Article pubs.acs.org/JAFC
Characterization of the Major Aroma-Active Compounds in Mango (Mangifera indica L.) Cultivars Haden, White Alfonso, Praya Sowoy, Royal Special, and Malindi by Application of a Comparative Aroma Extract Dilution Analysis John P. Munafo, Jr.,† John Didzbalis,† Raymond J. Schnell,† Peter Schieberle,‡ and Martin Steinhaus*,‡ †
Mars Global Chocolate Science and Technology, Mars, Incorporated, 800 High Street Hackettstown, New Jersey 07840, United States ‡ Deutsche Forschungsanstalt für Lebensmittelchemie (German Research Center for Food Chemistry), Lise-Meitner-Strasse 34, 85354 Freising, Germany ABSTRACT: The aroma-active compounds present in tree-ripened fruits of the five mango (Mangifera indica L.) cultivars Haden, White Alfonso, Praya Sowoy, Royal Special, and Malindi were isolated by solvent extraction followed by solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography−olfactometery (GC-O). Application of a comparative aroma extract dilution analysis (cAEDA) afforded 54 aroma-active compounds in the flavor dilution (FD) factor range from 4 to ≥2048, 16 of which are reported for the first time in mango. The results of the identification experiments in combination with the FD factors revealed 4-hydroxy-2,5-dimethyl-3(2H)-furanone as an important aroma compound in all cultivars analyzed. Twentyseven aroma-active compounds were present in at least one mango cultivar at an FD factor ≥128. Clear differences in the FD factors of these odorants between each of the mango cultivars suggested that they contributed to the unique sensory profiles of the individual cultivars. KEYWORDS: mango, Mangifera indica, aroma extract dilution analysis, 4-hydroxy-2,5-dimethyl-3(2H)-furanone
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INTRODUCTION Mangoes are the fruits of Mangifera indica L., a tropical tree native to South Asia and a member of the sumac family (Anacardiaceae). Mango cultivation is said to have started more than 4000 years ago in the region of eastern India. Today, mango trees are grown throughout the tropical and selected subtropical parts of the world, and mangoes are among the most important fruit crops of the tropics with the major producers being India, China, Thailand, and Pakistan.1−3 Mango fruits grow at the end of a long, string-like stem. They are drupes, consisting of a leathery exocarp, a fleshy, juicy mesocarp representing the edible part, and a stony endocarp encasing a single large, flat, oblong seed. The pulp normally sticks to the pit, as fibers extend from the endocarp into the flesh. Size, shape, skin color, skin smoothness, and flesh color strongly depend upon the cultivar. Today, several hundred different mango cultivars are known, over 350 of which are propagated in commercial nurseries. In general, mangoes are between 6 and 25 cm long and weigh up to 2 kg. Typically, the shape is slightly kidney-like and somewhat flattened, with a beak at the apex, but sometimes also nearly round, oval, or ovoid-oblong. The immature fruit has a green skin that gradually turns yellow, orange, red, or purple as the fruit matures. Combinations of several colors in one fruit also occur. The skin surface may be velvety or smooth and waxy. The flesh color ranges from whitish yellow to orange. Mangoes are usually picked before they are fully ripe to prevent them from falling and being damaged. After the fruits have ripened, they can be stored under refrigeration for up to 3 weeks. Mangoes are mainly consumed as fresh fruits. A minor percentage is © 2014 American Chemical Society
processed to preserves, juice, dried fruit, or chutney. The mango flesh consists of ∼80% water and up to 20% sugar. It is a rich source of dietary fiber, vitamin C, and β-carotene.1,2 A major factor contributing to the popularity of mango is its flavor. In Western countries, mangoes are generally considered high in quality if they combine a low fiber content with a strong sweet taste, a balanced acidity, and an aroma profile high in fruity and low in terpeny notes. Similar to phenotypical traits such as fruit size, shape, and color, the flavor properties of mangoes are strongly influenced by the cultivar.3 Numerous studies have been conducted on mango volatiles of different cultivars,3,4 which has led to the identification of several hundred compounds to date.4 It has been demonstrated that besides the cultivar,3,5−26 the maturity,3,18,22,23 and the geographic origin26 have an influence on the volatile profile of fresh mangoes. Despite the large number of investigations on mango volatiles, studies aimed at evaluating the contribution of individual volatile compounds to mango aroma are surprisingly scarce.15−17,20,25 Application of an aroma extract dilution analysis (AEDA)27,28 to headspace extracts obtained from mangoes of different cultivars grown in Brazil, (Carlota, Haden, Espada, Coraçaõ de Boi, Rubi, and Tommy Atkins) revealed the fruity-smelling ethyl butanoate as an important aromaactive compound in all samples investigated, whereas the Received: Revised: Accepted: Published: 4544
February April 22, April 28, April 28,
19, 2014 2014 2014 2014
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have an oblong shape. The skin is yellow and thin, and the flesh is firm with little fiber. Royal Special is a lesser known Indian mango cultivar that is mainly used for mango products such as pickles, dried mangoes, and canned juice.32 The skin is thick and tough, and the flesh is juicy and fibrous. The cultivar Malindi is a chance seedling of unknown parentage from the Kenyan coastline. It is also known as apple mango due to the round fruit shape resembling an apple. Malindi mangoes grow to approximately 1 kg. The skin is smooth and thin and the flesh yellow, juicy, and low in fiber.
importance of ethyl 2- and 3-methylbutanoates, δ-3-carene, and α-pinene clearly depended on the cultivar.15 On the basis of odor activity values (OAVs; ratio of concentration to odor threshold), hexanal, (E)-2-hexenal, (Z)-3-hexenal, (E)-2decenal, γ-terpinene, and (E)-β-ocimene were suggested as key aroma compounds in Thai Khieo Sawoei mangoes16 and βdamascenone, terpinolene, ethyl hexanoate, (E,Z)-2,6-nonadienal, 4-methoxy-2,5-dimethyl-3(2H)-furanone (MDMF), (R)-linalool, and ethyl butanoate were proposed as characteristic aroma components in yellow Thai Keaw mango fruits.17 A detailed study including the analysis of 20 mango cultivars followed by OAV calculation resulted in the identification of ethyl 2-methylpropanoate, ethyl butanoate, (E,Z)-2,6-nonadienal, (E)-2-nonenal, methyl benzoate, (E)-β-ionone, decanal, and MDMF as potentially most important mango aroma compounds.20 A more recent study on odor-active compounds in Corazón mangoes showed high OAVs for β-damascenone, ethyl butanoate, (E,Z)-2,6-nonadienal, ethyl 2-methylpropanoate, (E)-2-nonenal, (E)-β-ionone, and terpinolene.25 A major deficiency in the body of previously published work on aroma-active compounds in mango is the application of simultaneous distillation−extraction (SDE) for the isolation of the volatile fraction.16,17,20,25 The elevated temperatures acting on the fruit material during the SDE procedure are known to lead to compound degradation and artifact formation.29 The use of mild volatile compound isolation techniques, such as solvent-assisted flavor evaporation (SAFE),30 therefore, is an important factor in the identification of the authentic aromaactive compounds present in the fruits. The aim of the present study was to apply a comparative AEDA (cAEDA) on the volatiles obtained by SAFE distillation from fresh, tree-ripened mangoes of different cultivars. To our knowledge, there are no reports on the aroma-active compounds in fresh mango fruit that employ the SAFE isolation technique to date. To gain insight into the compounds contributing to the specific sensory profiles of different mango cultivars, five cultivars exhibiting clear organoleptic differences were chosen for this investigation, namely, Haden, White Alfonso, Praya Sowoy, Royal Special, and Malindi. The cultivar Haden was initially introduced in Florida in 1910 and inspired the creation of the large-scale mango industry in southern Florida. Haden is a seedling of the Indian cultivar Mulgoba and probably resulted from Mulgoba × Turpentine. Haden is the seed parent of numerous other U.S. cultivars.31 Haden mango fruits are ∼10 × 8 cm in size and weigh up to 500 g. The skin is thick and tough, yellow in color, with crimson blush and numerous whitish-yellow glands. The fruit shape is egg-like with a depressed beak. The flesh is yellowish-orange, firm, and juicy, with a moderate fiber content and a pleasant aroma.2 Alfonso, also known as Appus, Badami, Gundu, Haphus, Kagdi, Khader, and Khader Pasand, is a small and traditional Indian cultivar dating back to the early 16th century. It is considered one of the finest dessert mangoes. The cultivar White Alfonso, also referred to as Safeda Afoos, originated in India, too, as a descendant of Alfonso and was collected in 1908 close to Mumbai. White Alfonso mangoes are large, with a weight up to 2 kg. They are yellow with a red blush skin, which is thick and tough. The orange colored flesh is sweet, firm, and juicy with minimal fiber. Praya Sowoy is a typical Southeast Asian mango cultivar originating in Thailand. Fruits are big, weighing up to 1 kg, and
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MATERIALS AND METHODS
Mango Fruits. All samples were provided by the USDA ARS Station in Miami, FL, USA. Fruits were harvested by hand when fully ripe. State of ripeness was estimated by experienced ARS personnel through sensory evaluation of color, firmness, taste, and aroma. Fruits were shipped overnight by air freight to the Mars Global Chocolate Science and Technology Laboratory (Hackettstown, NJ, USA). Sensory analyses and preparation of aroma isolates were performed on the day of arrival. Reference Aroma Compounds. The following reference aroma compounds were purchased from the commercial vendors given in parentheses: 1−2, 4−8, 10−16, 19−24, 26−36, 38−45, 47, 49−54 (Sigma-Aldrich, St. Louis, MO, USA); 37 (Penta Manufacturing Company, Livingston, NJ, USA). Compounds 3,33 9,34 17,35 18,36 46,37 and 4837 were synthesized as described in the literature. Miscellaneous Chemicals and Reagents. Diethyl ether and pentane were freshly distilled before use. Mercurated agarose gel was prepared from Affi-Gel 10 (Bio-Rad, Munich, Germany) using a procedure provided by Bio-Rad. Sensory Analyses. Fresh mango samples (15 g) were cut into cubes (2 cm) and placed into 20 mL borosilicate glass scintillation vials (Thermo Fisher Scientific, Fair Lawn, NJ, USA). Each sample was orthonasally evaluated by free choice profiling and in a quantitative descriptive analysis (QDA) by 12 trained sensory panelists. The descriptors used in the QDA were defined on the basis of the odor of a reference compound dissolved in water at a concentration of 100 times above the respective threshold value or using a standard reference material. Reference odorants used in the sensory experiments were ethyl butanoate (fruity), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) (caramel, sweet), butanoic acid (sweaty), linalool (floral, citrus), (Z)-3-hexenal (green), myrcene (terpeny), γ-octalactone (coconut), and 4-mercapto-4-methyl-2-pentanone (tropical). The standard sensory reference materials used in the study were fresh pineapple cubes (2 cm) (pineapple) and fresh raspberries (raspberry). Panelists rated the descriptor for each of the samples on a seven-point scale in 0.5 increments from 0 to 3, with 0 = not detectable, 1 = weak, 2 = moderate, and 3 = strong. Preparation of the Aroma Isolates. Fresh ripe mangoes (3 fruits) were peeled, seeds were removed, and the flesh was cut into sections (4 cm). The sections were immediately frozen in liquid nitrogen and ground into a fine powder with a laboratory mill. A portion of the powder (25 g) was sequentially extracted with freshly distilled diethyl ether (1 × 100 mL, 1 × 50 mL) on an autoshaker at ambient temperature for 10 min. After centrifugation (5000 rpm; 5 min), the supernatants were combined and the residue was discarded. The organic layer was isolated in a separatory funnel, and the aqueous layer was discarded. The ether extract was then subjected to highvacuum distillation using SAFE.30 The distillation apparatus was thermostated at 40 °C and kept under high vacuum (10−3 Pa). The sample was dropped into the evaporation flask of the device over 40 min. After an additional 30 min, the vacuum was broken, and the distillate was thawed at room temperature and dried over anhydrous sodium sulfate. The sample was then concentrated to approximately 2 mL using a Vigreux column (50 × 1 cm) and finally to 200 μL under a gentle stream of nitrogen. The aroma profile of the isolate was then 4545
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Two-Dimensional Heart-Cut Gas Chromatography-Olfactometry/Mass Spectrometry. A gas chromatograph Mega 2 (Fisons Instruments, Mainz, Germany), equipped with a cold-on-column injector, a column DB-FFAP (30 m × 0.32 mm, 0.25 μm film thickness) (Agilent Technologies, Waldbronn, Germany), a moving column stream switching system (MCSS), and an FID plus a sniffing port as monitor detectors, was coupled via a heated (250 °C) deactivated fused silica capillary serving as transfer line to a CP 3800 gas chromatograph (Varian, Darmstadt, Germany) equipped with a cold trap and a column DB-5 (30 m × 0.25 mm, 0.25 μm film thickness) (Agilent). The column end was connected via a Y-shaped glass splitter and deactivated fused silica capillaries to a sniffing port and a Saturn 2000 mass spectrometer (Varian) operated in the EI mode. The sniffing ports each consisted of a cylindrical aluminum device with a beveled top and a central drill hole for the capillary and were mounted on a heated detector base of the GC. The tailor-made trap consisted of a piece of steel tubing housing the capillary and, when active, was cooled (−100 °C) by means of liquid nitrogen. The length and diameter of the splitting capillaries in the second oven were adjusted to ensure simultaneous detection of eluted compounds at the sniffing port and in the MS, which was confirmed by the analysis of test odorants. For the structural assignment of compounds 3 and 9, in a first run, the mango fractions containing the target compounds were separated on the first column while the MCSS conveyed the eluate to the monitor detectors. The retention times of the target compounds were determined by sniffing the eluate at the sniffing port. In a second run, during the elution of the target compounds, the eluate of the first column was transferred to the precooled trap where the heart-cut was condensed. After trap cooling had been turned off, the second oven was started. The eluate was monitored by sniffing, and when the target compound was detected at the sniffing port, the mass spectrum was recorded.
evaluated to ensure that it closely matched the profile of the fresh ripe mango flesh. Gas Chromatography−Olfactometry (GC-O). A 6890 series GC system (Agilent Technologies, Santa Clara, CA, USA) was equipped with a DB-5 or an HP-FFAP capillary (each 30 m × 0.32 mm, 0.25 μm film thickness) (Agilent). The samples (1 μL) were injected cold-on-column at 35 °C using helium as the carrier gas. The flow rate was set to 1.0 mL/min. After 1 min at 35 °C, the oven temperature was increased at 60 °C/min to 60 °C, then increased at 6 °C/min to 230 °C, and held for 10 min. The effluent was split 1:1 by volume at the end of the capillary by a Y-type splitter into two 50 cm sections of uncoated deactivated fused silica capillaries. One section was directed to the flame ionization detector (FID) held at 250 °C and the other part to a heated sniffing port held at 180 °C. The sniffing port was mounted on the front FID detector base and consisted of a custom-machined aluminum cylindrical cone (80 mm × 25 mm i.d.) housing the capillary. During GC-O analysis, the odor of the effluent from the sniffing port was evaluated by a panelist. As an odor was detected, the retention time and the odor quality were recorded. Linear retention indices (RI) were calculated from these retention times and the retention times of adjacent n-alkanes by linear interpolation. Comparative Aroma Extract Dilution Analysis. Aroma isolates were diluted to obtain serial dilutions of 1:2, 1:4, 1:8, ..., 1:2048. Dilutions 1:4, 1:8, 1:32, 1:128, 1:512, and 1:2048 were additionally analyzed by GC-O using the FFAP column and the conditions described above. For best comparison, corresponding dilutions of each cultivar were analyzed consecutively. For each cultivar, each aromaactive region was assigned an FD factor corresponding to the dilution factor of the highest diluted sample in which the odor was detectable.27,28 Fractionation of the Mango Aroma Isolates. Samples prepared as described above were concentrated to 1 mL with the use of a Vigreux column and applied to a silica gel solid phase extraction (SPE) cartridge (Phenomenex, Torrance, CA, USA) that was conditioned sequentially with pentane (5 mL), diethyl ether (5 mL), and a second portion of pentane (5 mL). Elution was performed with pentane (5 mL; fraction A) followed by pentane/diethyl ether (98:2, v/v; 5 mL; fraction B), pentane/diethyl ether (95:5, v/v; 5 mL; fraction C), pentane/diethyl ether (9:1, v/v; 5 mL; fraction D), pentane/diethyl ether (1:1, v/v; 5 mL; fraction E), and finally diethyl ether (5 mL; fraction F). Each fraction was then concentrated, first to 2 mL using a Vigreux column and finally to 200 μL under a gentle stream of nitrogen prior to analysis. The volatile thiol fraction (fraction T) of each mango cultivar was isolated from a SAFE distillate obtained from 25 g of fruit pulp by affinity chromatography.38 The SAFE distillate was concentrated (Vigreux column; 5 mL) and applied onto mercurated agarose gel (1 g) in a glass column (0.5 cm i.d.). After the column had been rinsed with dichloromethane (50 mL), the thiols were eluted with dithiothreitol (10 mmol/L) in dichloromethane (50 mL). The excess of dithiothreitol was removed by SAFE distillation, and the distillate was concentrated to 200 μL using a Vigreux column (60 cm) and a microdistillation device.39 The odorants detected during AEDA were localized in fractions A− F and T by GC-O, and mass spectra were recorded by gas chromatography-mass spectrometry (GC-MS) or two-dimensional heart-cut gas chromatography−olfactometry/mass spectrometry (GCO/GC-O/MS). Gas Chromatography−Mass Spectrometry. An Agilent 6890 series GC system equipped with an HP-FFAP column (30 m × 0.25 mm, 0.25 μm film thickness) (Agilent) was coupled via a heated (250 °C) transfer line to an Agilent 5973 mass spectrometer detector. Helium at 1 mL/min constant flow was used as the carrier gas. One minute after on-column injection at 35 °C, the oven temperature was increased at 60 °C/min to 60 °C and then at 6 °C/min to 230 °C. The final temperature was held for 10 min. The mass spectrometer was operated in electron impact (EI) ionization mode at 70 eV and a scan range of m/z 50−550.
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RESULTS AND DISCUSSION Sensory Characteristics of the Mango Cultivars. Freshly cut pieces of the flesh of tree-ripened fruits of each of the five mango cultivars were evaluated by trained panelists, first using free-choice profiling (Table 1) and subsequently a Table 1. Sensory Characterization of the Five Mango Cultivars by Orthonasal Free-Choice Profiling (12 Experienced Panelists) cultivar Haden White Alfonso Praya Sowoy Royal Special Malindi
aroma description sweet mango aroma with fruity, tropical, coconut, and pineapple notes sweet mango aroma with terpeny, green, and coconut notes mildest sweet mango aroma with green and mild fruity notes sweet mango aroma with some terpeny, fruity, and raspberry notes sweet mango aroma with some mild terpeny, green, pineapple, and tropical notes
QDA (Figure 1). Results showed distinct differences between the cultivars. The aroma of Haden mangoes was characterized as typical sweet mango-like with strong fruity, tropical, coconutlike notes. White Alfonso also showed a characteristic sweet mango-type aroma, but was less fruity than Haden, instead showing a pronounced terpeny note that distinguished it from all other varieties investigated. The sensory profile of Praya Sowoy was clearly dominated by a strong green, grassy odor note, whereas the scores of the other aroma notes were rather low in this cultivar. The overall aroma of Royal Special mangoes included the characteristic sweet mango-like note, a pronounced fruity note, pineapple-like and floral notes, and, in 4546
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assignments were achieved on the basis of the comparison of RIs and odor characteristics as determined by GC-O on two capillaries of different polarities (FFAP, DB-5) with data of reference compounds analyzed in parallel. No reference compound was available for (E,Z,Z)-1,3,5,8-undecatetraene (25); thus, its structure was tentatively assigned by comparing RIs, odor characteristics, and mass spectra with published data.40−42 The results of the identification experiments in combination with the FD factors revealed the 27 compounds depicted in Figure 2 as the most potent aroma-active compounds in the five mango cultivars, all of which exhibited an FD factor of ≥128 in at least one of the samples analyzed. Among them, sweet, caramel-like-smelling HDMF (47) exhibited the highest FD factor (≥2048) in all five mango cultivars. HDMF, therefore, might be a major contributor to the characteristic sweet mango aroma note common to all cultivars investigated. HDMF has been reported in mangoes before43 but has never been recognized as a major aroma-active compound yet. This might be associated with the volatile isolation techniques applied in previous GC-O studies. Hot steam distillation procedures such as SDE not only imply the problem of artifact formation and compound deterioration but also give rise to low recovery of rather polar odorants such as HDMF.30 For the same reason, most probably, 4-hydroxy-3-methoxybenzaldehyde (vanillin, 54), had never been identified in mangoes before. High FD factors were further determined for some fruitysmelling esters including ethyl butanoate (5), ethyl 3methylbutanoate (7), ethyl 2-methylpropanoate (1), and ethyl 2-methylbutanoate (6). These compounds most probably accounted for the general fruity note in the mango aroma profiles. All of these have already been reported as potent aroma-active compounds in mango,15,20,25 and particularly the importance of ethyl butanoate for the aroma of Haden has been suggested before.15 Similarly, lactones such as γ-octalactone (43) and δ-octalactone (45) have already been held responsible for the coconut-like odor note in mangoes.20,25 The particular pineapple-like aroma note clearly detected in Haden, White Alfonso, Royal Special, and Malindi corresponded quite well to high FD factors of the pineapple-likesmelling odorants (E,Z)-1,3,5-undecatriene (21) and/or (E,Z,Z)-1,3,5,8-undecatetraene (25) in these cultivars. A peculiar raspberry note perceived in the sensory profile of Royal Special might be explained by high FD factors of violetlike-smelling aroma compounds β-ionone (44, FD 512) and dihydro-β-ionone (40, FD 128). Whereas β-ionone is known to be an important contributor to the aroma of raspberries44 and has already been reported as an aroma-active compound in mangoes,20,25 dihydro-β-ionone is reported here for the first time in M. indica. Although β-ionone was also detected as a potent odorant in White Alfonso (FD 512), no such strong raspberry note was present in the sensory profile of this cultivar, probably due to a dominating terpeny odor note. This note might most likely be caused by the terpeny-smelling compounds (Z)-β-ocimene (14) and (E)-β-ocimene (15), which were present in high amounts (FD 512 and 128) in White Alfonso, but rather low (FD ≤32 and ≤4) in the other four cultivars. (E)-β-Ocimene had already been shown to contribute to the aroma of Thai Khieo Sawoei mangoes.16 The tropical aroma note detected in the mango samples might be associated with the tropical, passionfruit-like-smelling 4-mercapto-4-methyl-2-pentanone
Figure 1. Aroma profiles of fresh fruit flesh obtained from five mango cultivars. Panelists rated the intensity of each attribute on a scale from 0 to 3 in 0.5 increments, with 0 = not detectable, 1 = weak, 2 = moderate, and 3 = strong.
particular, an intense and unique raspberry note. The aroma of Malindi was characterized as having a very balanced sweet mango aroma profile with pineapple-like, fruity, green, tropical, and mild terpeny notes, but lacking any special note. Screening the Mango Volatiles for Aroma-Active Compounds. Tree-ripened mango fruits of each cultivar were peeled, the seeds were removed, and the flesh was cut into small sections. To stop enzymatic reactions, the sections were immediately frozen in liquid nitrogen and ground into a fine powder, which was subsequently extracted with diethyl ether. Nonvolatile compounds were removed from the extracts by SAFE,30 and the distillates were concentrated. Elevated temperatures were avoided throughout the entire workup to avoid artifact formation and compound degradation. In particular, the extraction was performed at ambient temperature, and SAFE was carried out at 40 °C. As a result, the smell of the aroma isolates still clearly represented the typical aroma characteristics of the fresh flesh of the corresponding mango cultivars. Aroma isolates were submitted to a cAEDA,27,28 which resulted in 54 aroma-active compounds in the FD factor range from 4 to ≥2048 (Table 2). To assign the structures of the odorous compounds, their RIs, odor characteristics, and mass spectra were compared to data obtained from authentic reference substances. To separate aroma-active compounds from coeluted components and to aid in their identification by GC-MS, each of the aroma isolates was fractionated over silica gel to afford six fractions (A−F). Further aroma isolates of each cultivar were submitted to affinity chromatography38 on mercurated agarose gel to selectively enrich thiols (fraction T). All fractions were subsequently analyzed by GC-O to localize the odorants and then by GC-MS to obtain their mass spectra. This procedure allowed for the structural assignment of 42 of the 54 aroma-active compounds (Table 2). When mass spectra could not be obtained using this procedure, due to either insufficient selectivity or sensitivity of the approach, fractions were further concentrated and analyzed by two-dimensional GC-O with heart-cutting and MS detection. This GC-O/GC-O/MS approach led to the structural identification of two further compounds, namely, compounds 3 and 9. For nine compounds (16, 18, 20, 24, 28, 46, 48, 52, and 53) sufficiently pure mass spectra for identification could not be obtained, but unequivocal structural 4547
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Table 2. Aroma-Active Compounds (FD ≥4) in the SAFE Distillates Obtained from Mangoes of Five Different Cultivars: Haden (H), White Alfonso (WA), Praya Sowoy (PS), Royal Special (RS), and Malindi (M) RId no.
a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 a
odorant
b
ethyl 2-methylpropanoate 2,3-butanedione (E)-2-butene-1-thiol (R)-α-pinene ethyl butanoate ethyl 2-methylbutanoate ethyl 3-methylbutanoate hexanal 3-methyl-2-butene-1-thiol (E)-3-hexenal (Z)-3-hexenal myrcene ethyl hexanoate (Z)-β-ocimene (E)-β-ocimene 1-octen-3-oneh 2-acetyl-1-pyrroline (Z)-1,5-octadien-3-oneh dimethyl trisulfide 4-mercapto-4-methyl-2-pentanoneh (E,Z)-1,3,5-undecatriene ethyl octanoate acetic acid 2-isopropyl 3-methoxypyrazineh (E,Z,Z)-1,3,5,8-undecatetraenei 3-(methylthio)propanal (Z)-3-hexenyl butanoate 2,3-diethyl-5-methylpyrazineh decanal (E)-2-nonenal linalool MDMF (E,Z)-2,6-nonadienal butanoic acid phenylacetaldehyde 2- and 3-methylbutanoic acidj 3-methyl-2,4-nonanedione 2-phenylethyl acetate (E)-β-damascenone dihydro-β-ionone 2-methoxyphenol 2-phenylethanol γ-octalactone β-ionone δ-octalactone trans-4,5-epoxy-(E)-2-decenalh HDMF trans-4,5-epoxy-(E)-2-undecenalh 4-methylphenol γ-decalactone δ-decalactone sotolonh 2-aminoacetophenoneh 4-hydroxy-3-methoxybenzaldehyde
odor quality
c
fruity buttery sulfurous pine-like fruity fruity fruity green sulfurous green green terpeny fruity terpeny terpeny mushroom cooked rice geranium cabbage tropical pineapple fruity vinegar earthy pineapple cooked potato fruity earthy soapy fatty floral, citrus caramel cucumber sweaty, rancid floral, honey sweaty, rancid hay floral cooked apple violet smoky floral, rose coconut violet coconut metallic caramel metallic barnyard peach coconut maple floral vanilla
FD factore
FFAP
DB-5
H
WA
950 985 1008 1010 1015 1020 1055 1085 1090 1130 1140 1155 1200 1250 1270 1295 1350 1360 1385 1388 1400 1419 1420 1430 1435 1450 1460 1495 1480 1530 1550 1578 1580 1610 1640 1660 1715 1785 1810 1825 1860 1901 1910 1930 1963 2005 2015 2095 2070 2140 2190 2195 2200 2600
750
