y ' 

e 6i&R' 

METHODS OF ANALYSES 

Hf±*iH±i 4 :g;p p:na pee+ A ¥ M'iWli A ., EA&E;:m< Wtta 

for 

TOMATO PRODUCTS 

FOR USE OF USDA PROCESSED FOODS INSPECTORS 

UNITED STATES DEPARTMENT OF AGRICULTURE 

CONSUMER AND MARKETING SE.RY!CE 

FRUIT AND VEGETABLE DIVISIOI'< 

PROCESSED PRODUCTS STANDARDIZ.ATION AHO INSPECTION BII-'NCH 

I 

P R E F A C E 

These instructions are designed primarily for Processed 

Fruit and Vegetable Inspectors of the U. S. Department of 

Agriculture. They are not intended to be a comprehensive 

treatise on the subject but give background information 

and guide-lines to assist in the uniform application and 

interpretation of USDA grade standards and other simila~ 

specifications. 

These instructions are revised as necessary without public 

notice and no mailing list is maintained as a public 

advisory of such changes. 

The citation nf any data, criteria, techniques, illustrations, 

copyrighted material, or pictorial representation accredited 

to private authorship is used with the permission of the 

individuals or sources cited. Unless a specific accreditation 

is referenced, the information herein has been compiled and/or 

developed from sources available to the public as well as from 

technical knowledge of personnel in the Department. 

Compliance with the suggested guide-lines and other pertinent 

information herein does not excuse any one from failure to 

comply with the Federal Food, Drug, and Cosmetic Act or any 

other applicable Federal or State laws and/or regulations. 

Except for official USDA inspection aids or devices and color 

guides (or standards) produced under license of the Department, 

the mention of any supplier, patented device, product, brandname, or equipment does not imply endorsement by the Department 

over any other similar, or equally effective, material. 

Information contained in this instruction is available to the 

public. Inquiries as to availability of portions of this 

instruction and copying or reproduction privileges should be 

addressed to: 

Chief 

Processed Products Standardization 

and Inspection Branch 

Fruit and Vegetable Division, C&MS 

U. S. Department of Agriculture 

Hashington, D. C. 20250 
METHODS OF A..~ALYSES 

for 

TOMATO PROUJCTS 

SOLIDS C01\'TF7'/T DETERMI:\ATIONS 

TABLE OF CO~TD>TS 

September 

1970 

Supersedure: All portions of instructions "Solids Content Determinations" dated January 1967 and previous to Feb:-uary l970, are superseded and may be discarded. Content of the revised instruction 

February 1970 -- is as follows: 

NATIJRAL TOMATO SOLIDS 

INTROD..JCTION • • • • 

REFRACTOMETRIC METHOD 

GENERAL METIWDJLOGY - Step by Step Procedure 

DETAILED METi:lOOOLOGY 

Equipment and Reagents 

A 1 ternat ive 1 - Direct Filtration - no enzyme 

Alternative 2 - Direct Filtration - dry enzyme 

Alternative 3 - 1 to 1 Dilution with l9o enzyme 

solution . . . . . Alternative 4 - l to l Dilution - nc enzyme 

solution 

Centrifuge Procedure for Obtdining Serums 

Added Salt Correction 

Examples . 

NOTES ON METHOD (REFRACTOMETRIC 

Starting 

On Page 

1 

5 

7 

9 

9 

10 

l 2 

12a 

13 

14 

19 
.: 

METnOf'S OF ANALYSES 

for 

TO\i:'.TO PROIJJCTS 

SOLIDS COt\ t ZI\T DETER~I\ATICt\3 

TABLE OF CONTENTS -- Con:inued 

VACUlTM OVE\ MIT'rl'JD 

BAQ<GROUND, wnEN TO USE, ~UIPMENT 

PROCEOORE 

SPECIFIC GP~VITY METHOD 

B.ACI<GROUND .. 

\.triEN TO USE -- AND HOw NOT TO USE 

PROCED.JRE 

U.S.D.A. TOMATO CONCENTRATE TABLES 

TABLE I - February 1970 

Refractive Indices of Sucr0se Solutions at 20° C . 

September 

1970 

21 

22 

25 

2'j 

25 

26 

i thru 

XV 

TABLE II - Temperature Correction Table - % Sucrose at 20° C. 

TABLE III - Tomato Catsup (Sucrose value plus l%) 

TABLE IV- Temper2ture Correction Table - Refractive Index 

to 20° C. (Tomato S;;uce, Catsup) 

TABLE V - Temper;;ture Correction Table - Refractive Index 

to 25° C. 
/ 

TOMATO 

P.ltOOOCTS 

M!'T80DS 

Solida Content 

Introduction 

February 1970 

NA'I'UR.AL TOMATO SOLUBLE SOLIDS 

Introduction 

In the applic•tion of the United Statea Stand&rda and Federal Specific•tioa. for co.ninuted tomato producta it is neceaaary to deteraine 

the aolida content of the s~lea to properly certify the product. 

In producta such •• toaato paste and tomato puree, aa?.ea and purchues 

are made on the baait of the tomato solida preaent or s~ equivalent 

~aaure of concentration, Furthermore, the Food and Drug atandardl of 

identity for t~to puree and tomato paste require a minimum natural 

tomato aoluble solida. In view of the economica and regulatory aapecta 

of the aituation, it is of utmost importance that the degree of concentration or solids content be properly deterained and ~ccurately reported, 

The FDA atandards of identity were revised in January 1970 to change 

the ~tbod of expresaics concentration in to.ato paate and puree from -

"aalt-!ree tomato aolidA" 

to 

"n•tural toa.ato soluble solidsJI 

In addition the ~thodology vas changed from the former vacuum oven 

aethod (correlated by NCA to refract~ter) to the refractometric 

method uaing the International Sucrose Scale (200 C) as the referenced 

converaion table. In effect the newly reviaed procedure results in a 

aliihtly lower value aince only soluble solids •~e meaaured (inaoluble 

tomato aolida are diaregarded), Naturally occurring aalt ia aov cocaidered a part of aoluble solids; however, such salta are not naturally 

pre&ent in sufficient a.ounta to compenaate for the difference incurred 

in diaregarding insoluble tomato aaterial - hence the reason for 

alightly lower valuea. 

The reviaed FDA atandardl of identity have brought about necessary 

cbangea in determining limits of concentration for the following USDA 

atandarda in the manner specified. 

PROOOC'! MI NDru'M 

Toaato Puree 81 < 241. 

Toaato Paste 24! 

Concentrated Toaato Juice 201 (24! 

- 1 -
TOMATO 

l'RODOCTS 

Mn'HODS 

Solida Content 

Introduction 

February 1970 

The degree of concentration may be ~reseed in aeveral ways depending 

upon the requirement• of the apecifie&tion or, in •~ inttancea, upon 

the wiahea of the applicant. 

Tomato paste and tomato puree are e%presaed in terms of natural t~to 

soluble solids when applying OSDA and Food and Drug Standards or Federal 

and other Specificationa, whereas induatry frequently purchases tomAto 

puree on the basis of apecific gravitz, Tasato catsup is axpresaed in 

teras of total solids and toa£to aauce and chili aauce on the bacia 

of refractive indicea. 

!rix of the filtrate ia often used in international trade. 

Regardleaa of the ~thod of expressing reaulta, certain fuoda.entala 

.u•t ~ obaerved to attain accuracy and achieve uniioraity, 

- 2 -
TOMATO 

PRODUCTS 

ME:TRODS 

When to Use the Refractometric Method 

Solida Content 

Refractometric ~thod 

FebruAry 1970 

Ose the refractometric method for determining solids content for all 

tomato products when applying the United States standards or Federal 

or other specification unless: 

1) another method is specified in the specification; 

2) another recognized method is requested by the applicant. 

Accuracy of the Refractometric Method. 

The accuracy of refractometric readings depends, in part, upon the 

technique used. It is imperative that a clear, sharp line be obtained. 

This generally necessitates filtering the samples to ~emove insolubla 

materials. Nevertheless, readings may be taken on unfiltered s~lea · 

of tomato products (usually juice) by placing a direct smear on the 

refr~ctometer prism, providing a sharp line can b£ obtained and providing the sample is not borderline in solids or of a controversial 

nature. 

TemPerature Corrections of Suerose Value 

It is often necessary to convert a Refractive Index, taken or quoted 

at one temperature, to another equivalent. The accompanying table of 

cosversion to the sucrose ~cale is standardized at a tecperature of 

20 C. Therefore, if the refractometer is read at a temperature other 

than 20° C a correction must be applied in accordance ~ith Table II of 

this instruction -

a plus correction for temperatures above 20° C. 

a minus correction for temperatures below 20° C. 

Before making the necessary temperature corrections the refractive index 

is converted to the corresponding sucrose value in accordance with the 

following three steps -

1) Record the Refractive Index and temperature. 

2) Convert the RI froz Step 1) to sucrose value by referring to Table 1. 

- 3 -
TOMATO 

PRODUCTS 

ME"''HODS 

Solids Content 

Refract~tric Method 

Febr-u.ary 1970 

3) Correct the sucrose value in Step 2) for temperature according to 

Table II. 

Theu· a tepa are i llua trated by the following examples: 

ExamQle 1 (RI at 25° • 1.3480) 

1) RI at 25° • 1.3480 

2) Sucrose Value (Table!) • 10.11 

3) Adjusted sucrose value (200) • 

10.1 + 0.36 or 10.461 - Round up to 10.51 

E:tu:ple 2 (RI at 17° C • 1.3612) 

1) RI at 17° C • 1.3612 

2) Sucroae value (Table !) • 18,41 

3) Adjusted sucrose value (200) • 

18.4 - 0.2 or 18.21 

- 4 -
I 

TO¥.ATO 

PRODUCTS 

M....."'THODS 

GENERAL METHODOLOGY 

Solid& Content 

Refractometric Method 

February 1970 

In determining "natural tomato soluble solid&" there are a number of 

things to keep in mind. They are listed numerically for ease of reference and must be followed exactly as apecified in this instruction. 

A general outline of the step by step procedure is as follows: 

1) Alvaya uae 100 grama of well mixed product as the test s4mple. 

2) Alternative 1 - (Direct filtration) 

Obtain the refractive index of the clear aerum fros the test saaple 

in Step 1. 

3) Convert the RI (from Step 2) to sucrose value in accordance vith 

Table II. 

4) Correct the sucrose value (from Step 3) to 200 C, if read at temperature& other than 200, in accordance vith Table II. Do not correct 

the Refractive Index for temperature before converting to percent 

sucrose -- correct the sucrose value, If the refractometer bas a 

"aagar scale" on it, read the scale directly as the "aucrose valu." 

and then correct for temperature per Table II. 

5) Deduct any ~salt and the result ia "natural tomato soluble aolida". 

6) If unable to readily obtain a clear aerum under Step 2) take one of 

the following alternAtives: 

Alternative 2 (Direct Filtration With Enryme) 

Add 1 grcm of dry enzyme to the 100 gr~ s£mple. Mix ~ell and filter. 

Alternative 3 (1 to l Dilution With Enzyme Solution) 

Mix 100 gr~ of test sample vith 100 gr~ of 1! pectic enzyme 

solution. Mix •ell and filter. 

- 5 -
TOMATO 

PRO DOerS 

METHODS 

Alternative 4 (1 to 1 Dilution - No Enzyme) 

So lica Content 

~fractometric Method 

February 1970 

Mix 100 gr~ of wat~r with the 100 gram teet sa.ple. Mix vell and 

filter. 

7) Obtain the RI of the clear serum resulting from Step 6, 

8) Refer to Table I and convert the RI to sucrose value. Apply temper• 

ature correction, if any. 

9) If Alternative 2 is used, apply a minus correction for the 1~ 

enzyme solution and deduct any added salt. The result is then 

"natural ta.a.to soluble salida". 

10) If Alternative 3 is used, apply a minus correction for the 11 enryme 

solution and a plus correction for the effect of insoluble aolida 

in the product. Deduct any added salt and the result is "natural 

tomato soluble solidi". 

11) If Alternative 4 is followed, apply a plus correction for the effect 

of insoluble solids in the product, deduct any ~ salt and the 

result ia "natural tomato soluble aolidl". 

The foregoing 11 steps prescribe the general outline of the ~ethod. 

Detailed procedures in applying these principles are given in the following 

section of this instruction. The inspector will soon know which of the 

general procedures vill best fit the type of tomato concentrates in 

his area. Normally it will always be necessary to use t~ 1 to 1 

dilation ~thod on the higher concentrations - e.g. over 321. solids. 

Likewise, 1t is advantageous to use a pectic enzyme to digest the natural 

pectins in the product so it ia recommended that Alternative 3 be ~ed 

in preference to Alternative 4. 

- 6 -
TOMATO 

PRODUCTS 

METHODS 

Equipment 

DETAILED METHODOLOGY 

Solids Content 

Refractometric Method 

June 1975 

Supersedes page 7 dated 9/74 

Abbe Refractometer, such as B&L, Zeiss Opton or Zeiss Sugar and Oil. 

Glass Funnels 75 mm diameter with stems cut off 1 inch or shorter 

at a 90° angle, fire polished (stemless funnels may be used). 

Fluted funnels must be used with nylon bolting cloth. 

Erlenmeyer Flasks 200 ml or 250 ml (wide mouth preferred). 

Filter~. Fast Filtering Whatman No. 2V, 12.5 em or the equivalent folded paper. Nylon bolting cloth can used No. HC-3-132 

Nitex monofilament nylon - known supplier: 

* H. R. Williams Mill Supply Co., 208 West 19th Street, Kansas City, 

Missouri 64108, Phone~ (816) 474-1511. (40 inch width, 6 inch length 

makes approximately 10 to 12 filters; 56 inch width is also available.) 

Balance capable of weighing to an accuracy of + 0.1 gram. 

Capacity 500 grams or more. 

Half pint Mason jars for blending apparatus. 

Osterizer (or the equivalent) capable of blending samples in one-half 

pint Mason jars. Blender should have a slow speed or be used in 

conjunction with a powerstat. The lid and blending attachment must 

be sealed properly to prevent loss of liquid during mixing operation. 

Glass or Plastic Petri Dishes to cover funnels and prevent 

evaporation. 

Kleenex or similar tissue for cleaning refractometer. 

Reagents 

Dis tilled Water 

* Pectic enzvme: KlerzYTIJe Analytical or Pectinal 10-R, or the 

equivalent (enzyme must be in a diatomaceous earth base). 

Revised - June 1975 

- 7 -
TOMATO 

PRODUCTS 

METHODS 

Solids Content --

Refractometic Me~hod 

June 1975 

Supersedes page 8 dated 

Pectic Enzyme Suppliers: 

1) Klerzyme 200 (Analytical); (Wallenstein Co., Kingstree, 

South Carolina 29556) 

2) Pectinal 10-R (Rohm & Haas Co., Independence Mall, West, 

Philadelphia, Pennsylvania 19105) 

Pectic Enzyme Solution 

Prepare a 1 percent solution o£ pectic enzyme by dissolving in 

water 1 gram of dry pectic enzyme for each 100 grams of solution. 

Obtain the Refractive Index of this solution, convert it to the 

appropriate sucrose value at 20° C. Use this value in subsequent 

calculations of the "Enzyme Correction Factor" in accordance with 

the following: 

1) Dry Enzyme Added to Test Sample (No dilution) 

Subtract 1.15 AC from the sucrose value of the tomato product 

where A = l (17. solution) and C = sucrose value of a 17. solution 

of pectic enzyme. 

2) 1 to 1 Dilution with 17. Pectic Enzvme 

Subtract 0.55 BC from the sucrose value of the tomato product, in 

which B = amount of enzyme added to pectic solution (1 gram) 

and C equals sucrose value of a 1% solution of pectic enzyme. 

SUCROSE VALUES OF 1% ENZYME SOLUTIONS @ 20° c 

Refractive Index Sucrose Index Refractive Index Sucrose Index 

1.3330 0.00 1.3338 0.56 

l. 3331 0.08 l. 3339 0.63 

l. 3332 0.15 1. 3340 0.70 

l. 3333 0. 21 1. 3341 o. 77 

1. 3334 0.28 1. 3342 0.84 

1. 3335 0.35 1. 3343 0.91 

1. 3336 0.42 1. 3344 0. 98 

1. 3337 0.49 

Revised - June 1975 

- 8 -
TO~ TO 

PROOOC'I'S 

/ ME'!'RODS 

Alternative 1 - Direct Filtration - No Enzyme 

Solids Content 

Refract~tric ~~thod 

february 1970 

1) If the product is easily filtered --when an abundance of filtrate 

appears immediately after placing on a filter paper -- make a 

smee.r of the filtrate directly on the priam of the Refractometer, 

working rapidly to prevent evaporation. 

2) Convert to RI to Sucrose Value, Table I. 

3) Make correction for temperature if other than 200 C (Table!!). 

4) Deduct for any added salt, as hereinafter outlined under "Correction 

For Salt". 

5) Report as Natural To~to Soluble Solids 

Alternative 2 - Direct Filtration With Dry Enzyme 

1) The tomato product does not filter readily so thoroughly mix 1 gr~ 

of dry pectic en~yme with 100 gr~ of t~to concentrate. 

2) Place aufficent tap water (room temperature) in the Erlenmeyer flask 

so that when funnels are placed in the neck of the flask, the water 

layer will be about 1/2 inch from the t5tem of the funnel. (To 

prevent evaporation). 

3) Place the bolting cloth or filter paper in the funnel. 

4) Fill the bolting cloth or filter paper with sample and cover the 

funnel with an inverted fetri dish (bottom or top portion). The 

dish should come in direct contact with the funnel and not rest on 

the filter paper or bolting cloth. 

5) Allow to filter until filtrate becomes reasonably clear. (No more 

than a slight turbidity should be apparent). Normally this should 

not require more than 10 to 15 minutes. 

6) Quickly remove funnel from Erlenmeyer flask, allow a large drop 

of filtrate to drop octo refractometer pri~, immediately close 

pri~. read and record. 

7) Return fu~uel and sample to flask and allow filtration to continue f~r 

2 minutes or longer. 

- 9 -
TOMATO 

PRODUCTS 

ME'l'RODS 

Solids Content 

Refractometrie Method 

february 1970 

8) Repeat procesa aod compare with first value. If readings vary by 

no more than 0.0001, regard as the correct refractive index (R.I.). 

If 16cond reading varies by more than 0.0001, repeat again after 2 

minutes or longer additional filtration. 

9) Continue until consecutive readings do not vary by more than 0.0001, 

and no trend is shown to indicate continuously increaaing or 

decreasing readings. If readings show a continuous drift, one of 

the following conditions mAy be responaible: 

a) Prisms not properly cleaned and dried. 

b) Improperly prep&red filters. 

c) Filtering process too slow; use another Alternative or a N1TEX 

filter. A reasonable rate is about 5 ml. in 30 minutes, 

tO) Convert the RI to Sucrose Value, Table I. 

11) Make temperature correction if other than 20° C (Table II). 

12) Apply a minus correction for the 1 gram of pectic enzyme, by 

aubtracting 1.15 from the sucrose value, in which C • the sucrose 

value of a 1~ pectic enzyme solution and A • 1. 

13) ~duct for any added salt aa outlined under "Correction For Salt". 

14) Report as Natural Tomato Soluble Solids. 

Alternative 3 • 1 to 1 Dilution With li. ~n%yme Solution 

1) Place sufficient tap valer in each of the wide ~uth Erler.meyer 

flasks so that wheo the funnels are placed on the necks of the flasks 

the water layer will be about one-half inch from the stems of the 

funnel. Place a filter paper (12.5 em folded paper) or bolting cloth 

in the funnel and place a Petri dish (bottom or top portion) over 

th~ funnel with the rim of the Petri dish extended downward. The 

Petri dish should come in direct contact with the top of the funnel 

an4 not rest on tbe paper. The filters should be assembled before 

use and alto~ed to stand long enough to saturate the air at the base 

of the funnel, but care should be taken that moisture does not condense 

on the stem of the funnel. Water and glassware must be at room 

_t em:pe rat ure. 

- 10 -
I 

TOMATO 

PRODUCTS 

MITRO OS 

So lids Content 

Refractometric Kethod 

February 1970 

2) Tare a one-half pint ~son jar and weigh into it 100 gr&ms of 

enzyme solution. Add to this 100 gr~ of a well-mixed sample of 

tom.to concentrate. The last portion of concentrate ahould be placed 

against the aide of the jar above the water level so that the weight 

can be accurately adjusted by adding to or removing concentrate 

before it contacts the water. 

3) Screw the blending assembly onto the flask and shake vigorously 

for a few seconds to loosen the paste from the sides of the jar. 

Place jar on blender and mix at low speed for about 15 seconds. Remove 

and shake vigorously for a few more seconds. Blend for 15 second£ 

more at low speed, then inspect jar carefully to see if any lumps 

of product are still sticking to the sides. Shake again, being sure 

that all lumps of paste are loosened, and blend again at high speed 

for 15 seconds. Be sure that product is circulating at all times 

during blending. (A "po<.~erstat" is very useful for adjusting the speed 

of blending; a setting of from 50 to 60 is equivalent to "slo'ol" 

speed.) 

4) Remove Petri dish from fu:-~nel and quickly pour blended rhixture onto 

paper. Replace Petri dish and push down until it contacts rim of 

funnel. 

5) Allo<.~ to filter until filtrate becomes reasonably clear (no more 

than a slight turbidity should be apparent). This should not require 

more than 10 to 15 minutes. 

6) Remove funnel from Erlenmeyer flask and allow a large drop of filtrate 

to drop onto refractometer prism. 

7) Record the refractive index of the serum. 

8) Repeat Steps 7, 8 and 9 under Alternative 2, 

9) Convert the RI to Sucrose Value (Table I). 

10) Apply temperature correction if other than 20° C (Table II) and 

record as indicated sucrose value. 

11) Apply ~ correction for the 1~ pectic enzyme solution by subtracting 0.55 BC from the indicated sucrose value (Step 10), in 

which ! • 1 and C • the sucrose value of a 1! en%~e solution. 

This correct ion factor ie referred to as the ''Enzyme Correction 

Factor". 

- 11 -
TOMATO 

PRODUC!S 

METHODS 

Solids Content 

Refractometric Meth0~ 

P'ebruary 1970 

12) Multiply the corrected Sucrose Value (Step 11) by 2 to relate 

such value back to the original product. 

13) Apply a plus correction for the effect of insoluble solids (applicable 

to all 1 to 1 di lution.s). This plus correction factor is ascertained 

by referring to the following Table: 

Degree of Concentration 

25. 01. 

30.0 

35.0 

40.0 

45.0 

50.0 

Correction Factor For Insolubl~ Sobids 

0.31 

0.4 

0.5 

0.7 

0.8 

0.9 

Do not go to the next higher correction tf the calculated result 

falls anywhere between the ranges. For example, if a sample was 

found to have a concentr•tion of 38.8l, add the Dilution Correction 

Factor of 0.51; ~ 0.71. 

14) Deduct any ~salt from the value obtained in Step 13. 

15) Report this final sucroae value (after applying corrections for 

enzyme, insoluble solids and added salt) aa natural tomato soluble 

solid&. 

Alternative 4 - 1 to 1 Dilution, No Enz~ Solution 

Follow all the steps exactly a1 outlined in Alternative 3 but do not 

make a minus correction for enzyme solution since none is ~ed. 

However, make a plus correction for insoluble tomato solids and deduct 

for any added salt. 

- 12 -
TOt> !A. TO 

PRODUCTS 

METHOD 

Solids Content -- Refractometric ~e~hoc 

September, 1970 

CENTRIFUGE PROCEDURE FOR OBTAINING SERUMS 

Background 

The ultra centrifuge procedure is an effective and rapid method of 

obtaining sera from concentrated comminuted or homogeneous products. 

Tne method involves high speed (over 100,000 r.p.m.) centrifugation 

whereby heavier insoluble tomato particles are spui'l to the perimeter 

of a rotor, leaving a well of soluble tomato serum. The degree of 

concentration of this serum is determined by refractometer and by 

conversion to the appropriate sucrose value. 

lfnen to Use 

Tne centrifuge method may be used .,.henever a refractive index 1s 

needed in order to determine the degree of concentration of a product. 

Equipmer:t 

Adams Ultra - Centrifuge with special solid rotor containing "0" nng. 

[w'hen ordering, specify: "Adams Ultra Centrifuge complete 

.,.ith tomato rotor, Catalog No. -- Like 0610."] 

Metal or Plastic spatula 

Plastic cocktail straws -- or -- Medicine dropper (Van ~aters and Rogers 

Catalog ~o. 52950-046 or equivalent). 

~vlon svringe 5 cc capacity {W&R No. 60350-066 or equivalent). 

Abbe refractometer (such as Bausch and Lomb, :eiss Opton, Zeiss Sugar 

and 011 --or equivalent). 

Distilled .,.ater and Cleaning tissue for cleaning refractometer. 

Insert as ne~ pages-Sept. 1970 
TOM.A.TO 

PROLUCTS 

METHODS 

Procedure 

1) Cool (or warm, if necessary) 

temperature before testing. 

Sol ids Content 

Refractometric Method 

September 1970 

tomato paste to or near room 

1--hx the sample thoroughly. 

2) Unscrew rotor ring and remove plastic cap. Be sure rotor is 

clean and dry and "0" ring is in position. 

3) Fill rotor with paste using spatula or syringe to a level near 

the top of the rotor, but avoid overfilling. 

A 5 cc capacity nylon syringe is recommended for filling the 

rotor. 

For highly concentrated products, fill the rotor to complete 

capacity. 

Remove any excess paste from the "0" ring and top edge of 

rotor. 

Threads on ring and rotor must be thoroughly clean. 

4) Position plastic cap on rotor so that it makes complete direc~ 

contact with the "0" ring. 

The raised portion of the plastic cap must be on top and, 

when the rotor is assembled, must extend through the hole 

in the rotor ring. 

5) Screw on the rotor ring and hand tighten. 

Do not use wrench to tighten rotor. 

If excess friction is encountered in assembling rotor, remove 

ring and inspect threads for presence of foreign matter. 

Clean carefully and reassemble rotor. 

6) Raise protective guard from centrifuge ~~d place rotor in 

position on stator pad. 

7) Close protective cover and tighten retaining screw with the 

fingers. 

8) Rotate pressure regulator control slowly and gradually until 

rotor is turning smoothly. 

Care should be taken to assure uniform distribution of sample 

in rotor; such distribution will result in an even, smooth 

spin of the rotor. 

If rotor spin is wobbly or noisy, remove rotor and redistribute 

sample to effect even dispersion. 

Insert as new pages, Sept. 1970 -12b-
T0~1ATO 

FPP~)DJCTS 

~ ITHODS 

Sol ids Con tent 

Refractometcic ~ethod 

September ~970 

9) Graduallv increase air pressure until adequate operating pressure 

is obtained. The pressure, in turn, will affect the r.p.m. 's of 

the rotor; the higher the pressure, the greater the r.p.m. 's 

For safety reasons the centrifuge should not be operated at 

a speed higher than necessary to provide good separation of 

the paste. 

Centrifuge time will vary and will depend upon the speed 

(r.p.m. 's) of the centrifuge and the type and concentration 

of the paste . 

10) Wnen adequate separation of the paste has been achieved decrease 

the centrifuge speed by lowering the air pressure to about 1 lb. 

pressure. wnen the centrifuge has slowed to its equilibrium 

speed at that pressure, decrease the air pressure gradually until 

the rotor starts to contact the stator pad; then shut off air 

pressure completely and allow the rotor to come to rest. 

It is important that the rotor come to a smooth stop; 

othen•ise the serum will mix to a certain extent with the 

tomato pulp and a clear serum will not be obtained. 

ll) Raise the protective guard, carefully remove rotor and unscrew 

rotor ring. 

If the ring can not be unscrewed by hand, use the ..... renches 

furnished with the instrument to loosen it. 

12) Separate ring from rotor and remove plastic cap -- being careful 

to disturb contents of rotor as little as possible. 

13) Use plastic cocktail straw as a pipette. Hold finger over one 

end of the straw and insert other end into serum lL"ltil straw 

extends nearly to the bottom of the rotor. 

Avoid contact of the straw ...,ith pulpy matter as much as 

possible. 

Remove finger from end of straw and allow serum to enter 

s t ra~<•. 

Replace finger and carefully withdrav> straw from serurn. 

T::-ansfer a drop from the straw directly to.the refractometer 

prism; immediately close prism and read the instrwnent, allowlng a few seconds for temperature equillbruim to be obtained. 

The straw is discarded after one use. 

The serum should be removed from the rotor as soon as ooss~~:e. 
TO"'LA.TO 

PRODUCTS 

'1ITHODS 

Soli.ds Content 

Refractometri.c '1ethod 

September 1970 

ALTERJ~ATIVE : i'-1edicine droppers may be used to withdraw the serum from 

the rotor. If medicine droppers are used, care should be taken that 

they are thoroughly cleaned and dried before using. The same care 

should be exercised in withdrawing the serum using a medicine dropper as 

with the straw. 

NOTE 

14) 1ne resulting serum should be reasonably clear, but this does not 

mean that it will be free of all turbidity or colored matter. 

Some samples may be a light straw color, but others -- especially 

those given an efficient hot break -- will be colored red from 

the presence of colloidal particles of lycopene pigment. These 

extremely small particles do not affect refractometer reading 

accuracy or line sharpness, but do reduce the contrast between 

the light and dark portions of the field. The criteria should be 

the sharpness of the line and the ability to obtain highly reproducible readings. If a distinct line cannot be obtained, the 

sample has not been centrifuged for a long enough time or at a 

sufficiently high speed. 

15) Clean all equipment and dry completely before reuse. 

I:-:sert as new pages, Sept. 197D -12 d-
I 

TOMATO 

PRODOC'I'S 

ME"l'HODS 

Solids Content 

Refract~tric Method 

February 1970 

ADDED SALT CORRECTION 

As previously explained the principle of the revised FDA Standards of 

Identity is to relate concentration in te~ of sucrose value and to 

include naturally occurring salt as a part of the soluble tomato solids, 

Therefore, any add~d salt must be deducted fro~ the final value. 

Observe the follo'lling procedure in making correction for added salt. 

When it is known that no salt is added -

This can only be determined with reliability by in-process inspection, 

-- Make no correction for added salt. 

Vhen salt has been added, or if in doubt -

Thi1 can be determined by in-process inspection, by label declaration -

or if in doubt assume salt ~s been added, 

l) 

2) 

3) 

Determine the percent salt (Na Cl) --Hii the<is of Ana lysis t SQ 1t Titration 

preferably the Potenti~ter Method (also File Code 135; 

Subtract the percent salt, as determined in Step 1), from the 

Sucrose Value obtained after all correctiona have been applied with 

the exception of Salt. 

Multiply the Salt-fre,a Sucrose Value (Step 2) by tb.e constant 1.016, 

The resultant value is considered the percent natural t~to soluble 

aolida. 

- 13 -
TOMATO 

PRODUC'!S 

METHODS 

Solids Content 

Ref~actametric Method 

February 1970 

Ex&mple 1: Tomato puree of about 10 percent natural tomato soluble 

solids and in which there is no added salt; no enzyme or 

dilution. 

Teat Results: 

Refractive Index: 1,347S 

Temperature 17° C 

Calculations: 

Sucrose Value (RI 1.3478) • 

Temperature Correction • 

Natural To.ato Soloble Solids 

10.0 

(-)~ 

9. 8'1 -

Example 2: Tomato puree of about 15 percent natural tcrmato soluble 

solids to which salt haa been added; no ena~ or dilution. 

Test Reaulta: 

C&lculationa: 

Refractive Index: 

Temperature 

Total Sal': 

1. 35 60 

24° c 

0. 6'1. 

Sucrose Value (RI 1.3560) • 

T~erature Correction • 

Corrected Sucrose Value 

Total Salt • 

Salt Correction Constant 

Natural Tom&to Soluble Solid8 

- 14 -

15.2 

(+)..Q.d 

15.5 

(·)...Q.:2 

14.9 

Xl. 016 

15 . ll. 
TOMATO 

PRODUCTS 

I MEm:>DS 

Zxa:mple 3: 

Solids Content 

Refractometric Method 

February 1970 

Approxi~te mioimum tomato paate to which oo salt haa 

been added, but to which 1.0 gr~ of dry ensyme has been 

added. 

Teat R.eaulta: 

Calculation: 

Refractive Index: 

Te~~~Pera ture 

Added Salt 

RI of 1 '7. El1%yme 

Solution 

Sucrose Value of 

EO%yme 

1.3728 

24° c 

0. 0'1. 

1.3336 

0.4~ 

Sucrose Value (RI 1.3728) • 

Tamperature Correction • 

Corrected Sucrose Value 

Leas En%yme Correction 

(1.15) (1) (0.40) • 

1/ Adjusted Sucrc•se Value 

Salt Correction 

Natural T~to Soluble Solids 

ll No aalt added so no salt correction oecesaary 

- 15 -

:~5. 3 

(+)_Q_d 

25.6 

_Q,2 

25.1 

...2.Jl 

ll.:J.'i. 
TOMATO 

PRODUCTS 

METHODS 

Example 4: 

Solids Cor·tent 

R~fractometric Method 

Febtilary 1970 

Concentrated tomato juice of about ZZ percent natural 

tomato soluble solids tc which salt has been added and 

1 gram of dry enzyme ha~ been added. 

Test Results: 

Calculations: 

Refractive Index 

of Concentrate: 

Temperature 

Total Salt 

(Potentiometric 

Method) 

Refractive Index 

o f 1!. So 1 n • o f 

1. 3682 

Z3° c 

o.n 

enzyme 1. 3336 @ Z0° C 

Sucrose Value of 

eruyme@ Z0° C : 0.4Z 

Sucrose Value (RI 1.368Z) • 

Temperature Correction • 

Corrected Sucrose Value 

~ss enzyme Correction 

(1.15 I 1 X 0.42 • 

Adjusted Sucrose Value 

Less Total Salt • 

Salt Free Soluble Solids 

Salt Correction Constant • 

Natural T~to Soluble Solids 

Report &I 

- 16 -

Z2.6 

(+) 0.2Z 

22.8Z 

(-)~ 

21.34 

(-)...£:.1_ 

21.64 

X~ 

21. 98'l 

22.07. 
TOMATO 

I PRODUCTS 

METHODS 

Solida Content 

Refractometric Meth~d 

Fe bru&ry 19 70 

Example 5: Approximate 45 percent natural tomato ioluble solids 

tomato paate to vhich ~ salt has been added and which 

haa been prepare4 by a 1 to 1 dilution with a ll pectic 

7 enzyme solvtiou. 

'!est Results: 

Calculations: 

Refractive Index: 

Temperature 

Added Salt 

RI of ll Pectic 

Solution @ 20°: 

Sucrose Value 

of Enzyme 

1. 3682 

25° c 

O.Ol 

1.3334 

0.28 

Sucrose Value (RI 1.3682) 

Temperature Correction 

Corrected Sucrose Value 

~ss enzyme correction 

(0.55) (1) (0.28) 

Adjusted sucrose value 

Multiply by 2 

Indicated sucrose value 

Plus correction for insoluble 

solids 

Total Soluble Solids 

Salt Correction (None) 

Natural TomAto Soluble Solids 

Report as 

- 17 -

-

• 

-

22.6 

(+) 0.38 

22.98 

(-) . 15 

22.83 

X2 

45.66 

(+) o. 8 

46.46 

o.o 

46.46 

46.5 
TOHAIO 

PRODUCTS 

ME'!' BODS 

Solids Content 

Refractometric Metbod 

February 1970 

Example 6: Approximate 40 percent natural t~to soluble solids 

tomato paste to which salt has been added, and which 

haa been prepared by a 1 to 1 dilution with water -

no eru:yme. 

Teat Results: 

Calculations: 

Refractive Index: 1.3645 

Temperature 

Total Salt Po23° c 

0. 8'l. 

tentiometric Method) 

Sucrose Value (RI 1.3645) • 

!~perature Correction 

Corrected sucrose value 

Multiply by 2 

Indicated sucrose value 

• 

Plus correction insoluble solids 

Total Soluble Salida 

!Ass total salt 

Salt-free soluble solids 

Salt Correction Constant 

Natural Tomato Soluble Solids 

- 18 -

20.4 

(+) -2.:1l 

20. 62 

X 2 --- 41.24 

(+) ...22_ 

41.94 

(-)~ 

41. 14 

X 1. 016 

L; l. ~: 
/ 

TOMATO 

PRODUCTS 

METHODS 

NOTES ON METHOD 

Enzvrne Correction Constant 

Solids Content 

Refractometric Method 

February 1971 

The methodology in the foregoing sections has standardized on the use 

of 

(a) a I% pectic enzyme solution when a 1 to 1 dilution is followed 

Or 

(b) 1 gram of dry pectin per 100 grams when direct filtration 

is used. 

This has been done for standardization purposes only and to simplify 

calculations. It is possible, however, to use more or less pectic 

enzyme and still follow the approved method. It would be unlikely to 

ever need more than a 1% solution or 1 gram of dry pectin. 

In the event it is necessaD' or desired to deviate from the standardized 

1% value, correction for added pectic enzyme must be made in accordance 

with the following as may be applicable: 

For Dry Enzyme - No dilution 

Subtract from the sucrose value 1.15 AC in which--

A = weight of added pectic enzyme (grams) 

C = sucrose value of a 1% solution of pectic enzyme. 

For Enz\~e In Solution - (1 to l Dilution) 

Subtract from the sucrose value 0.55 BC in which--

B = weight of pectic enzyme per 100 grams of solution 

C = sucrose value of a 1% pectic enzyme solution. 

The constants 1.15 and 0.55 are predicated on an average of 12.5 percent 

of the total tomato solids being insoluble material, thus 87.5 percent 

being soluble solids. The pectic enzyme has a plus effect on the 

No change in text 

- 19 -
* 

TO~ !A TO 

PRODUCTS 

METHODS 

Solids Content 

Refractometric ~ethod 

February 1971 

refractometer thereby adding to the value contributed solely by soluble 

tomato solids. However, when using the pectic enzyme either dry or in 

solution it is completely soluble with only the soluble portion of the 

tomato solids. To correct for enzyme dilution only it is necessary to 

divide 100 by 87.5 or 100 = 1.15 in the case of dry pectin 87.5 

In the case of a 1 to 1 dilution only half as much enzyme is available 

~~d consequently l.lS = 0.55 (rounded) 2 

Correction For Insoluble Tomato Solids 

The table for correcting the effect for 1 to 1 dilution (either pectic 

enzyme solution or water) is also based upon the fact that the insoluble 

tomato material does not contribute to soluble solids. Therefore if 

100 grams of water is added to 100 grams of tomato concentrate the insoluble 

solids do not contribute to the refractometer reading and a slightly low 

reading results. This is compensated for by applying the "dilution 

correction factor" found in the table on page 12 of this instruction. 

Correction For Salt 

The constant 1.016 used in making the salt correction is predicated on 

the assumption that 1.6 percent of the natural tomato solids is naturally 

occurring salt (Na Cl). Thus 98.4 percent is salt-free solids. 

So 100 = 1.016 which is the constant used to apply to the salt free 98.4 

sucrose value to compensate for naturally occurring salt. 

Correction 

- 20 -
TOMATO 

PRODUCTS 

MElli ODS 

Background 

VACUUM OVEN MElliOD 

Solids Content --

Vacuum Oven Method 

February 1970 

The vacuum oven procedure -- described in the AOAC (Methods of 

Analyses of Official Analytical Chemists) is an official method 

used by the Food and Drug Administration to determine the solids 

in many comminuted products. The method involves d~ring a sample 

of the product to constant dryness under vacuum and at a specified 

temperature. 

When to Use 

The vacuum oven method is used: 

Equipment 

Whenever this method is specifically requested 

by the packer or applicant. 

Analytical balance. 

Flat-bottomed drying dishes approximately 2-1/2 to 3-1/2 inches 

in diameter ( 8 em ) 

Vacuum-oven, with necessary accessorie,!. 

Desiccator. 

[All of the above equipment is obtainable 

from any reputable chemical apparatus 

supply house.] 

- 21 
TOMATO 

PRODUCT 

METI-lODS 

Procedure 

VACUUM OVEN METHOD 

Solids Content -- Vacuum Oven Method 

February 19 70 

1) Thoroughly mix the contents of the container by stirring 

with a dry spoon for approximately 1 minute before removing portions for analysis. 

2) Determine approximate natural tomato soluble solids of 

sample by the refractometric method. 

3) Weigh, into flat-bottomed drying dish with tight fitting 

cover about 15 mg diatomaceous earth filter aid per 

square centimeter and dry 30 minutes at 110° C. 

Example ( ..,. . R2 = A] 3.14159 = 7( expressed as 22 

7 

[~ (Diameter] 2 = area of dish 

[7) [ 2 ] 

Thus, if the measured diamter of a drying dish is 8 em., 

the amount of filter aid to use is determined as follows: 

[~ 

[ 7) 

[8)2 = (22 (4) 2 = (22) _(_16) = 50.3 sq. em. [2) 7 ........_..__..,..., __..._..... 

Therefore 

50.3 x 15 mg = 754.5 mg (amount of filter aid for this dish) 

.. 

--Continued on next page --

22 -
TOMATO 

PRODUCJ'S 

METHOOS 

Solids Content --

Vacuum Oven Method 

February 1 9 7 0 

VACUUM OVLN METiiOU continuation 

4) After cooling in dessicator, weigh (dish and filter aid) 

and to the drying dish adc· enough sample so that the 

c~uivalent weight of the dry residue of the sample will 

not be less than 9 mg. nor greater than 30 mg. per square 

centimeter. 

Example. 

Assuming the area of the drying dish is SO. 3 sq. em. (See 3 above) 

and the approximate natural tomato soluble solids is 36% 

(refractometric method) --

Therefore 

a) 9 mg. per sq. em. = (9) . (50.3) = 453 mg. 

b) 30 mg. per sq. em. =(30) . (50.3) = 1509 mg. 

c) 36\ solids lS equivalent to 300 mg. dried residue per l gram. 

d) 360 mg. 

4;:,3 mg. 

360 X. 

X. 

e) 3b0 mg. 

1509 mg 

360 X. 

X 

= 

= 

= 

= 

= 

= 

1 grn 

:x. gnns 

453 

l. 26 grams (Minimum Sampl 

1 grn 

:x. grms 

1509 

4.19 grams (1--la:x.imum Sample) 

of 36% product 

to be used 

in dish of 

8 em diameter 

5) Weigh (sample, filter aid, and dish) as rapidly as possible 

to avoid moisture loss. 

6) Mix filter aid and distribute uniformly 0ver bottom of dish, 

diluting with water, if necessary, to facilitate distribution. 

7) Place dish (sample) in vacuum oven at 70° C. with release cock 

left partly open so that the amount of v~cut~ is not less than 

310 mm. of Mercury (13 inches). Examine dish (sample) at 30 

minute intervals and until the remaining moisture is not more 

than about SO% dry solids. If running more than one sample, 

remove faster drying samples, cover and place in dessicator 

until all samples have reached this apparent dryness. 

[There are other acceptable methods for 

obtaining this apparent dryness see AOAC] 

- 23 -
TOMATO 

PRODUCTS 

MElli ODS 

VACUUM OVEN METHOD -- continuation 

Procedure -- continuation 

Solids Content --

Vacuum Oven Method 

February 1970 

8) Place partially dried sample in vacuum oven with bottoms of 

dishes in direct contact with shelf. (Oven thermometer is 

to be in direct contact with shelf and variation of 

te~erature is not more than 2°C,) 

~~) Close re leas1! cock and admit dry air to oven at the rate of 

2 to 4 bubbles per seconds by bubbling through concentrated 

sulfuric acid. 

10} Dry samples 2 hours at 70°C. at a vacutml not greater than 

100 mm. of Mercury (4 inches). 

11) As dried s~les will absorp appr~ciable ~ount of moisture, 

on removing dishes from- oven, cov~r quickly and place in 

dessicator. weigh as soon as the sample reaches room 

temperature. 

12) Determine the weight of the dry residue, and 

calculate the percent of total solids 

Sample of 1.5429 grams spread uniformly on 

bottom of dish and dried as specified. 

Dried residue • 0.5477 grams. 

Total solids • 0.5477 • 35.5 percent. 

1. 5429 

13) To adjust total solids to salt-free tomato solids, 

subtract the l salt from the Total solids, and 

report the result as "Salt-free Tomato Solids." 

Salt content • 0.4 percent (deterMined analytically) 

Salt-free tomato solids • 35.5 minus 0,4 • JS.l percent. 

Report as "Salt-free Tomato Solids • 35.1%" 

(Vacuum Oven ~ethod). 

- H -
TOMATO 

PRODUCT'S 

METI-iODS 

Background 

SPECIFIC GRAVITY METHOD 

Specific Gravity 

Method 

August 1971 

TI1is is an official method, described in the ADAC, and is 

applicable to concentrated tomato products. It is one of 

the more accurate methods to use for determining specific 

gravity. It is based on the relation between the weight 

of equal volumes of water and the product at a specified 

temperature -- for our purposes, 20° C. 

When to use 

This procedure, although official, is not used often. In 

some instances, however, this procedure may be used by 

packers or requested in buyers' contracts. 

Use this method only when specifically requested to report 

the results as specific gravity. [Do not convert the specific 

gra.vity, thus found, to total solids, salt-free solids or any 

other method of expressing degree of concentration. And 

STATEMENTS 

WITHI~ BRACKETS [) ARE 

SUSPEI\DED 

do not determine specific gravity of DURING tomato products by the 

refractometric method.] EFFECTIVE 

PERIOD OF B~~CH 

Equipment NOTICES 1420 & 1424 

(July, 1971) 

Specific gravity bottles -- round, wide-mouth two-ounce~g~.r,a~s~s~--~----~-----­

bottles (preferably Pyrex) with a ground top rim and a 

cover disc ground to fit, obtainable from scientific 

supply houses. 

Balance scale -- accurate to 0.5 gram or less, up to 700 grams. 

Analytical balance -- accurate to 0.001 gr~~ at 100 grams. 

Laboratory centrifuge-- International, Size 1, Type SB, or 

similar equipment (capable of 1,000 rpm). 

Freshly distilled deaerated water. 

Thermometer. 

A suitable straight edge. 

Funnels, glass -- 2-1/2 inch diameter (for filling bottles). 

Alcohol (denatured) or acetone for drying bottles. 

Dry towels 

Medicine dropper - z; -
TOMATO 

PRODUCTS 

METHODS 

Procedure 

Specific Gravity 

Method 

August 197_1 __ 

No Change In Text 

Calibrating the Specific Gravity Bottles 

1) Thoroughly clean and dry the bottle with cover disc. 

2) Weigh on the analytical balance to the nearest 0.001 gram. 

3) Fill bottle to over-flowing with freshly distilled, deaerated 

water at 20° C. (Centrifuge, if necessary, to remove any 

entrapped air) . 

4) Adjust the level of the water exactly even with the top (by 

means of an eye droppe~. if necessary). 

5) Slip the cover disc on to top of bottle with care to exclude 

all air bubbles. 

6) Quickly wipe the bottle and cover dry on the outside, and 

weigh the full bottle on the analytical balance to the 

nearest 0.001 gram. 

7) Subtract the weight of the bottle and cover to determine the 

weight of water at 20° C. 

In the course of routine work, it is a great 

convenience to construct a table, showing 

the weight of the full bottle and cover at 

20° C. for a series of specific gravities 

over a normal working range. 

- l6 -
TOMA.TO 

PRODUCTS 

MElliODS 

Specific Gravity 

Method 

February 1970 

Weighing the product and calculating specific gravity 

1) Cool the sample to between 16° C. and 18" C. 

2) Open container, and stir well for at least one minute. 

3) Fill previously calibrated bottle with the product, and 

centrifuge for 1 minute at about 1,000 rpm. 

4) Add enough product to fill bottle to top and centrifuge again. 

5) Remove bottle and take temperature of product, inserting 

thermometer so that no air is introduced. 

6) When temperature is just 20° C., remove thermometer, add 

enough product at same temperature (20" C.) to have bottle 

slightly over full, and strike off even with top of bottle 

with straight edge. 

7) Clean outside of bottle and weigh at once to nearest 0.001 gram. 

8) Specific gravity = weight of product at 20° C., divided by 

weight of water at 20° C. that same 

bottle holds. 

The bottles may be conveniently dried after thorough 

washing by rinsing with denatured alcohol or acetone 

and centrifuging a fe.,..· seconds upside down. A very 

brief air blast will then remove the last traces of 

liquid from the inside of the bottles. 

EX.AJ•1PLE 

S.G. = Wt. of product at 20°C. 

Wt. of equal volume of water at 20° C. 

a) Weight of bottle plus water at 20° C ............. . 203.815 

Weight of bottle .................................. . 

b) Weight of bottle 

Weight of bottle 

c) S.G. = 130. 275 

124.605 

d) Report as: 

Weight of water 

plus product at 20° c. .. .. .. . . . .. . . .. . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . . . . . . Weight of product . . . . . . . . . 

= 1. 0455 

"Specific Gravity - 1.0455 

(Official SpeCl fie Gravity Method)" 

- 27 -

-79.210 

124.605 

209.485 

-79.210 

130.27 5 

g. 

g. 

g. 

g . 

g. 

g . 
I 

TOMATO 

PRODUCTS 

METHODS 

TABLE I 

TOMATO CO!'lCENTRATES 

Pt1ree (or Pulp) 

Paste 

Juice Concentrate 

USDA - February 1970 

Refractive Indices of Sucrose Solutions at 20• C 

Refract. t1l Refract. "' Refract. '7o )0 /0 

Index Sucrose Index Sucrose Index Sue rose 

1.3376 3.2 1.3396 4.5 1. 3416 5. 9 

l. 33 7 7 3. 3 l. 3397 4.6 l. 3417 6.0 

1.3378 3.3 1.3398 4.7 l. 3418 6.0 

1.3379 3.4 1.3399 4.7 l. 3419 6. l 

1.3380 3.5 1.3400 4.8 1. 34 20 6. 2 

1.3381 3.5 1. 3401 4.9 1. 34 21 6.2 

1. 3382 3.6 1.3402 5.0 1. 34 2 2 6. 3 

1.3383 3.7 1.3403 s.o l. 34 2 3 6.4 

1.3384 3.7 1.3404 5. 1 l. 34 24 6.4 

1.3385 3.8 1. 3405 5. 2 1.3425 6.5 

1.3386 3.9 1. 3406 5. 2 1. 34 2 6 6.6 

1.3387 3.9 l. 3407 5.3 1. 34 2 7 6.6 

l. 3388 4.0 1. 3408 5.4 1.3428 6. 7 

1.3389 4. 1 1.3409 5.4 l. 34 2 9 6.8 

1.3390 4. 1 1. 3410 5. 5 1. 34 30 6.8 

1.3391 4.2 l. 3411 5. 6 l. 34 31 6.9 

1.3392 4.3 1. 3412 5.6 1. 34 3 2 7. 0 

1.3393 4. 3 1. 3413 5.7 1. 34 3 3 7. 0 

l. 3394 4,4 1. 34 14 5.8 1.3434 7. l 

1.3395 4.5 l. 3415 5.8 1. 343 5 7. 2 

Adapted from the International Scale of Refractive Indices of Sue rose 
, 

TOMATO 

PROI:XJCTS 

MEI'HODS 

TABLE I -- cont i.nua t ion 

TOMATO CONCENTRATES 

Puree (or Pulp) 

Paste 

Juice Cone ent rate 

USDA - February 1970 

Refractive Indices of Sucrose Solutions at 20° C. 

Refract. 

Index 

1. 3436 

l. 34 3 7 

l. 3438 

1. 34 3 9 

1.3440 

1. 3441 

1. 344 2 

1. 3443 

1.3444 

1. 3445 

1. 3446 

l. 344 7 

1.3448 

1.3449 

1. 34 50 

1 • 34 5 l 

l. 34 52 

1. 34 53 

l. 34 s:.. 

l . }4 55 

"' /0 

Sucrose 

7.2 

7. 3 

7.4 

7.4 

7.5 

7. 6 

7.6 

7. 7 

7.8 

7.8 

7. 9 

8.0 

8.0 

8. 1 

8.2 

8.2 

8. 3 

8.3 

8.4 

8.5 

Refract. 

Index 

l. 3456 

l. 34 57 

1.3458 

l. 34 59 

1. 3460 

1. 3461 

l. 3462 

l. 34 63 

1. 3464 

l. 3465 

l. 3466 

1. 34 6 7 

1. 34 68 

1. 3469 

1. 34 70 

1. 34 71 

l. 34 7 2 

l. 34 7 3 

l. 34 74 

l. 34 75 

% 

Sucrose 

8.5 

8.6 

8.7 

8. 7 

8.8 

8.9 

8.9 

9.0 

9. 1 

9. l 

9.2 

9.3 

9.3 

9 ,, 

.-

9.5 

9.5 

9. 6 

9. 7 

9. 7 

9.8 

- ii -

Refract. 

Index 

l. 34 7 6 

l. 34 77 

1. 34 7 8 

l. 34 7 9 

l. 3480 

1. 3481 

1.3482 

l. 3483 

l. 3484 

l. 3485 

1. 3486 

1.3487 

1. 3488 

1.3489 

l. 3490 

1 . 34 91 

1.3492 

l. ]4 9 3 

l. ]4 94 

1. 34 9') 

'l'c 

Sue rose 

9.9 

9.9 

10.0 

10.0 

10.1 

10.2 

10.2 

10.3 

10.4 

10.4 

10.5 

10. 6 

10.6 

10.7 

10.8 

10.8 

10.9 

11.0 

11.0 

ll. l 
, 

TOMATO 

PRODUCTS 

METHOD 

TABLE I -- cent i.nuat ion 

TOMATO CONCENTRATES 

Puree (or Pulp) 

Paste 

Juice Concentrate 

USDA - February 1970 

Refractive Indices of Sucrose Solutions at 20° C. 

Ref:- act. <II Refract. 't Refract. ~ 

/0 /0 

Index sucres e Index sucrose Index sucrose 

l. 34 9 6 11. 1 1.3516 12.4 1. 3536 13. 7 

l. }49 7 11. 2 1.3517 12.5 1.3537 l3. 8 

1.3498 11.3 1.3518 12.6 1.3538 l3. 8 

1.3499 11.3 1.3519 12. 6 1.3539 13. I') 

l. 3500 11.4 1. 3 5 20 12. 7 1. 3 540 13.9 

1.3501 11.5 1.3521 12.7 1. 3 541 14.0 

1.3502 11.5 1.3522 12.8 1.3542 14. l 

1.3503 11.6 1.3523 12.9 1. 3 54 3 14. 1 

1.3504 11. 7 1.3524 12.9 1. 3 544 14. 2 

1.3505 11.7 1.3525 13.0 1. 3 54 5 14.3 

1.3506 11.8 1.3526 13. l l. 3 54 6 14.3 

1.3507 11.9 1.3527 l3. 1 l. 3 54 7 14.4 

1.3508 11.9 1.3528 13. 2 l. 3 54 8 14. 5 

1.3509 12.0 1.3529 13.3 1. 3 549 14. 5 

1.3510 12.0 l. 3530 13.3 l. 3 5 50 l!.i. 6 

1.3511 12. 1 1.3531 13.4 1.3551 14. 6 

1.3512 12. 2 1.3532 13.4 1.3552 14. i 

1.3513 12.2 1. 3533 13. 5 l. 3553 14.5 

1.3514 12.3 1.3534 13.6 l. 3 5 54 14.5 

1.3515 12.4 1.3535 13.6 1.3555 14. 9 

- iii -
TOMATO TOW. TO CONCENTRATES 

PROIXJCTS Puree (or Pulp) 

METHOD Paste 

Juice Concentrate 

USDA - February 1970 

TABLE I cont inu<'lti.on 

R,,fr:tct ive Ind i.e es ()f Sucrose Solutions ;It 20° c. 

Refract. % Refract. a< 

10 !i.efract. "' /0 

Index Sue rose Index Sue rose Index Sue rose --- 1.3556 15.0 1.3576 16.2 1.3596 17.4 

1.3557 15.0 1.3577 16.3 1.3597 17.5 

1.3558 1 'i. 1 1.3578 16.3 l. 3 5 98 l 7. 6 

1.3559 15. 1 1.3579 16.4 1.3599 17. 6 

1.3560 15. 2 1.3580 16.4 l. 3 600 17. 7 

1.3561 15.3 1.3581 16.5 l. 3 601 17. 7 

1.3562 15. 3 1.3582 16.6 1.3602 17.8 

l. 3 5 63 15.4 l. 3583 16.6 l. 3 603 17. 9 

1.3564 15. 5 1.3584 16. 7 l. 3 604 l 7. 9 

1.3565 15. 5 1.3585 16.7 1. 3 605 18.0 

1.3566 15. 6 1.3586 16.8 1.3606 18.0 

1.3567 15.7 1.3587 16.9 1.3607 }8. 1 

1.3:68 15.7 l. 3 5 88 16.9 1.3608 18.2 

l. 3569 15.8 1.3589 17.0 1.3609 18. 2 

1.3570 15.8 1.3590 17.0 1.3610 18.3 

1.3571 15.9 1.3591 17. 1 1.3611 18.3 

1.3572 15.9 1.3592 17. 2 1.3612 18.4 

l.3'i73 16.0 1.3593 17.2 1.3613 18. 5 

1. 3 5 7t; 16. 1 1.3594 17. 3 1. 3 6 14 1 g. 5 

1.3575 1 6. 1 1.3595 17.4 1.3615 18. 6 

- iv -
TOMATO T\JMATO CONe El'l TKA T E5 

PR0Dl1CTS Puree (or Pulp) 

METHOD Paste 

Juice Cone er.t rate. 

usDA. - rebruary ~970 

' TABLE I -- continuation 

Refractive Indices of Sucrose Solutions at 20° c. 

RefrRct. '7'o Refract. '7'o Refract. "' /0 

Index Sue rose Index Sucrose Index Sucrr;se ---- 1.3616 18.6 1.3636 19.9 1.3656 21.1 

1.3617 18.7 1.3637 19.9 1.3657 21. l 

1.3618 18.8 1.3638 20.0 1.3658 21.2 

1.3619 18.8 1.3639 20.0 1.3659 21.2 

1.3620 18.9 1. 3 640 20. 1 l. 3660 21.3 

1.3621 19.0 1. 3 641 20.2 1.3661 21.4 

1.3622 19.0 l.3642 20.2 l. 3 66 2 21 /, . ·- 1. 3623 19. l 1. 3 643 20.3 1.3663 21.5 

1.3624 19. 1 l. 3 644 20.3 1. 3 6 64 21.5 

1.3625 19. 2 1. 364 5 20.4 l. 3 66 5 21.6 

1.3626 19.3 1. 3 64 6 20.5 1.3666 21.6 

l. 3627 19.3 l. 3 64 7 20.5 1.3667 21. 7 

1.3628 19 .4 1. 3 648 20.6 1.3668 21.8 

1.3629 19.4 ' l. 3649 20.6 1.3669 21.8 

1.3630 19.5 1.3650 20. 7 1.3670 21.9 

l.3631 19.6 1.3651 20.8 1.3671 21.9 

1.3632 19.6 1.3652 20.8 1.3672 22.0 

1.3633 19. 7 1.3653 20.9 1.3673 2 2. 1 

l.3634 19. 7 1.365'- 20.9 l. 3 6 74 2 2. ! 

1.3635 19.8 1.3655 21.0 1.3675 2 2. 2 

- \.? -
·-~ - tOMATO TCMATO CONCENTRATES 

P~ODUCTS Puree (or Pulp) 

METI!OD Paste 

Juice Co:oc e:ot rate 

USDA - February l970 

, TABLE I -- cont inuat :.on 

Refractive Indices of Sucrose So 1ut ions at 20" c. 

Refract. 'l"o Refract. '7o Refract. "' 10 

Index Sucrose Index Sucres e Index Sue rose 

1.3676 2 2. 2 1.3696 23.4 1.3716 24. 6 

1.3677 22.3 l. 3697 23.5 1.3717 21.;. 6 

1.3678 22.4 1.3698 23.5 1. 3 7 18 24. 7 

1.3679 22.4 1.3699 23. 6 1.3719 24. 8 

1.3680 22.5 l. 3 700 23. 7 1.3720 2'\ ~ -·--' 

1.3681 22.5 l. 3 70 l 23.7 1.3721 2~. 9 

1.3682 22.6 1.3702 23.8 1.3722 24. 9 

1.3683 22.7 l. 3 703 23.8 1.3723 25.0 

1.3684 22.7 l. 3 704 23.9 1. 3 7 24 2 5. l 

1.3685 22.8 1. 3 705 23.9 1.3725 2 5. 1 

l. 3686 22.8 l. 3 706 24.0 1.3726 25.2 

1.3687 22.9 1.3707 24. 1 1.3727 25.2 

1.3688 23.0 1. 3 708 24 0 l 1.3728 ., - < .. ) . ~ 

1.3689 23.0 1. 3 709 24.2 1.3729 25.4 

l. 3 6 90 23. 1 1.3710 24.2 1.3730 25.t.. 

l.3691 2 3. 1 1.3711 24.3 1.3731 25.5 

1.3692 23.2 1.3712 24.4 1.3732 25.5 

1.3693 23.2 1.3713 24.4 1.3733 25.6 

1. 3694 23.3 l. 3 714 24. 5 1.3734 25. 6 

1.3695 23.4 1.3715 24. 5 1.3735 25. -

- v l. -
TOMA'!'O TC'--\J. TO CONCENTRATES 

PROUJCTS Puree (or ?u lp) 

METHODS Paste 

Juice Concentrat.e 

usDA. - rebruary 1970 

I TABLE I -- cont i.nuat ion 

Refractive Indices of Sucrose Solutions at 20° c. 

Refract. % Refract. "' 10 Ref rae t. "' 10 

Index Sucrose Index Sue rose Index Sucrose 

1.3736 25.8 1.3756 26.9 1.3776 28.0 

1.3737 25.8 1.3757 27.0 1.3777 28. l 

1.3738 25.9 1.3758 27.0 1.3778 28.2 

1.3739 25.9 1.3759 2 7. l 1.3779 28. 2 

l.3740 26.0 l. 3 7 60 2 7 0 l l. 3 7 80 28. 3 

1.3741 2 6. 1 1.3761 27.2 1.3781 28.3 

l. 3 74 2 2 6. l 1.3762 27.3 1.3782 28.4 

1.3743 26.2 1.3763 27.3 1. 3 7 83 28.4 

l. 3 744 26.2 l. 3 7 64 27.4 1.3784 28.5 

l. 3 74 5 26.3 1.3765 27.4 1.3785 28.6 

1.3746 26.3 l. 3 7 66 27.5 1.3786 28.6 

l. 3 74 7 26.4 1.3767 27.5 1.3787 28.7 

l. 3 748 26.5 1.3768 27.6 1. 3 7 88 28. 7 

l. 3 74 9 26.5 1.3769 27.7 1.3789 28.8 

1.3750 26.6 1.3770 2 7. 7 l. 3 7 90 28.8 

1.3751 26.6 1.3771 27.8 1.3791 28.9 

1.3752 26.7 1.3772 27.8 1.3792 29.0 

1.3753 26.8 1.3773 27.9 1.3793 29.0 

l. 3 7 54 26.8 l. 3 774 27.9 1. 3 7 94 2 9. 1 

1.3755 26.9 1.3775 28.0 1.3795 2 9. l 

- vii -
' 

TCMATO 

PRODUCfS 

MITHODS 

Refract. 

Index 

1.3796 

1.3797 

l. 3 7 98 

1.3799 

1.3800 

l. 3801 

l. 3802 

1.3803 

1. 3804 

1. 3805 

l. 3806 

1.3807 

1.3808 

1. 3809 

1.3810 

l. 3811 

1.3812 

l. 3813 

1.3814 

l. 3815 

TABLE I -- continuation 

TCMATO C0NC:::::TRt~.7:::~ 

Puree (or Pulp) 

Paste 

Juice Concentrate 

USDA - February 1970 

Refractive Indices of Sucrose Solutions at 20° C. 

"' /O 

Sucrose 

29.2 

29.3 

29.3 

29.4 

29.5 

29.5 

29.6 

29.6 

29.7 

29.7 

29.8 

29.8 

29.9 

30.0 

30.0 

30. l 

30. 1 

30.2 

20.2 

Refract. 

Index 

1.3816 

1.3817 

l. 3818 

1.3819 

1.3820 

1.3821 

l. 382 2 

1.3823 

l. 3824 

1.3825 

1.3826 

1.3827 

1.3828 

1.3829 

1.383;) 

1.3831 

1.3832 

1.3833 

l. 3 8 34 

l. 38 3 5 

Sucrose 

30.3 

30.3 

30.4 

30.4 

30.5 

30.6 

30.6 

30.7 

30.7 

30.8 

30.8 

30.9 

30.9 

31.0 

31. l 

31. 1 

31.2 

31.2 

11 - -- • .5 

31.3 

- viii -

Refract. 

Index 

1.3836 

1.3837 

1.3838 

1.3839 

1.3840 

l. 3841 

l. 384 2 

l. 3 84 3 

1.3844 

l. 3845 

1. 3 84 6 

1.3847 

l. 3848 

1. 384 9 

1.3850 

1.3851 

1.3852 

1.3853 

1.3854 

1.3855 

"' /0 

Sucrose 

31.4 

31.4 

31. 5 

31.6 

31. 6 

31.7 

31.7 

31.8 

31.8 

31.9 

31.9 

32.0 

3 2. l 

3 2. 1 

32.2 

3 2. 2 

32.3 

32.3 

32.4 

32.4 
TOMATO 

PRODUCTS 

MITHODS 

R~fc-;1ct. 

lncie>. 

J.38'i6 

1. 38 7 

1.3858 

l. 3859 

1.3860 

l. 38 6 l 

1.3862 

1.3863 

1. 3864 

1. 38bS 

1.3866 

1.3868 

1.3869 

1.3870 

l. 38 7 1 

1.3872 

l. 3873 

]. 38 74 

1.387) 

TABLE I-- continuation 

Pur.;;z.: (or Pulp) 

Paste 

Juice Concentrate 

USDA - Febr-uary l 9 7 0 

R~fr~ctive Indices of S1crose Solutions at 20" C. 

"' 10 

Sue rose 

32.5 

32.5 

32.6 

32.6 

32.7 

32.8 

32.8 

32.9 

32.9 

33.0 

33.0 

3 3. 1 

33. l 

33.2 

33.3 

33.3 

33.4 

33.4 

33.5 

33.5 

Refract. 

Index 

1.3876 

1.3877 

1.3878 

1.3879 

1. 3880 

1. 3881 

1.3882 

1.3883 

1.3884 

1.3885 

1.3886 

l. 3 88 7 

1.3888 

1.3889 

1.3890 

1.3891 

1.3892 

1.3893 

1.3894 

1.3895 

ar 

10 

Sucrose 

33.6 

33.7 

33.8 

33.8 

33.9 

33.9 

34.0 

34.0 

34. 1 

34. 1 

34.2 

34.2 

34.3 

34.3 

34.4 

34.5 

34. 5 

34.6 

34. 6 

- ix -

Refract. 

Index 

1.3896 

1.3897 

1.3898 

1.3899 

l. 3 900 

1.3901 

1.3902 

1.3903 

1. 3 904 

1.3905 

1.3906 

1.3907 

1.3908 

l. 3909 

1.3910 

1.3911 

1.3912 

1.3913 

l. 3 914 

1.3915 

"' Jo 

Sue ruse 

34. 7 

34. 7 

34.8 

34. 5 

34.9 

34. 9 

35.0 

35.0 

3 5. l 

3 5. l 

3 5. 2 

3 5. 3 

35.3 

35.4 

1" - ~ 1.) 

3 5. 5 

3S.6 

3 5. i 

3 5. 7 
TOM..A.TO 

PRODUCTS 

METHODS 

Refract. 

Index 

1.3916 

1.3917 

1.3918 

1.3919 

1.3920 

1.3921 

1.3922 

1.3923 

1.3924 

1.3925 

1.3926 

1.3927 

1.3928 

1.3929 

l. 3930 

1.3931 

1. 3932 

. 1.3933 

1.3934 

1.3935 

TABLE I -- continuation 

TOMATO COt~CENTRATES 

Puree (or Pu 1 p) 

Paste 

Juice Co~centrate 

USDA -

Refractive Indices of Sucrose Solutions at 20° C. 

"' 10 Refract. "' /0 Refract. 'l'o 

Sucros.: Index Sucrose Index Sue rose 

35.8 1.3936 36.8 1.3956 37.9 

35.8 1.3937 36.9 1.3957 37.9 

35.9 1. 3938 36.9 1.3958 . 38.0 

35.9 1. 3939 37.0 1.3959 38.0 

36.0 1. 3940 37.0 1. 3960 38.1 

36.0 l. 3 941 37.1 1.3961 38.1 

3 6. 1 1. 394 2 37.1 1. 3962 38.2 

3 6. 1 1. 3943 37.2 1.3963 38.2 

36. 2 l. 3944 3 7. 2 l. 3964 38.3 

36.2 1.3945 37.3 1.3965 38.3 

36.3 1. 3946 37.3 1.3966 38.4 

36.3 l. 394 7 37.4 1.3967 38.4 

36.4 1. 3948 37.5 1.3968 38.5 

36.5 1. 3 94 9 37.5 1.3969 38.5 

36.5 1.3950 37.6 1.3970 38.6 

36.6 1.3951 3 7. 6 1.3971 38.6 

36.6 1. 3952 37.7 1.3972 38.7 

3 6. 7 1.3953 3 7. 7 1.3973 38.7 

36.7 1. 3 9 54 37.8 1.3974 38.8 

36.8 1.3955 37.8 1.3975 38.8 

- X -
'i'UMATU 

PRODJCTS Puree (or: Pu 1 p) 

METHODS Paste 

Juice Con cent rate 

USDA -

TABLE I -- cont inuot i-:ln 

Refractive Indices of Sucrose So lu: ions at 20° c. 

Refract. '7o Refract. ar Refract. "' Jo 10 

Index Sucrose Index Sucrose Index Sucrose 

1.3976 38.9 1.3996 39.9 1.4016 41.0 

1.3977 38.9 l. 3997 40.0 1.4017 41.0 

l. 397R 39.0 1. 3 998 40.0 l. 40 l8 41.: 

1.3979 39.0 1.3999 40. l 1.4019 4 l. 1 

L.3980 J g. l 1.4000 40. l 1.4020 41.2 

t. 3 98 1 39. 1 l. 4001 40.2 1.4021 41.2 

1.3982 39. 2 l. 4002 40.2 1.4022 4 l. 3 

1. 3983 39.2 1.4003 40.3 l. 4023 41.3 

l. 3 984 39.3 1. 4 004 40.3 1. 4024 41..:. 

1.3985 39.3 1. 4005 40.4 1. 4025 41,:.. 

1.3986 39.4 1.4006 40.5 1.4026 41.5 

l.3987 39.5 1. 4007 40.5 l. 402 7 41. 5 

1.3988 39.5 1.4008 40.6 1. 4028 41.6 

1.3989 39.6 1.4009 40.6 1. 4029 41.6 

l. 3990 39.6 1. 4010 40.7 l. 4030 41. 7 

1.3991 39. 7 1.4011 40.7 1.4031 41.7 

1.3992 39.7 1.4012 40.8 1. 403 2 41.8 

1.3993 39.8 1.4013 40.8 l. 403 3 41.8 

1.3994 39.8 1. 4014 40.9 1. 4034 41.9 

: l. 399') 39.9 l. 4015 40.9 l.4CJ5 4:.9 

- xi -
TCMATO T~..ATC' CGt\ CE:~TR.A.T'SS 

PROOOCTS Puree (or Pulp) 

METHODS Paste 

Ju i.ce Concentrate 

USDA -

TABLE I -- cont i nuat i.on 

Refractive Indices of Sucrose Solutions at 20° c. 

Rt:fract. "' ro Refract. % Refract. '7o 

Index Sucrose Index Sucres e Index Sucres e 

l. 403 6 4 2. 0 1.4056 43.0 1.4076 44.0 

1.4037 4 2. 0 l. 405 7 43.0 1.4077 44.0 

1. 4038 4 2. 1 1. 4058 43. l 1.4078 44.1 

l. 4039 42.1 l. 4059 43.1 1.4079 44. 1 

l. 4040 42.2 1.4060 43.2 l. 4080 44. 2 

l. 404 1 4 2. 2 1.4061 43. 2 l. 4081 44. 2 

l. 404 2 42.3 1.4062 43.3 1. 4082 44,3 

1.4043 4 2. 3 1.4063 43.3 1. 4083 44.3 

1.4044 42.4 1. 40 64 43,4 1. 4084 44.~ 

l. 4 04 5 42.4 1.4065 43,4 l. 4085 ~j, I, -.-

1.4046 4 2. 5 1.4066 43.5 l. 4086 4LJ..) 

1. 404 7 42.5 1.4067 43.5 1.408 7 44.) 

l. 4048 42.6 1.4068 43.6 l. 4088 44,6 

l . 404 9 42.6 l. 4069 4 3. 6 1.4089 !.!4. 5 

1.4050 42.7 1.4070 - j • I 1.4090 4h 7 -·' 

l. 4051 4 2. 7 1.4071 LLJ.7 l. 4091 ~4.i 

1.4052 4 2. 8 1.4072 43.8 1.4092 ~~.8 

].4053 42.8 1.4073 43.8 1.4093 4U.8 

1. 4054 4 2. 9 l. 4074 43.9 l. '-<094 44.9 

1.4055 4 2 0 9 1.4075 43.9 1.4095 44 0 9 

- Xi i -
TOMATO TOMATO CONCB\TRATES 

PRODUCTS Puree (or Pulp) 

MITHODS Paste 

Juice Concentrate 

USDA -

TABLE I -- continuation 

Refractive I nd ices of Sucrose So 1ut i.ons at 20° ~ 

'-'• 

Refract. ar Refract. lo ar 

to Refract. 'l'o 

Index Sue rose Index Sucrose Index Su erose 

1.4096 4 5. 0 1.4116 45.9 1.4136 46.9 

1.4097 45.0 1.4117 46.0 l. 413 7 4 7. 0 

1.4098 4 5. 1 1.4118 4 6. 0 1.4138 47.0 

1.4099 4 5. 1 1.4119 46.1 1.4139 47.1 

1.4100 45.2 1.4120 4 6. 1 1.4140 4 7. l 

1.4101 45.2 1.4121 46.2 l. 4 14 1 47.2 

1.4102 45.3 1.4122 46.2 l. 4 14 2 47.2 

1.4103 45.3 1.4123 46.3 1.4143 47.3 

1. 4104 45.4 l. 4124 4 6. 3 l. 4144 4 7. 3 

1.4105 45,4 1.4125 46,4 1.4145 47.4 

1.4106 45.5 1.4126 46.4 1. 414 6 4 7. 4 

1.4107 45.5 1.4127 4 6. 5 l. 414 7 47,5 

l. 4108 45.6 1.4128 46.5 l. 4 148 47.5 

l. 4109 45.6 l. 4 129 46.6 1. 4 149 47.6 

1.4110 45.6 1.4130 46.6 l. 4 1 so 4 7. 6 

1.4111 45.7 1.4131 46.7 1.4151 47.6 

1.4_112 45.7 1.4132 46.7 1.4152 47.7 

l.4ll3 45.8 1.4133 4 6. 5 l.4153 47.7 

1.4114 45.8 l. 4134 46.8 l. 4 154 4 7. 8 

l.41i5 45.9 1.4135 46.9 l.~lSS 47.8 
TOMATO 

PROUJCTS 

METHODS 

Ref r;Jct. 

Index 

1.4156 

1.4157 

1.41S8 

1.4159 

1 . 4 160 

1.4161 

1.4162 

1.4163 

l. 4 164 

l.4165 

1. 4166 

1.4167 

1.4168 

1.4169 

l. 4 l 70 

1.4171 

_1.4172 

1.4173 

1 ,4174 

1.4 l 7 ') 

TABLE I -- conti.nuati.on 

TOMATO CONCENTRATES 

Puree (or Pu l p) 

Paste. 

Ju1ce Concentrate 

USDA -

Refractive Indices of Sucrose Sol~ti.ons at 20° C. 

"' Refract. "' Refract. "' /0 10 10 

Sucrose Index Sue res e InGex Sucrose 

4 7. 9 1.4176 48.8 l.'-'196 49.8 

47.9 L4177 48.9 1.4197 49.8 

48.0 1.4178 48.9 1.4198 49.9 

48.0 1.4179 49.0 l. 4 199 49.9 

48. 1 l. 4180 49.0 l. 4 200 50.0 

48. 1 l. 4181 49.1 l. 4 201 50.0 

48.2 1.4182 49.1 l. 4 205 50.2 

48.2 1.4183 49.2 1. 4 209 50.4 

48.3 1.4184 49.2 l.421U 50.6 

48.3 1.4185 49.3 1. 4218 50. 5 

48.4 1.4186 49.3 1.4222 5l.O 

48.4 1.4187 49.4 l.U226 51.2 

48.5 l. 4 188 49.4 1.4230 51 I, .. - 48.5 1.4189 49.5 1.4235 51.6 

48.6 1.4190 4 9. 5 1.4239 51.8 

48.6 1.4191 49.6 l • 4 2 ... 3 52.0 

48.6 1.4192 49.6 1 • 4 2jJ 8 ~ ~ ') ") L • ~ 

48.7 l.4193 49.6 1.4252 52 .. 4 

45.7 l. 4 194 4 9. 7 1 

~ • -..:: ,, ~"'' ..... 0 ~ ') ' ') .... o 

48.8 1.4195 49.7 1. ~ 2 60 c-; ~ ...- .L • -

-Xi V -
TOMATO 

PROCU CTS 

METHODS 

Refrilct. 

Index 

1.426'5 

1.4 26Y 

1.4273 

l. 4 2 7R 

1.4282 

1. 4286 

1.4291 

1. 4 295 

l. 4 299 

l. 4 304 

1.4308 

1.4312 

].4317 

1. 4 3 2 1 

1.4326 

1.4330 

1 • 4 3 34 

1 .4339 

l. 4 34 3 

I .4348 

TABLE I-- continuation 

TOW.. TO CONCENTRATES 

Pu r e e ( or Pu l p ) 

Paste 

Juice Concentr~te 

USDA -

Refri1ctive Indices of Sucrose Solutions at 20° C. 

~v Refract. "' /0 Refract. "' IO 

Sucrose Index Sucrose Index Sucrose 

53.0 1.4352 57.0 1.4442 61.0 

53.2 1.4356 57. 2 

S3.4 1.4361 57.4 

53.6 1.4365 57. 6 

53.8 1.4370 57.8 

54.0 r. 4 3 74 58.0 

54. 2 1.4379 58. 2 

54.4 1.4383 58.4 

54.6 1.4388 58.6 

54.8 1.4392 58.8 

55.0 1.4397 59.0 

55.2 l. 4401 59.2 

55.4 1. 4406 59.4 

55.6 l. 44 10 59.6 

55.8 l. 4415 59.8 

56.0 1. 44 19 60.0 

56.2 1.4424 60.2 

5 6.4 l. 44 28 60.4 

56.6 l. 44 33 60.6 

56.8 1. 44 3 7 60.8 

- XV -
Corrections for Determining Percent Sucrose in Sugar Solutions 

by Means of Refractometer when Readir,gs are Made at Temperatures 

Other than 20° C. 

TABLE II 

(International Temperature Correction Table, 1936) 

Per Cent Sue rose 

TEMP. 

I I I I oc. 0 5 10 15 20 25 30 40 I so 60 

Subtract from the per cent sucrose 

70 

10 0.50 0.54 0.58 0.61 0. 64 0.66 0.68 0.72 0.74 0.761 0.79 

11 .46 .49 . 53 .55 .58 .60 .62 .65 .67 .69 . 71 

12 .4 2 .45 .48 .so .52 .54 .56 .58 • 60 • 61 .63 

13 .37 I .40 .42 .44 ,46 ,48 .49 • 51 .53 .54 . 55 

14 .33 .35 .37 .39 ,40 .41 .42 ,44 .45 .46 ,48 

15 . 27 .29 .31 .33 .34 ,34 .35 ,37 .38 .39 ,40 

16 . 22 .24 .25 .26 . 27 .28 .28 .30 .30 . 3 1 . 3 2 

17 • 17 .18 .19 .20 • 21 • 21 • 21 .22 .23 . 2 3 . 24 

18 . 12 I • 13 .13 • 14 . 14 • 14 • 14 . 15 . 15 1 ' • -0 . 16 

19 .06 J .06 .06 .07 .07 .07 .07 .08 .08 .08 .08 

Add to the per cent sue rose 

' 

21 0.06 0.07 0.07 0.07 0,07 O.D8 0.08 0,08 0.08 0.08 0.08 

22 • 13 .13 • 14 . 14 . 15 . 15 • 15 . 15 . 16 . 16 • 16 

23 . 19 . 20 • 21 . 22 . 22 .23 • 23 I .23 . 24 . 24 . 24 

24 . 26 . 27 • 28 • 2 9 .30 .30 . 31 .31 . 31 . 3 2 . 3 2 

25 .33 .35 .36 .37 .38 

I 

.38 .39 .40 .40 .40 .40 

26 .40 .42 ,43 .44 • 4 5 I .46 .47 .48 ,48 ,48 .48 

27 ,48 .50 • 52 .53 .54 . 55 .55 .56 .56 .56 .56 

28 . 56 .57 . 60 .61 .62 .63 • 63 . 64 • 64 . 64 . 64 

29 • 64 .66 • 68 .69 . 71 • 7 2 .72 . 7 3 . 73 .73 . 7 3 

30 . 7 2 .74 .77 .78 . 79 I .80 .80 .81 .81 • g 1 .81 

-
I J~·t~Tu Tomato 

PRUUULTS Catsup 

M!:.THuUS March llPO TABLE III 

T 0 M A T 0 c A T s u p " 

Refractive Index Corrected to 20° c. -- to Total Solids 

% Total % Total % Total % Total 

R. I. Solids R. I. Solids R. I. Solids R. I . Solids 

1 . .3589 18.0 1.3682 23.6 1.3778 29.2 l.3e79 34, R 

1.3592 18.2 1.3685 23.8 1 . .3782 29.4 1.3863 35.Ci 1 • ~ 0,.. .1.,..):;,~:::. 18.4 1. 3688 24.0 1. 37 85 29.6 l.38c7 35.) 

1 . .3598 18.6 1.3692 24.2 1. 3 7 89 29.8 1.3891 35.4 

1 . .3o02 18.8 l. 3695 24.4 1.3792 30.0 1.3894 .3S.o 

1. 3o05 19.0 1.3699 24.6 1.3796 30.2 1.3898 35.8 

1 . 3608 19.2 1.3702 24.8 l. 3800 30.4 1.3902 :;6,0 

1 . 3612 19.4 1. 3 706 25.0 1.3803 30.6 1.3906 36.2 

1.3olS 19.6 1.3709 25.2 1.3807 30.8 l . 3909 36.4 

1. 3ol8 19. 8 1.3712 25.4 1.3810 31.0 1.3913 36.6 

. 3t21 20.0 l. 3716 25.6 1.3814 31. 2 l. 3':116 36.8 . .3o2S 20.2 l. 3719 25.8 l. 3818 31.4 1.3920 37.0 

1. 3o2 8 20.4 1.3723 26.0 1.3821 31.6 1.3924 37.2 

1. 3o 31 20.6 1.3726 26.2 1.3825 31.8 1.3928 37.4 

l. 3635 20.8 1.3729 26.4 1.3829 32.0 1.3931 37.6 

l. 36 38 21.0 1.3733 26.6 1.3832 32.2 ' - Q-- 1,..)_.):;, 37.8 

1 . 3641 21.2 l. 37 36 26.8 l. 3836 32.4 l,.)_.)_ ' ·o-o 38.0 

l. 3045 21.4 l. 3740 27.0 l. 3839 32.6 1.3943 .38.2 

1. 364 8 21.6 1.3743 27.2 l. 3843 32.8 l. 394 7 .38.4 

1. 3651 21. 8 1.3747 27.4 1. 384 7 33.0 1. .3950 38.6 

l. 3oSS 22.0 1.3750 27.6 1. 3850 33.2 1 ~ 39 s 4 38.5 

•. 3o.:;e 22.0 1.3753 27.8 1.3854 33.4 l. 39 58 39. 

l . 3t>o 1 22.4 1.3757 28.0 1. 3858 33.6 l.39o2 39.: 

l. 3n65 22.0 l. 3 76 l 28.2 1. 3861 33.8 1. 3966 39 . .1 

l. 3oo8 22.8 1.3764 28.4 1.3865 34.0 1 . .3970 3?.b 

l. 3o 7 2 23.0 l. 3768 28.6 1.3869 34.2 1.3974 ~c ,, -'·. ~ 

l. 3o 7 5 23.2 1.3771 28.8 1. 3872 34.4 1. 3rs 4 .0 

1. 3t 7 8 23.4 1.3775 29.0 1.3876 34.6 1.398: t .'i I ..... ,_.,.-

Sucrose Value plus 1% 
'OMA :'0 

. RODUCTS 

METHO:)S 

CORRECTIONS FOR ?llE.AC- ·.;;_ fNJEX Ru.DINGS WHEN 

DSTE?J<:INEJ AT TEMPE? .. Al'"JF.S' ,":'E.E?. T:-LAJ'~ 2SOC. ~77°F. 

June, l~7G 

Temperc;ture Refrc.cti•·r 1ndex Reading 

oc. CF 1. 34 00 l. 3500 :. 3600 1. 3700 1. 1800 l. 3Ci00 

To be subtr;o;cteci from reading 

1 5 .0009 .0010 . 0 0 1 1 .0012 .0013 . 00 14 

16 .0009 . 0009 . 0 010 . 0 0 1 l .0012 .0012 

17 .0008 .0008 .0009 .0009 . 0 0 J l . ·J 0 j 1 

19 . 0007 . 0007 .0008 .0008 .0009 . 00 l 0 

19 .0006 .0006 .0007 . 0007 .0008 .0008 

.0005 ,0005 .0006 .0006 .0007 . 0007 

.; 1 .0004 .0004 .0005 .0005 .0006 .JOOo 

22 .0003 .0003 . 0004' .0004 . 0004· 0004 

23 .0002 ,0002 .0003 • . 000 3 .0003 . 0003 

2.4 .0001 .0001 .0001 .0001 .0002 .0002 

To be add~d to rea ding 

26 .0001 .0001 .0001 .0002 .0002 ,0002 

2.7 .0002 ·":'o003 .C003 .0003 .0003 ,0003 

28 .0003 .0004 .0005 .0005 .0005 .0005 

29 .0005 • 0005 .0006 .0006 .0006 .0006 

30 .0006 .0007 .0007 .0007 . 0007 .0007 
I 

TOMATO 

PRODUCTS 

METHODS 

TABLE IV 

Temperature 

Correction Chart 

February 1970 

CORRECTIONS FOR REFRACTIVE INDEX READINGS 

WHEN DETERMINED AT TEMPERATURES OTiiER TiiAN 68• F (20 1 C) 

Temperature Refractive index reading 

·c 1 .. 3400 1. 3500 1. 3600 1. :noo 1. 3800 l. 3900 

To be subtracted from readin~: 

15 59.0 . 0004 . 0005 . 0005 • 0006 .0006 .0007 

16 60.8 . 0004 . 0004 . 0004 • 0005 . 0005 . 0005 

17 62.6 . 000 3 . 000 3 . 0003 • 000 3 . 0004 . 0004 

18 64.4 .• 0002 . 0002 . 0002 ,0002 . 0002 . 000 3 

19 66.2 . 0001 • 000 l . 0001 . 0001 . 0001 . 0001 

To be added to reading: 

Zl 69. 8 • 0001 • 0001 . 0001 • 0001 . 0001 . 000 l 

22 71. 6 .0002 . 000 2 . 0002 . 0002 .0003 .0003 

23 73.4 .0003 . 000 3 . 0003 ,0004 .0004 .0004 

24 75.2 • 0004 . 0004 . 0005 • 0005 .0005 . 0006 

25 77' 0 • 0005 . 0005 . 0006 • 0006 .0007 .0007 

26 78.8 • 0006 . 0006 . 0007 • 0008 .0008 . 000 8 

27 80.6 • 0007 . 0008 . 0008 • 0009 . 0010 . 0010 

28 82.4 . 0008 ,0009 . 0010 • 0010 • 00 11 . 001 1 

29 8-4. 2 . 0010 . 0010 . 001 1 • 0012 . 0012 . 00 l 3 

30 86.0 • 0011 . 0012 . 0012 • 0013 . 0014 . 0014