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Flavor chemistry of butter cultureLindsay, Robert C. (Robert Clarence), 1936- 14 May 1965 (has links)
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. / Graduation date: 1965
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Actaldehyde production and utilization by lactic culturesKeenan, Thomas William 29 September 1965 (has links)
Acetaldehyde is known to be responsible for the green
or yogurt-like flavor defect of lactic cultures. This study was undertaken
to extend the knowledge of acetaldehyde production and utilization
by microorganisms normally found in mixed-strain butter cultures.
It is anticipated that the resulting information will contribute
to a more thorough understanding of the development of a green
flavor defect; hence, to methods of avoiding and overcoming this
defect.
Acetaldehyde production by single-strain cultures of S. lactis,
S. cremoris, and S. diacetilactis was found to parallel the increase in
microbial population. S. lactis and S. cremoris were found to remove
some of the acetaldehyde produced on continued incubation at
21°C. S. diacetilactis did not remove any of the acetaldehyde produced.
The ratio of diacetyl to acetaldehyde in the strains of S.
diacetilactis studied was found to be unfavorable for a good culture flavor at all times up to 22-24 hr incubation. All of the cultures
studied produced a distinct green flavor when grown in milk media.
All of the lactic streptococci studied produced both ethanol
and acetone when grown in a boiled milk medium. No evidence of
acetone utilization by S. diacetilactis was observed. A tentative
mechanism for the formation of acetone from pyruvate via acetoacetate
was proposed.
Single-strain cultures of Leuconostoc dextranicum and Leuconostoc
mesenteroides were shown to be capable of utilizing added
acetaldehyde under a variety of culturing conditions. These two
organisms, along with L. citrovorum were combined into two-strain
mixtures with various lactic streptococci. The production and utilization
of acetaldehyde varied widely among different two-strain mixtures.
The ratio of different lactic organisms comprising the flora
of a desirably flavored commercial mixed-strain butter culture was
determined. The microbial shift occurring when this culture developed
a green flavor defect was found to be an overgrowth of the homo-fermentative
lactic streptococci by the S. diacetilactis population.
It was found that the concentration of acetaldehyde in a
ripened single-strain lactic culture could be significantly reduced by
adding a large inoculum of a culture of L. citrovorum and continuing
incubation at 21°C or by cooling and holding the culture at 5°C after
the addition of L. citrovorum. / Graduation date: 1966
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Some factors affecting oxidation-reduction potentials in dairy productsAikins, Glenn Allen. January 1931 (has links)
Call number: LD2668 .T4 1931 A34
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Consumer attitudes on filled milkEyster, Carol Irene, 1938- January 1969 (has links)
No description available.
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Flavor chemistry of blue cheeseAnderson, Dale Fredrick 27 September 1965 (has links)
Numerous attempts have been made to identify the flavor
compounds in Blue cheese, however, duplication of Blue cheese
flavor has not yet been accomplished. Therefore, it was desirable
to make a qualitative and quantitative investigation of Blue
cheese flavor compounds and to study the effect of certain microorganisms
on Blue cheese flavor.
The aroma fraction of Blue cheese was isolated by centrifugation
of the cheese and molecular distillation of the recovered
fat. The volatiles were separated by gas chromatography on
packed columns containing polar and nonpolar phases and by temperature
programmed capillary column gas chromatography. Relative
retention time data and fast scan mass spectral analysis of the
capillary column effluent were used to identify compounds in the
aroma fraction. Compounds positively identified were as follows:
2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone,
2-decanone, 2-undecanone, 2-tridecanone, 2-propanol, 2-pentanol, 2-heptanol, 2-octanol, 2-nonanol, methyl butanoate, methyl hexanote,
methyl octanoate, methyl decanoate, methyl dodecanoate, ethyl formate,
ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate,
ethyl decanoate, ethanal, 3-methyl butanal, 2-methyl butanol, 3-methyl
butanol, 1-pentanol, benzene, and toluene.
Tentatively identified compounds included acetone, delta-octalactone,
delta-decalactone, methyl acetate, isopropyl hexanoate,
3-methylbutyl butanoate, pentyl hexanoate, ethyl-2-methylnonanoate,
isopropyl decanoate, furfural, 2-methyl propanal, methanol, ethanol,
2-phenylethanol, cresyl methyl ether, dimethylcyclohexane, diacetyl,
methyl mercaptan, and hydrogen sulfide.
A combination of liquid-liquid column chromatography and gas-liquid
chromatography was utilized to quantitate the major free fatty
acids in Blue and Roquefort cheese samples. The average concentration
(mg acid/kg cheese) in three Blue cheese samples was as
follows: 2:0, 826; 4:0, 1, 448; 6:0, 909; 8:0, 771; 10:0, 1,318; 12:0,
1,588; 14:0, 5,856; 16:0, 12,789; 18:0, 4,243; 18:1, 12,455; 18:2,
1,072; 18:3, 987. Roquefort cheese was found to be proportionately
more abundant in 8:0 and 10:0 acids and low in 4:0 acid compared to
Blue cheese. No formic, propionic, or isovaleric acid was detected
in any of the cheeses tested.
A quantitative procedure involving adsorption chromatography,
liquid-liquid chromatography and absorption spectrophotometry was used to isolate and measure the concentration of the C₃, C₅, C₇,
C₉, and C₁₁ methyl ketones in the fat of Blue and Roquefort cheese.
The average methyl ketone concentration (micromoles ketone/10 g
cheese fat) of five Blue cheese samples was as follows: acetone,
1.7; 2-pentanone, 5.9; 2-heptanone, 11.2; 2-nonanone, 9.3; 2-undecanone,
2. 4. Considerable variation in ketone concentration was noted
between samples, but no consistent differences were observed between
Blue and Roquefort cheese. One Roquefort sample contained
no acetone. The annount of ketone formed during cheese curing does
not depend directly on the amount of available fatty acid precursor.
There appears to be a selective conversion of the 8:0, and to a lesser
extent the 6:0 and 10:0, fatty acids to methyl ketones by the Penicillium
roqueforti spores.
The concentration of the C₅, C₇, and C₉ secondary alcohols
was determined in the same cheeses used for ketone analysis. The
previously measured ketones acted as internal standards and facilitated
a semi-quantitative calculation of alcohol concentrations from
peak areas of gas chrorriatograms. The average alcohol concentration
(micromoles alcohol/10 g cheese fat) in five Blue cheese samples
was as follows: 2-pentanol, 0. 3; 2-heptanol, 2. 1; 2-nonanol,
0. 8. The alcohols were present in approximately the same ratios
as their methyl ketone analogs, but at much lower concentrations.
A synthetic Blue cheese flavor was prepared using a blend of butterfat, dry curd cottage cheese, cream, and salt as a base.
The most typical flavor was obtained using the following' compounds:
the 2:0, 4:0, 6:0, and 8:0 fatty acids at two-thirds the average concentration
found in cheese; twice the average concentration of the
C₃, C₅, C₇, C₉, and C₁₁ methyl ketones and C₅, C₇, and C₉ secondary
alcohols found in cheese: 2.0 mg/kg of base of 2-phenylethanol;
1.5 mg/kg of base of ethyl butanoate; 6.0 mg/kg of base of both methyl
hexanoate and methyl octanoate. Incorporation of higher acids
caused a soapy flavor. The presence of 2-phenylethanol and the esters
was judged as very important in duplicating Blue cheese flavor.
The mycelia of Penicillium roqueforti appear to be more active
in the reduction of methyl ketones to secondary alcohols than the
spores. Yeasts associated with Blue cheese are capable of reducing
methyl ketones to secondary alcohols. Yeasts also may play a role
in Blue cheese flavor by producing ethanol and other alcohols and
certain esters. / Graduation date: 1966
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Properties and composition of milk productsAcosta, Judith S January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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Solvent desorption dynamic headspace analysis of dairy product aroma compoundsRankin, Scott A. 15 December 1995 (has links)
A method for the assessment of volatile compounds in dairy products
was developed using solvent desorption dynamic headspace sampling. The
method was first applied to assay for diacetyl and acetoin in buttermilk.
Major buttermilk volatiles recovered included diacetyl, acetic acid, and
acetoin. Normalized detector responses were linear over the range of
concentrations tested for diacetyl and acetoin. The method enabled
quantitative estimation of diacetyl and acetoin in <30 min, including sample
preparation time.
Next, the ability of stabilizing and emulsifying agents to inhibit the
release of diacetyl from a model dairy matrix was examined using modified
purge parameters. Stabilizers (guar, xanthan, and carrageenan) and
emulsifiers (lecithin, carboxymethyl cellulose, and Tween 80) were
examined for their effects on headspace available diacetyl at 0.05, 0.10, and 0.20% (wt/wt) in a 5% milkfat model system. Guar gum and carrageenan
exhibited similar diacetyl release inhibition when corrected for viscosity.
Xanthan gum exhibited the greatest decrease in headspace available diacetyl
after correction for viscosity at increasing gum levels. Tween 80 imparted no
significant viscosity and had no effect on recoverable diacetyl. Lecithin had
no effect on viscosity, however it did inhibit the release of diacetyl as a
function of lecithin level. Carboxymethyl cellulose increased viscosity and
inhibited diacetyl release.
Finally, a rapid dynamic headspace sampling technique was evaluated
for its ability to differentiate between Cheddar cheese samples for volatile
aroma compounds. Seven samples of Cheddar cheese were examined
ranging in flavor from mild to extra sharp. A total of 14 volatile compounds
were tentatively identified with published retention indices and retention
times of known standards. Major volatiles recovered were 2-butanol,
acetoin, propanoic acid, butyric acid, and caproic acid. Other identified
compounds were 2-butanone, diacetyl, ethyl butyrate, 1-butanol, ethyl
caproate, hexanol, acetic acid, 2,3-butanediol, and octanoic acid.
The application of solvent desorption dynamic headspace sampling of
dairy volatiles is a simple, rapid method for the determination of volatile
compounds previously shown to influence flavor and aroma of dairy
products. This research was conducted to demonstrate the optimized
application of this technology to tracking dairy products aroma compounds. / Graduation date: 1996
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The role of ethanol and certain ethyl esters in the fruity flavor defect of Cheddar cheeseBills, Donald D., 1932- 18 February 1966 (has links)
During the course of ripening, Cheddar cheese frequently develops
a flavor defect described as fruity. Recent work has indicated
that the use of certain starter cultures ultimately results in the
development of the defect as the cheese ages. The flavor compounds
responsible for the defect, however, have not been elaborated. The
purpose of this investigation was to isolate and identify the components
responsible for the fruity flavor defect and to evaluate the role
of certain cheese starter cultures in the development of the defect.
Since the fruity character of the defect is apparent in the aroma
of the cheese, the compounds responsible for the defect were expected
to be reasonably volatile. Volatile constituents were isolated
by a distillation technique from fat expressed from a typically fruity
cheese by centrifugation. The volatile constituents were then separated
by gas-liquid chromatography. By monitoring the odor of the
effluent stream of the column, it was possible to determine which components had fruity odors, and these were subsequently identified
by mass spectral analysis and coincidence of retention time with the
authentic compounds. Ethyl butyrate, ethyl hexanoate, and ethyl
octanoate were found to be the only compounds with detectable fruity
odors.
The volatiles from the fat of four cheeses possessing varying
degrees of the defect and their matching non-fruity controls were
analyzed by a gas entrainment, on-column trapping, gas-liquid chromatographic technique. The manufacturing and curing conditions of
each fruity cheese and its matching control were identical, except
for the use of different starter cultures. Ethanol, ethyl butyrate,
and ethyl hexanoate were more abundant in each of the fruity samples.
The approximate concentration range of these compounds was
as follows: In fruity cheese; ethanol 400 to 2,040 ppm, ethyl butyrate
1.6 to 24 ppm, ethyl hexanoate 0.9 to 25 ppm. In non-fruity cheese;
ethanol 36 to 320 ppm, ethyl butyrate 0.7 to 4.7 ppm, ethyl hexanoate
0.3 to 2.2 ppm. In ten commercial Cheddar cheeses selected at
random from the market, the concentration of ethanol ranged from
5.5 to 620 ppm.
Single-strain cultures of Streptococcus lactis, Streptococcus
diacetilactis, and Streptocococcus cremoris as well as three mixedstrain
commercial cultures were evaluated for ethanol and acetaldehyde
production in non-fat milk medium. Among the single-strain cultures there appeared to be no correlation between ethanol production and
species, although considerable variation was noted for strains within
a species. The mixed-strain cultures were designated A, B, and C.
Cultures B and C had been implicated in the development of the fruity
flavor defect in Cheddar cheese, while culture A produced normal
cheese of good quality. Cultures B and C produced approximately 40
times more ethanol than culture A when incubated in non-fat milk
medium for one month at 7°C.
Certain single-strain cultures and the three mixed-strain cultures
were tested for their ability to reduce acetaldehyde and propanal,
and to catalyze the formation of ethyl butyrate when ethanol and
butyric acid were provided as substrates. Acetaldehyde and propanal
were reduced to the corresponding alcohols by all cultures, but the
formation of ethyl butyrate was not observed in any culture.
A good correlation between high levels of ethanol and high levels
of ethyl butyrate and ethyl hexanoate in the fruity cheeses suggests
that the quantity of ethanol present in the cheese may determine the
amount of ester formed. Further, starters resulting in the defect
produced considerably more ethanol than cultures resulting in normal
cheese when incubated at 7°C, a normal temperature for curing Cheddar
cheese. This observation adds weight to the hypothesis that certain
cultures are directly responsible for the defect. / Graduation date: 1966
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Flavor chemistry of Swiss cheeseLangler, James Edward 31 March 1966 (has links)
The unique flavor of high quality Swiss cheese is difficult to
reproduce in commercial market cheese. Swiss cheese flavor has
never been duplicated or thoroughly understood. New techniques and
advances in flavor research have enabled better definition and understanding
of food flavors. Therefore, it was desirable to make a detailed
investigation of Swiss cheese flavor.
Neutral volatile flavor compounds were isolated from Swiss
cheese fat by low-temperature low-pressure distillation. The compounds
were separated by temperature programmed gas chromatography.
Direct analysis of cheese fat and whole cheese from four
domestic and two imported good flavored cheeses by gas entrainment
and on-column trapping provided a further means of isolation of volatile
flavor compounds in Swiss cheese. Gas chromatography in conjunction
with rapid scan mass spectrometry and relative retention
time data were used to identify compounds.
Compounds positively identified by the distillation and on-column trapping techniques were as follows: methanol, ethanol, 1-propanol,
1-butanol, 2-pentanol, trans-2-hexene-1-ol, 2-phenylethanol, acetaldehyde,
2-methyl propanal, 2-methyl butyraldehyde, benzaldehyde,
phenylacetaldehyde, acetone, butanone, 2-pentanone, 2-hexanone,
2-heptanone, 2-nonanone, 2-undecanone, 2-tridecanone, 2-pentadecanone,
hexane, octane, 1-octene, nonane, 1-nonene, dodecane,
pentadecane, toluene, α-pinene, methyl acetate, methyl hexanoate,
methyl octanoate, methyl decanoate, ethyl propionate, ethyl butanoate,
ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl dodecanoate,
butyl acetate, 3-methyl butyl acetate, γ-valerolactone, γ-dodecalactone,
δ-octalactone, δ-decalactone, δ-dodecalactone, dimethyl sulfide,
diacetyl, benzothiazole, o-dichlorobenzene, 1, 2, 4-trichlorobenzene,
di-isobutyl adipate, and chloroform.
Compounds tentatively identified include an aromatic hydrocarbon,
pinane, α-fenchene, ethyl benzene, a di-methyl benzene,
methyl benzoate, 2-phenyl-2-methyl butane, 5-methyl-5-ethyl decane,
3-methyl butyl octanoate, 2, 5-dimethyl tetra decane, methyl
vinyl ether and 2-methyl propenal.
The concentration of selected volatile compounds identified by
the on-column trapping technique were determined by relating their
peak heights to known quantities of compound. Average concentrations
calculated from the mean values for all the six cheeses and
expressed in parts per million were as follows: dimethyl sulfide. 0.107; diacetyl, 0.8; acetaldehyde, 1.4; acetone, 1.6; butanone, 0.3;
2-methyl butyraldehyde, 0.42; 2-pentanone, 0.98; 2-heptanone, 0.45;
ethanol, 16.3; 2-butanol, 0.3; 1-propanol, 2.9; 1-butanol, 0.7; methyl
hexanoate, 1.5; and ethyl butanoate, 0.6.
Liquid-liquid partition chromatography and gas chromatography
were utilized to determine quantitatively the major free, fatty acids in
the six Swiss cheeses. 2-Methyl butyric acid was detected in all
cheeses and varied from 9.0 to 100.0 mg/kg cheese. The other
isomeric acid, 3-methyl butyric, was detected in only two cheeses.
Formic acid was detected in only one cheese. No n-valeric or
2-methyl propionic acids were detected.
A synthetic Swiss cheese flavor was prepared utilizing the data
obtained in this investigation and that available in the literature for
free amino acids. A satisfactory reproduction of Swiss cheese flavor
could be achieved only if the mixture contained free fatty acids, volatile
constituents, and free amino acids and was adjusted to the pH of
natural cheese. / Graduation date: 1966
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Flavor chemistry of irradiated milk fatKhatri, Lakho Lilaram 25 October 1965 (has links)
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: C₁ through C₁₂, C₁₄ , and C₁₆ n-alkanals; C₃ through C₉,
C₁₁, C₁₃ and C₁₅ alk-2-ones with only traces of C₆ and C₈ alk-2-
ones; and C₅, C₆, C₉, and C₁₂ 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 C₅ through C₁₇
1-Alkenes C₅, C₇ through C₁₇
Fatty acids C₄, C₆, C₈ and C₁₀
n-Alkanals C₅ through C₁₁
Others γ-decalactone, δ-decalactone, 2-heptanone,
benzene, ethyl acetate, chloroform, and
dichlorobenzene.
The tentative identification was obtained for the following
compounds:
γ-lactones C₆ and C₈
δ-lactones C₆, C₈, C₁₁, and C₁₂
1, ?-alkadienes C₁₀, C₁₁, C₁₂, C₁₆ and C₁₇
iso-alkanes C₁₀, C₁₁, C₁₂, and C₁₃
Others methyl hexanoate, 2-hexanone, 4-heptanone
and n-dodecanal.
The compounds present in unirradiated control milk fat included:
short chain fatty acids (C₄, C₆, C₈, and C₁₀), C₈, C₁₀,
and C₁₂ δ-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. / Graduation date: 1966
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