DRAFT UGANDA STANDARD  
  DUS 51  
 
Second  Edition  
2020-mm-dd 
 
 
 Reference number  
DUS 51: 2020 
© UNBS 2 020  
  
Mayonnaise  — Specification  
 
 
 DUS 51: 20 20 
ii © UNBS 2020 – All rights reserved  
 Compliance with this standard does not; of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct applicatio n 
© UNBS 2020 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission from UNBS . 
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 7 333 2 50/1/2 
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 51: 20 20 
© UNBS 20 20 – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ................  iv 
1 Scope  ................................ ................................ ................................ ................................ ..........  1 
2 Normative references  ................................ ................................ ................................ ..................  1 
3 Terms and definitions  ................................ ................................ ................................ .................  3 
4 Description ................................ ................................ ................................ ................................ .. 4 
5 Essential composition and quality  criteria  ................................ ................................ ..................  4 
5.1 General Requirements  ................................ ................................ ................................ ................  4 
5.2 Raw mate rials  ................................ ................................ ................................ ...........................  45 
5.3 Compositional requirements  ................................ ................................ ................................ .......  5 
5.4 Optional ingredients ................................ ................................ ................................ ....................  5 
6 Food  additives  ................................ ................................ ................................ ............................  6 
7 Contaminants  ................................ ................................ ................................ ..............................  6 
7.1 Heavy metals ................................ ................................ ................................ ...............................  6 
7.2 Pesticides re sidues  ................................ ................................ ................................ .....................  6 
8. Hygiene  ................................ ................................ ................................ ................................ .......  6 
9. Weights and  measures ................................ ................................ ................................ ................  7 
10 Packaging  ................................ ................................ ................................ ................................ ... 7 
11 Labelling  ................................ ................................ ................................ ................................ ..... 7 
11.1  General ................................ ................................ ................................ ................................ ........  7 
11.2  Nutrition declaration  ................................ ................................ ................................ ...................  8 
12 Sampling  ................................ ................................ ................................ ................................ ..... 8 
Annex A  (normative)  Determination of oil  ................................ ................................ .............................  9 
A.1 Pre-Extraction  ................................ ................................ ................................ .............................  9 
A.1.1  Requirements  ................................ ................................ ................................ ..............................  9 
A.1.2  Procedure  ................................ ................................ ................................ ................................ ... 9 
A.2 Hydrolysis  ................................ ................................ ................................ ................................ ... 9 
A.3 Drying  ................................ ................................ ................................ ................................ .......  10 
A.4 Procedure for Solvent Extraction  ................................ ................................ ..............................  10 
A.5 Calculation  ................................ ................................ ................................ ................................  10 
Bibliography ................................ ................................ ................................ ................................ ..........  12 
 
 DUS 51: 20 20 
iv © UNBS 2020 – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives  (MTIC ) established  under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to 
co-ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on Technical Barriers to Trade (TBT) Agreement  of the World Trade 
Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standar ds in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committ ee UNBS/TC 2, Food and Agriculture , 
Subcommittee SC 2, Edible Oil seeds, Fats  and oils.  
This second edition cancels and replaces the edition (US 51-1:2000 ), which has been technically revised.  
This revision was undertaken to provide for microbiological requirements consistent with current technology  
and combine the standards of  US 51 -1:2000 Specification for mayonnaise - Part 1: Real mayonnaise  and US 
51-2:2000 Specification for mayonnaise - Part 2: Low fat mayonnaise  into one standard.  DUS 51: 20 20 
© UNBS 20 20 – All rights reserved  v 
 Introduction  
Mayon naise is a condiment sauce obtained by emulsifying edible vegetable oil(s) in an aqueous phase 
consisting of vinegar  or lemon juice , salt, sugar and spices to cater for the varying consumer preferences.  The 
oil-in-water emulsion being produced by the poultry ’s egg yolk . The colo ur of mayonnaise varies from near 
white  to pale yellow, and its texture from a light cream to a thick gel.  Commercial egg -free alternatives are 
made for vegans and others who avoid poultry eggs or dietary cholesterol.  
 
Mayonnaise is prod uced in a batch process by slowly adding the oil to the water phase under vigorous mixing;  
thereby creating an emulsion . The egg yolk material forms a thin layer around each minute globule of oil 
dispersed throughout the mayonnaise.  Production techniques s uch as mixing/homogenization may have a 
considerable effect on the final product structure  affect ing the sensory  properties of the final product.  
 
 
The larger the quantity of yolks used in the manufacture of mayonnaise, the greater will be the stability o f the 
product. It protects the mayonnaise from oil separation when it is subjected to shaking or jarring during 
transportation, or when it is subjected to summer heat or to freezing temperatures in the wintertime.  
The yolk, therefore, is the frame structu re of the mayonnaise, which keeps all its constituents intact and 
preserves the physical consistency of the product, its texture, smoothness and homogeneity. The yolk also 
modifies the individual taste and flavour of the other ingredients of the mayonnaise  such as the oil, 
condiments and spices by keeping them in a finely dispersed and emulsified condition, thus effecting a perfect 
blend, which produces a pleasing sensation of taste and flavour.  
The watery part of the emulsion carries the oil globules; eac h coated with its shell of egg yolk material and 
also serves to dissolve the sugar and salt and helps to suspend the spices used in the product . Due to a high 
oil content, mayonnaise exhibits a semisolid and viscoelastic behaviour that influences its parti cular 
rheological properties, which in turn contribute to the perceived texture and flavour of the product . 
Due to the general desire by most populations to reduce their fat intake,  the preference has drifted to low fat 
content foods . Substitution of fat i n mayonnaise is conducted to create low fat mayonnaise. Some thickener 
material commonly able to increase texture of mayonnaise is used. Low fat mayonnaise is aimed at providing 
consumers with mayonnaise while enabling them to take less fat. Low fat mayonn aise is produced by 
decreasing  the dispersed  phase  (oil) and increas ing the aqueous  phase. Using fat replacer is recommended 
to decrease the fat content.  
This standard aims at providing manufacturers with the minimum guidelines on the quality of the produ ct. DRAFT UGANDA STANDARD  DUS 51: 20 20 
 
© UNBS 2019 – All rights reserved  1 
 Mayonnaise  — Specification   
1 Scope   
This Draft Uganda standard specifies the requirements, sampling and methods of test,  for mayonnaise  
intended  for human consumption .  
2 Normative references   
The following documents are referred to in the text in such a way that some or all of their content constitutes 
requirements of this document. For dated references, only the edition cited applies. For undated references, 
the latest edition of the referenced document (including any amendments) applies.   
AOAC 942.17 , Arsenic in foods Molybdenum blue method  
AOAC 990.05 , Copper, iron, and nickel in edible oils and fats. Graphite furnace atomic absorption 
spectrophotometric method  
AOAC 994.02 , Determination of Lead (Pb) in Edible Oils and Fats by Graphite Fu rnace atomic absorption 
spectrometer -AAS 
AOAC 998.09 ,  Salmonella in Foods; Colorimetric Polyclonal Enzyme Immunoassay Screening Method with 
Rappaport -Vassiliadis (R10) Broth and/or Tetrathionate Broth 3Mä TECRAä Sal mo nella Visual 
Immunoassay (VIA)  
AOAC  999.11 , Determination of lead, cadmium, copper, iron and zinc in foods. Atomic absorption 
spectrophotometry after dry ashing  
US CAC/RCP 15 , Code of hygienic practice for eggs and egg products  
US CAC/GL 50 , General guidelines on sampling  
US 28 EAS 39 , Code of practice for Hygiene in the Food and Drink Manufacturing Industry  
US EAS 12 , Potable water — Specification  
US EAS 16 , Plantation (mill) white sugar – Specification  
US EAS 35 , Fortified food grade salt – Specification  
US EAS 38 , Labelling of pre -packaged  foods — General requirements  
US EAS 123 , Distilled water — Specification (2nd Edition)  
US EAS 147 -1, Vinegar - Specification Part 1: Vinegar from natural sources  
US EAS 147 -2, Vinegar - Specification Part 2: Vinegar from artificial sources  
US EAS 803 , Nut rition labelling – Requirements   
2 © UNBS 2020 – All rights reserved  
 US EAS 804 , Claims on food – Requirements  
US EAS 805 , Use of nutrition and health claims – Requirements  
US ISO 660 , Animal and vegetable fats and oils — Determination of acid value and acidity  
US ISO 661 , Animal and vegetabl e fats and oils — Preparation of test sample  
US ISO 663 , Animal and vegetable fats and oils — Determination of insoluble impurities content  
US ISO 676 , Spices and condiments — Botanical nomenclature  
US ISO 948 , Spices and condiments — sampling  
US ISO 1842 , Fruit and vegetable products — Determination of pH  
US ISO 4833 -1, Microbiology of the food chain — Horizontal method for the enumeration of microorganisms 
— Part 1: Colony count at 30 degrees C by the pour plate technique  
US ISO 5555 , Animal and vegetable  fats and oils —Sampling  
US IS0 6888 -1, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of 
coagulase -positive staphylococci (Staphylococcus aureus and other species) -- Part 1: Technique using Baird 
Parker agar mediu m 
US ISO 7251 , Microbiology of food and animal feeding stuffs - Horizontal method for the detection and 
enumeration of presumptive Escherichia coli - Most probable number technique  
US ISO 11290 -1, Microbiology of the food chain — Horizontal method for the detection and enumeration of 
Listeria monocytogenes and of Listeria spp. — Part 1: Detection method  
US ISO 16050 , Foodstuffs — Determination of aflatoxin B1, and the total content of aflatoxins B1, B2, G1 and 
G2 in cereals, nuts and derived products — High-performance liquid chromatographic method  
US ISO 21527 -1, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of 
yeasts and moulds -- Part 1: Colony count technique in products with water activity greater than 0.95  
ISO 6658 , Sensory analysis — Methodology — General guidance  
ISO 11035 , Sensory analysis — Methodology — Texture profile  
US 45, General Standard for Food Additives  
US 168 , Edible oils and fats – Specification  
US 738 , General Standard for Contaminants and Toxins  in Food and Feed  
US 1659 , Materials in contact with food - Requirements for packaging materials  
 
 
 DUS 51: 2 020 
© UNBS 2020 – All rights reserved  3 
 3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply   
ISO and IEC maintain terminological databases for use  in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
mayonnaise  
condiment sauce obtained by emulsifying edible vegetable oil(s) in an aqueous phase consisting of vinegar, 
the oil -in-water  emulsion being produced by the hens' egg yolk . 
3.2  
emulsion  
mixture  of two or more liquids  that are normally immisc ible (unmixable or unblendable). It is to be used when 
both phases, dispersed and continuous, are liquids.  One liquid (the dispersed phase ) is dispersed  in the other 
(the continuous phase)  
3.3  
emulsifier  
substance that stabilizes an emulsion by increasing its kinetic stability . These compounds typically have a 
polar or hydrophilic (i.e. water -soluble) part and a non -polar (i.e. hydrophobic or lipophilic) part . Because of 
this, they tend to have more or less solubility either in water or in oil. The more soluble in water (and 
conversely, less soluble in oil) will generally form oil -in-water emulsions, while those that are more soluble in 
oil will form water -in-oil emulsions  
3.4  
texture  
sensory perception of the structure of a food  
 
3.5  
phase  inversion  
phenomenon that occurs when agitated oil in water emulsion, reverts to a water in oil and vice versa  
3.6  
vinegar  
liquid, fit for human consumption, produced exc lusively from suitable products containing starch and/or sugars 
by the process of double fermentation, first alcoholic and then acetous  
3.7  
organoleptic  
qualities (such as taste, colour, odour, and feel) of mayonnaise  that stimulate the sense  organs  involv ing the 
use of the sense organs . 
3.8  
winterized oil  
oil which has the higher -melting glycerides  removed by slow cooling , filtration or centrifuging . So that the oil in 
the mayonnaise does  not separate out when refrigerated.  
3.9  
low fat mayonnaise  
produced by decreasing the dispersed phase  (oil) and increasing the  aqueous phase. Using fat replacer is 
recommended to decrease fat content  
3.10  
 condiment  
spice, sauce, or preparation that is  added to food, typically after cooking, to impart a specific flavour, to 
enhance the flavour, or to complement the dish   
4 © UNBS 2020 – All rights reserved  
 4 Description  
Mayonnaise is a condiment sauce obtained by emulsifying edible vegetable oil(s) in an aqueous phase 
consisting of vinegar , the oil -in-water emulsion being produced by the hens' egg yolk. Mayonnaise may also 
contain optional ingredients in accordance with 5.4 . The egg York contains lecithin, a fat emulsifier that serves 
as a stabilizer between the two liquids  
High quality may onnaise has a firm texture and a small droplet size. Mayonnaise reaches a peak in texture 
and a minimum in droplet size during mixing. At longer mixing times the quality decreases and the 
mayonnaise becomes over -sheared. When the ingredients are cold and a  high amount of egg yolk is used , 
mayonnaise with a high quality can be made . 
Mayonnaise with an increased oil content has a firmer texture but is also more sensitive to over -shear . Full-fat 
mayonnaise contains around 65 - 80% a no-go for many of today’s nu trition focused consumers . The oil is 
dispersed in a water phase to form an oil -in-water (O/W) emulsion. A low viscosity characterizes phase 
inversed mayonnaise, or broken mayonnaise, which is close to the viscosity of oil resulting in a water -in-oil 
(W/O)  emulsion .  
Low or reduced -fat mayonnaise, on the other hand, is a growing market, with continually reducing oil content  
while maintaining si milar product taste and texture . As the oil is present in levels of at least 30  to 60% by 
weight in light or low c alorie mayonnaise , substantial reformulation is necessary in order to produce a 
mayonnaise product with less than 5% by weight vegetable oil.  
 
 
5 Essential composition and quality  criteria  
5.1 General requirements  
Mayonnaise  shall meet the following charact eristics : 
a) the products, when stored under refrigeration, shall maintain their consistency ; 
b) the colour of full fat mayonnaise, shall be white or creamy, or even yellowish  in accordance with ISO 
6658 ; 
c) the taste of mayonnaise shall be characteristic of mayonn aise in accordance with ISO 11035 ;  
d) be free from animal fats  and oils ; 
e) the texture of the product shall be semisolid, uniform, smooth and free from lumps due to poor 
manufacturing  in accordance with  ISO 11035 ; 
f) be free from impurities and foreign materials,  rancidity and any other foreign flavours  in accordance 
with US ISO 663 ;  
g) bubbles of oil shall be small and uniform in size  and 
h) egg white content shall not be more than 20% and the egg yolk shall not be less than 6%  in 
accordance with  US CAC/RCP 15   
5.2 Raw materials  
a) all ingredients shall be of sound quality and fit for human consumption  and shall comply with the 
requirements of the relevant  standards  especially  US EAS 147 -1, US EAS 147 -2 and US 168 ; 
b) water used shall comply with the requirements laid down in US EAS 12  and US EAS 123 ; DUS 51: 2 020 
© UNBS 2020 – All rights reserved  5 
 c) eggs and egg produ cts shall be from the poultry birds , unless otherwise specified ; 
d) ingredients added to impart a characterizing flavour to the products shall be used in quantities 
sufficient to influence significantly the organ oleptic properties of the product ; 
e) the winterized oil  shall be used.  The phases of the oil shall not separate when placed in the 
refrigeration . 
f) raw materials shall be stored, treated and handled under suitable conditions so as to maintain their 
chemical a nd microbiological characteristics in accordance with US 28 EAS 3 9 
5.3 Compositional requirements  
Mayonna ise shall comply with the following compositional requireme nt when tested with the specified test 
methods in Table  1. 
Table 1 — Requirements for  mayonn aise (real  and low fat)  
 
S/No.  
Parameter  Requirement  
Method of test  
Real  Low fat  
i) Total fat content  % by mass  ,max  80 60 Annex A  
ii) pure egg yolk1 % by mass , max  6 4  
iii) Edible vegetable oil% (m/m), max  50  Annex A  
1) Technically pure egg yolk means that 20 % of albumen is tolerated related to the egg yolk 
 
 
a)  water in accordance  with US EAS 12  and US EAS 123 ; 
b) acidifying agents such as lemon juice or vinegar in accordance  with US EAS 147 -1, US EAS 147 -2, 
US ISO 6 60 and US ISO 1842 ; 
c) egg white ; and  
d) food grade salt in accordance with US EAS 35 . 
5.4 Optional ingredients  
Food ingredients  among others  intended to influence significantly and in the desired fashion the physical and 
organoleptic  characteristics of the pro duct or as technologically may be considered ; 
a) sugars complying with US EAS 16;  
 
b) condiments, spices, herbs  in accordance with US ISO 948 and US ISO 676 ; 
c) fruits and vegetables including fruit juice and vegetable juice  in accordance with US ISO 676 and ; 
d) musta rd: and  
e) dairy products .  
6 © UNBS 2020 – All rights reserved  
 6 Food  additives  
Any additive used shall be in accordance with US 45  
7 Contaminants  
7.1 Heavy metals  
Mayonnaise  (real and low fat)  shall comply with the limits for heavy metal contaminants in accordance with US 
738 when tested with  the specified test methods in Table  1. 
Table  1 — Maximum level of metallic contaminants in mayonnaise  
 
Contaminant  Maximum limit 
(mg/kg)  Method of test  
Lead (Pb)  0.2  AOAC 994.02  
Arsenic (As)  0.2 AOAC 942.17  
Copper (Zn)  5  AOAC 990.05  
Zinc (Zn)  5 ISO 9831  
Iron (Fe)  15 AOAC 999.11  
Sum of copper, zinc, and iron  20  
7.2 Pesticides residues  
The products covered by the provisions of this standard shall comply with those maximum limits of pesticide 
residues established by Codex Alimentarius Commission  
7.3 Mycotoxins  
The level of mycotox ins in mayonnaise (real and low fat)  shall not exceed those prescribed in Table 2 
Table 2  — Mycotoxins le vels in mayonnaise (real and low fat)  
Mycotoxins  Maximum limit 
µg/kg  Test method  
Aflatoxin B1 (AFB1)  5 ISO 16050  
Total Aflatoxin (B1, B2, G1, G2)  10 
 
8. Hygiene  
Mayonnaise shall be handled in accordance with US 28 EAS 39 and US CAC/RCP 15 and shall comply with 
the microbiological limits given in Table 3 when tested in accordance with the test methods specified there in . DUS 51: 2 020 
© UNBS 2020 – All rights reserved  7 
  
 
 
Table  3 — Microbiological limits for mayonnaise  
 
Type of micro -organism  Limits  Method of test   
Total plate count, CFU/g, max  500  US ISO 4833 -1 
E. Coli, CFU/g, max  Absent  ISO 16649 -2 
Salmonella, 25 g, max.  Absent  AOAC 998.09  
Staphylococcus aureu s, CFU/g, max  Absent  IS0 6888 -1 
Yeast and moulds, CFU/g, max  < 100  US ISO 21527 -1 
Listeria  monocytogenes  count/25g  Absent  ISO 11290 -1 
9. Weights and  measures  
The weight of the package of the product shall comply with the Weights and Measures Act . 
10 Packaging  
Real mayonnaise  shall be packaged in food grade packaging materials in accordance with US 1659 . 
11 Labelling  
11.1 General  
11.1.1  In addition to the requirements in US EAS 38, the following specific labelling requirements shall apply 
and shall be le gibly and indelibly  marked : 
 
a) name of the product  as “Real  fat mayonnaise ” and “Low fat mayonnaise” ; 
b) Net contents by weight (`System International') units;  
c) name and physical address of processor/producer ; 
d) country of origin   
e) lot/batch code number ; 
f) shelf life : best before/use by date;  
g) statement ‘Food for Human Consumption’ shall appear on the package;  
h) storage conditions and instructions as “Store in a cool dry place away from any contaminants’ ;  
8 © UNBS 2020 – All rights reserved  
 i) list of ingredients in descending order  
11.1.2  When labelling non -retail packages, information for non -retail packages shall be given either  on the 
packages or in enclosed  documents, except that the name of the produce, lot identification and the name and 
address of the manufacturer or packer shall appear on the package.  
11.2 Nutrition declaration  
Any added essential nutrients declaration shall be labelled in accordance with US EAS 803, US EAS 804 and 
US EAS 805 . 
12 Sampling  
Sampling and sample preparation for testing shall be carried out in accordance with ISO 5555 , US C AC/GL 50  
and ISO 661 respectively  
 
 DUS 51: 2 020 
© UNBS 2020 – All rights reserved  9 
 Annex A  
(normative)  
 
Determination of oil  
A.1 Pre-Extraction  
As high fat levels can prevent effective hydrolysis;  samples with 10 per cent content shall be preextracted with 
the same type of solvent as used in the final  extraction . 
A.1.1  Requirements  
Usual laboratory apparatus  
A.1.2 Procedure  
A.1.2.1  Weigh in the sample with a precision of 1000 
  2 mg.  Load the glass thimble with 1  g celite and 
the sample.  Do not cover with cotton  
A.1.2.2  Fit adapters on the thimbles, by introducing them into the thimbles in such a way that the circlip is 
compressed progressively into the thimble, (i.e. the closed side of the circlip is pressed in first and then 
working towards the open side) and insert them into the Soxtec HT extraction unit  
A.1.2.3  Add solvent and extract for 10 minutes in rinsing position  
A.1.2. 4 After the extraction, dry the extraction cups in an oven at 100 ºC for 30 minutes.  Let them cool 
down and weigh them.  Calculate percentage extracted fat.  If the fat content is higher than 20 per cent, it is 
recommended to use a second extraction cup for the final extraction  
A.1.2.1  Remove the thimble holders from the glass thimbles.  Transfer the pre -extracted sample as 
quantitatively as possible from the glass thimble to a sample tube for acid hydr olysis.  Proceed from step 2 of 
the hydrolysis part  
A.2 Hydrolysis  
A.2.1  Procedure  
A.2.1.1 Weigh the sample s with a precision of 1000 ± 2 mg and transfer them to the sample tubes  
A.2.1 .2 Add 1g to 2 g of celite and 100 mL to 120 mL of the acid solution to each sample tube.  The level 
of the acid solution shall b e over the top of the cover of the heaters  
A.2.1.3 Insert the tubes into position in the 1047 hydrolyzing unit.  Lower the suction tubes to the fume 
exhaust position by pulling the handle upwards.  The Teflon  part shall rest on the top of the sample tubes and 
suction tubes shall be about one centimetre down in the sample tubes  
A.2.1 .4 Place the glass thimbles into the thimble supports and insert them into the hydrolyzing unit  
A.2.1 .5 Start the water aspirator pump for the fume exhaust system. Open vac uum va lves under each 
thimble. Adjust during boiling for low fume exhaust   
10 © UNBS 2020 – All rights reserved  
 A.2.1 .6 Turn on the heater to maximum effect and place the reflector in front of the sample tubes.  When 
the solution starts boiling, adjust to a gently boiling speed with the heater contr ol 
A.2.1 .7 At the end of the hydrolyzing period, turn off the heater and remove the reflector  
A.2.1.8  Open the cold-water  tap for the condensers (approximately 2 L/min)  
A.2.1.9  Pull down the suction tube handle.  Dilute the acid solution in each tube with  some 100 mL of 20 
ºC to 25 ºC-distilled  water.  Close the vacuum valve under each thimble  
A.2.1.10  Lower the suction tubes.  Open the vacuum valve under one thimble and suck up the sample 
solution and as much as possible of the solid particles in the solut ion.  Close the valve and repeat in the same 
way with the rest of the tubes  
A.2.1.11  Wash each tube by opening the vacuum valve and spray 5 mL x 50 mL of approximately 50 ºC 
distilled water, by using the water sprayer  
A.2.1.12  Raise the suction tubes and t ake out one of the sample tubes.  Cover the cleaning rod with a thin 
layer of deflated  cotton wool and wet it with acetone.  Clean the inside of the tubes by gently pushing and 
pulling the cleaning rod up and down in the tube.  Take a small piece of the co tton wool and clean the outside 
of the suction tube if necessary.  Place each pad of the cotton wool on the top of the sample residue in the 
glass thimble  
A.3 Drying  
A.3.1  To make the wet sample residue hyophilic  and achieve effective solvent extraction, t he residue and 
thimble must be dried . 
a) Alternative 1:  Dry overnight at 60 ºC  to  80 ºC in an oven  
b) Alternative 2:  Dry in a microwave oven with turntable at medium power for 30 min to 60 min  
A.3.2 Most samples can be dried in a microwave oven, except meat and fish products . 
A.4 Procedure for Solvent Extraction  
A.4.1 Fit the adapters, as in A1.2.2, to each thimble and insert them into the Soxtec HT extraction unit . 
A.4.2  Extract  and  analyse  the  samples  according to  the Soxtec  HT  extraction  unit  inst ructions  (see  
Soxtec HT manual).  
A.5 Calculation  
A.5.1 Calculate the fat content according to the formula below . 
 
 
 
 DUS 51: 2 020 
© UNBS 2020 – All rights reserved  11 
 Where ,  
 = the extraction cup weight after fat extraction and cooling in a desiccator ; 
 = clean and pre -dried extraction cup  and  
 = sample weight . 
A.5.2 If a pre -extraction is required, using two extraction cups, add the two results that have been 
calculated, and the sum is the total fat in the sample.  
 
 
Where ,  
 = fat content after pre -extraction and  
 = fat content in final extrac tion. 
 
  
12 © UNBS 2020 – All rights reserved  
 Bibliography  
[1] Draft Rwanda Standard DRS 370: 2017 , Mayonnaise — Specification  
[2] Draft Kenya Standard DKS 551: 2012, Emulsified Sauces — Specification  
[3] The Effect of Emulsion Intensity on Selected Sensory and Instrumental Texture Properties o f Full -Fat 
Mayonnaise -Viktoria Olsson , Andreas Håkansson , Jeanette Purhagen , and Karin Wendin  
[4] Chemical Engineering Transactions vol . 32, 2013  Phase Inversion Emulsification Valentina Preziosi, 
Antonio Perazzo, Sergio Caserta *, Giovanna Tomaiuolo, Stefano Guido  
[5] Proposed Draft Revis ed Regional Standard for Mayonnaise  CL 2000/17 -EURO June 2000  Codex 
Alimentarius Commission  
[6] Master thesis Mayonnaise  Quality and Catastrophic Phase Inversion Lund University Department of 
Food Technology Engineering and Nutrition Ebba Widerström & Rebe cca Öhman 2017 Supervisors: 
Fredrik Innings, Dragana Arlov and Björn Bergenståhl  Examiner: Marilyn Rayner  
[7] Effect of Naturally Contaminated Feed with Aflatoxins on Performance of Laying Hens and the 
Carryover  of Aflatoxin B  Residues in Table Eggs - Salwa A. Aly  and W. Anwer Departmentof Food 
Hygiene, Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo 
University,  Cairo, Egypt  
 
 
 
 
 
 
 
 DUS 51: 20 20 
© UNBS 2019 – All rights reserved  13 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the c ertification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirement s of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Furthe r particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 51: 20 20   
 
ICS 67.200.10  
Price based on 11 pages  
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