Food grains and Food grain Industry Sectional Committee, AFDC 32

FOREWORD

This Indian Standard (First Revision) was adopted by the Bureau of Indian Standards on 28 October 1988, after the draft finalised by the Food grains and Food grain Industry Sectional Committee had been approved by the Agricultural and Food Products Division Council.

Flour constitutes the most essential ingredient in the manufacture of bread, biscuits and other bakery products. The quality of flour has an immense bearing on the quality of these end products. Therefore, it was considered necessary to formulate a separate standard for bread flour. In the formulation of this standard, the committee took note of the existing conditions regarding the availability of wheat for milling. However, in view of the fact that the present difficulties were likely to be overcome in future and that this standard would serve as a guideline to the bakers, it was considered desirable to make a beginning by prescribing these standards. In the first instance, it was decided to limit the requirements in this standard to only such characteristics, which were considered to be most important. Subsequently, as and when wheat supply position became comfortable, this standard was to be further elaborated.

This standard was first published in 1974. While finalizing the standard, the technical committee responsible for formulation of this standard felt that the limit for rope spore and mould should also be specified in this standard as they reflected the hygienic conditions under which the material had been produced. But as no significant data was available in the country, these limits were not being specified, and it was decided that the position would be reviewed for incorporating these limits in the standard as and when more data was available. Now with the availability of this data, microbiological limits have been specified in this revised version. The minimum limit for sedimentation value has been revised and the packaging clause has also been modified to specify only B-twill jute bags for packaging. Method for determination of water absorption by farinograph and valorigraph has been introduced.

In the preparation of this standard, due consideration has been given to provisions stipulated under the Prevention of Food Adulteration Act, 1954 and Rules framed thereunder, and the Standards of Weights and Measures (Packaged Commodities) Rules, 1977. However, this standard is subject to the restrictions imposed under these Rules, wherever applicable.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 (Rules for rounding off numerical values (revised)). The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

Indian Standard

WHEAT FLOUR (MAIDA) FOR USE IN BREAD INDUSTRY - SPECIFICATION

(First Revision)

1 SCOPE
This standard prescribes the requirements and the methods of sampling and test for wheat flour (MAIDA) for use in the bread industry.

2 REFERENCES
The Indian Standards listed in Annex A are necessary adjuncts to this standard.

3 REQUIREMENTS
3.1 Description
Wheat flour (MAIDA) shall be the product obtained by milling, cleaned hard or soft wheat or blends thereof in a roller flour mill, and bolting. The flour shall be free flowing, dry to touch, should not pack when squeezed, should be creamy in colour and free from any visible bran particles. The flour shall have a characteristic taste and smell, and shall be free from insect and fungus infestation, rodent contamination, dirt and other extraneous matter. It should not have any musty flavour or rancid taste.
NOTE -The appearance, taste and odour shall be determined by sensory tests.

3.2 The material shall also comply with the requirements given in Table 1.
3.3 Microbiological Requirements
The wheat flour (MAIDA) shall he tested periodically to comply with the requirements given in Table 2.

4 PACKING AND MARKING
4.1 Packing
The packages may preferably be of 50, 75 or 90 kg as desired by the purchaser.
4.1.1 For packages above 65 kgs, unless otherwise agreed to between the purchaser and the vendor, the material for packing shall he single, clean, sound, B-twill jute bags conforming to IS 2566 : 1984. The bags shall be free from weevil infestation.

4.1.2 The mouth of each bag shall be either machine-stitched or hand-stitched. If it is hand- stitched, the mouth shall be rolled over and then stitched. The stitches shall he in two cross rows with at least 14 stitches in each row for jute bags of 65 kg and above.

4.2 Marking
Each bag shall be suitably marked so as to give the following information:

• Name of the material
• Name and address of the manufacturer
• Date of manufacture
• Batch or code number
• Net mass

• Any other details required under the Standards of Weights and Measures (Packaged Commodities) Rules, 1977 / PFA Rules.

  4.2.1 All markings shall be applied on the bags in such a manner that the dye or ink (IS 1234:1980) does not penetrate into the material.
  4.2.2 The bags may also be marked with the Standard Mark

5 SAMPLING
Representative samples of the material shall be drawn and conformity of the material to the requirements of this specification shall be determined by the method prescribed in IS 5315 : 1978.

6 TESTS
6.1 Tests shall he carried out as prescribed under 3.1 and in the appropriate Annexes and Indian Standards referred to in Tables 1 and 2.

6.2 Quality of Reagents
Unless specified otherwise, pure chemicals shall be employed in tests and distilled water shall be used where the use of water as a reagent is intended.
NOTE- 'Pure chemicals' shall mean chemicals that do not contain impurities, which affect the results of analysis.

Table 1 Requirements for Wheat Flour (MAIDA) for Use in Bread Industry ( Clause 3.2 )

Sr. No.	Characteristic	Requirement	Method of Test, Ref to
1	Moisture, percent by mass, Max	13.0	Annex A of IS 1009. 1979 IS 7219 : 1973
2	Protein (N X 5.7) percent by mass (on dry basis), Min	11	Annex D of IS 1009 : 1979
3	Gluten, percent by mass (on dry basis), Min	9.5	Annex B of IS 1009 : 1979
4	Total ash (on dry basis), percent by mass, Max	0.5	Annex C of IS 1009 : 1979
5	Acid insoluble ash, percent by mass (on dry basis), Max	0.05	Annex E, of IS 1009 : 1979
6	Alcoholic acidity (as H2SO4) in 90 percent alcohol (percent by mass), Max	0.1	IS 12516 ( Part 1 ) : 1988 or IS 12516 ( Part 3 ) : 1988
7	Water absorption, percent, Min	60	Annex B of this standard IS 4782 : 1968
8	Maltose, percent	2 to 3	Annex F of IS 1009 : 1979
9	Sedimentation value, Min	22	-
10	Granularity	To satisfy test	-
11	Uric acid mg / 100 g, Max	10	IS 4333 (Part 5) : 1970

Table 2 Microbiological Requirements for Wheat Flour (MAIDA) for Use in Bread Industry (Clauses 3.3 and 6.1)

Sr. No.	Characteristic	Requirement	Method of Test, Ref to
1	Total bacterial count per g, Max	100000	IS 5402 : 1969
2	Coliform bacterial count per g, Max	500	IS 5401 : 1969
3	E coli	Absent (in 1 gram)	IS 5887 (Part 1) : 1976
4	Yeast / mould count per g, Max	10000	IS 5403 : 1969
5	Acid insoluble ash, percent by mass (on dry basis), Max	100	Annex C of this standard

ANNEX A (Clause 2) LIST OF REFERRED INDIAN STANDARDS

IS Nos.	Title
1009 : 1979	Specification for MAIDA of general purposes (second revision)
1070 : 1977	Specification for water for general laboratory use (second revision)
1234 : 1980	Specification for ink, stencil, oil base, for marking porous surfaces (first revision).
2566 : 1984	Specification for B-twill jute bags for packing food grains (second revision)
4333 (Part 5) : 1970	Methods of analysis for food grains: Part 5 Determination of uric acid
4782 : 1968	Method for determination of sedimentation value of wheat (flour)
5315 : 1978	Methods of sampling for milled cereals and pulses products
5401 : 1969	Methods for detection and estimation of coliform bacteria in foodstuffs
5402 : 1969	Method for plate count of bacteria in foodstuffs
5403 : 1969	Method for yeast and mould count in foodstuffs
5887 (Part 1) : 1976	Methods for detection of bacteria responsible for food poisoning: Part 1 Isolation, identification and enumeration of Escherichia coli (first revision)
7219 : 1973	Method for determination of protein in foods and feeds
12516 (Part 1) : 1988	Determination of physical characteristics of dough made from wheat flour: Part 1 Water absorption and rheological proper ties using farinograph
12516 (Part 3) : 1988	Determination of physical characteristics of dough made from wheat flour: Part 3 Water absorption and rheological properties using a valorigraph

ANNEX B Table 1, Item (viii)
DETERMINATION OF MALTOSE

B-1 REAGENTS
B-1.1 Buffer Solution (pH 4.6 - 4.8)

Mix 3 ml glacial acetic acid and 4'1 g anhydrous sodium acetate and make up to one liter.
B-1.2 Sulphuric Acid Solution (V / V) (10 percent).

B-1.3 Sodium Tungstate Solution
Dissolve 120 g of sodium tungstate in water and make up to one liter.
B-1.4 Standard Alkaline Ferricyanide Solution (0.05 N) Dissolve 16.5 g pure, dry potassium ferricyanide and 22 g anhydrous sodium carbonate in distilled water and dilute to one liter. Keep in a dark glass bottle away from light.

B-1.5 Sodium Thiosulphate Solution: Dissolve 12.41 g of sodium thiousulphate in boiled and cooled distilled water containing 1 ml of chloroform, and make up to one liter.

B-1.6 Acetic Acid Reagent: Dissolve 70 g of potassium chloride and 20 g of hydrated zinc sulphate (ZnSO4.7H20) in 500 ml of distilled water and add 200 mi of acetic acid. Make up to one liter.

B-1.7 Potassium Iodide Solution: Add 50 g of potassium iodide to 100 ml of distilled water and add 1 drop of 10 N sodium hydroxide. This solution should be freshly prepared and should contain no free iodine.

B-1.8 Soluble Starch Solution: Pour a suspension containing one gram of starch into 100 ml of boiling water. Add 30 g of sodium chloride.

B-2 PROCEDURE
B-2.1 Introduce 5 g of flour and one teaspoonful of ignited quartz sand into 100 or 125-ml Erlenmeyer flask and mix well by rotating the flask. Add 46 ml of buffer solution and again mix by rotating the flask until all the flour is thoroughly in suspension. The flour-sand mixture and the buffer solution should be separately and individually brought to 300C before the two are mixed. Digest for one hour at 30'C, preferably in an accurately thermo- statically controlled water bath, shaking the flask (by rotation) every 1 5 minutes. At the end of the hour, add 2 mi of 10 percent sulphuric acid solution and mix thoroughly. Then add 2 ml of sodium tungstate solution, mix, and allow to stand for 1 to 2 minutes. Filter through paper (Whatman No. 4 or its equivalent), discarding the first 8 or 10 drops and pipette 5 mi of the filtered extract into a test tube of approximately 50-mi capacity ( 18 to 20 mm diameter ). Add by means of a pipette, exactly 10 mi of alkaline ferricyanide solution to 5 ml of extract in the test tube and immerse the test tube in a vigorously boiling water bath (the surface of the liquid in the test tube should he 3 or 4 cm below the surface of the boiling water).

Allow the test tube to remain in boiling water for exactly 20 minutes and pour at once into a 100 or 125-ml Erienmeyer flask. Rinse out the test tube with 25 ml of acetic acid reagent and add to the contents of the Erienmeyer flask, mixing thoroughly. Add 1 ml of potassium iodide solution followed by 2 ml of the soluble starch solution and mix thoroughly. Titrate with 0'05 N sodium thiosulphate to complete disappearance of the blue colour. A 10-mi burette is recommended for the titration. For high maltose flours, use 2.5 ml of extract for oxidation together with 2.5 ml of water.

B-2.1.1 Carry out a blank determination using the same quantities of reagents under similar conditions as specified in B-2.1.

B-3 CALCULATION
Subtract the number of ml of sodium thiosulphate used in the titration from 10, which gives the ml of standard alkaline ferricyanide solution reduced to ferrocyanide by the reducing sugars in the flour extract. This value represents a definite quantity of maltose, which may be ascertained by consulting Table 3. The table has been prepared by applying specified procedure to standard solution, of pure maltose using all reagents in precisely the same quantities and volumes as employed for flour extracts. The maltose values are given in mg. When 5 ml of flour extracts are used, as specified, it is necessary merely to multiply mg of maltose by 20 to give the mg of maltose per 10 g of flour in one hour's diastasis. This is the value that is recorded and reported as the measure of the diastatic value of the flour in question; when 2.5 ml of extract is used, this factor will be 40.

Table 3 Maltose Conversion Table

0.05 N	Maltose	0.05 N	Maltose	0.05 N	Maltose	0.05 N	Maltose
Ferricyanide	Equivalent	Ferricyanide	Equivalent	Ferricyanide	Equivalent	Ferricyanide	Equivalent
0.1	0.2	2.6	4.2	5.1	8.3	7.6	12.3
0.2	0.3	2.7	4.4	5.2	8.4	7.7	12.5
0.3	0.3	2.8	4.5	5.3	8.6	7.8	12.7
0.4	0.6	2.9	4.7	5.4	8.7	7.9	12.9
0.5	0.8	3.0	4.9	5.5	8.9	8.0	13.0
0.6	1.0	3.1	5.0	5.6	9.1	8.1	13.2
0.7	1.1	3.2	5.2	5.7	9.2	8.2	13.4
0.8	1.3	3.3	5.3	5.8	9.4	8.3	13.5
0.9	1.5	3.4	5.5	5.9	9.6	8.4	13.7
1.0	1.6	3.5	5.7	6.0	9.7	8.5	13.9
1.1	1.8	3.6	5.8	6.1	9.9
1.2	1.9	3.7	6.0	6.2	10.0
1.3	2.1	3.8	6.2	6.3	10.2
1.4	2.3	3.9	6.3	6.4	10.4
1.5	2.4	4.0	6.5	6.5	10.5
1.6	2.6	4.1	6.6	6.6	10.7
1.7	2.8	4.2	6.8	6.7	10.9
1.8	2.9	4.3	7.0	6.8	11.0
1.9	3.1	4.4	7.1	6.9	11.2
2.0	3.2	4.5	7.3	7.0	11.3
2.1	3.4	4.6	7.5	7.1	11.5
2.2	3.6	4.7	7.6	7.2	11.7
2.3	3.7	4.8	7.8	7.3	11.8
2.4	3.9	4.9	7.9	7.4	12.0
2.5	4.1	5.0	8.1	7.5	12.2

ANNEX C Table 2, Item (v)

DETERMINATION OF BACTERIAL ROPE SPORE COUNT

C-1 REAGENTS
C-1.1 Peptone Water, 0.1 %, sterilized.
C-1.2 Tryptone Glucose Extract (TGE)

• Tryptone 5.0 g
• Yeast extract 2.5 g
• Glucose (dextrose) 1.0 g
• Sodium chloride 6.5 g
• Agar, bacteriological grade 15.0 g
• Water, distilled 1000.0 ml
• Final pH 7.0 ± 0.1
  

  NOTE - Granulated or chopped shreds, practically free from thermophilic bacteria, shall be used.

  C-2 PROCEDURE
  

  C-2.1 Weigh 22 g of flour in a suitable sterile container and transfer to 100 ml of sterile 0,1 percent peptone water in a conical flask containing sterile sand or glass beads. Disperse by blending on a shaker for about two minutes. Dilute the blended material further 1 : 10, 1 - 100, 1 : 1000, 1 : 10000, etc, by dilution technique, using sterile peptone water.
  
  C-2.2 Prepare tryptone glucose extract (TGE) agar or any other suitable medium 100 ml per 250-ml conical flask. Prepare one additional flask of medium to serve as a sterility control. Sterilize at 121'C for 15 minutes and then cool to 45 d C in a water bath. Pipette volumes of blended material into a set of flasks of TGE agar while they are held in the water bath 10 ml into the first, 1 ml into the second and 1 ml of each dilution into the third, fourth and fifth TGF, flask and so on. Gently agitate the flask to disperse the blended material throughout the medium.
  
  C-2.3 Transfer the flask without delay to a water bath adjusted to 85 to 90 d C and hold for 30 minutes with gentle shaking occasionally to assist heat distribution. After 30 minutes of heat treatment, cool the flasks to about 45 d C without allowing the agar to congeal. Pour 100 ml medium in each flask representing the test material and sterility control into a set of 5 sterile petri dishes in approximately equal volumes, that is, about 20 mi per plate, when agar has solidified, invert the plates and incubate at 35'C for 48 hours.
  
  C-2.4 Count the surface and sub-surface colonies. The sum of colonies on the set of 5 plates poured from TGE agar, containing 10 ml of blended food material represents the number of aerobic and mesophillic spores per gram of material. Similarly, 1 ml of blended and 1 ml of each dilution is equal to 0.01, 0.001, 0.0001 and 0.00001 of the number of spores per gram and shall be multiplied by the respective dilution factor. Generally, the set of plates showing about 30-60 colonies per plate are to be chosen for counting purposes.

  C-3 PRECAUTIONS AND LIMITATIONS
  The procedure permits enumeration of aerobic and mesophillic spores in food samples containing relatively higher number of spores by higher dilution of the sample prior to heat treatment.

  C-3.1 Certain thermophilic strains may also be indicated in this method in which case these shall be determined with an additional pre- heat treatment at 150-200 d C (to knock off all spores and account only for thermophiles) and their numbers be subtracted from the spore count.
  
  STANDARD MARK
  The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of the standard under a well-defined system of inspection, testing and quality control, which is devised and supervised by BIS and operated by the producer. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. Details of conditions under which a license for the use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.