The tendency for certain single- and mixed-strain lactic
starter cultures to develop a fruity and/or fermented off-flavor
in ripening Cheddar cheese was traced to certain strains of
Streptococcus lactis in the starter. A very intense fruity and/or
fermented flavor developed in experimental cheeses when one particular
S. lactis strain was used as a component microorganism
in the starter culture. Contrary to previous implications, strains
of Streptococcus diacetilactis did not produce a fruity and/or fermented
flavor in experimental cheeses made with starter cultures
containing these organisms. Mixed-strain cultures of Streptococcus
cremoris were used to produce control cheeses, which did not develop
the fruity and/or fermented flavor defect.
The starter culture and treatment of the cheese milk were
the only variables used in the cheesemaking trials. Results obtained indicate that the specific species and/or strain of lactic streptococci
contained in the starter culture affect the flavor score and type of
flavor in the resultant cheese, independent of the temperature of
the heat treatment or hydrogen peroxide-catalase treatment of
cheese milk.
There were no apparent correlations between "normal" and
"defective" starter cultures for the level of proteolytic activity or
production of acetaldehyde or diacetyl to the development of fruity
and/or fermented off-flavor in cheeses. Existing procedures for
the quantification of acetaldehyde, diacetyl and volatile esters were
adapted and modified for determining the concentration of these compounds
in cheese curd and ripened cheese. The method of slurry
preparation, type of diluent and the pH were factors found to affect
the recovery rate for acetaldehyde from cheese.
The relative flavor preference for typical experimental cheeses
was determined with the aid of a flavor panel. A sample of fermented-
unclean cheese received the lowest hedonic flavor score, whereas
the flavor score of a slight fruity and/or fermented sample compared
favorably with that of the reference sample. / Graduation date: 1967
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26793 |
| Date | 10 May 1967 |
| Creators | Bodyfelt, F. W. (Floyd W.), 1937- |
| Contributors | Lindsay, Robert C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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