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Title: Quality tests for citrus fruits. What every grower should know.
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 Material Information
Title: Quality tests for citrus fruits. What every grower should know.
Translated Title: Circular / Agricultural Extension Service ; no. 315 ( English )
Physical Description: Book
Language: English
Creator: Soule, James
Grierson, W.
Blair, J. G.
Publisher: Agricultural Extension Service, IFAS, University of Florida
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Bibliographic ID: UF00049925
Volume ID: VID00001
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Table of Contents
    Historic note
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        Page 28
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




Circular 315


QUALITY

TESTS FOR

CITRUS FRUITS
Whi Emy G6waw SodaU X/ow


Agricultural Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville


J. Soule
W. Grierson
J. G. Blair


t
,
~~-)


P -Liq








TABLE OF CONTENTS
Page
Minimum Quality (Maturity) Standards ......- .....------......... 3
Legal Basis .. .... .........-------------.------ 3
Factors & Terms-Standard box .........................-....- 5
Crop year .--------- ----.. ....-- 5
Samples for maturity tests ...-......-...--.........-- .......-- 5
Color break ....... ...........------------- -- ------- 5
Juice content ...........------------------ .....---- 6
Brix (total soluble solids) .-----. ...-- ......----------- ---... 6
Total titratablee) acid .........-- .....-- ...... -- -..... 8
Ratio of Brix to total acid ....- ....----- ----------------. 9
Pounds-Solids .. ---.........- --... ----- -----------------. 9
Application of Minimum Quality (Maturity) Requirements ------- 15
Check Current Requirements .................................. 15
Representative Samples: How and Where to Harvest Test Fruit ..... 15
Sampling .-------------- -- 15
Spot Picking .....-------... ----------.......-- 17
Facilities and Equipment .......-------------.....--- 19
Field Tests ........----------......----- -..... 19
Packinghouse ........ ....... ------------...... 19
Cannery ---....-.........---------------...-...- 21
Evaluation of Maturity: Making A Test For Minimum Quality ...... 21
Fresh Fruit ..-..............--------..-... ..- 21
Cannery Fruit ------------- ------- ........--....--..---.... 22
Certification --. ----.........-... .------- .-------------- 24
Fresh Fruit ---.........-....------------ -------. ... .. 24
Cannery Fruit -----....-....... ---------....-.- .- ... 24
Evaluation of Fruit: What Is Your Fruit Worth? ...................... 25
Fresh Fruit ................--------------.......... .. 25
Cannery Fruit ...-.......--------..... ---- ...... ..-.. 25
APPENDICES
I. Minimum Quality (Maturity) Standards for Oranges, Grape-
fruit, Tangerines, 'Temples', Tangelos and 'Murcotts' -....... 27
II. Minimum Quality (Maturity) Standards for Lemons
and Limes ..-------.--- .-------.. -----------..- 27
III. Internal Quality Standards for SunFLAvor Grade ....--.....--- 28

The use of trade names in this publication is solely for the purpose of providing
specific information. It is not a guarantee or warranty of the products named and
does not signify that they are approved to the exclusion of others of suitable com-
position.
June 1967








QUALITY TESTS FOR CITRUS FRUIT
WHAT EVERY GROWER SHOULD KNOW
J. Soule, W. Grierson and J. G. Blair'


More than a hundred million
boxes of oranges, grapefruit, tan-
gerines, 'Temples,' tangelos, 'Mur-
cott' honey oranges, lemons, and
limes are harvested annually in
Florida. About four-fifths are
processed. The remainder is
marketed in fresh form. All citrus
fruits, with minor exceptions, are
subject to inspection for minimum
quality (maturity) before they can
be processed at a cannery or
shipped from a packinghouse.
Tests for minimum quality of
citrus in Florida are utilized in 3
ways. First, as the shipping sea-
son of a variety approaches, the
grower or member of the organiza-
tion that will pick the fruit will
collect periodic samples in the


grove. Tests of these samples
serve the important function of
providing information on the
progress of maturity. They are
used, along with certain other
factors such as market condition
and weather, to determine when
part or all of the fruit may be
harvested. Second, official tests are
run on each lot delivered to a
packinghouse or cannery to see
that the fruit meets minimum legal
standards. Third, tests for juice
and sugar content are run on a
representative sample of each
truckload of fruit received at a
cannery. This provides a fair,
equitable, and legally sound basis
for buying and selling cannery
fruit.


MINIMUM QUALITY (MATURITY) STANDARDS


Legal Basis.-With the excep-
tion of lemons and limes, all of the
laws pertaining to minimum quali-
ty are collected together in The
Florida Citrus Code of 1949, as
amended, Chapter 601, Florida
Statutes. The Code can be changed
-as it has been frequently--only
by legislative action. These legal
requirements, commonly called ma-
turity standards, are really mini-
mum quality standards. They are


designed to keep off the market
green, immature fruit which prov-
ed so detrimental to the interests
of citrus growers, handlers, and
processors before these standards
were developed. To this end, cer-
tain requirements are higher early
in the season of a given variety
and progressively lower as the sea-
son progresses. It is recognized
that citrus fruits undergo favor-
able changes in juice content,


SAssociate Horticulturist, Department of Fruit Crops, Gainesville; Horticulturist,
Citrus Experiment Station, Lake Alfred; and Associate Mechanical Engineer, Florida
Citrus Commission, Lake Alfred, respectively.









sugars, acidity, flavor, and aroma,
as they mature to prime quality
on the tree. Unlike apples, pears,
or bananas, citrus fruits contain
little or no starch and will not ripen
after they are harvested. Thus,
quality must be obtained while the
fruits are still on the trees.
Provisions of the Code relating
to minimum quality and other
matters are administered by the
Florida Citrus Commission. The
commission, a body of 12 citrus
growers, handlers, fresh fruit
shippers, and processors appointed
by the governor, issues regulations,
rules, and orders to carry out the
intent of the Code on a day-to-day
basis. These regulations, rules,
and orders, unlike the Code, can
be, and often are, changed as cir-
cumstances require during the
season.
The Florida Citrus Code, as
amended, and the regulations,
rules, and orders of the Florida
Citrus Commission are enforced by
the Division of Fruit and Vege-
table Inspection, Florida Depart-
ment of Agriculture. Inspectors of
the Fruit and Vegetable Inspection
Division test samples of citrus
fruit for minimum quality under
provisions of the Code. In coopera-
tion with the United States De-
partment of Agriculture, the same
inspectors also enforce U. S.
standards for grade and regula-
tions issued by the (U. S.) Secre-
tary of Agriculture in compliance
with the Citrus Marketing Agree-
ment and -other applicable federal
laws. Each lot shipped as fresh


fruit or processed products is thus
inspected at least twice, once for
minimum quality and again for
grade.
Lemons and limes are in a
special category with respect to
minimum quality standards. At
present, there are no legal stand-
ards for lemons under the Florida
Citrus Code. Production is small
and fresh fruit handlers and
processors are few in number.
Eventually, standards will be
established, probably in the same
manner as for 'Murcotts,' by regu-
lation of the Florida Citrus Com-
mission, until the volume warrants
legislative action and inclusion in
the Citrus Code proper.
Limes were dropped from the
Citrus Code in 1957, and are now
under the Avocado and Lime Ad-
ministrative Committee. Sections
603.151, and 603.152, Florida
Statutes, provide that maturity
standards for limes shall be set by
regulations issued under the Fed-
eral Marketing Agreement for
limes and enforced by state in-
spectors.
U. S. standards for grade of
Florida oranges and tangelos (in-
cluding 'Temples,' 'Murcotts,' and
other mandarin-type hybrids not
classified as tangerines), grape-
fruit, tangerines, and lemons
specify that fruits must be mature
according to the Florida Citrus
Code of 1949, as amended. Similar
Florida standards apply to fruit
within the state. There are sepa-
rate U. S. and Florida standards
for processed citrus products.








In 1965, the Florida Department
of Agriculture established a new
grade, SunFLAvor, to strengthen
the position of Florida produce
relative to other fresh fruits and
processed products. Only fruits
which meet the stringent require-
ments for internal and external
quality may be marketed as Sun-
FLAvor grade.
Factors and Terms Standard
box.-The unit of measure in the
Florida citrus industry is the
"standard-packed-box" of 1-3/5
bushel capacity. Equivalents to
this box are the 2-compartment
jumble-filled field box, which has
a volume of 4800 cubic inches or
2.23 bushels, and a legal weight of
90 pounds for oranges, 'Temples,'
tangelos, 'Murcotts,' and limes, 85
pounds for grapefruit, and 95
pounds for tangerines, respectively.
In the field, fruit maybe handled
either on a volume basis in field
boxes, where each container nomi-
nally has the requisite number to
fill a packed box of 1-3/5 bushels,
or on a weight basis, where the
weight of a lot is divided by the
legal per box weight for the fruit
in question to give the number of
equivalent standard packed boxes.
The latter system is widely used
in the industry, especially for bulk
or cannery fruit.
Crop year.-The administrative
crop year for oranges, grapefruit,
tangerines, 'Temples,' tangelos,
'Murcotts,' and lemons is from
August 1 to July 31, and for limes,
April 1 to March 31.


Samples for maturity tests.-A
standard sample for maturity tests
(exclusive of color break) consists
of ten oranges, 'Temples,' tange-
los, 'Murcotts,' lemons, or limes;
five grapefruit, or fifteen tanger-
ines. With a few exceptions-for
example, the early season ratio
test on oranges-each sample is
composed of fruit of a given size.
Both halves of each fruit must be
used in testing.
Color break.-Before oranges or
other varieties for fresh fruit ship-
ment can be harvested, the dark
green color of the immature fruits
must be replaced or converted sole-
ly by nature to the extent that a
yellow or orange tinge is present.
Color break is required on a stated
percentage of the fruit surface in
the aggregate. "In the aggregate"
means that color break in several
small areas on the fruit surface
is added together as if it were one
large area. The test for color break
is made on a representative sample
of at least 50 fruits which are re-
moved from the lot before the
fruits are put into a degreening
room. Each fruit is compared with
a standard color plaque (Color L-2
on Plate 22 in Dictionary of Color,
Maerz and Paul, 1930). At least
75 percent of the fruits in the
sample must meet the required
color break for the variety in ques-
tion. A test made at night under
artificial light may be repeated in
daylight if either the inspector or
packinghouse representative so de-
sires. In practice, a test for color
break is not always made on a par-









ticular lot, since the fruit must be
examined for color later in connec-
tion with U. S. grade inspection.
Juice content. Quantity of
juice in citrus fruits is expressed
in three different ways; as gallons
per box for oranges, cubic centi-
meters per fruit for grapefruit,
and percentage by volume for
limes and lemons. To obtain the
first two, fruits of a given size
are cut in half across the stem-
to-blossom axis. Juice is extracted
by hand, with the official reamer
and orange burr, or with a me-
chanical extractor. It is strained
through a double layer of cheese-
cloth, wire strainer, or colander,
with sufficient pressure applied to
squeeze out the juice while leav-
ing the juice sacs, pulp, seeds, and
"rag" behind. Too little pressure
will result in a lower volume of
juice; too much will introduce par-
ticles which may interfere with
pipetting. Strained juice is then
measured in a graduated cylinder.
Conversion of cubic centimeters of
juice per 10-fruit orange sample to
gallons per box is given in Table 1.
The volume of whole limes or
lemons is found by water displace-
ment. The simplest device is a cyl-
inder with a side spout as shown in
Figure 1. The cylinder is first
filled to overflowing. Then the
sample is introduced, with care
that all of the fruits are sub-
merged. The water displaced is
measured. Quantity of juice is
found as for oranges or grapefruit
above, measured in cubic centi-
meters, and converted to percent-


age by dividing the cubic centi-
meters of water displaced times
100.


FIGURE 1. Cylinder for determination
of volume of lemons or limes.

Brix (total soluble solids). -
Juice of citrus fruits contains a
large number of soluble constit-
uents, chiefly sugars, with smaller
amounts of organic acids, vita-
mins, proteins, free amino acids,
essential oils, glucosides, and other
compounds also present. Approxi-
mately 85 percent of the total
soluble solids are sugars. They are
measured as such in official tests
by means of a Brix hydrometer.
This instrument, which actually
measures specific gravity, is cali-
brated to read directly in degrees
Brix, or percent pure sucrose, at a
temperature of 17.5C. In citrus
testing, the term "Brix" or "de-
grees Brix" is synonymous with
total soluble solids and is used
throughout this bulletin to avoid
confusion with "pounds-solids."





Table 1.-Conversion of Cubic Centimeters of Juice Per 10-Fruit Orange Sample to Gallons per 1-3/5 Bushel Box.'
DIRECTIONS: 1. To use the table, find the closest figure (under the size column of fruit being tested) that corresponds to the actual
cubic centimeter reading on the graduated cylinder in which the juice is measured, then trace the line beneath the number to the gallons
per box column on right or left. The figure above the line followed will show the computed number of gallons per box to the nearest tenth
gallon. 2. For example, if 10 navel oranges of size 216 gave 967 cubic centimeters of juice, a 1-3/5 bushel box of this size would contain
5.5 gallons of juice.
Gal. Fruit Size or Count Per 1-3/5 Bushel Box Gal.
Per 96 125 250 Per
Box 100 126 150 163 176 200 216 252 288 324 Box
4.0 1577 1202 1009 929 860 757 701 606 526 467 4.0
4.1 1617 1232 1035 952 882 776 719 612 539 479 4.1
4.2 1656 1262 1060 975 903 795 736 636 552 491 4.2
4.3 1696 1292 1085 999 925 814 754 651 565 502 4.3
4.4 1735 1322 1110 1022 946 833 771 666 578 514 4.4
4.5 1774 1352 1136 1045 968 852 789 681 591 526 4.5
4.6 1814 1382 1161 1068 989 871 806 697 605 537 4.6
4.7 1853 1412 1186 1091 1011 890 824 712 618 594 4.7
4.8 1893 1442 1211 1115 1032 909 841 727 631 561 4.8
4.9 1932 1472 1237 1138 1054 927 859 742 644 572 4.9
5.0 1972 1502 1262 1161 1075 946 876 757 657 584 5.0
5.1 2011 1532 1287 1184 1097 965 894 772 670 596 5.1
5.2 2050 1562 1312 1208 1118 984 911 787 683 670 5.2
5.3 2090 1592 1338 1231 1140 1003 929 802 697 619 5.3
5.4 2129 1622 1363 1254 1161 1022 946 818 710 631 5.4
5.5 2169 1652 1388 1277 1183 1041 964 833 723 643 5.5
5.6 2208 1682 1413 1300 1204 1060 981 848 736 654 5.6
5.7 2248 1712 1438 1324 1226 1079 999 863 749 666 5.7
5.8 2287 1742 1464 1347 1247 1098 1017 878 762 678 5.8
5.9 2326 1773 1489 1370 1269 1117 1034 893 775 689 5.9
6.0 2366 1803 1514 1393 1290 1136 1052 908 789 701 6.0
6.1 2405 1833 1539 1417 1312 1155 1069 924 802 713 6.1
6.2 2445 1863 1565 1440 1334 1173 1087 939 815 724 6.2
6.3 2484 1893 1590 1463 1355 1192 1104 954 828 736 6-3
6.4 2524 1923 1615 1486 1377 1211 1122 969 841 748 6.4
6.5 2563 1953 1640 1509 1398 1230 1139 984 854 759 6.5


'Adapted from Citrus and Vegetable Inspection Division,


Florida Department of Agriculture. Based on 3785.4 cubic centimeters per gallon.










The test for Brix may be run on
the same juice which was measur-
ed previously for juice content or
on a separate sample of fruit of
a given size. The Brix hydro-
meter and a thermometer are in-
serted into a tall cylinder filled
with juice. Samples squeezed by
hand or with the official reamer
contain comparatively little trap-
ped air so that the hydrometer and
thermometer can be read after a
few moments. (If a high-speed
reamer is used, the juice should be
deaerated with an aspirator prior
to insertion of the hydrometer into
the cylinder.) Temperature correc-


tions for Brix readings to the stan-
dard 17.5C are given in Table 2.
Unofficial readings of Brix con-
tent may be obtained with a re-
fractometer. Refractive index ex-
pressed in terms of pure sucrose
may be measured in seconds with
a few drops of juice. Hand models,
which can be read to the nearest
0.1 percent Brix, or more accurate
table models are available. At
present, neither instrument can be
used for official tests.
Total titratablee) acid.-Acid in
citrus juices is principally citric
acid, with smaller amounts of
malic, tartaric, and succinic acids


TABLE 2.-Temperature Correction
17.5C.


for Degrees Brix to


Standard Temperature


Correction Factor
oBrix
-0.45
-0.40
-0.40
-0.35
-0.30
-0.30
-0.25
-0.25
-0.20
-0.15
-0.10
-0.10
-0.05
-0.05
0.00
0.00
+0.05
+0.05
+0.10
+0.10
+0.15
+0.15
+0.20
+0.20
+0.25


Temperature
C
22.5
23.0
23.5
24.0
24.5
25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0


Correction Factor
*Brix
+0.25
+0.30
+0.35
+0.35
+0.40
+0.40
+0.45
+0.50
+0.55
+0.55
+0.60
+0.65
+0.65
+0.70
+0.75
+0.75
+0.80
+0.85
+0.90
+0.90
+0.95
+1.00
+1.05
+1.10
+1.10
+1.15


Temperature
C
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
21.0
21.5
22.0


--








also present. Twenty-five cubic
centimeters of the same juice used
for the Brix test are drawn up in
a pipette and drained into an erlen-
meyer flask. Three or four drops
of phenolphthalein indicator solu-
tion are added. The burette is
filled with the solution of 0.3125
N standard sodium hydroxide and
adjusted to the zero mark. Alkali
is added slowly to the flask with
constant agitation until the pink
endpoint is reached. Titration may
be carried out with one of three
methods:
A. With a special "direct read-
ing" burette, acid is read to the
nearest 0.1 percent on the burette.
B. If an ordinary burette is used
with 0.3125 N alkali, the quantity
consumed must be converted to
percent acid by means of Table 3.
C. Another method, which can-
not be used for official tests, is
titration with "direct reading
alkali." In this case, each cubic
centimeter of 0.4063 N sodium
hydroxide in an ordinary burette
corresponds to 0.1 percent citric
acid. Titration with this stronger
alkali does sacrifice a little ac-
curacy, but is rapid and does not
require a special burette.
Although it is universally called
"total acid," strictly speaking the
amount of acid found by titration
should be termed titratablee acid"
since additional acid not ordinarily
neutralizable is actually present in
the juice.


In maturity testing acid found
by titration is always expressed in
terms of percent anhydrous citric
acid.
Ratio of Brix to total acid.-The
proportion of Brix to total acid,
or ratio, is found by simple
division, reference to a ratio book1,
or using the nomograph for ratio
(Figure 2).
There is a sliding scale for ratio
requirements of oranges, grape-
fruit, 'Temples,' tangerines, and
tangelos. Fruit with higher Brix
can have higher acid, or a lower
ratio, than one with lower Brix.
The proportion of sugars to acid
plays a large part in palatability;
hence, when sugars are low, ratio
requirements are increased so that
acid is proportionately even lower.
This makes the sugars more per-
ceptible to the taster's palate.
Note, however, that maturity re-
quirements of most varieties also
include a minimum ratio, which
must be met regardless of the Brix
content of the juice.

POUNDS-SOLIDS
Each season canneries in Flori-
da process about four-fifths of the
citrus crop into frozen concentrate,
chilled juice, single-strength juice,
sections, salads, blends, and other
products. Fruit for single-strength
juice and similar uses is common-
ly purchased by weight. Fruit of
the highest possible internal quali-
ty is desired for frozen concen-


"'Citrus Maturity Ratio Tables," E. E. Raasch, Fla. Citrus Inspection Division
Published by Fla. Grower Press, Inc., Tampa.











Table 3.-Conversion of Standard (0.3125 N) Alkali Solution to Percent Anhydrous
Citric Acid. (For Method B only; do not use with either Method A or Method C.)


Standard Citric
(0.3125 N) Acid
Alkali Anh.
C. C. Pet.
1.0 .........----........ 08
2.0 ........................ .15
2.5 ......................-- .. .19
3.0 ................-- ...- 23
3.5 ..................- ... 27
3.6 .................-- ..28
3.7 ...----............. 285
3.8 ...................... .29
3.9 ..................... .30
4.0 ........- .......- .31
4.1 .... ..--....... .315
4.2 .-...... .......... .32
4.3 ........--.......... .33
4.4 .............---- .34
4.5 ............... 345
4.6 .... ............ .35
4.7 .........--...--. .36
4.8 .......... --..... .37
4.9 .........-- ......- .38
5.0 .... ... .... .... .385
5.1 ...-..-.... ....... .39'
5.2 ......... .... .... .40
5.3 .........-.. ........ .41
5.4 ................ 415
5.5 ............-.. .42
5.6 ............... .43
5.7 ............ ..... -- .44
5.8 ...... ...... .445
5.9 -............-- .45
6.0 .......-........ 46
6.1 ............... .... .47
6.2 ................. .48
6.3 ...... ... ... .485
6.4 ................- .49
6.5 .. ............... 50
6.6 .... ......... 51
6.7 .......... .515
6.8 ................ 52
6.9 ........ .. ........... 53
7.0 .....................- .54
7.1 ...... ............ .. .545
7.2 ......... ............ 55
7.3 ............... .56
7.4 -........ ....-.. .. .57
7.5 ... ............... .58
7.6 .......... ..... .585
7.7 ............... .59


Standard
(0.3125 N)
Alkali
C.C.


Citric
Acid
Anh.
Pct.


7.8 ........................ .60
7.9 ....................... .61
8.0 ........-.......--- .615
8.1 ................... ..... .62
8.2 .............. .... .63
8.3 .................. .64
8.4 ................... .645
8.5 .............. ....... 65
8.6 ...... .... .... ... .66
8.7 ......-.........- -...- .67
8.8 ...........-..... .68
8.9 ........... ... .685
9.0 ............... .69
9.1 ...........--.... .70
9.2 .... ....~.... .71
9.3 -............... .. .715
9.4 .........-.... ..72
9.5 ............ ... .. .73
9.6 ......... ..... .74
9.7 ............ .... .745
9.8 .......... .... 75
9.9 ............ .. -..- .76
10.0 .................. .77
10.1 .... .............. .78
10.2 ..... ............... 785
10.3 --............- ..... 79
10.4 ........................ 80
10.5 ..... .... ... 81
10.6 ................... .815
10.7 .............. ...... .82
10.8 ... ............... .83
10.9 .... .......... .84
11.0 ................... .845
11.1 ................ ..... 85
11.2 .....................86
11.3 ................... .87
11.4 ................... .88
11.5 .............. ..... .. .885
11.6 ..................... 89
11.7 ............... .... .90
11.8 ........... ....... .91
11.9 ................... .915
12.0 ................... .92
12.1 ................... .93
12.2 .......... ......... .94
12.3 ........... ........ .945
12.4 ...... .. .95


Standard
(0.3125 N)
Alkali
C.C.


Citric
Acid
Anh.
Pet.


12.5 ................... .96
12.6 ~.........-.......97
12.7 .........--..--- ..98
12.8 .....-.............--- .985
12.9 ......................... .99
13.0 ............-......... 1.00
13.1 ... ...........---...- 1.01
13.2 .................. 1.015
13.3 ..-...... .......-- 1.02
13.4 ...............---... 1.03
13.5 ............ ..- 1.04
13.6 ................... 1.045
13.7 .................... 1.05
13.8 .................... 1.06
13.9 ................ 1.07
14.0 ........... .- .. 1.08
14.1 ............... .. 1.085
14.2 .... --... ..... 1.09
14.3 ............ ......... 1.10
14.4 .....................-.. 1.11
14.5 ............... 1.115
14.6 -.......... -...... 1.12
14.7 ...........-... 1.13
14.8 ................ 1.14
14.9 ..... .............. 1.145
15.0 --......... ----- 1.15
15.1 .......... ....... 1.16
15.2 ....... 1.17
15.3 ..........- .... 1.18
15.4 -........ ..... 1.185
15.5 .................... 1.19
15.6 .......... ...... 1.20
15.7 ................ 1.21
15.8 ................ 1.215
15.9 .................. 1.22
16.0 ........................ 1.23
16.1 -...... .......... 1.24
16.2 ............... 1.245
16.3 ............... 1.25
16.4 ..................... 1.26
16.5 ....................... 1.27
16.6 .............. 1.275
16.7 ................... 1.28
16.8 ... .... .......... 1.29
16.9 .---........... 1.30
17.0 .......................... 1.31
17.1 ..... -1.315










Standard Citric
(0.3125 N) Acid
Alkali Anh.
C. C. Pet.
17.2 .......................... 1.32
17.3 .......................... 1.33
17.4 ............---..--... 1.34
17.5 .......................... 1.345
17.6 ........-....-............ 1.35
17.7 ......................... 1.36
17.8 -....................-.... 1.37
17.9 .......................... 1.38
18.0 .......................... 1.385
18.1 .................-........ 1.39
18.2 ......................... 1.40
18.3 .................-....... 1.41
18.4 ......................... 1.415
18.5 ......................... 1.42
18.6 ......-........--...... 1.43
18.7 ............... ........... 1.44
18.8 ................... ... 1.445
18.9 ............-..-...... 1.45
19.0 -........................ 1.46
19.1 ......................... 1.47
19.2 .......................... 1.475
19.3 ---....... ---.... 1.48
19.4 ......................... 1.49
19.5 .......................... 1.50
19.6 .............. .... .. 1.51
19.7 .........---.--. 1.515
19.8 ............----...----1.52
19.9 --..-..... ---.... 1.53
20.0 ................~........ 1.54-
20.1 -.....-- .......-.. 1.545
20.2 ...................... 1.55
20.3 ...... ......-..---... 1.56
20.4 -.... ... 1.57
20.5 .......................... 1.58
20.6 .......................... 1.585
20.7 --.-- 1.59
20.8 ............. .......... 1.60
20.9 --....-..- 1.61
21.0 .--...--........ 1.615
21.1 ..................... 1.62
21.2 ..----- 1.63
21.3 .................. ..... 1.64
21.4 ...............---.. 1.645
21.5 .-......... ... -- 1.65
21.6 ........----- ... 1.66
21.7 .......................... 1.67
21.8 ................ ....... 1.68
21.9 ..................... .. 1.685
22.0 -.. ..- ...... 1.69
22.1 .......................... 1.70
22.2 ................ ...... 1.71


Standard Citric
(0.3125 N) Acid
Alkali Anh.
C. C. Pct.
22.3 -..--......-... ....-- -- 1.715
22.4 ..--- -................. 1.72
22.5 ...-- ....-...--.. 1.73
22.6 .......- -.........-- 1.74
22.7 ...---.........---- .. 1.745
22.8 -............. .. 1.75
22.9 -............ ........ 1.76
23.0 ..---....--..- ... --- 1.77
23.1 .----...- ...---.. 1.775
23.2 .................... .. 1.78
23.3 ......---.....-- 1.79
23.4 .--..........- ---- .. 1.80
23.5 --........-..- 1.81
23.6 ............... 1.815
23.7 -.........--........... 1.82
23.8 .............- 1.83
23.9 ..--.......--....--- 1.84
24.0 ........--- ...----.. 1.845
24.1 ---.........-- 1.85
24.2 ..................-- 1.86
24.3 .....................-- 1.87
24.4 -.................... 1.88
24.5 --..-.... .. ......... 1.885
24.6 ..... ........ ....... 1.89
24.7 -----..-............ 1.90
24.8 ...... .......... 1.91
24.9 --- ..... ........... 1.915
25.0 ....--- 1.92
25.1 ..................... ---1.93
25.2 ..................-- 1.94
25.3 ... .... ........... 1.945
25.4 .....................-- 1.95
25.5 ....................--- 1.96
25.6 -.... 1.97
25.7 ........ .. 1.98
25.8 ..... .... ..... 1.985
25.9 ..----......-.... .. 1.99
26.0 .....- .............. 2.00
26.1 --- 2.01
26.2 ..-------.............. 2.015
26.3 ......... .......... 2.02
26.4 ........................ 2.03
26.5 ..... ....... ...... 2.04
26.6 --.....-......-.. 2.045
26.7 ....--- ....-- ...--... 2.05
26.8 .......................... 2.06
26.9 ..-- ..-.........---. 2.07
27.0 .......................... 2.075
27.1 .................. .. ... 2.08
27.2 ........................ 2.09
27.3 .......................... 2.10


Standard Citric
(0.3125 N) Acid
Alkali Anh.
C. C. Pct.
27.4 .......................... 2.11
27.5 .......................... 2.115
27.6 ......................... 2.12
27.7 ......................... 2.13
27.8 .--......--....... .. 2.14
27.9 ............ ----..... .. 2.145
28.0 ......................-. 2.15
28.1 .......................... 2.16
28.2 ........-..........--- .... 2.17
28.3 .......................... 2.175
28.4 .......................... 2.18
28.5 .........-................ 2.19
28.6 ........---......-........ 2.20
28.7 .............-........... 2.21
28.8 ...........-- ..-..- .... 2.215
28.9 ...........-- ............. 2.22
29.0 --... -..-... ---......-- 2.23
29.1 .........-----.. .......--- 2.24
29.2 ........................ 2.245
29.3 ....--.....-----........ 2.25
29.4 .......................... 2.26
29.5 .......................... 2.27
29.6 --.........---........--- 2.28
29.7 .......................... 2.285
29.8 ......... ~~...-........ 2.29
29.9 ........................ 2.30
30.0 --.. ...-- ---........ 2.31
30.1 ..------ ........ 2.315
30.2 .......................... 2.32
30.3 .......................... 2.33
30.4 .............-........... 2.34
30.5 .............-- .......... 2.345
30.6 .......................... 2.35
30.7 -..-.....- ----- ..-. 2.36
30.8 ......................... 2.37
30.9 ................... -- 2.375
31.0 .......................... 2.38
31.1 .......................... 2.39
31.2 .......................... 2.40
31.3 .......................... 2.41
31.4 .......................... 2.415
31.5 .......................... 2.42
31.6 .......................... 2.43
31.7 .........--......... .. 2.44
31.8 .............-..-......... 2.445
31.9 .......................... 2.45
32.0 ......................... 2.46
32.1 .....--.......-....-.... 2.47
32.2 .......................... 2.48
32.3 .......................... 2.485
32.4 -....................... 2.49
32.5 ....................... 2.50











Percent Brix


Brix/Acid I


18.0


17.0


16.0


15.0


14.0


13.0


12.0


11.0


10.0


9.0


8.0


7.0


6.0


2.0
SRatio

4.0


S6.0


8.0


S10.0


12.0


S14.0


-16.0


18.0


20.0


Percent Acid
3.0
2.5

2.0
1.8
1.6
1.5
1.4
1.3
1.2
1. 1
1.0
.90
.80

.70
.65
.60
.55
.50

.45

.40

.35

.30


FIGURE 2.-Conversion of Brix and percent acid to Brix-acid ratio.


trate since, in addition to having
better flavor and aroma, values
rise rapidly as the quantity of
juice and Brix increase. Most
plants buy their fruit for concen-


trate, chilled juice, and the like
on the basis of pounds-solids. This
is a good arrangement for the
grower and processor alike be-
cause higher internal fruit quality


22.0


24.0


26.0







is rewarded by a commensurate re-
turn. Today, the grower who sends
fruit to the cannery is no longer
producing merely boxes of citrus
but rather juice and pounds of
sugar per acre.,
Pounds-solids-is calculated as
follows:


Pounds-solids=Weight Brix
of juice per box X 100.

For example, if a box of oranges
contained 45.0 pounds of juice and
the Brix was 10.0 percent, the
pounds-solids per box would be
10.0
45.0 X --= 4.5000.
100


APPLICATION OF MINIMUM QUALITY
(MATURITY) REQUIREMENTS


Minimum quality requirements
prescribed in the various laws,
standards for grade, and lime
marketing agreement apply
throughout the year. Tests may
be made at anytime after the fruit
is harvested, except in cases where
violation of arsenic provisions of
the Florida Citrus Code, as amend-
ed, is suspected. Samples then
may be taken from the trees. (Use
of arsenic in any form on bearing
citrus trees except grapefriut is
illegal and renders the fruit liable
to seizure.)
The laws, standards for grade,
and lime marketing agreement
have been amended numerous
times. For this reason, the legal
requirements for each type of fruit
have been assembled in dated sup-
plements to this bulletin. Appen-
dix I contains minimum quality re-
quirements for oranges, grapefruit,
tangerines, 'Temples,' tangelos, and


'Murcotts'; Appendix II for lemons
and limes; and Appendix III for
SunFLAvor grades. Supplements
will be revised when changes in
the requirements make this advis-
able.
Requirements f o r minimum
quality are based on color break,
juice content, Brix, acid, and Brix-
to-acid ratio, but these are not ap-
plied to every type of fruit. Factors
which apply to fresh fruit are sum-
marized in Table 4, and to can-
nery fruit, in Table 5. Information
is current as of June 30, 1966.
Check Current Requirements.-
Requirements for minimum quali-
ty, standards for grade, and
marketing agreements are con-
stantly being revised. Check with
the Division of Fruit and Vegeta-
ble Inspection to be sure that the
standards you are using are up to
date. If necessary, send for revised
Appendices to this bulletin.


REPRESENTATIVE SAMPLES:
HOW AND WHERE TO HARVEST TEST FRUIT


Sampling.-A test for maturity
is no more accurate than the


sample that is taken from a group
of trees or lot of fruit. To be use-



























Br



















A


17.0


16.0


15.0


14.0


13.0


12.0


11.0


10.0


9.0


8.C


7.0


6.0


FIGURE 4.-Conversion of Brix and pounds of juice per box into pounds of solids
per box and price per box of oranges.


Pounds Solidi per Box
2.0


3.0

Pri



5.0


4o 6.0
e


7.0
o

8.0


9.0


10.0


11.0

C


ce per
d Solids
1.00
0.90
0.80
0.70
0.60
0.55
0.50
0.45
0.40
0.35
0.30

0.25


D(


S




B


I A


dollars p




























15





D .05
E


Box
6.00

5.50


5.00


4.50


4.00


3.50


3.00


2.50


2.00


1.50


1.00


0.50







ful, a sample must be representa-
tive, that is, it must reflect as
nearly as possible actual condi-


TABLE 4.-Factors Used in Minimum (
Citrus Fruits, as of June 30,


tions on the trees or among the
lot brought to the packinghouse or
cannery.


quality Requirements for Florida Fresh


Color Juice Brix/Acid Ratio
Fruit Break Content Brix Acid Required' Minimum

Oranges' Yes Yes' Yes Yes Yes Yes
Grapefruit Yes Yes' Yes" No Yes Yes
Tangerines Yes No Yes No Yes Yes
'Temples'2 Yes No Yes No Yes Yes
Tangelos Yes No Yes Yes Yes Yes
'Murcotts' No No No Yes No Yes
Lemons' No Yes7 No No No No
Limes8 No Yes' No No No No
Notes: 1. For appropriate Brix.
2. Separate standards for natural color and color added fruit.
3. Gallons per 1-3/5 bushel box.
4. Cubic centimeters per fruit.
5. Separate standards for seeded, white seedless, and pink and red seed-
less varieties.
6. No specific Florida standards; California standards are quoted in
Appendix II.
7. Volume basis.
8. Restrictions on size of fruit.


TABLE 5-Factors Used in Minimum Quality Requirements for Florida Cannery
Fruit, as of June 30, 1966.1
Color Juice Brix/Acid Ratio
Fruit Break Content Brix Acid Required' Minimum
Oranges* No No Yes No Yes Yes
Grapefruit* No No Yes No No Yes
Tangerines* No' No Yes No Yes Yes
'Temples'* No No Yes No Yes Yes
Tangelos* No No No No No Yes
'Murcotts" No No Yes No Yes Yes
Lemons No Yes" No No No No
Limes No Yes5 No No No No
*From August 1 through November 30, fruit must meet fresh fruit standards
(Table 4).
Notes: 1. December 1, through July 31, unless noted otherwise.
2. Required ratio applies until January 1.
3. No color break after November 15.
4. Standards for oranges apply.
5. Volume basis.









Some years ago, all of the fruits
on a large, heavily laden 'Valencia'
orange tree at the Citrus Experi-
ment Station were picked and test-
ed individually. Findings are sum-
marized in Table 6.
This study showed that fruits on
the south side of the tree were
higher in Brix and had a higher
Brix-to-acid ratio than those on
the north side of the tree. There
was an increase in Brix and Brix-
to-acid ratio as fruits were picked
from successively greater heights.
Fruits on the outside portion of
the tree were brighter in color and
higher in Brix and Brix-to-acid
ratio than those partially shaded,
in the canopy, or fully shaded near
the trunk. Fruits in the top of the
tree, whether in full sunshine or
partially shaded, were more bright-
ly colored and higher in Brix and
Brix-to-acid ratio than either out-
side or canopy fruits. Titratable
acidity (total acid) tended to be
low in fruits from the northeast
side of the tree and to increase in
inside fruits picked from succes-
sively greater heights. A system-
atic pattern was not encountered
with juice content, although large,
coarse textured, poorly colored in-
side fruit tended to have less juice.
A sample taken from the outside
on all sides at a height of 3 to 6
feet was representative of the en-
tire tree.
Citrus trees are harvested in two
ways, spot picking when only cer-
tain fruit or portions of a tree are
taken and clean picking when all
of the fruit, except those which


are obviously immature, are taken.
Early in the season, many varieties
are spot picked for size, color, or
maturity to obtain higher prices
for the fruit. Specialty fruits, such
as tangerines, 'Temples,' or 'Mur-
cotts,' and varieties for the gift
trade are best spot picked if suit-
able labor is available. Oranges,
grapefruit, and other varieties go-
ing to a cannery or when fully ma-
ture are clean picked as a rule.
Spot Picking.-Spot picking in-
volves selection of certain fruit
from the trees; hence, samples
should be harvested with the
knowledge that fruit from the top
outside and outside portions, es-
pecially on the south and south-
west sides, will be the most bright-
ly colored and have the highest
Brix and Brix-to-acid ratio. Fruit
from the canopy of inside portions
will be less well colored and low-
er in Brix and Brix-to-acid ratio
than the average for the entire
tree. Enough samples should be
taken to insure that variations
within a grove are included.
Twenty to fifty fruits properly
chosen will be more representative
than several times that number
simply grabbed from the trees.
Systematic sampling will help
to take the guesswork out of the
question, "Should the fruits be
harvested now or left on the
trees?" Where clean picking is
contemplated or checking the
progress of internal quality is the
object, samples of outside fruit
taken from all four sides of the
trees at a height of three to six










TABLE 6.-Effect of Position on the Tree on Various Quality Factors in Valencia Oranges.1

Quality Factor Light Classes' Height on Tree Direction of Exposure Rind Color
Total soluble Highest in outside Strong tendency Highest in SW quadrant Very strong
solids fruit. Lowest in to increase Lowest in NE quadrant, tendency; green-
(Brix) inside fruit, with height of lowest solids;
Canopy fruit almost tree. breaking-medium
identical with solids; orange-
average for all highest solids.
fruit.
Titratable Very variable. Inside fruit Acid tends to be low Slight tendency
acidity No well defined tends to increase in NE quadrant, to be lowest in
(Acid) trend, in acid with green fruit and
height on tree. higher in orange
For other fruit fruit.
no correlation
with height.
Brix
Acidratio Strong tendency Increases with Highest in NE quadrant. No correlation.
to be higher in height on tree.
outside fruit.
Juice Inside and top No correlation. No correlation. No correlation.
volume lower than the
average.
'Adapted from Sites, P. W., and Reitz, H. J., Proc. Amer. Soc. Hort. Sci. 54:1-10; 55:73-80; 56:103-110, 1949, 1950.
'Light classes: Outside-exposed, clearly visible fruit.
Canopy-fruit embedded in the leafy canopy.
Inside-fruit borne among the inner, largely leafless main limbs.









feet from the ground should be
representative of the entire crop.
When maturity is marginal, and
any error may mean that the pick-
ed fruit must be destroyed, it is
wise to "weight" the sample by
deliberately picking low and reach-


ing into the leafy canopy. A num-
ber of boxes representative of the
block should be sampled from the
tree, taking into consideration
variety, rootstock, soil, drainage,
cultural factors, and size of
fruit.


FACILITIES AND EQUIPMENT


Field Tests. Facilities and
equipment required by the grower
and picking crew depend largely
upon the extent of their operation
and their need or desire to have
results for minimum quality tests.
Growers with large holdings gen-
erally have access to fruit testing
facilities at their normal outlets,
whether it be a packinghouse or
cannery. Several of the large pick-
ing and hauling organizations have
their own testing facilities. For
growers and picking crews who
have need for and interest in mak-
ing occasional fruit quality tests,
the equipment listed in Table 7
for oranges, grapefruit, tangerines,
'Temples,' tangelos, and 'Mur-
cotts,' or in Table 8 for lemons
and limes, would be the minimum
required.
Packinghouse. Regulations of
the Florida Citrus Commission
stipulate that each packinghouse
shall provide a suitable place for
official minimum quality (maturi-
ty) tests. Each shipment of fruit
must be tested and certified by an
inspector of the Fruit and Vege-
table Inspection Division, Florida
Department of Agriculture. The
testing place consists of a small
laboratory-type room, conveniently


located to the receiving area, with
a sink, running water, drain, coun-
ter, cabinet space, power outlets,
and desk space, where the in-
spector can comfortably carry out
maturity tests. The room must be
well lighted, heated in the winter,
well ventilated in the summer, and
screened against flying insects.
Equipment and chemicals used by
the inspector are furnished by the
Fruit and Vegetable Division.
Packinghouses wishing to make
their own unofficial minimum
quality tests will need similar fa-
cilities. Equipment, indicator solu-
tion, and standard alkali listed in
Tables 7 and 8 may be purchased
at nominal cost from citrus sup-
ply houses.
The official reamer has two
burrs, the larger for grapefruit
and the smaller for other types.
It may be turned by hand or motor,
provided the burr speed does not
exceed 400 rpm. Most packing-
houses and inspectors have motor-
driven reamers to save time in
juicing numerous samples. Ream-
ers operated at more than 400 rpm
introduce so much air into the
juice that it should be deaerated
before attempting to obtain a Brix
reading. For many years, it was









FIGURE 3-Official hand reamer with orange and grapefruit burrs.


TABLE 7.-Equipment for Minimum Quality (Maturity) Tests of Oranges, Grape-
fruit, Tangerines, 'Temples,' Tangelos, and Murcotts."

Hand reamer, with orange and grapefruit burrs. .(See Figure 3).
Cheesecloth, #60 or #80 mesh; collander; or strainer
Pans (2)-0.5 gal., metal or plastic, round
Graduate-400 or 500 cc., with smooth lip
Graduate-400 or 500 cc., with pouring lip
Hydrometer-scaled from 5 to 15 degrees Brix in 0.1 degree divisions
Thermometer-centigrade-scaled from 0 to 50 degrees in 0.1 degree divisions
Erlenmeyer flask (2)-125 cc.
Burette, direct reading-calibrated to read percent anhydrous citric acid, scaled in
0.01 percent divisions, capacity 2.85 percent
Pipette-25 cc.
Burette stand
Funnel, small
Official fruit sizer
Medicine dropper and dropping bottle
Maturity chart (See Appendix I or III)
Juice chart for oranges (See Table 1)
Standard sodium hydroxide solution (0.3125N)
Phenolphthalein indicator solution









TABLE 8.-Equipment for Minimum
Quality (Maturity) Tests
of Lemons and Limes.
Juice extractor, Hamilton Beach No. 32
or equivalent
Cylinder for fruit volume (See Figure
1)
Graduate, 400 or 500 cc., with pouring
lip
Pans (2), 0.5 gal. metal or plastic

the custom to strain juice through
fine mesh cheesecloth to remove
juice sacs, seeds, rag, and other
solid materials which would clog
the fine tip of the pipette for draw-
ing acid samples. Now, a collander
or dipper-type strainer is used to
eliminate large particles from the
juice. A special pipette with a
large bore is used to draw acid
samples. Burettes not calibrated
to read percent anhydrous citric


acid directly may be used, but re-
quire a special table for conversion
of cubic centimeters of alkali to
percent acid. (See Table 3.)
Cannery.-All fruit going to a
cannery to be processed into frozen
concentrate, chilled juice, single-
strength juice, and other products
must be inspected for minimum
quality. In addition to the regular
tests required by law, the Fruit
and Vegetable Inspection Division
also furnishes, on a voluntary
basis, certain additional informa-
tion with respect to juice yield,
Brix, and pounds of solids per box
on every lot of fruit. Facilities and
equipment for testing of cannery
fruit, additional to those mention-
ed above for packinghouses, are
listed in Table 9.


EVALUATION OF MATURITY:
MAKING A TEST FOR MINIMUM QUALITY


Fresh Fruit.-Samples for of-
ficial tests may be drawn from a
lot any time after the fruit is
picked and before it is shipped.
Testing of individual fruit rather
that a composite sample is per-
mitted. Fruit of a single size is
used unless only ratio is being
checked, when mixed sizes are
used. Samples are drawn from the
largest size, smallest size, and one
or more intermediate sizes of fruit
in a lot. If any of the samples fail
to pass, at least two additional
samples may be drawn. If the
average of the three tests still
falls below the minimum require-
ment, that size of fruit or the lot


is considered immature and liable
to seizure. Drawing of samples and
tests subsequent to the first may
be witnessed by the owner or man-
ager of the packinghouse, but of-
ficial tests must be run without in-
terference of any sort.
Between August 1 and October
15, immediately upon arrival of
fruit, a packinghouse composite
sample of unsized fruit will be
tested. If the ratio fails the mini-
mum requirement by more than
0.5 point, two additional such
samples shall be tested. If the
average of the three composite
samples fails the minimum require-
ments by more than 0.5 point, the









TABLE 9.-Equipment for Cannery Fruit Quality Tests.
Equipment listed in Table 7 plus:
A. Items furnished by processor
Truck scale-platform, capacity 73,222 lb.
Mechanical sampler-Kinsey type
Extractor-Brown Citrus Machinery Company Model 400: or FMC Model
091
Scale-60 lb. capacity, with 1 oz. or 0.05 lb. graduations
B. Items furnished by Fruit and Vegetable Inspection Division
Sample baskets, wire gauge-60 lb. capacity
Juice buckets-aluminum, with bail and pouring spout, 5 gal. capacity
Juice aspirator flask-8 in. diameter, round bottom, long neck (2 in.
diameter)
Water aspirator or
Vacuum pump } -to produce 25 in. vacuum in 30 seconds
Vacuum pump


fruit shall be condemned and de-
stroyed.
Mixing of varieties or lots of
fruit for the purpose of securing
a lot which will pass minimum
quality requirements is prohibited.
Cannery Fruit. From August
1 to December 1, all oranges,
grapefruit, tangerines, 'Temples,'
and tangelos for canning must
meet fresh fruit requirements.
From December 1 through July 31,
there are no requirements for color
break, juice content, or minimum
acid.
All Florida citrus canneries avail
themselves of the service provided
by the Fruit and Vegetable In-
spection Division. Facilities and
equipment are considerably more
complex than those required for
the packinghouse. Both the num-
ber of tests run and the desired
accuracy require high speed and
complicated machinery. The selec-
tion of the sample, for example,


must be completely mechanical,
with a minimum bias so as to as-
sure a representative sample. The
size of the sample should be the
same regardless of the size of the
load or the rate of unloading. A
recently developed device to select
a representative sample, regardless
of size of load or rate of unloading,
has been recommended for uni-
versal use. To discourage tamper-
ing with the sample selection, all
troughs, chutes, conveyors, and
belts used for collecting and trans-
porting samples must be enclosed
or covered with wire to make the
sample inaccessible except at point
of delivery.
The first requirement for state
inspection is a sampler that will
mechanically select a representa-
tive sample of approximately 50
pounds from each load of fruit re-
ceived and deliver this sample to
the inspector in the test room in
a condition for further analysis.









Average unloading time is ap-
proximately ten minutes at most
canneries. The number of unload-
ing positions is generally two. It
is thus necessary to make a com-
plete analysis approximately every
five minutes. To accomplish this,
something faster than a hand
reamer for extracting juice is
necessary. Modified commercial ex-
tractors are now used for this pur-
pose. About 60 percent of those
in use are FMC machines and 40
percent, Brown Citrus machines.

Legally, only the determination
of minimum quality is required;
however, the Fruit and Vegetable
Inspection Division, as an impar-
tial agency, has been requested
to make pounds-solids determina-
tions. Weight of fruit is very im-
portant in this determination so
printing scales are used for all
weighing.

Yield of juice is affected by a
large number of environmental
factors, among them variety,
stock, soil type, cultural practices,
and temperature. Tables for de-
termining pounds of juice per box
for oranges, grapefruit and tanger-
ines are available from the Florida
Division of Fruit and Vegetable
Inspection.

The juice is strained in the ex-
traction operation to exclude un-
wanted pulp, seeds, and juice sacs.
Great care is taken by inspection
personnel to maintain uniformity
of juice extraction within a can-
nery and between canneries. The


variation in juice yield of care-
fully drawn samples extracted with
machines in proper adjustment is
about plus or minus 1.0 percent.
The normal tolerance for a Brix
determination would be plus or
minus 0.1 degree. The effect on
pounds-solids would be as follows:
1. Assume true yield as 50% =
45 lb. juice per box, but the
2. Actual yield is 51% = 45.9
lb. juice per box.
3. If the true Brix is 100, then
10Brix x 45.0# juice =
100 4.5000 lb.
solids per box,
4. But the Brix measured is
10.10, then 10.10 Brix x 45.91b
100
juice = 4.6359 lb solids per
box.
5. And the difference would be
4.6359 4.5000 = 0.1359 lb.
6. If the pounds-solids price is
$0.25 per pound, this differ-
ence becomes 0.1359 x $0.25
=$0.03398 per box, or $13.59
for a 400 box load.
This example shows clearly the
effect of minor variations in either
juice yield or Brix determinations.
Quantity of juice per box may
be expressed as pounds or gallons
per box. The former is preferred,
as it is a more exact figure. Gal-
lonage of juice per box is subject
to some inaccuracy because the
weight per gallon varies according
to Brix (percentage of total solu-
ble solids present). The yield of
juice per standard box is calculated
as follows:









(a) Weight of fruit sample (orange): 5,.0 lb.
(b) Weight of juice: 25.0 lb.
(c) Yield of juice per box =
weight of juice x weight of std. box:
weight of fruit sample
e.g. 25.0 x 90 = 45.0
50.0


of juice per box =
weight of juice x weight of std box
weight of fruit weight of juice per gal.'
sample
e.g. Assuming the juice contains 12.0 pet
solids = 8.72 lb. per gallon juice, then
25.0 x 90 = 5.16 gal.
5.50 8.72


CERTIFICATION


Fresh Fruit.-Each shipment of
fruit from a packinghouse must be
accompanied by a certificate of in-
spection for maturity (and grade).
The certificate shows the date, lo-
cation, packinghouse registration
number, car or truck identification,
time when inspection was made,
destination, kind and type of fruit,
whether color added, number of
packages, type and size of contain-
ers, size of fruit, label, grade,
where samples were taken, num-
ber of equivalent standard boxes,
and revenue fees. Two copies of
the certificate go to the Fruit and
Vegetable Inspection Division of-
fice in Winter Haven; one is given
to the truck driver; one is given
to the shipper, and one is retained
by the inspector.
Inspection and certification in-
sures that only mature wholesome


fruit is shipped in or out of the
state.

Cannery Fruit. Each lot of
fruit received by a cannery must
be inspected and certified before
it can be processed. The cannery
certificate of inspection shows in-
formation on internal quality as
well as maturity; pounds of juice
per box, Brix, total acid, Brix-to-
acid, Brix-to-acid ratio, and
pounds-solids. Thus, in addition to
the mandatory requirements for
minimum quality, the Fruit and
Vegetable Inspection Division cus-
tomarily supplies that cannery
with the information necessary for
pounds-solids evaluation. Copies of
the inspection certificate go to the
canner, Fruit and Vegetable In-
spection Division (two), and the
grower, if he wishes one.


(d) Gallons









EVALUATION OF FRUIT:
WHAT IS YOUR FRUIT WORTH?


Fresh Fruit. Fresh fruit is
sold on a box basis in some agreed
upon manner, such as on the tree,
delivered to the packinghouse, con-
tract, consignment, etc. The grow-
er generally receives a price de-
pending to greater or less extent
on the buyer's estimate of what
proportion he can pack. Since fruit
graded out for surface blemishes
goes to the cannery as "elimina-
tions", pounds-solids still contrib-
utes to the value of the crop,
though to a lesser extent than with
crops that go direct to the can-
nery.
Cannery Fruit.-Inspection of a
representative sample ensures that
only wholesome oranges which
meet legal requirements for mini-
mum quality are processed. At the
same time, the information pro-
vided by the tests is utilized by
the cannery to determine whether
the fruit is suitable for concentra-
tion purposes, how the load should
be blended with other oranges as
they are processed in order to
maintain a uniform product, and
finally, the basic upon which pay-
ment to the seller shall be made.


Cannery fruit is sold in two
ways, pounds-solds or pounds of
juice per box. Both afford the
grower a return commensurate
with the quality of his fruit. In
the case of pounds-solids, the price
is calculated by multiflying the
pounds-solids by the price per
pounds-solids, as shown in the fol-
lowing example:
(a) Pounds-solids per box:
5.4 lb.
(b) Price per pound of solids:
$0.25
(c) Price per box = 5.4 x 0.25
= $1.35
Similarly, the price, based on
pounds of juice per box, is com-
puted by multiplying pounds of
juice by the price per pound, as
shown in the following example:
(a) Pounds of juice per box:
45.0 lb.
(b) Price per pound of juice:
$0.05
(c) Price per box (pounds juice
basis): 45 x 0.05 = $2.25
The monographs (Figures 4 and
5) can be used to obtain price per
box for pounds-solids and pounds
of juice, respectively.






POUNDS JUICE
PER BOX
PRICE PER


A


- -


Figure 5.-Conversion of pounds of juice per box into price per box.


DOLLARS
PER BOX


4.00




3.50


3.00




2.50




2.00




1.50




1.00




0.50




0.00









APPENDIX I. MINIMUM QUALITY (MATURITY)
STANDARDS FOR ORANGES, GRAPEFRUIT,
TANGERINES.

For Appendix I see enclosed folder inserted in this circular.


APPENDIX II. MINIMUM QUALITY (MATURITY)
STANDARDS OF LEMONS AND LIMES
AS OF JUNE 30, 1966


Issued:


Amended.


Sample:
Juice Content:


LEMONS
10 fruit
30% by volume for U. S. No. 31, U. S. Combina-
tion, and U. S. No. 2; 28% by volume for export
grades. (Sec. 51.2801, U. S. grade standards for
lemons. Effective Sept. 1, 1964).


LIMES
Persian (Tahiti, Bearss, Pond, Idemor) Type:1
Sample: 10 fruit
Juice Content: 2 42% by volume for fruit 1-7/8 inches in diameter
or more; 50% by volume for fruit between 1-5/8
and 1-7/8 inches in diameter.
Size: 1-7/8 inches in diameter minimum March 15
through May 31;
1-3/4 inches in diameter minimum June 1 through
March 14.


KEY (MEXICAN, WEST INDIAN) TYPE:
Sample: 10 fruit
Juice Content: 42% by volume
Size: None
1 Standards listed are under Lime Marketing Agreement, Federal Marketing Order
No. 911.
2If a federal marketing agreement is not in force, then limes must contain an
average of 42% juice by volume with no fruit with less than 38% (Sec. 603.152,
Florida Statutes)










APPENDIX III. INTERNAL QUALITY STANDARDS
FOR SUNFLAVOR GRADE.1

ORANGES


Juice Content:
Acid:
Brix:
Brix/Acid Ratio:


GRAPEFRUIT
Brix:
Brix/Acid Ratio:


TANGERINES
Brix:
Brix/Acid Ratio:


'TEMPLES'
Brix:
Brix/Acid Ratio:


TANGELOS
Brix:
Brix/Acid Ratio:
Acid:
Brix/Acid Ratio:


5.0 gal. per box
0.55% minimum
10.5% minimum
11.0 to 1 minimum


7.0% minimum
Increase of 0.50
point throughout
present scale
(See Appendix I)


10.0% minimum
9.0 to 1 minimum



11.0% minimum
9.0 to 1 minimum



9.5% minimum
10.0 to 1 minimum
1.0% maximum or
14.0 to 1 minimum


SAdapted from Standards for Grades of SunFLAvor Citrus Fruits, Florida Department of Agriculture,
1965.




This is a revision of Extension Circulars 184 and
191 by M. J. Soule, Jr. and F. P. Lawrence




COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida
and
United States Department of Agriculture, Cooperating
M. O. Watkins, Director




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