Group Title: Citrus Station mimeo report - Florida Citrus Commission ; CES 64-5
Title: Effect of freeze damage on internal quality of oranges
Full Citation
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 Material Information
Title: Effect of freeze damage on internal quality of oranges
Series Title: Citrus Station mimeo report
Physical Description: 4 leaves : ; 28 cm.
Language: English
Creator: Blair, James G
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Florida Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1963
Subject: Oranges -- Effect of cold on -- Florida   ( lcsh )
Oranges -- Quality -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: James G. Blair.
General Note: Caption title.
General Note: "October 8, 1963."
 Record Information
Bibliographic ID: UF00072418
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 75957746

Full Text

Citrus Station Mimeo Report CES 64-5
October 8, 1963

Effect of Freeze Damage on Internal Quality of Oranges

James G. Blair
Florida Citrus Commission
Lake Alfred, Florida

The freeze of 1962 is now ancient history. While many serious operating
problems were encountered, most of them were corrected through the cooperative
efforts of everyone associated with the citrus industry. Time for processing -
and condition of fruit were important factors in this past season's operation.
The necessity of processing the crop without delay made only the most primitive
of improvisions possible. Then there was the condition of the fruit for which
most plants were not suitably equipped. Since this condition was caused by an
unusual freeze, the expense of making permanent changes to handle fruit of this
type, in most cases, could not be justified.

Ample time has passed so that review and analysis of all the problems
should have been made and decisions derived as to the course of action to be
taken in case of future emergencies. Even though the complete answer to each
new problem may not be found in the records of those of the past, there is us-
ually some little gem of wisdom that can be utilized. The more problems en-
countered, the more knowledge gained and the longer our industry exists under
this method of learning, the better the chances will be to cope with any future

The freeze had many serious effects on the industry but the one that will
be touched on here this afternoon, is the effect on the determination of pounds
of solids. This can be a problem even under ideal conditions and is, therefore,
very much aggravated by the additional variables introduced as a result of using
freeze damaged fruit. The variable that most effected the pounds of solids de-
termination was- condition of the fruit. This can be best illustrated by referring
to Graph No. 1. This graph was constructed from data furnished by the Inspection
Service of the Florida Department of Agriculture and Dr. Koo of the Citrus Experi-
ment Station. The basic comparison here is the average for 1962 versus that for
1963. Two points can be seen from this comparison; first, there was roughly two
pounds of solids per box more in 196? than in 1963 and second, the 1962 average
was much more uniform than the one for 1963. One reason for this latter difference
was the greater number of boxes processed in 1962 (65,379,000 as against 43,510,000).
The main reason for the wide variance in the 1963 average was the condition of
fruit being measured. The effect of various types of fruit can be seen from the
curves labelled Rozenski, Stuart and East Coast. These curves were selected to
illustrate the effect of averaging and sample selection; the first two were plotted
from data of tests conducted by Dr. Koo of the Citrus Experiment Station in con-
junction with Florida Citrus Mutual. Blocks of Valencia oranges with varying
degrees of freeze damage were selected for these tests and weekly pounds of solids

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
0OO-10/8/63 JGB


analyses were made until the fruit had been harvested. Individual plots on the
curves represent results of tests on single, field selected small samples. The
East Coast curve was plotted from data obtained from tests made on fruit from the
Indian River Branch of the Citrus Experiment Station. Each individual plot on
the curve represents the average results of tests made on at least three repre-
sentative samples. These samples were prepared from fruit from four trees which
had been graded, sized, counted and weighed. As would be expected, the results
from these tests were more uniform than those from either the Stuart or Rozenski
blocks. Most of the Central-or Ridge-fruit was like that shown by the Rozenski
curve but scattered blocks like those shown by the Stuart and East Coast curves
increased the pounds of solids average to that shown by the 1963 curve. The pro-
nounced upswing of this curve at the end of the season was due principally to the
early depletion of the Ridge fruit, and, of the 2,895,000 boxes of fruit measured
subsequent to May 1st, most of it came from the East Coast.

So much for the review of how the pounds of solids this year compared with
those of last year. In passing on, it is interesting to note that the differences
in the two year's figures were mainly the result of juice yield. Condition of the
fruit had very little effect on the other components such as peel and pulp, so as
a result, the juice content from damaged fruit was less than that from undamaged
fruit. Most equipment had been designed to handle a normal juice flow, so when
presented with flows containing smaller percentages of juice, many systems bogged
down. Problems were not similar throughout the State but, in most cases, there
was some loss of recovered solids. This loss in efficiency was sometimes attribu-
ted to the method of testing, and one theory was that,when there was no finishing
after State Test extraction, excess amounts of pulp got into the juice sample.
Therefore, a comprehensive study was made at the Citrus Experiment Station to de-
termine whether results obtained from the State Test extractor were fair and
equitable representation of the loads of fruit measured regardless of condition.
A report of this study was made and distributed last March. Complete details of
the methods and equipment used were included in this report and anyone who did not
receive a copy can pick one up at the reception desk.

Curves shown on Graph No. 2 were plotted from data extracted from the afore-
mentioned study. These curves show the main components of both damaged and un-
damaged Valencia oranges namely, peel, pulp, and juice. In order to better
illustrate the point, one liberty was taken with the previously reported data in
that the juice yield of the damaged fruit was adjusted. This was accomplished by
finding the difference in the average yields between damaged and undamaged fruit
and then adding this difference to the yields of the damaged fruit. Percentages
of pulp for the damaged fruit were then recalculated on the basis of the new
figures. The lower set of curves on Graph No. 2 at just under the 20% line indi-
cate that there is very little difference between the pulp content of the fruit
tested regardless of condition. When the juice yield figures are added to those
of the pulp, the curves indicate that this combination of components represents
about 80% of the total fruit. The remaining amount to complete the 100% would be
made up of peel.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400-10/8/63 JGB

Percentages of pulp, as a function of the total fruit, were obtained by
weighing the orifice discharge from the extractor plus the pulp discharge from
the finisher, when used. Graph No. 2 shows that this percentage varies inversely
as the juice content, i.e. if the juice percentage is decreased either the peel
or pulp or both most increase.

The extracted juice was now analyzed to determine the amount of pulp carry-
over. Several samples were taken from each test and centrifuged. It was found
that there was no significant difference in the percentage of centrifuged pulp
from damaged fruit versus that of undamaged.

The following conclusions can be drawn from the two graphs:

1. The average pounds of solids :for 1963 was off approxi-
mately 30% from that of a normal year, due principally to
decreased juice content.

2. Pounds of solids tests areobviously effected by the
method of selecting samples.

3. The method of extraction used by the Inspection Service
to measure juice yields was not effected by the varying
conditions of the fruit.

h. No additional finishing was necessary with the FMC State
Test extractor.

A great deal of progress has been made on improving the methods of deter-
mining pounds of solids despite adversities such as last year's freeze. Improved
sampling methods have been developed and installed both at the processing plants
as well as here at the Citrus Experiment Station. The development of a new test
extractor continues and the testing of automated methods for measuring Brix and
acid have been very successful. A preliminary report on the performance of the
Mechtron pounds-solids determinator has been made and, unfortunately, this
instrument did not seem to have a practical use in our program. Florida Citrus
Mutual has asked the U.S.D.A. to further evaluate this machine to determine
whether it can be redesigned for use in the citrus industry. Mutual in the
August 22nd issue of the Triangle showed, "Improved Methods of Determining Pounds
of Solids" as one of their primary objectives for this coming year. The basic
groundwork for successful progress on this program during the next biennium has
been laid and with complete cooperation of all interested agencies, it is believed
that this problem can be carried through to a satisfactory conclusion.

For this coming season plans are being formulated to make the primary effort
on completing a satisfactory method of selecting a truly representative sample.
The secondary effort will be made on the continued development of a single satis-
factory method of juice extraction. A principle of extraction that shows promise
has been developed to the point where several experimental machines will be field

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400-10/8/63 JGB

tested in selected fresh fruit houses. The work on automating the internal
quality measurements has been curtailed due to a reduction in the funds re-
quested. Most of the equipment used for experimental purposes is here at the
Citrus Experiment Station where it can easily be viewed and demonstrated; for
those that have not already availed themselves of this opportunity will find
it worth their while to visit the Canning Planb area before they leave.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
h00-10/8/63 JGB












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