1,570 research outputs found
Flavor chemistry of virgin olive oil: An overview
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth. The present review aims to give an overview on VOO flavor, with particular emphasis on the mechanisms affecting its production and release during a tasting
The flavor chemistry of fortified wines: a comprehensive approach
For centuries, wine has had a fundamental role in the culture and habits of different
civilizations. Amongst numerous wine types that involve specific winemaking processes, fortified
wines possess an added value and are greatly honored worldwide. This review comprises the
description of the most important characteristics of the main worldwide fortified winesâMadeira,
Port, Sherry, Muscat, and Vermouthâstructured in three parts. The first part briefly describes the
chemistry of wine flavor, the origin of typical aroma (primary, secondary and tertiary), and the
influencing parameters during the winemaking process. The second part describes some specificities
of worldwide fortified wine, highlighting the volatile composition with particular emphasis on
aroma compounds. The third part reports the volatile composition of the most important fortified
wines, including the principal characteristics, vinification process, the evolution of volatile organic
compounds (VOCs) during the aging processes, and the most important odor descriptors. Given
the worldwide popularity and the economic relevance of fortified wines, much research should be
done to better understand accurately the reactions and mechanisms that occur in different stages of
winemaking, mainly during the oxidative and thermal aging.info:eu-repo/semantics/publishedVersio
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Flavor chemistry of butter culture
Numerous investigations have been made on the contribution of
butter cultures to the flavor of cultured cream butter, but production
of uniform cultured cream butter has not been possible in industry.
Therefore, it was desirable to investigate in detail the qualitative
and quantitative chemistry of the flavor of high quality butter cultures,
and to examine more closely some of the aspects of flavor
production by butter culture organisms.
Volatile flavor components of high quality butter culture and
control heated milk were isolated from intact samples by means of
a specially designed low-temperature, reduced-pressure steam distillation
apparatus. Most of the flavor compounds present in the resulting
distillate fractions were tentatively identified by gas chromatographic
relative retention time data. Flavor concentrates obtained
by ethyl ether extractions of aqueous distillates were also separated by temperature-programmed, capillary column gas chromatography,
and the effluent from the capillary column was analyzed by a fast-
scan mass spectrometer. Many of the flavor compounds in the flavor
concentrates were positively identified by correlation of mass spectral
and gas chromatographic data. In addition, supporting evidence
for the identification of some flavor components was obtained through
the use of qualitative functional group reagents, derivatives and headspace
gas chromatography.
Compounds that were positively identified in butter culture include
ethanol, acetone, ethyl formate, methyl acetate, acetaldehyde,
diacetyl, ethyl acetate, dimethyl sulfide, butanone, 2-butanol,
methyl butyrate, ethyl butyrate, methane, methyl chloride, carbon
dioxide and methanol; also included were 2-pentanone, 2-heptanone,
acetoin, formic acid, acetic acid, lactic acid, 2-furfural, 2-furfurol,
methyl hexanoate, ethyl hexanoate, 2-nonanone, 2-undecanone,
methyl octanoate and ethyl octanoate. Compounds that were tentatively
identified in butter culture include hydrogen sulfide, methyl
mercaptan, n-butanal, n-butanol, 2-hexanone, n-pentanal, n-pentanol,
2-mercaptoethanol, n-butyl formate, n-butyl acetate,
2-methylbutanal, 3-methylbutanal, methylpropanal, methyl heptanoate,
n-octanal, 2-tridecanone, methyl benzoate, methyl nonanoate,
ethyl nonanoate, ethyl decanoate, methyl dodecanoate, ethyl dodecanoate,
delta-octalactone and delta-decalactone.
Compounds that were positively identified in control heated milk
include acetaldehyde, ethyl formate, ethyl acetate, 2-heptanone,
2-furfural, 2-furfurol, 2-nonanone, 2-undecanone, ethyl octanoate
and methyl decanoate. Compounds that were tentatively identified in
control heated milk include dimethyl sulfide, hydrogen sulfide, ammonia,
methyl mercaptan, methyl acetate, acetone, methanol, butanone,
butanal, n-butanol, methyl butyrate, ethyl butyrate, 2-pentanone,
2-hexanone, 2-mercaptoethanol, 2-furfuryl acetate, ethyl
hexanoate, methyl heptanoate, 2-tridecanone, ethyl decanoate, ethyl
dodecanoate, delta-octalactone and delta-decalactone. The data indicated
that the qualitative flavor composition of control heated milk
and butter culture were very similar. Diacetyl, ethanol, 2-butanol
and acetic acid were noted to be consistently absent in the data for
the control heated milk. Other compounds were not observed in the
heated milk fractions, but were also absent from some of the culture
fractions. This was attributed to their presence in low concentrations,
chemical instability or inefficient recovery.
A modified 3-methyl-2-benzothiazolone hydrazone spectrophotometric
procedure was adapted for the determination of acetaldehyde
produced in lactic starter cultures. The procedure was applied in
conjunction with diacetyl measurements in studying single- and
mixed-strain lactic cultures. The diacetyl to acetaldehyde ratio was
found to be approximately 4:1 in desirably flavored mixed-strain butter cultures. When the ratio of the two compounds was lower
than 3:1 a green flavor was observed. Acetaldehyde utilization at
21°C by Leuconostoc citrovorum 91404 was very rapid in both acidified
(pH 4.5) and non-acidified (pH 6.5) milk cultures. The addition
of five p.p.m. of acetaldehyde to non-acidified milk media prior to
inoculation greatly enhanced growth of L. citrovorum 91404 during
incubation at 21°C. Combinations of single-strain organisms demonstrated
that the green flavor defect can result from excess numbers
of Streptococcus lactis or Streptococcus diacetilactis in relation
to the L. citrovorum population.
Diacetyl, dimethyl sulfide, acetaldehyde, acetic acid and carbon
dioxide were found to be "key" compounds in natural butter culture
flavor. Optimum levels of these compounds in butter culture were
ascertained by chemical or flavor panel evaluations. On the basis of
these determinations, a synthetic butter culture prepared with heated
whole milk and delta-gluconolactone (final pH 4.65) was flavored with
2.0 p.p.m. of diacetyl, 0.5 p.p.m. of acetaldehyde, 1250 p.p.m. of
acetic acid, 25.0 p.p.b. of dimethyl sulfide and a small amount of
sodium bicarbonate for production of carbon dioxide. The resulting
synthetic butter culture exhibited the typical aroma, flavor and body
characteristics found in natural high quality butter cultures, except
that the delta-gluconolactone was found to contribute an astringent
flavor
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Flavor chemistry of irradiated milk fat
Increasing interest has been shown in the irradiation sterilization
and irradiation pasteurization of foods, but problems of off-flavors
and odors are still unsolved, especially in the case of dairy products.
From the flavor chemistry point of view, milk lipids are very highly
susceptible to irradiation effects. Therefore, this investigation was
designed to study some irradiation induced reactions involving flavor
changes in the milk fat and to identify the volatile components produced
in the milk fat upon irradiation.
Milk fat, prepared from raw sweet cream and washed free of
phospholipids, was first irradiated in the presence of air and under
vacuum in glass vials at 4.5 Mrad with gamma rays from cobalt-60.
The irradiation resulted in increase in TBA number, peroxide value,
total monocarbonyls, bleaching of color, slightly rancid and typical
candle-like off-flavors. Free fatty acids were also produced upon
irradiation. The changes were more drastic in air along with production
of a slight oxidized flavor. The monocarbonyls identified by
column and paper chromatographic methods in irradiated milk fat include: Câ through Cââ, Cââ , and Cââ n-alkanals; Câ through Câ,
Cââ, Cââ and Cââ
alk-2-ones with only traces of Câ and Câ alk-2-
ones; and Câ
, Câ, Câ, and Cââ alk-2-enals.
Irradiation of milk fat that had been dried over calcium hydride
also caused free fatty acid production, especially short chain fatty
acids. Methyl octanoate treated with calcium hydride and irradiated
at 1.5, 3.0, 4.5, and 6.0 Mrad yielded small quantities of free
octanoic acid, confirming that irradiation caused fission of the ester
linkage even when traces of water were removed. The quantities of
octanoic acid formed increased with increasing dose of irradiation.
For identification of volatile components, the milk fat was irradiated
in 307x409 'C' enameled cans under vacuum. The headspace
analysis showed some air still left in the cans. Irradiation resulted
in consumption of oxygen and production of hydrogen, carbon
monoxide, carbon dioxide, and methane as identified in the headspace
gases. The volatiles were isolated from the irradiated and
control milk fats by low temperature, vacuum steam distillation at
40°C and 1-2 mm Hg. The volatile components were then extracted
from the aqueous distillate with ethyl ether. The ethyl ether extract
exhibited the typical candle-like defect. The ethyl ether concentrate
was analyzed by combination of GLC and fast-scan mass spectrometric
techniques. Identification of various components was achieved
on the basis of mass spectral data and coincidence of gas chromatographic retention times. In the case of the components
for which only GLC t[subscript r]/t[subscript r] evidence was available or the mass spectra
obtained were not satisfactory, the identity assigned was only tentative.
The volatile compounds that were positively identified to be
present in irradiated milk fat are given below:
n-Alkanes Câ
through Cââ
1-Alkenes Câ
, Câ through Cââ
Fatty acids Câ, Câ, Câ and Cââ
n-Alkanals Câ
through Cââ
Others Îł-decalactone, ÎŽ-decalactone, 2-heptanone,
benzene, ethyl acetate, chloroform, and
dichlorobenzene.
The tentative identification was obtained for the following
compounds:
Îł-lactones Câ and Câ
ÎŽ-lactones Câ, Câ, Cââ, and Cââ
1, ?-alkadienes Cââ, Cââ, Cââ, Cââ and Cââ
iso-alkanes Cââ, Cââ, Cââ, and Cââ
Others methyl hexanoate, 2-hexanone, 4-heptanone
and n-dodecanal.
The compounds present in unirradiated control milk fat included:
short chain fatty acids (Câ, Câ, Câ, and Cââ), Câ, Cââ,
and Cââ ÎŽ-lactones, 2-heptanone, chloroform, dichlorobenzene,
benzene, toluene, and ethyl-benzene. Only tentative identity was
established for most of these components in control milk fat.
Possible reaction mechanisms are presented for the formation of
the compounds in irradiated milk fat
Hybrid Extraction Method; Innovative Method to Produce Non Oxidative Tuna Oil
Summary: The function of Polyunsaturated Fatty Acid such as DHA, EPA are now well known world widely through strong scientific evidences and the importance of nutritional value and popularity are increasing every day all over the world with the name of omega 3 fatty acids.^1,2,3^ However, the fish oil, the source of omega 3 fatty acid had been considered as very vulnerable to oxidation. Many papers say the reason why is because its very easy to oxidize fish oil. The greater the Polyunsaturated Fatty Acid contents in the fish oil is, the faster oxidation takes place.^4,5^ Here I show that tuna oil extracted from Albacore Tuna Head in closed circuit under low temperature, at first decompressing then pressurizing and heating in a container, is very stable against the oxidation and conserved natural contents of Vitamins richly. The oil ware kept in a transparent bottle under natural light and some time under the sun light, with room temperature and opened every day for the sensual odor test during three months. This oil showed a stability of Fatty Acid Composition, Acid Value and Peroxide Value. That mean omega 3 fatty acids are more easy to handle and ample use as food ingredient to put it in many foods such as in a ketchup, mayonnaise, bread and noodle, rather than use in the capsules only
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Wine, Fraud and Expertise
While fraud has existed in various forms throughout the history of wine, the establishment of the fine and rare wine market generated increased opportunities and incentives for producing counterfeit wine. In the contemporary fine and rare wine market, wine fraud is a serious concern. The past several decades witnessed significant events of fine wine forgery, including the infamous Jefferson bottles and the more recent large-scale counterfeit operation orchestrated by Rudy Kurniawan. These events prompted and renewed market interest in wine authentication and fraud detection. Expertise in wine is characterized by the relationship between subjective and objective judgments. The development of the wine fraud expert draws attention to the emergence of expertise as an industry response to wine fraud and the relationship between expert judgment and modern science
Carbocations and the Complex Flavor and Bouquet of Wine: Mechanistic Aspects of Terpene Biosynthesis in Wine Grapes.
Computational chemistry approaches for studying the formation of terpenes/terpenoids in wines are presented, using five particular terpenes/terpenoids (1,8-cineole, α-ylangene, botrydial, rotundone, and the wine lactone), volatile compounds (or their precursors) found in wine and/or wine grapes, as representative examples. Through these examples, we show how modern computational quantum chemistry can be employed as an effective tool for assessing the validity of proposed mechanisms for terpene/terpenoid formation
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