DRAFT UGANDA STANDARD  
  DUS 571 
Second Edition  
2018 -mm-dd 
 
 
 Reference number  
DUS 571: 2018 
© UNBS 2018   
  
Baking powd er — Specification   
 
 
  
 DUS 571: 2018  
ii © UNBS 2018  – 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 application  
© UNB S 2018   
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 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 571: 2018  
© UNBS 2018  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .....................  i 
Introduction  ................................ ................................ ................................ ................................ ................  ii 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Ingredients  ................................ ................................ ................................ ................................ .... 1 
5 Requirements  ................................ ................................ ................................ ................................  2 
5.1 General requirements  ................................ ................................ ................................ ..................  2 
5.2 Specific requirements  ................................ ................................ ................................ ..................  2 
5.2.1  Physicochemical requirements  ................................ ................................ ................................ .. 2 
6 Contaminants  ................................ ................................ ................................ ................................  2 
7 Packaging  ................................ ................................ ................................ ................................ ...... 2 
8 Weights and Measures ................................ ................................ ................................ .................  2 
9 Labelling  ................................ ................................ ................................ ................................ ........  2 
10 Sampling  ................................ ................................ ................................ ................................ ....... 3 
Annex  A  (normative)   Determination of available carbon dioxide ................................ ......................  4 
A.1 Me thod One  ................................ ................................ ................................ ................................ .........  4 
A.2 Method Two  ................................ ................................ ................................ ................................ .........  5 
Annex  B  (normative)   Sampling of baking soda  ................................ ................................ ..................  7 
B.1 General requirements of sampling  ................................ ................................ ................................ ... 7 
B.2 Scale of sampling  ................................ ................................ ................................ ...............................  7 
B.3 Random sampling  ................................ ................................ ................................ ...............................  7 
B.4 Test samples and referee s amples  ................................ ................................ ................................ ... 8 
B.4.1 Preparation of individual samples  ................................ ................................ ................................ . 8 
B.4.2 Preparation of a composite sample  ................................ ................................ ...............................  8 
B.4.3 Referee samples  ................................ ................................ ................................ ..............................  8 
B.5 Number of tests  ................................ ................................ ................................ ................................ ... 8 
B.6 Criteria for conformity  ................................ ................................ ................................ ........................  8 
Bibliography  ................................ ................................ ................................ ................................ ...............  9 
 
 
 
 
 
 DUS 571: 2018  
© UNBS 2018  – All rights reserved  i 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives 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, an d  
(c) the National Enquiry Point on 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 standards in a given field or ar ea 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 co mments. 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 UNBS/TC 2 [ Food and Agriculture standards ], Subcommittee 
SC 6, [ Food Additives and contaminants ]. 
This second edition cancels and replaces the first edition (US 57 1: 2006) which has been technically revised.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DUS 571: 2018  
ii © UNBS 2018  – All rights reserved  
 Introduction  
Baking powder finds widespread use as a chemi cal leavener of dough for baked  products. The constituents of 
baking powder are (a) sodium bicarbonate, (b) edible starch, and (c) acid reacting component (s). On wetting, 
the powder produces carbon dioxide by the action of the acid reacting component on sodium bicarbonate . The 
released c arbon dioxide is entrapped in the batter or dough mix resulting in volume increase and lightened  
textu re of baked goods.  
The starc h in baking powder improves  the product’s  consistency and stability  by absorb ing moisture  and thus  
prolong ing its  shelf life . By keeping the product dry, the starch  prevents the powder's  alkaline an d acidic 
components from  react ing with each other prematurely .  
This standard has b een revised to keep up  with advancemen ts the baking powder industry  and t o ensure the 
safety of products traded.  
 DRAFT UGANDA STANDARD    DUS 571: 2018  
  
© UNBS 2018  – All rights reserved  1 
 Baking powder  — Specification  
1 Scope   
This Draft Uganda S tandard s pecifies  the requir ements and the methods of sampling and test  for baking powder . 
2 Normative references    
The following referenced documents are referred to in the text in such a way that some or all of their content 
constitute  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.  
US 277 , Labelling of food additives when sold as such — General requirements  
US 572, Sodium bicarbonate — Specification   
US 738, General standard for contaminants and toxins in food and feed  
FDUS ISO 760, Determination of water — Karl Fischer Method (General method)  
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 address:  
— ISO Online browsing platform: available at http://www.iso.org/obp   
food grade material  
material made of substances which are safe and suitable for their intended use and which will not impart any 
toxic substance or undesirable odour or flavour to the product  
4 Ingredients  
Baking powder shall contain the following ingredients:  
a) refined grade sodium bicarbonate conforming to US 572 ; 
b) edible starches  such as maize starch  and cassava  starch or other neutral material such as calcium 
lactate, anhydrous calcium sulphate and  sodium sulphate ; 
c) One or a combination of the following acid reacting componen ts: 
(i) sodium acid pyrophosphate with or without mono acid calcium phosphate;  
(ii) mono acid calcium phosphate with or without dicalcium orthophosphate;  
(iii) potassium hydrogen tartrate or tartaric acid or a mixture of both;  
(iv) acid compounds of aluminium; and  
(v) glucono del ta lactone.  DUS 571 : 2018  
2 © UNBS  2018  – All rights reserved  
 5 Requirements   
5.1 General requirements  
Baking powder  shall be in the form of a free -flowing white  powder , free from  off odour s, dirt, insect infestations, 
fungal infections , foreign matter and adulterants.  
5.2 Specific requirements  
5.2.1  Physicochemical requirements  
Baking powder shall comply with the physicochemical requirements  in Table 1  when tested in accordance with 
the test methods  specified therein.  
Table 1 — Physicochemical  requirements for baking powder  
S/N Characteristic  Requirem ent Test method  
i.  Available carbo n dioxide, % (m/m), min.  12 Annex A  
ii.  Moisture  % (m/m),  max.   2 FDUS ISO 760  
 
6 Contaminants  
Baking powder shall comply with  the maximum levels for the con tamina nts given in Table 2  when tested in 
accordance with the test methods  specified therein.  
Table 2 — Permitted maximum levels of  contaminants in  baking powder  
S/N Heavy metal  Requirement  Test method  
i.  Lead ( Pb), mg/kg, m ax. 1 AOAC 999.11  
ii.  Copper (Cu), mg/kg, max.  2 AOAC 999.11  
iii.  Arsenic (As), mg/kg, m ax. 0.05 AOAC 920.46 (B)  
 
7 Packagin g  
The products shall be packaged in clean, sound and airtight food grade materials.  
8 Weights and Measures  
The weight of the  product packages shall comply with the  Weights and Measures Regulations . 
9 Labelling  
In addition to the requirements of US 277, the p roduct packages shall be legibly a nd indelibly labelled with the 
following information:  
a) Name of the product as “Baking powder”  
b) Date of manufacture;  
c) Best before date ; 
d) Instructions of use (These could as well be on an accompanyin g leaflet) and;  DUS  571: 2018  
© UNBS 2018  – All rights reserved  3 
 e) Storage  instructions.  
10 Sampling  
Representative samples of the  product sh all be drawn in accor dance with the procedure elaborated  in Annex 
B. 
 DUS 571 : 2018  
4 © UNBS  2018  – All rights reserved  
 Annex  A  
(normative )  
 
Determination of available carbon dioxide  
A.1 Introduction  
Two methods have been described. Any  can be used depending on the available facilities . 
A.1 Method O ne 
A.1.1 Apparatus  
Schroedter's alkalimeter, as shown in Figure 1  
A.1.2 Reagent  
Sulphuric acid  
A.1.3 Procedure  
Fill bulb (A) with distilled water and bulb (B) with sulphuric aci d to a height of 25 mm above  port (C) through 
which carbon dioxide escapes into  the acid. Weigh the alkalimeter  (M). Introduce 1 g  of sample through  side 
opening (D) into the decomposition flask (E). Weigh the alkalimeter again  (M2). Open the stopcock (F) and allow 
about 25 ml  of water to flow into  (E). Allow the initial vigorous reaction to subside . Place the apparatus over a 
flame  and boil the solution for about 3 min utes. Aspirate carbon dioxide  free air through the so lution by ap plying 
suction at G,  the air first passing through soda lime. Weigh the alkalimeter again  (M1). 
 
Figure 1: Schroedter's alkalimeter  
DUS  571: 2018  
© UNBS 2018  – All rights reserved  5 
 A.1.4 Calculation  
Available carbon dioxide, percent by mass = 
M M)M (M

21 2 100  
where  
M2 is the mass , in grams,  of alkalimeter with sample, before decomposition;  
M1 is the mass , in grams,  of alkalimeter with sample, after decomposition;  and 
M is the mass , in grams, of alkalimeter before introducing the sample.  
A.2 Method Two  
A.2.1 Apparatus  
Gasometric assembly, as  shown in Figure 2.  
The apparatus consists of a 250 ml , wide mouthed extraction flask (A) made of heat resistant glass  connected 
by a short bent glass tube to a rubber tube (B). B is connected by a two -way stopcock (C) to a gas measuring 
tube (D) graduated  in millilitres; the  zero mark at the point just below th e top and graduated up to 500 ml . 
Additionally connected to flask A is a 40 ml burette (H) graduated  in millimetres . The gas measuring tube is 
connected to a levelling tube (F) through a rubber tube (E) having  a pinchcock (P) to control the flow of the 
solution.  
 
Figure 2 — Gasometric assembly  
A.2.2 Reagent s 
Displacement solution — Dissolve 100 g of sodium chlor ide or sodium sulphate in 350 ml  of distilled water. 
Accurately add 1 g of sodium bicarbon ate (conforming to US 572) and 2 ml methyl orange (0.5 % aqueous 
solution) and then enough sulphuric a cid or hydrochloric acid to turn the solution acid  (solution turns to  pale 
pink). Stir until all the released carbon dioxide is removed.  
DUS 571 : 2018  
6 © UNBS  2018  – All rights reserved  
 This solution is used in  the gas measuring tube and the  levelling bulb and seldom needs correction.  
A.2.3 Procedure  
Accurately weigh 2.5 g of the sample into flask (A). Using the two -way stopcock (C), connect the gas measuring 
tube (D) and levelling tube (F) to the atmosphere and through a funnel on the open end of tube F, fill both tubes 
with displacement solution up to the zero mark of tube D. Connect the decomposition flask A with rubber tube 
B and turn  the stopcock so that the gas measuring tube is connected to f lask A and disconnected from the 
atmosphere. Fill  burette (H) with distilled water up to the 40 ml mark  and let the  apparatus stand for 1 to  2 
minutes so that the temperature and pressure within the apparatus comes to ro om conditions. Open pinchcock  
(P) and bring down the so lution level in tube F to reduce pressure within the apparatus. Collect the displaced  
solution in a glass beaker and reserve for re -use later. Slowly add 35 ml of distilled water to  decomposition flask, 
from burette H.  
To allow unifor m mixing of contents  and complete evolution of CO2, occasionally rotate the decomposition fl ask 
by swirling  and boil the flask and its contents  over a tripod stand using a Bunsen  burner. To prevent overflowing 
of displacement solution in levelling tube , fill to a level lower th an the overflow capacity . When the mixture in  
flask A foams up and the foam reaches the neck of the flask, stop heating and quickly immerse the 
decomposition flask in cold tap water kept in a tray below. Also pour water over the decom position flask while 
rotating it to bring the contents to the temperature of water in the tray. Wh en this happens wait for  5 min utes to 
secure equilibrium. Equalize pressure in the measuring tube by pouring solution in levelling tube, using the 
pinchcock P if necessary and read the volume V in the measuring tube.  
A.2.4 Calculation  
Deduct from this volume V, the volume of distilled water added ( 35 ml ) to get the correct volume of CO2 evolved 
after decomposition at atmospheric temperature and pressure.  
The volume of CO2 evolved, in millilitres, at normal temperature and pressure shall be calculated as follows : 
 X
22
2
121
TPVP
PTV1
 
where  
V2 is the volume of CO2, calculated at normal temperature and pressure;  
T2 is the normal temperature (273 °K or 0 °C);  
P2. is the normal pressure (760 mm);  
P1 is the corrected barometric pressure at temperature T1;  
V1 is the V - 35 ml = corrected volume of CO2 evolved after decomposition;  and  
T1 is the observed temperature of displacement solution .  
One gram mole (44 g ) of carbon dioxi de, at NTP will occupy 22 400 ml, that is, 22 400 ml  of CO2 at NTP, 
weigh 44 g.  
 
V2 ml CO2 a obtained from 2.5 g of baking powder  NTP will weigh , in grams : 
144
224002V
.  
Therefore, available carbon  dioxide, percent by mass     =     
44
22400 2.51002V         =       
2240044 402V  DUS  571: 2018  
© UNBS 2018  – All rights reserved  7 
 Annex  B  
(normative)  
 
Sampling of baking soda  
B.1 General requirements of sampling  
In drawing, preparing, storing and handling samples, the following precautions and directions shall be observed.  
(a) The product shall be kept in a protected place not exposed to damp air, dust or soot.  
(b) The sampling instrument shall be clean and dry when used.  
(c) Precautions shall be taken to protect the samples, the material being sampled, the sampling instrument  
and the containers for samples from contamination.  
(d) The samples shall be placed in clean, odourless and dry glass containers. The sample containers shall 
be of such size that they are almost completely filled by the sample.  
(e) Batch containers shall be sealed  airtight after filling and marked with full details of sampling, batch or 
code number, name of the manufacturer and other important particulars of the consignment.  
(f) Samples shall be stored following the product storage conditions prescribed by the manufact urer. 
(g) Sampling shall be done by a qualified and authorised person.  
B.2 Scale of sampling  
The number of containers to be tested from a lot shall depend on the size of the lot and shall be in accordance 
with Table 2.  
Table 2 — Number of containers to be sele cted for sampling  
Total Number of containers in the lot  
 (N) Number of containers to be selected  
(n) 
Up to 50  3 
51 to 100  4 
101 to 300  5 
301 to 500  6 
501 and above  7 
 
B.3 Random sampling  
Sampling shall be done randomly from the lot and  random number tables shall be used. In case such tables are 
not available, the following procedure may be adopted:  DUS 571 : 2018  
8 © UNBS  2018  – All rights reserved  
 Starting from any container, count them as 1, 2, 3, …..r and so on, in one order. Every rth container counted 
shall be chosen, r being the i ntegral part of N/n, where N is the total number of containers in the lot and n the 
number of samples to be selected as shown in Table 2. 
B.4 Test samples and referee samples  
B.4.1 Preparation of individual samples  
Empty  the container on a clean sheet of paper and mix thoroughly. Cone and quarter as often as necessary till 
about 75 g of the material is left. From this , take about 15 g of the material and divide it into three equal parts. 
Each part so obtained shall constitute an individual sample represent ing the container and shall be transferred 
immediately with particulars given in B.1 (e). The individual samples  obtained shall be divided into three sets in 
such a way that each set has a sample representing each selected container. One of these sets shal l be marked 
for the purchaser, the other for the vendor and the third being the referee  sample . 
B.4.2 Preparation of a composite sample  
Equal quantities of the product shall be taken the containers from where the individual samples were obtained 
and mixed together to obtain a composite sample weighing not less than 160 g. This composite sample shall 
be divided into three equal parts and transferred to clean dry glass containers and labelled with the particulars 
given in B.1 (e). One of these composite sampl es shall be marked for the purchaser, the other for the vendor 
and the third being a referee sample.  
B.4.3 Referee samples  
Referee samples shall consist of a set of individual samples (B.4.1) and a composite sample (B.4 .2) marked for 
this purpose and shall  bear the seals of the purchaser and the vendor. These shall be kept at a place agreed to 
between the two.  
B.5 Number of tests  
Tests for requirements given in 5 .1 and 5.2.1 ( Table 1 ) shall be conducted on each set of individual samples.  
Tests fo r contamina nts (Table 2)  shall be conducted on the composite sample (B.4 .2). 
B.6 Criteria for conformity  
The lot shall be declared to be in conformity with all the requirements of this specification, if it has been found 
satisfactory in accordance with B.5 . DUS  571: 2018  
© UNBS 2018  – All rights reserved  9 
 Bibliogra phy 
[1] IS 1159  (1981) (Reaffirmed in 2010) — Specification for baking  powder (First Revision ) 
[2] US 571: 2006, Baking powder — Specificat ion 
[3] KS 346: 2000, Specification for baking powder (First Revision)  
 DUS 571: 2018  
© UNBS 2018  – All rights reserved  11 
 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 b y the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by the 
Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The presenc e of 
this mark on a product or in relation to a product is an assurance that the goods comply with the requirements 
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.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda National 
Bureau of Standards.  
 
DUS 571: 2018    
 
ICS 67.220.20   
Price based on nn pages  
© UNBS 2018  – All rights reserved