Citrus Station Mimeo Report 56-8
October 4, 1955
Some Processed Grapefruit Products of Good Quality
R. W. Olsen and E. L. Moore
The utilization of early or high acid content grapefruit has always been a
problem confronting Florida citrus processors. This is especially serious if
the glycoside content is also high thus imparting a bitterness to the extracted
juice. To help overcome these objections, many housewives have diluted grape-
fruit juice with water and added sugar to the diluted juice thereby reducing the
acid and glycoside content, but also unfortunately the flavor. A very acceptable
product could be made commercially by adding sugar and grapefruit oil to grapefruit
juice or concentrate which the housewife could then dilute with water.
As may be readily seen a whole series of both canned and concentrated grape-
fruit packs of various concentrations may be prepared. Thus a canned juice may
be produced by adding sugar to the grapefruit juice of 1.4% acid or higher, to a
final Brix of 210 and then adding the proper amount of grapefruit oil. This
would result in a two-fold canned juice for the housewife. Sugar and oil may
also be added to a 210Brix concentrate to a final 380Brix for the production of a
four-fold frozen concentrate. There are many such combinations that could be
Furthermore artificial sweetening agents may be used to replace sugar for
dietetic packs, especially in concentrated products. Thus by adding the artificial
sweetening agent to the standard 4-fold frozen concentrate a product for dilution
with 7 parts of water could be produced.
Incidentally one of these artificial sweeteners, Sucaryl, is according to the
label 30 times sweeter than sugar. However, we have found that the higher the
acidity in a product the greater the sweetening power of Sucaryl. In limeade
concentrates for instance, we find that the sweetening power of Sucaryl is 60
times that of sugar. However, with grapefruit juices precautions must be taken
as there is the possibility of the Sucaryl accentuating the bitterness normally
found in grapefruit juice.
The main disadvantage in products of this type, particularly from the grow-
er's viewpoint, is that twice as much of this product must be sold to utilize as
much grapefruit juice as is now sold undiluted. However, with possible increased
sales and higher percent profit this disadvantage might be overcome.
Preference Studies on Grapefruit Juices. During the past seven years, we
have been cooperating with the Agricultural Marketing Service, U.S.D.A. to deter-
mine consumer preferences for citrus juices. The survey conducted in Indianapolis,
Indiana on consumer preference for orange juices having a varying Brix/acid ratio
has been completed and was published in December, 1954, as Marketing Research Re-
port No. 76. The AMS publication "Taste Tests on Canned Orange Juice" June, 1953,
provided the necessary background for this survey.
Florida Citrus Experiment Station .
and Florida Citrus Commission,
Lake Alfred, Florida. lI
644 9/30/55 RWO RW J
Due to the difficulty in disposing of the large Florida grapefruit production
a survey was started to determine exactly what the consumer desires as to Brix/
acid ratio and sugar content in grapefruit juices. The U.S.D.A. realizing the
importance and immediate necessity for determining these factors gave this work
a high priority in their outlined projects with the result that a survey, similar
to that conducted on orange juice in Indianapolis, was started. It was believed
that due to the urgency of the work and from experience gathered in the orange
juice survey that much of the preliminary work could be eliminated and the act-
ual project started immediately.
The characteristics of the grapefruit juice packs processed at the Station
for this survey were as follows:
OBrix Ratio OBrix Ratio
10 7 12.6 9
10 9 12.2 11
10 11 11.8 13
10 13 11.6 15
The grapefruit used consisted of about one-half seedy and one-half seedless, since
this was the consensus of opinion of a number of producers of grapefruit juices
as to the normal proportions of seedy and seedless grapefruit used commercially.
These single-strength grapefruit juices were delivered to various homes, se-
lected for the survey, and were graded by the entire family. As a result of this
work we should find out the most desirable ratios and the sugar level most de-
sired by this panel. Almost one-half of each pack was labeled either "Sweetened"
or "Unsweetened", so that the results will further indicate whether people are
prejudiced to these terms.
The results of the survey should be completed and compiled by the end of
Sugar Hydrate Formations in Frozen Citrus Concentrates. In a previous
publication- it was explained that further work was necessary to clarify several
factors involved in sugar hydrate formations in frozen grapefruit and limeade con-
As a result, a series of packs of frozen grapefruit concentrates were pre-
pared, stored, and examined to determine whether heat treatment had any effect on
sugar hydrate formation. These packs consisted of combinations of heated and un-
heated concentrates and syrups, half of which were seeded with sugar crystals.
Examination of these packs seemed to indicate that heat treatment in itself had no
effect on sugar hydrate formation, but heat treatment of the syrup would tend to
insure that all sugar crystals were in solution and hence reduce the possibility
ofchance seeding. Another series of packs were alternately stored at -80F. and
+50F. each month. This temperature fluctuation greatly increased the possibility
of sugar hydrate formation.
1 Olsen, R. W. and Moore, E. L. Sugar hydrate formations in frozen citrus con-
centrates. Food Technol. 8, 175-176 (1954). Reprints available on request.
a Prepared by addition of sugar to the unsweetened juices as listed on left.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
644a 9/30/55 RWO