ICS 67.180  
 
Reference number
DRS 25: 2020
© RSB 2020
  
 RWANDA 
STANDARD  DRS
25
Third edition
2020 -mm-dd
Edible maize starch —Specification  
   
DRS 25: 2020  
©RSB 2020  - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2020  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without  
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ePortal: www.portal.rsb.gov.rw   DRS 25: 2020  
iii                ©RSB 2020  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and defi nitions  ................................ ................................ ................................ ...................... 2 
4 Requirements  ................................ ................................ ................................ ................................ ...3 
4.1 Raw materials  ................................ ................................ ................................ ................................ ...3 
4.2 General requirements ................................ ................................ ................................ ....................... 3 
4.3 Specific r equirements  ................................ ................................ ................................ ...................... 3 
4.4 Microscopic appearance and granule size  ................................ ................................ ...................... 3 
4.5 Particle size  ................................ ................................ ................................ ................................ ......4 
5 Contaminants  ................................ ................................ ................................ ................................ ...4 
5.1 Heavy metals  ................................ ................................ ................................ ................................ ....4 
5.2 Mycotoxins  ................................ ................................ ................................ ................................ .......4 
5.3 Pesticide residues  ................................ ................................ ................................ ............................ 4 
6 Hygiene  ................................ ................................ ................................ ................................ ............. 5 
7 Packaging  ................................ ................................ ................................ ................................ ......... 5 
8 Labelling  ................................ ................................ ................................ ................................ ........... 5 
9 Sampling  ................................ ................................ ................................ ................................ ........... 6 
Annex  A (informative)  Photomicrograph of maize starch  ................................ ................................ .......... 7 
 DRS 25: 2020  
©RSB 2020  - All rights reserved                  iv 
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with  Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 25 was prepared by Technical Committee RSB/TC 003, Cereals, pulses, legumes and derived products  
In the preparation of this standard, reference was made to the following standard  (s): 
1) KS 340: 2007, Edible maize starch — Specification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This third edition cancels and replaces the secon d edition (RS  25: 2015 ), which has been technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Cereals, pulses, legumes and 
derived products  TC (RSB/TC 003) in the preparation of this standard.  
ADMA International  
Africa Improved Food (AIF)  
MANOSALIWA Food Industries Ltd  
Ministry of Agriculture and Animal Resources (MINAGRI)  
National Industrial Research and Development Agency (NIRDA)  
Radisson Blu Hotel and Convention Centre  
Rwanda Consumer's Rights Protection Organization (ADECOR)  
SOSOMA Industries  
Universi ty of Rwanda, College of Agriculture, Animal Science and Veterinary Medicine (UR -CAVM)  
ZIMA Enterprise  DRS 25: 2020  
v                ©RSB 2020  - All rights reserved  
 Rwanda  Standards Board  (RSB) – Secretariat  
  DRS 25: 2020  
1                ©RSB 2020  - All rights reserved  
 Edible maize starch —Specification  
1 Scope   
This Draft Rwanda Standard specifies the requirements , sampling and  test methods for edible maize starch 
commonly referred to as edible corn starch . 
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 reference d document (including any amendments) applies.  
AOAC 2001.04, Fumonisins B1 and B2 in corn and corn flakes  
AOAC 999.10, Lead, Cadmium, Zinc, Copper, and Iron in Foods Atomic Absorption Spectrophotometry after 
Microwave Digestion  
ISO 3593 , Starch —Determinat ion of ash  
RS 28,  Edible Starches — Test methods  
RS CAC/RCP 1, Code of practice — General Principle for food hygiene  
RS EAS 38, General standard for the labelling of pre -packaged foods  
RS ISO 10520 , Native starch ─ Determination of starch content ─ Ewers polarimetric method  
RS ISO 11085 , Cereals, cereals -based products and animal feeding stuffs — Determination of crude fat and 
total fat content by the Randall extraction method  
RS ISO 16050 , Foodstuffs — Determination of aflatoxin B1, and the total c ontent of aflatoxins B1, B2, G1 and  
G2 in cereals, nuts and derived products — High-performance liquid chromatographic method  
RS ISO 16649 -2, Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of 
beta-glucuronidase -positive Escherichia coli — Part 2: Colony -count technique at 44 degrees C using 5 -
bromo -4-chloro -3-indolyl beta -D-glucuronide  
RS ISO 20483, Cereals and pulses — Determination of the nitrogen content and calculation of the crude 
protein  content — Kjeldahl metho d 
RS ISO 21527 -2, Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of  
yeasts and moulds —Part 2: Colony count technique in products with water activity less than or equal to 0,95   
©RSB 2020  - All rights reserved                  2 
 RS ISO 24333, Cereals and cereal products — Sampling  
RS ISO 4833 -1, Microbiology of the food chain — Horizontal method for the enumeration of microorganisms – 
Part I Colony count at 30 degrees C by the pour plate technique  
RS ISO 5985 , Animal feeding stuffs — Determination of ash insolubl e in hydrochloric acid  
RS ISO 6541, Agricultural food products — Determination of crude fibre content — Modified Scharrer method  
RS ISO 6579 -1, Microbiology of the food chain — Horizontal method for the detection, enumeration and 
serotyping of Salmonella — Part 1: Detection of Salmonella spp  
RS ISO 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 medium  
RS ISO 712, Cereals and cereal products — Determination of moisture content -- Reference method.  
3 Terms and definitions   
For the purposes of this standard, the follow ing terms and definitions apply . 
3.1 
edible maize starch (edible corn starch)  
product  obtained from maize kernel endosperm (Zea mays Linn) manufactured by the wet /dry milling process.  
3.2 
wet milling process  
milling operation which is primarily performed by steeping kernels in water for the purpose of the i solation and 
recovery of s tarch  
3.3 
dry milling process  
obtaining the maximum yield of grits; while making the minimum amount of flour, and recovering the m aximum 
amount of germ in the flour of large particles with the maximum oil content . Dry milling may or may not include 
de-germ ing as a preliminary step.  
3.4 
food grade packaging material  
packaging 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  DRS 25: 2020  
3                ©RSB 2020  - All rights reserved  
 4 Requirements  
4.1 Raw material s 
Maize grains  complying with RS EAS 2  
4.2 General  requirements  
Edible maize starch shall:  
a) be in the form of a fine powder;  
b) be white in colour, except when prepared from yellow maize in which case it may be light creamy;  
c) be free of rancidity, adulterants, insect or fungus infestation, and from fermented musty or other  
objectionable odours;  
d) not contain added sweetening, flavouring, colouring agents or any foreign matter ; and  
e) be free from dirt and other suspended and extraneous matter . 
4.3 Specific requirements  
Edible maize starch shall also comply with the requirements given in Table 1  when tested in accordance with 
test methods therein.  
Table 1 —Spec ific r equirements for edible maize starch  
S/N.  Characteristic  Requirement  Test method  
i. Moisture, % by mass, max  12.5 RS ISO 712  
ii. Total ash % by mass, max  0.15 ISO 3593  
iii. Acid-insoluble ash , % by mass, max  0.10  RS ISO 5985  
iv. Starch  content  , % by mass, min  98.0 RS ISO 10520  
v. Protein , % by mass, max  0.6 RS ISO 20483  
vi. Fat ,% (m/m), max  0.15 RS ISO 11085  
vii. pH of aqueous extract  5.4-6.4 RS 28  
viii. Free acidity, expressed as ml of 0.1 N NaOH/100 
g, maximum  40.0 
4.4 Microscopic appearance and granule size  
When Edible maize starch is subjected to microscopic examination prescribed in RS 28, the granules shall 
conform to the following description:   
©RSB 2020  - All rights reserved                  4 
 a) Maize starch granules should be polygonal or rounded in shape and appear to be quite uniform in size ; 
b) the longest axis ranges from 10 µm to 30 µm (0.01 mm to 0.03 mm); and  
c) the hilum shall be fairly marked and starred with fissures but no striae shall be observed; distinct pol arized 
crosses shall, however, be seen.  
NOTE: To facilitate easy identification of the starch granules, a copy of a photomicrograph of maize  starch is provi ded in 
Annex A.  
4.5  Particle size  
When tested by the method prescribed in RS 28, not more than 2 % by mass of the material shall be re tained 
on a 75 -µm sieve and not more than 0.5 % by mass shall be retained on a 150 -µm sieve . 
5 Contaminants  
5.1 Heavy metals  
Edible  maize starch shall comply with those limits for heavy metals in Table 2  when tested in accordance with 
test methods specified therein  
Table 2 ▬ Limits for heavy metal contaminants  
S/N  Heavy metal  Maximum limit , mg/kg  Test method  
i. Lead (Pb)  0 .2  AOAC 999.10  
 ii. Cadmium   0.1 
5.2 Mycotoxin s 
Edible maize starch shall comply with those maximum levels of mycotoxins specified in the table 3  when 
tested in accordance with test methods specified therein . 
Table 3 ▬ Maximum limits for mycotoxins  
S/N  Mycotoxins  Requirement , µg/kg, max  Test method  
i. Total Aflatoxin (AFB1+AFB2+AFG1+AFG2)  10 RS ISO 16050  
ii. Aflatoxin B1  5 
iii. Fumonisin  2000 AOAC 2001.04  
5.3 Pesticide residues  
Edible maize starch shall comply with those maximum residue limits established by the Codex Alimentarius  
Commission for this commodity.  DRS 25: 2020  
5                ©RSB 2020  - All rights reserved  
 6 Hygien e 
6.1 Edible maize starch shall be produced, prepared and handled in accordance with RS CAC/RCP 1 . 
6.2 Edible maize starch shall not exceed microbiological limits given in Table 3 when tested in accordance 
with the test methods specified therein . 
Table 3 ▬ Microbiological limits for edible maize starch  
S/N  Microorganisms  Maximum limit  Test method  
i. Total viable count, cfu/ g, max . 104 RS ISO 4833 -1 
ii. E. Coli, cfu/g  max.  Absent  RS ISO 16649 -2 
iii. Salmonella  spp, per 25 g, max.   Absent  RS ISO 6579 -1 
iv. Staphylococcus aureus, cfu/g max . Absent  RS ISO 6888 -1 
v. Yeast sand mould s , cfu/g, max . 103 RS ISO 21527 -2 
7 Packaging  
Edible maize starch shall be packaged in suitable food grade packaging materials that shall not affect the 
quality of the product.  
8 Labelling  
In addition to the requirements in RS EAS 38, each package shall be legibly and indelibly marked wit h the 
following:  
a) name of the product as “ Edible maize starch/ Edible corn  starch ”; 
b) name, location and physical address of the manufacturer;   
c)  net content;  
g) batch number;  
h) country of origin;  
i) date of manufacture;  
j) expiry date ; 
d) instructions for use; and  
m) storage conditions .  
©RSB 2020  - All rights reserved                  6 
 9 Sampling  
Sampling  of edible maize starch  shall be done in accordance with RS ISO 24333.  DRS 25: 2020  
7                ©RSB 2020  - All rights reserved  Annex  A 
(informative)  
 
Photomicrograph of maize starch  
 
  
 
©RSB 2020  - All rights reserved                  8 
 Bibliography  
[1] RS 25: 2015, Edible maize starch —Specification , Second edition  
 DRS 25: 2020  
 
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