|Abstract or Summary
- It has long been recognized that fermented food products possess
a characteristic but pleasant flavor. The use of such foods, however,
has been limited by the presence of ethanol. Thus the objective of
this research was to investigate the possibility of producing non-alcoholic
fermented juice concentrates.
Three varieties of juices, Concord grape, apple, and blackberry,
were ameliorated as needed and fermented to five to seven
percent alcohol by volume. The fermented flavor was extracted with
ethyl chloride and concentrated by distillation. These extracts were
analyzed by gas chromatography using two different column temperatures.
Low column temperature was 100°C while high column temperature
Four peaks were found to contribute from 93 to 97 percent of
the flavor compounds chromatographically separated from the three
juices at low temperature. By use of the enrichment technique, these peaks appeared to be propyl alcohol, isobutyl alcohol, butyl alcohol,
and a mixture of isoamyl and active amyl alcohol. At high temperature
separation, four peaks were observed to comprise 56 to 64 percent
of the flavor components fractionated. These four peaks appeared
to be a mixture of acetic acid and ethyl octanoate, caproic acid,
phenethyl alcohol and caprylic acid. Other components were tentatively
identified to be acetone, ethyl acetate, ethanol, n-amyl alcohol,
ethyl hexanoate, n-hexanol, propionic acid, 2, 3-butylene glycole,
butyric acid, isovaleric acid, diethyl succinate, 4-butyrolactone,
valeric acid and capric acid.
Freeze drying and a combined method of distillation and freeze
centrifugation were the two methods employed to remove ethanol and
water from the fermented juices. A fivefold concentration of the
original juices was obtained. From 91 to 95 percent of the alcohol
and 80 percent of the water were removed from the juices by freeze
drying while the combined technique removed only 79 percent of the
ethanol and 80 percent of the water. Total acids, color and total
soluble solids were not affected by the freeze drying procedure whereas
the combined technique for removal of the alcohol resulted in some
loss of these constituents.
The fermented dealcoholized juices were analyzed by gas
chromatography using only high temperature columns. These data
indicate that dealcoholization resulted in a decrease in the peak heights of the first ten peaks to be separated. The remainder of the
peaks generally showed an increase although a few exceptions were noted.
The dealcoholized fermented juice concentrates were reconstituted
and evaluated by a flavor panel. The panel data indicated
that the rank order of preference for the three juices was blackberry,
apple and Concord grape. The flavor panel also preferred the juices
served at the higher levels of sweetness. The total average panel
score for these three juices was observed to be about a neutral rating
of "neither like nor dislike".