The malty flavor defect produced by Streptococcus lactis var.
maltigenes has been the cause of considerable economic distress to
various segments of the dairy industry. This study was conducted
in order to develop a more thorough understanding of the chemical
nature of this defect, and to formulate a synthetic malty flavor preparation.
An 18 hour malty culture and an acidified heated skim milk
control were steam distilled using a specially designed, low temperature,
reduced pressure glass apparatus fitted with ground
glass ball or standard taper joints. After subsequent ethyl ether
extractions, the aqueous distillates yielded flavor concentrates
which were suitable for gas-liquid chromatographic (GLC) and
mass spectrometric analysis. Flavor component identifications
were made on both a tentative and positive basis. Tentative identifications were made using the technique of GLC relative
retention times. Identifications were considered positive when
GLC retention data could be coupled with mass spectral data.
Compounds positively identified as being present in the malty
culture included acetaldehyde, 3-methylbutanal, phenylacetaldehyde,
ethanol, butanol, 2-methylpropanol, 3-methylbutanol, 2-furfurol,
phenethyl alcohol, acetone, butanone, 2-pentanone, 2-heptanone,
2-nonanone, ethyl formate, ethyl acetate, ethyl butyrate, ethyl
isovalerate, ethyl octanoate, isoamyl acetate and toluene. Compounds
tentatively identified included 2-methylpropanal, pentanal,
benzaldehyde, 2-furfural, 2-undecanone, 2-tridecanone, ethyl
hexanoate, ethyl decanoate, methyl acetate, γ-octalactone, δ-octalactone,
formic acid and acetic acid.
In the heated skim milk control, acetaldehyde, benzaldehyde,
2-furfural, 2-furfurol, 2-pentanone, 2-heptanone, 2-nonanone,
2-undecanone, 2-tridecanone, ethyl acetate and methyl chloride
were positively identified while pentanal, hexanal, octanal, nonanal,
2-hexanone, 2-octanone, ethyl formate, ethyl octanoate, methyl
acetate, γ-octalactone and δ-octalactone remained as tentative
identifications.
Quantitative evaluations of the volatile constituents present in
each of four strains of the malty culture were conducted using a gas
entrainment, on-column trapping, GLC technique. From the quantitative data obtained from a 24 hour S. lactis var. maltigenes
L/M-20 culture, a synthetic malty flavor preparation, suitable for
use in baked foods, was developed. This investigation used biscuits
as a model system for the baking studies. The biscuits were prepared
using the General Mills' Bisquick mix and a malty milk preparation
replaced the normal milk requirement. The milk contained
1.70 p.p.m. acetaldehyde, 34.20 p.p.m. 3-methylbutanal, 17.90
p.p.m. 2-methylpropanolr 90.10 p.p.m. 3-methylbutanol and 10.00
p.p.m. diacetyl. / Graduation date: 1968
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27013 |
| Date | 09 August 1967 |
| Creators | Sheldon, Ross Mark |
| Contributors | Lindsay, R. C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0021 seconds