tobacco s t a l k . Phenidone ( l - p h e n y l - 3 - p y r a z o l i d o n e ) inhibited total volatile o i l y i e l d in wheat by 43%, which was the l a r g e s t decrease we found (Table V ) . Nordihydroguaiaretic a c i d , an a r o m a t i c polyphenol caused a 3 2 % i n h i b i t i o n in t o t a l volatile o i l yield. A c e t y l s a l i c y l i c a c i d , on t h e o t h e r hand, d i d n o t a f f e c t y i e l d s . A c e t y l s a l i c y l i c a c i d is a s t r o n g i n h i b i t o r o f c y c l o o x y g e n a s e b u t a weak i n h i b i t o r o f l i p o x y g e n a s e (28). On t h e b a s i s o f these


108

BIOGENERATION OF A R O M A S

Table V.

Effect of Fatty Acid Oxidation Inhibitors on Yields of Total V o l a t i l e s in Steam D i s t i l l a t e s

Plant sample tobacco, KY 14 burley ( ) a

Agent

SnCl


NaCl

2

Reported as major in hibitor of

(10 mil)

Total v o l a t i l e s , >ig/g Treated Control

c

L< >

(1 M)

5.2

4.1

4.6

4.1

acetylsali c y l i c acid (10 mM)

C< >

d

4.9

4.1

phenidone (100 ^uM)

L,C

8.6

15.2

nordihydroguaiaretic acid (100 ^μΜ)

L

18.5

27.3

w h e a ^ Arthur

(a) (b)

acetylsali c y l i c acid (100 ptt) 0.5 cm stalk sections whole plant, homogenized

C (c) (d)

14.5 14.6 lipoxygenase cyclooxygenase

results and the known target enzymes inhibited by these agents, the lipoxygenase system appears to play a s i g n i f i c a n t role in the p r o d u c t i o n of v o l a t i l e compounds in wheat. The effect of phenidone on the y i e l d of individual v o l a t i l e compounds in SDE of wheat is i l l u s t r a t e d in Figure 4. Comparisons of phenidonet r e a t e d and control y i e l d s at a given Kovats index indicate relatively s t r o n g r e d u c t i o n s of 6-carbon v o l a t i l e s with phenidone. On the other hand, there were some increases of 9-carbon compounds with phenidone treatment.


9.

Volatile Compounds

ANDERSEN ET AL.

from


Θ36 C

15 24 H

int. s t d . ) dodccanc ,258

\


2

981 ncophytadicne

,

methylsal icylatG

ethylarnyl k e t o n e

n-pentadecanal

344-^

1039^

°Ι5*^24 c a r y o p t i y l lene 734 II

I

297

UJU 120

360

600

_1 848

I

L_ 1080

S C A N NUMBER

F i g u r e 3. C a p i l l a r y G C - t o t a l i o n c u r r e n t p r o f i l e o f Tenax-bound t o b a c c o s t a l k headspace v o l a t i l e s .

F i g u r e 4. distillate

E f f e c t o f phenidone on y i e l d s v o l a t i l e s f r o m wheat.

o f steam


109

110


Acknowledgments The authors thank Mr. John Loughrin for assistance in carrying out analyses. We are indebted to the Tobacco Health Research Institute and Mr. Charles Hughes for mass spectral analyses. Literature Cited 1. 2.


3. 4. 5.

6. 7. 8. 9. 10. 11. 12.

13. 14. 15. 16. 17. 18. 19. 20. 21.

22.

Davis, D. L. Recent Advances in Tobacco Science, 1976, 2, 80-111. Demole, E.; Berthet, D. Helv. Chem. Acta. 1972, 55, 1866-1882. Rix, C. E.; Lloyd, R. Α.; M i l l e r , C. W. Tobacco Science 1977, 21, 93-96. Burton, H. R.; Bush, L. P.; Hamilton, J. L. Recent Advances in Tobacco Science, 1983, 9, 91-154. Lloyd, R. Α.; M i l l e r , C. W.; Roberts, D. L.; G i l e s , G. Α.; Dickerson, J. P.; Nelson, N. H.; Rix, C. E.; Ayers, P. H. Tobacco Science 1976, 20, 40-48. E n z e l l , C. R.; Wahlberg, I. Recent Advances in Tobacco Science, 1980, 6, 64-122. Buttery, R. G.; Ling, L. C.; Wellso, S. G. J. Agric. Food Chem. 1982, 30, 791-792. French R. C. J. Agric. Food Chem. 1983, 31, 423-427. Pharis, V. L.; Kemp, T. R.; Knavel, D. E. Scientia Horticulturae 1982, 17, 311-317. Hamilton-Kemp, T. R.; Andersen, R. A. Phytochem. 1985 in press. Andersen, R. Α.; Lowe, R.; Vaughn, T. A. Phytochem. 1969, 8, 2139-2147. Cochran, W. G.; Cox, G. M. "Experimental Designs"; 2nd Edit.; John Wiley and Sons, Inc.: New York, 1957; Chapter 4. Likens, S. T.; Nickerson, G. B. Am. Soc. Brewing Chemists Proceedings 1964, 5-13. Buttery, R. G.; S e i f e r t , R. M.; Guadagni, D. G.; Black, D. R.; Ling, L. C. J. Agric. Food Chem. 1968, 16, 1009-1015. Hamilton-Kemp, T. R.; Andersen, R. A. Phytochem. 1984, 23, 1176-1177. Perry, J. A. "Introduction to A n a l y t i c a l Gas Chroma tography"; Marcel Dekker, Inc.: New York, 1981; p. 246. Chaven, C.; Hymowitz, T.; Newell, C. A. J. Am. Oil Chem. Soc. 1982, 59, 23-25. G a l l i a r d , T.; P h i l l i p s , D. R.; Reynolds, J. Biochimica et Biophysica Acta 1976, 441, 181-192. Hatanaka, Α.; Kajiwara, T.; Harada, T. Phytochem. 1975, 14, 2589-2592. Sekiya, J.; Kajiwara, T.; Hatanaka, A. Plant and C e l l Physiol. 1984, 25, 269-280. Loomis, W. D.; Croteau, R. In "The Biochemistry of Plants"; Stumpf, P., Ed.; Academic Press: New York, 1980; 4, pp. 364-410. Hamilton-Kemp, T. R.; Rodriguez, J. G.; Andersen, R. Α., unpublished r e s u l t s .


9.

ANDERSEN ET AL.

23. 24. 25. 26. 27. 28.

Volatile Compounds

from


111

Tappel, A. L.; Lundberg, W. O.; Boyer, P. D. Archiv. Biochem. Biophys. 1953, 42, 293-304. Takahama, U. Phytochem. 1985, 24, 1443-1446. Josephson, D. B.; Lindsay, R. C.; Stuiber, D. A. J. Agric. Food Chem. 1984, 32, 1347-1352. Blackwell, G. J.; Flower, F. J. Prostaglandins 1978, 16, 417-425. Douillard, R.; Bergeron, E. Physiol. Plant 1981, 51, 335-338. Shafer, A. I.; Turner, Ν. Α.; Handin, R. I . Biochim. Biophys. Acta 1982, 712, 535-541.


RECEIVED January 27, 1986


Volatile Compounds from Vegetative Tobacco and Wheat Obtained by

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