Determination of the content of wax esters in some sea foods and their molecular composition. A comparison with ω-3 enriched wax esters

Wax esters enriched in ω-3 fatty acids have been recently shown to be readily absorbed by rats after dietary supplementation. Wax esters are less prone to oxidation and can be better formulated than liquid ω-3 derivatives. All these characteristics suggest a possible use of wax esters enriched in ω-3 as food supplements. However, some naturally occurring wax esters are defined as scarcely digestible (jojoba oil, spermaceti). On the other hand, wax esters have been found in several sources of marine origin, which can enter normal foodstuff. In order to better understand the digestibility of wax esters, we have analysed some foods from marine sources. The content of triglycerides and wax esters of the foods has been determined. Moreover, wax esters have been analysed for their composition in alcohols and fatty acids. Wax esters have been shown to be a part of the neutral lipid extract of the foods analysed. Their content, if compared with the content in triglycerides, shows striking differences. In the case of two botargo preparations, it has been shown that wax esters are more than 90% of the total neutral lipid extract. The content of fatty acids and alcohols found in the foods analysed is consistent with published data.     

VOLATILE CONSTITUENTS OF ORANGE WINE OBTAINED FROM MORO ORANGES (CITRUS SINENSIS[L.] OSBECK)

The volatile constituents of blood orange wine were determined. Moro variety (Citrus sinensis[L.] Osbeck) was used for the production of wine. The fermentation was performed spontaneously at 20C. Volatile components were extracted with dichloromethane, and analyzed by gas chromatography‐flame ionization detection (GC/FID) and gas chromatography‐mass spectrometry (GC/MS). A total of 64 volatiles, including higher alcohols (20), esters (13), terpenes (11), acids (7), volatile phenols (6), lactones (2), acetal compounds (2), ketone (1), aldehyde (1) and acetoin (1) were identified in wine. The total amount of volatile compounds was 125.0 mg/L. Higher alcohols and esters were the largest groups and made up more than 86% of the volatiles.     

The non-glyceride saponifiables of shea butter

Triterpene alcohols and sterols were found to be present in a commercial sample of shea butter (the seed fat of Butyrospermum parkii, Sapotaceae) as esters of both cinnamic and fatty acids. These non-glyceride saponifiables represented 6% by weight of the shea butter under study, whereas free triterpene alcohols and sterols accounted for only 1 % by weight. Cinnamic acid was found neither in the free form, nor esterified to glycerol. Saponification of the non-glyceride saponifiables yielded the triterpene alcohols α-amyrin, butyrospermol, lupeol, β-amyrin and germanicol as major components. Other alcohols identified were parked, 24-methylenelanost-9(11)-en-3-ol, dammaradienol, 24-methylenedammarenol and the two sterols α-spinasterol and Δ⁷-stigmastenol. Esterified to these alcohols were cinnamic (trans and cis), palmitic, stearic, oleic, linoleic and arachidic acids. The fatty acid composition of the non-glyceride saponifiables is different from that of the glycerides. No selectivity was observed in the esterification of these fatty acids by triterpene alcohols and sterols. Investigation of the products from acid catalysed transmethylation has led to two new experimental findings: (i) the difference in reaction rate of fatty acid and cinnamic acid esters and (ii) the formation of methoxylated artifacts from alcohols having unsaturation, in the C¹⁷ side chain, between C²⁴ and C²⁵ by the addition of methanol across the double bond. Analysis of the lipids extracted from shea kernels confirmed that the cinnamic acid esters were only present as non-glyceride saponifiables.     

Characterization of Crude Esterase Activity from Two Plants Used in Cheese Making: Cynara cardunculus L. and Ficus carica L.

For centuries, extracts of Cynara cardunculus and the latex of Ficus carica have been used in cheesemaking, thanks to their proteases that clot milk casein. Since esterase activity is important to release odorous compounds in cheese, in this study we characterized the esterase activity of an extract of Cynara cardunculus and the latex of Ficus carica. The results, obtained by titration, spectrophotometric techniques, zymograms, and tests on agar plates, show the presence of esterase activity in the samples tested, with affinity towards the esters of short chain fatty acids, such as acetic, propionic, and butyric acid. In conclusion, this study provides a background information on esterases of two plants used in cheesemaking and represents a starting point for further investigations of their applications, not only in dairying but also in other industries involved in the processing and transformation of lipids.     

Impact of two Williopsis yeast strains on the volatile composition of mango wine

The aim of the research was to study the volatile composition of mango wine fermented with two Williopsis yeast strains: Williopsis saturnus var. mrakii NCYC500 and W. staurnus var. suaveolens NCYC2586. Thirty terpenoids, twenty‐six esters, ten alcohols, nine acids, seven aldehydes and ketones, two ethers, two phenols and one sulphur compound were identified in the mango wine fermented with strain NCYC500, while twenty‐seven terpenoids, thirty esters, eleven alcohols, eight acids, eight aldehydes and ketones, three ethers, two phenols, one sulphur compound and one furan were detected in the mango wine fermented with the strain NCYC2586. The kinetic changes, final concentrations and odour activity values of major volatiles were compared between the two Williopsis yeast strains and also with other yeast reported in the literature. The results showed that Williopsis yeast strains NCYC500 and NCYC2586 were high producers of acetic acid and acetate esters, but low producers of medium‐ to long‐chain fatty acids and their corresponding ethyl esters. Unlike mango wine fermented with Saccharomyces cerevisiae, most terpenoids derived from mango juice were retained in the resultant mango wine fermented with the two Williopsis yeast strains, suggesting the mango wine could retain the aromatic hints of fresh mango.     

Analysis of volatile compounds in L. edodes blanched by hot water and microwave

The comprehensive flavour characterisation and volatile compounds of raw L. edodes, hot water blanching (HB) sample and microwave blanching (MB) sample were comparatively analysed by electronic nose technology and headspace solid‐phase micro‐extraction combined with gas chromatography‐mass spectrometry (HS‐SPME‐GC‐MS). Results indicated that volatile components in L. edodes markedly changed after HB and MB. Volatile compounds of raw L. edodes consisted mainly ketones, sulphide and alcohols, and 3‐octanone, as well as 1‐octen‐3‐one, were the major compounds. The content of ketones and sulphides in blanched samples markedly decreased, while the relative content of aldehydes, hydrocarbons and esters increased, which became the major volatile compounds of treatment samples. In addition, the percentage contents of esters, alcohols and sulphides in MB samples were significantly (P < 0.05) higher than that in HB samples, especially 1‐octen‐3‐ol, which contributes more to mushroom flavour. Therefore, MB is a better pretreatment method of L. edodes processing and cooking according to the results of experiment.     

Major constituents of fusel oils distilled from Australian grape wines

Fusel oils from Australian grape wines (Vine sp. Vitis vinifera) have been found to consist substantially of ethanol, n-propanol, isobutanol (2-methyl-1-propanol), isoamyl alcohol (3-methyl-1-butanol) and active amyl alcohol (2-methyl-1-butanol). In addition there are present large numbers of aliphatic esters, believed to be of considerable importance to grape brandy and spirit flavour and quality. The quantities and occurrence of these esters have been found to follow a systematic pattern. The major esterified alcohols are related to the free alcohols present and the major esterified acids occur as a series of acids of even carbon number with a maximum concentration at the n-decanoic acid. These relationships provide a basis for calculating the approximate ester composition of fusel oil.     

Insecticidal activity of pyrethrins and related compounds: II.—Relative toxicity of esters from optical and geometrical isomers of chrysanthemic,pyrethric and related acids and optical isomers of cinerolone and allethrolone

Department of Insecticides and Fungicides, Rothamsted Experimental Station, Harpenden, Herts. The relative toxicities of esters related to the natural pyrethrins and to allethrin were evaluated against Phaedon cochleariae (mustard beetle), Tenebrio molitor (yellow mealworm beetle), Dysdercus fasciatus (cotton stainer) and Plutella maculipennis (diamond-back moth) and the results were compared with those of workers who used Musca domestica (housefly). With the insect species used here there were no outstanding reversals of the toxicity ratings established in the studies with M. domestica. However, the toxicities of the esters depended more on the nature of the alcohol when two acids were compared and on the acid component with different alcohols. (+)-Allethrolone and (+)-cinerolone gave more toxic esters than their optical isomers but there was less difference than had been found with other insect species between esters from trans-and cis-chrysanthemic acids.     

HS-SPME-GC-MS analysis of volatile aromatic compounds in alcohol related beverages made with mulberry fruits

Wine aroma is one of the most important parameters responsible for its quality, and hence for consumer acceptance. In order to obtain an appropriate technique to study volatile aroma compounds in mulberry wines, headspace-solid phase microextraction (HS-SPME) comb 40°C for 30 min with a 50/30 μm divinylbenzenecarboxen-polydimethylsiloxane (DVB-CAR-PDMS) fiber. Approximately 80 volatile compounds have been quantified in the mulberry wine, pertaining at several chemical groups, mainly higher alcohols, fatty acids, esters, and some volatile phenols whose concentration range from few to 138.36 mg/L. This work describes a novel methodology for the analysis of mulberry wines by HS-SPME coupled to GC-MS. HS-SPME using a 50/30 μm DVB-CAR-PDMS fiber is provided the higher extraction efficiency (p<0.05) for the volatiles including the most esters, higher alcohols, and fatty acids than by the other fibers.     

Synthesis of aroma compounds by apples supplied with alcohols and methyl esters of fatty acids

Ester synthesis by apples supplied with alcohols (C2–C8) and methyl esters of short chain fatty acids (C4–C8) was studied using gas chromatographic analysis of the products. The substrates were supplied as vapours to whole fruits stored in 2% O₂ at 3°C. The alcohols were converted to the corresponding acetate ester; butanol, pentanol and hexanol were converted most rapidly. The methyl esters of short chain fatty acids (C_n) were converted to esters with an alkyl group (C_n-2, C_n-4) confirming the presence in whole fruits of an active β-oxidation pathway for fatty acids. Ester synthesis was stimulated when apples were supplied with methyl octanoate at different periods during long term storage in 2% O₂. Treatment of the fruit immediately postharvest did not enhance ethylene synthesis.     

The effect of inoculum level on the formation of higher alcohols,fatty acids and esters in the malt whisky fermentation

The levels of higher alcohols, fatty acids and esters formed in a small-scale whisky fermentation which had been inoculated with different amounts of yeast was investigated. The total level of higher alcohols increased with increasing inoculum levels. However, the relative levels of propanol, isobutanol, amyl alcohols and 2-phenyl ethanol were unaffected. The levels of octanoic, decanoic and dodecanoic acids and their ethyl esters were depressed at inoculum levels above 2 × 10⁷ cells ml^?1. Varying the inoculum levels did not have a consistent effect on the acetate esters of the higher alcohols. However, the highest values were obtained at inoculum levels 4 × 10⁷ cells ml^?1.     

Headspace volatiles from frozen berries of sea buckthorn (Hippophaë rhamnoides L.) varieties

The volatile compounds of frozen berries of seven sea buckthorn (Hippophaë rhamnoides L.) varieties of two growing seasons were isolated with solid phase microextraction (SPME), and analyzed with gas chromatography mass spectrometry. A total of 45 volatiles were identified from the headspace. The most numerous compounds found were esters of short chain normal or branched alcohols and acids. Ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl hexanoate, 3-methylbutyl 3-methylbutanoate, ethyl octanoate and 3-methylbutyl hexanoate were the most abundant compounds identified, and they contribute over 70% of the total peak area found in samples. Principal component analysis (PCA) showed differences between the years studied as well as between varieties. Raisa of ssp. rhamnoides origin had the highest variance in the volatile profile compared to the varieties of ssp. mongolica origin.     

Fermentative behavior of Saccharomyces strains during microvinification of raspberry juice (Rubus idaeus L.)

Sixteen different strains of Saccharomyces cerevisiae and Saccharomyces bayanus were evaluated in the production of raspberry fruit wine. Raspberry juice sugar concentrations were adjusted to 16°Brix with a sucrose solution, and batch fermentations were performed at 22 °C. Various kinetic parameters, such as the conversion factors of the substrates into ethanol (Y_p/s), biomass (Y_x/s), glycerol (Y_g/s) and acetic acid (Y_ac/s), the volumetric productivity of ethanol (Q_p), the biomass productivity (P_x), and the fermentation efficiency (E_f) were calculated. Volatile compounds (alcohols, ethyl esters, acetates of higher alcohols and volatile fatty acids) were determined by gas chromatography (GC-FID). The highest values for the E_f, Y_p/s, Y_g/s, and Y_x/s parameters were obtained when strains commonly used in the fuel ethanol industry (S. cerevisiae PE-2, BG, SA, CAT-1, and VR-1) were used to ferment raspberry juice. S. cerevisiae strain UFLA FW 15, isolated from fruit, displayed similar results. Twenty-one volatile compounds were identified in raspberry wines. The highest concentrations of total volatile compounds were found in wines produced with S. cerevisiae strains UFLA FW 15 (87,435 μg/L), CAT-1 (80,317.01 μg/L), VR-1 (67,573.99 μg/L) and S. bayanus CBS 1505 (71,660.32 μg/L). The highest concentrations of ethyl esters were 454.33 μg/L, 440.33 μg/L and 438 μg/L for S. cerevisiae strains UFLA FW 15, VR-1 and BG, respectively. Similar to concentrations of ethyl esters, the highest concentrations of acetates (1927.67 μg/L) and higher alcohols (83,996.33 μg/L) were produced in raspberry wine from S. cerevisiae UFLA FW 15. The maximum concentration of volatile fatty acids was found in raspberry wine produced by S. cerevisiae strain VR-1. We conclude that S. cerevisiae strain UFLA FW 15 fermented raspberry juice and produced a fruit wine with low concentrations of acids and high concentrations of acetates, higher alcohols and ethyl esters.     

Composition of the lipids of lupin seed (Lupinus angustifolius L. var. “uniwhite”)

The total lipids (8.6%) extracted from whole lupin seeds (Lupinus angustifolius L. var. “Uniwhite”) were found to be comprised of triglycerides (71.1%), phospho-lipids (14.9%), free sterols (5.2%), glycolipids (3.5%), sterol and wax esters (0.5%), free alcohols (0.4%), hydrocarbons (0.4%) and unidentified waxy material (4.0%). The main fatty acids in the total lipid extract were linoleic (48.3%), oleic (31.2%), palmitic (7.6%) and linolenic (5.4%). Erucic acid was not present, nor were cyclopropenoid acids. Seed coatings constituted 23.9% of the weight of the whole seeds and contained 1.5% lipids, the main classes of which were triglycerides (38.4%), free sterols (28.0%), phospholipids (9.7%), glycolipids (9.1%) and free alcohols (3.7%). The seed coatings and kernels contained the same fatty acid constituents, but the proportions of oleic, linoleic and linolenic acids were markedly different. β-Carotene was present, although at low concentration. When evaluated on its lipid composition, “Uniwhite” lupin seed appears suitable as a supplement for pig, poultry and stock feeding.     

Volatile constituents of palm wine and palm sap

Palm wine and pasteurised palm sap volatiles were collected, concentrated on a Tenax GC and analysed by gas chromatography and gas chromatography-mass spectrometry. Eighty-two components were identified: 47 esters, 9 alcohols, 5 acids, 6 carbonyls, 2 acetals, 4 terpenes and 9 hydrocarbons. These had all been found previously in conventional wines. Odour evaluation of the separated palm wine components as they eluted suggested that no one compound is responsible for the characteristic palm wine odour. The acetates of higher alcohols and the ethyl esters of straight-chain aliphatic C₆-C₁₀ acids seemed to be important and may play a big role in imparting the fruity nuances of characteristic palm wine odour. Their association with alcohols seemed also to be necessary for the expression of typical palm wine odour. The qualitative difference between palm sap aroma and palm wine aroma appeared to be due mainly to the presence of these esters and alcohols in palm wine and their apparent absence from palm sap, as well as to the presence of some low-boiling esters and alcohols in palm sap and their apparent absence from palm wine.     

Volatile composition and key flavour compounds of spirits from unifloral honeys

The volatile components of industrially produced spirits from three unifloral honeys of campanilla morada (Ipomoea crassicaulis [Benth.] B.L. Robinson), citrus (Citrus spp. L.) and romerillo de costa (Viguiera dentata [Cav.] Spreng.) were studied by combined sensory and instrumental techniques. GC and GC‐MS analyses of the isolated extracts led to the detection of 205 volatile compounds, 150 of them were positively identified. In general, the most abundant classes were saturated alcohols, ethyl esters of saturated fatty acids and terpenes in all samples. Relative aroma intensity of individual volatile components was evaluated by aroma extract dilution analysis of solvent extracts, by gas chromatography‐olfactometry and by odour activity values. Results indicated that 11 compounds: ethanol, ethyl esters of isopentanoic, hexanoic, octanoic and decanoic acids, 2‐phenylethyl acetate, (E)‐β‐damascenone, hotrienol, decanal, methyl anthranilate and ethyl (E)‐cinnamate were the most potent odorants in the honey spirits.     

Smoke and liquid smoke. Study of an aqueous smoke flavouring from the aromatic plant Thymus vulgaris L

An aqueous smoke flavouring from Thymus vulgaris L was obtained. The qualitative and quantitative composition of its dichloromethane extract was studied by gas chromatography and gas chromatography/mass spectrometry. In addition to the common smoke components such as aldehydes, ketones, diketones, esters, acids, furan and pyran derivatives, alkyl aryl ethers, phenol, guaiacol and syringol derivatives, some terpenic compounds were detected. Differences between this aqueous liquid smoke and others from various kinds of wood are due not only to the absence or presence of some compounds but also to the proportions of the different groups of components present in the mixture. Some aldehydes, esters, guaiacol and its derivatives and terpenic compounds contribute to the overall odour of this liquid smoke more significantly than the ketones, furan and pyran derivatives, acids, phenol and its derivatives and syringol. The yield in smoke components obtained from the pyrolysis of Thymus vulgaris L at 488 °C is of a similar order to that obtained from other woods. © 1999 Society of Chemical Industry     

Aroma composition and sensory quality of fruit juices processed from cultivars of elderberry (<Emphasis Type="Italic">Sambucus nigra</Emphasis> L.)

The experiment included identification and quantification of 25 aroma compounds and determination of the sensory quality of fruit juices processed from 32 cultivars of black elder using enzymation. It was concluded that disappearance of 15 esters and the increases of four alcohols, six terpenoids, six carbonyls, six aldehydes, three ketones, eight alcohols, trans-rose oxide, nerol oxide, and dihydroedulan primarily might be due to enzymatic conversion of esters of fatty acids and enzymatic hydrolysis of glucosides as found by processing of juices from other fruits. Juices processed from the elderberry cultivars significantly differed with respect to aroma compound composition and sensory characteristics. Factor analysis of the combined data from measurement of aroma composition and sensory evaluation resulted in extraction of four factors with factor scores that could be used for selection of cultivars with different promising sensory properties and varying concentrations of phenolic acids and flavonoids that may be useful for processing of functional elderberry juices with health promoting properties.     

Sorbent Extraction and Analysis of Volatile Metabolites Synthesized by Lactic Acid Bacteria in a Synthetic Medium

Volatile metabolites synthesized by strains of Luctobacillus brevis, L. fructivorans, L. hilgardii, L. plantarum, Pediococcus parvulus, and Leuconostoc oenos, originally isolated from commercial wines, were extracted from a synthetic medium using C₁₈ sorbent cartridges and analyzed using gas-liquid chromatography. All organisms synthesized isoamyl alcohol, 1-hexanol, 3-(methylthio)-1-propanol, and 2-phenyl ethanol in varying concentrations. Several other alcohols, acids, aldehydes, and esters were produced or utilized by some species or strains and enabled differentiation of the organisms. Recoveries of metabolites were dependent on the compounds, matrix, and presence of ethanol.