ICS 67.060  
 
Reference number
DRS 388: 2023
© RSB 2023
  
 RWANDA 
STANDARD  DRS 
388 
 
Second  edition  
yyyy-mm-dd  
Roasted soybean flour — Specification 
   
DRS 388: 2023 
©RSB 2023- 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 2023 
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 
prior written permission from RSB. 
Requests for permission to reproduce this document should be addressed to: 
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Toll Free: 3250 
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 388: 2023 
iii                ©RSB 2023- All rights reserved 
 Contents Page 
Foreword ............................................................................................................................................................ iv 
1 Scope ................................................................................................................................................................ 1 
2 Normative references ...................................................................................................................................... 1 
3 Terms and definitions ..................................................................................................................................... 2 
4 Requirements ................................................................................................................................................... 2 
4.1 Ingredients .................................................................................................................................................... 2 
4.1.1  Essential ingredient ............................................................................................................................. 2 
4.1.2 Optional ingredien ..................................................................................................................................... 2 
4.2 General requirements .................................................................................................................................. 3 
4.3 Specific requirements .................................................................................................................................. 3 
4.4 Antinutritional factors .................................................................................................................................. 3 
4.5 Particle size ................................................................................................................................................... 3 
4.6 Microbiological requirements ..................................................................................................................... 3 
5 Food additives ................................................................................................................................................. 4 
6 Hygiene ............................................................................................................................................................. 4 
7 Contaminants ................................................................................................................................................... 4 
7.1 Pesticide and veterinary drug residues ..................................................................................................... 4 
7.2 Heavy metals ................................................................................................................................................. 4 
7.3 Aflatoxins ...................................................................................................................................................... 4 
8 Packaging ......................................................................................................................................................... 5 
9 Labelling ........................................................................................................................................................... 5 
10 Sampling ........................................................................................................................................................ 5 
 DRS 388: 2023 
©RSB 2023- All rights reserved                  iv 
 Foreword 
Rwanda Standards 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 Standards 
adopted by Technical committees are ratified by members of RSB Board of Directors for publication and 
gazettment as Rwanda Standards. 
RS 388 was prepared by Technical Committee RSB/TC 003, Cereals, pulses, legumes and cereal products.  
In the preparation of this standard, reference was made to the following standard (s): 
1) RS EAS 799: 2014, Edible full fat soybean flour — Specification 
2) RS EAS 762: 2017, Dry soybeans — Specification 
The assistance derived from the above source is hereby acknowledged with thanks. 
This second edition cancels and replaces the firstedition (RS 388: 2018  which has  been technically revised. 
Committee membership  
The following organizations were represented on the Technical Committee on Cereals, pulses, legumes and 
cereal products  (RSB/TC 003) in the preparation of this standard. 
Enterprise URWIBUTSO/SINA GERARD 
MANOSALIWA Food Industries Ltd  
MINIMEX Ltd  
National Agricultural Export Development Board (NAEB) 
National Industrial Research and Development Agency (NIRDA) 
Nyarutarama Business Incubation Center 
One Acre Fund-Tubura 
Rwanda Food and Drugs Authority 
Zamura Feeds Ltd DRS 388: 2023 
v                ©RSB 2023- All rights reserved 
 Rwanda Standards Board (RSB) – Secretariat 
 DRS 388: 2023 
1                ©RSB 2023- All rights reserved 
 Roasted soybean flour — Specification 
1 Scope 
This Draft Rwanda Standard specifies the requirements, sampling and test methods for roasted soybean flour 
made from varieties (cultivars) grown from Glycine max (L.) Merr.  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. 
RS CAC/RCP 1, General principles of food hygiene 
RS CODEX STAN 192,  General standard for food additives  
RS EAS 38 , Labelling of Pre-packaged Foods —General requirements  
RS EAS 762, Dry soybeans — Specification  
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 14902, Animal feeding stuffs — Determination of trypsin inhibitor activity of soya products  
RS ISO 16050, Foodstuffs — Determination of aflatoxin B1 and the total content of aflatoxins B1, B2, G1 
andG2 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 method  
RS ISO 21527-2, Microbiology of food and animal feedstuffs — 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  
RS ISO 24333, Cereals and cereal products — Sampling  
RS ISO 4833-1 , Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of 
microorganisms — Part 1: Colony count at 30 degrees C by the pour plate technique   
©RSB 2023- All rights reserved                  2 
 RS ISO 5985, Animal feeding stuffs — Determination of ash insoluble in hydrochloric acid 
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 665, Oilseeds – determination of moisture content and volatile matter content 
RS ISO 7305, Milled cereal products — Determination of fat acidity 
3 Terms and definitions 
For the purposes of this standard, the following terms and definitions apply. 
3.1 
roasted soybean flour 
flour produced from dry soybean which have been roasted and ground to flour 
3.2 
soybean 
mature dry grains of variety grown from Glycine max  (L.) Merr 
3.3 
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 
4 Requirements 
4.1 Ingredients 
4.1.1  Essential ingredient  
Roasted soybean flour shall be prepared from soybeans complying with RS EAS 762. 
4.1.2 Optional ingredients 
The following optional ingredients including but not limited to the following may be used in roasted soybean 
flour and shall comply with relevant standards:: 
a) Salt complying with RS EAS 35; and DRS 388: 2023 
3                ©RSB 2023- All rights reserved 
 b) Spices. 
4.2 General requirements 
Roasted soybean flour shall: 
a) be of colour characteristic of the variety of the roasted soybean used; 
b) be free from off flavours and odours; 
c) be free from extraneous and foreign matter; and 
d) be free from live insect and filth. 
4.3 Specific requirements 
Roasted soybean flour shall comply with the specific requirements stipulated in Table 1 when tested in 
accordance with test methods specified therein. 
Table 1 — Specific requirements for roasted soybean flour 
S/N Characteristic Requirement Test method 
i.  Moisture content , %, m/m, max. 7.0 RS ISO 665 
ii.  Crude Protein (N x 6.25), %, m/m, min. 35.0 RS ISO 20483 
iii.  Crude fibre, % m/m, max.  3.0 
iv.  Soy oil (on dry basis), %, m/m, max.  25 RS ISO 11085 
v.  Fat acidity, mg KOH/100 g, max.  80 RS ISO 7305 
vi.  Total ash, %,m/m max. 4 RS ISO 2171 
vii.  Acid insoluble ash, %, m/m, max. 0.40 RS ISO 5985 
4.4 Antinutritional factors 
The urease activity in the roasted soybean flour shall not exceed 0.3 mg N/g/min (for trypsin inhibitor activity, 5 mg/g) 
when tested in accordance wi th ISO 5506 and RS ISO 14902  
4.5 Particle size 
Not less than 90 % shall pass through a 0.60-mm sieve for fine flour and not less than 90 % shall pass 
through a 1.20-mm sieve for coarse flour. 
4.6 Microbiological requirements 
Roasted soybean flour shall comply with the microbiological limits stipulated in Table 2 when tested in 
accordance with the test methods specified therein.  
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 Table 2 — Microbiological limits for roasted soybean flour 
S/N Microorganism Maximum limit Test method 
i. Total Viable Count, CFU/g 104 RS ISO 4833-1 
ii. Escherichia coli , CFU/g Absent  RS ISO 16649-2 
iii. Salmonella spp , in 25g Absent RS ISO 6579-1 
iv. Yeasts and moulds, CFU/g 103 RS ISO 21527-2 
5 Food additives 
Food additives which may be used in roasted soybean flour shall comply with RS CODEX STAN 192. 
6 Hygiene 
Roasted soybean flour shall be prepared and handled in accordance with  RS CAC/RCP 1. 
7 Contaminants 
7.1 Pesticide and veterinary drug residues 
Roasted soybean flour shall comply with those maximum pesticide and veterinary drug residue limits 
established by Codex Alimentarius Commission  
7.2 Heavy metals 
When tested in accordance with appropriate test methods roasted soybean flour shall not contain heavy metal 
contaminants in amounts which exceed those specified in Table 3 when tested in accordance with test 
methods specified therein. 
Table 3 — Heavy metal limits in roasted soybean flour 
S/N Heavy metals Maximum limit (mg/kg) Test method 
i.  Lead  0.1 AOAC 999.11 
ii.  Cadmium  0.1 
7.3 Aflatoxins 
Roasted soybean flour shall comply with the aflatoxin levels specified in Table 4 when tested in accordance 
with test methods specified therein. 
Table 4 — Aflatoxin limits for roasted soybean flour 
S/N Type of aflatoxin Maximum limit (μg/kg) Test method 
i.  Total aflatoxins   10 RS ISO 16050 
ii.  Aflatoxin B1  5 DRS 388: 2023 
5                ©RSB 2023- All rights reserved 
 8 Packaging 
Roasted soybean flour shall be shall be packaged in food grade packaging materials that do not affect the 
quality of the product. 
9 Labelling 
In addition to the requirements specified in RS EAS 38, each pack of Roasted soybean flour shall be legibly 
and indelibly marked with the following: 
a) name of the product shall be ‘Roasted soybean flour’; accompanied by whether “fine flour” or “Coarse 
flour”; 
b) name and address of the manufacturer/packer/distributor/ importer/exporter/vendor ; 
c) list of ingredients in descending order; 
d) food additivesused; 
e) batch number; 
f) net content shall be declared in the metric system; 
g) date of manufacture; 
h) expiry date; 
i) country of origin; 
j) instructions for use;  
k) storage conditions; 
l)  instructions for use; and 
m) the statement ‘Human Food’ shall appear on the package. 
10 Sampling 
Sampling shall be done in accordance with RS ISO 24333. 
   
©RSB 2023- All rights reserved                  6 
 Bibliography 
[1] RS 388: 2022 Roasted soya bean flour-Specification, First edition  
 DRS 388: 2023 
 
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