IS 4428:1967(Reaffirmed 2006)-Grading for mustard seeds for oil milling published by Bureau of Indian Standards.

Transcription

1 TANZANIA BUREAU OF STANDARDS DRAFT TANZANIA STANDARDS MUSTARD SEEDS-SPECIFICATION DRAFT FOR COMMENTS ONLY AFDC 19 (4019) P3 0 FOREWORD Mustard seeds are small round seeds of various mustard plants with colour ranging yellow-white to black, they are important herbs in many regional foods. This Standard has been prepared in order to guide traders, producers/processors in achieving the safety and quality of mustard seeds which is fit for oil milling. In the preparation of this Standard assistance was drawn from: IS 4428:1967(Reaffirmed 2006)-Grading for mustard seeds for oil milling published by Bureau of Indian Standards. ISO 1237:1981 Mustard seed-specification published by International Organization for Standardization. In reporting the results of a test or analysis made in accordance with this Standard, if the final value observed or calculated is to be rounded off, it shall be done in accordance with TZS 4 (see clause 2). 1 SCOPE This Standard specifies requirements, methods of sampling and tests for white mustard (Sinapis alba or Brassica hirta), brown and yellow mustard (Brassica juncea) or black mustard (Brassica nigra) for oil milling. 2 REFERENCES The following referenced documents are indispensable for the application 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 TZS 742 Oleaginous seeds-sampling. TZS 1314 Oleaginous seeds-methods of test. TZS 109 Food processing units -Code of hygiene - General. TZS 4 Rounding off numerical values. TZS 538 Packaging and labeling of foods. 1

2 TZS 76 Methods for determination of arsenic TZS 268 General atomic absorption Spectro Photometric method for determination of lead in food stuffs. TZS Fruits, vegetables and derived products-determination of cadmium content-method using flame atomic absorption spectrometry TZS 1501 Fruits, vegetables and derived products-determination of mercury content-flameless atomic absorption method TZS 59 Water for analytical laboratory use Specification and test method 3 TERMS AND DEFINITIONS For the purpose of this Standard the following terms and definitions shall apply: 3.1 mustard seeds: seeds obtained from the white mustard (Sinapis alba or Brassica hirta), brown and yellow mustard (Brassica juncea) or black mustard (Brassica nigra). 3.2 extraneous matter: organic and inorganic matter and anything else other than mustard seed, and includes loose and empty shells (hulls, husks). 3.3 immature or shriveled seed: mustard seed that has indications of lack of maturity or full development. 3.4 damaged seeds: seeds that are damaged mechanically, or by mould or weevils, or those showing internal discoloration of seeds materially affecting the quality. 4 REQUIREMENTS 4.1 General requirements The mustard seeds shall be dry and reasonably uniform in size The mustard seeds shall be free from other edible/non-edible seeds The mustard seeds shall be free from foreign odours Mustard seeds shall be free from living and dead insects, mould, mites, insect fragments, excrement and rodent contamination visible to the naked eye. 2

3 4.2 Specific requirements Grading requirements Mustard seeds shall comply with grading requirements specified in Table 1. Table 1 - Grading requirements for mustard seeds Characteristics Requirements Methods of test Grade 1 Grade 2 Grade 3 Oil content on moisture free basis% (m/m), min Acid value of extracted oil,max Extraneous matter% ( m/m),,max Immature/shriveled and damaged seeds % ( m/m),,max TZS Moisture and matter% max content volatile ( m/m),, Allyl isothiocyanate % (m/m), min Black mustard Brown and yellow AFDC 19 (4019)P3 Annex A 5 CONTAMINANTS 5.1 Heavy metal. The acceptable level of contaminants are given in Table 2 Table 2: Requirements for Heavy metal Characteristics Requirements Methods of tests(see clause 2) Lead (Pb) mg/kg, max 2.0 TZS 268 Arsenic (As) mg/kg, max 0.5 TZS 76 Cadmium(Cd)mg/kg, max 0.5 TZS Mercury(Hg) mg/kg, max 0.1 TZS Pesticide residues Mustard seeds shall comply with those maximum residue limits established by the Codex Alimentarius Commission for this commodity. 3

4 6 HYGIENE Mustard seeds shall be handled and processed in accordance with TZS 109 (see clause 2). 7 SAMPLING AND TESTS 7.1 Sampling Sampling of mustard seeds shall be done in accordance with TZS 742 (see clause 2). 7.2 Tests Mustard seeds shall be tested in accordance with TZS 1314 (see clause 2). 8 STORAGE AND TRANSPORTATION 8.1 Storage Mustard seeds shall be stored in a well ventilated environment. The bags shall be stacked on pallets to avoid moisture ingress. They shall be stored in leak proof warehouses. 8.2 Transportation Mustard seeds shall be transported in well secured wagons/trucks/ containers to avoid spillage and quality deterioration. 9 PACKING, MARKING AND LABELING 9.1 Packing Mustard seeds shall be packed in new, dry and food grade material which must not be a source of contamination and must protect the safety and quality of the product. 9.2 Marking and labeling The product shall be marked and labeled in accordance with TZS 538 (see clause 2). In addition the following particulars shall be marked or labeled legibly and indelibly on each container: a) Name of the product, b) Trade name or brand name, if any; c) Physical and postal address of the producer/seller; d) Grade; e) Date of packing; 4

5 f) Net mass in kg; g) Country of origin; h) Year of harvest i) Storage condition j) Phone number, and website, if any The containers shall also be marked with TBS Standards Mark of Quality. NOTE - The TBS Standards Mark of Quality may be used by the manufacturers only under license from TBS. Particulars of conditions under which the licenses are granted, may be obtained from TBS. 5

6 ANNEX A Determination of allyl isothiocyanate A.1 Principle After two successive soakings of the sample, the first in water at a temperature of 70 O C and the second in alcoholic medium, distillation of the allyl isothiocyanate liberated into an alcoholic ammonium hydroxide solution, addition to the distillate of a standard volumetric silver nitrate solution and titration of the excess silver nitrate with standard volumetric potassium or ammonium thiocyanate solution in the presence of ammonium iron (lll) sulphate. A.2 Reagents All reagents shall be of recognized analytical quality. The water used shall be distilled water in compliance with TZS 59: 2010 (see clause 2). A.2.1 Ethanol, 95 %(V/V). A.2.2 Ammonium hydroxide solution, ᵨ20 = 0.925g/ml. A.2.3 Nitric acid, ᵨ20 =1.40 g/ml. A.2.4 Silver nitrate, standard volumetric solution, (AgNo3) = 0.1 mol/l. A.2.5 Potassium thiocyanate or ammonium thiocyanate, standard volumetric solution, (KCNS) or (NH4CNS) = 0.1 mol/l. A.2.6 Ammonium iron(iii) sulphate solution, saturated when cold - 0.1% Solution in water Where, ᵨ20 is density at 20 0 C A.3 Apparatus A.3.1Grinding mill. A.3.2 Entrainment distillation for a suitable example apparatus (see the figure 1) A.3.3 Burette, graduated at 0.05 ml intervals,. 6

7 A.3.4 Analytical balance. A.4 Procedure A.4.1 Preparation of the sample After very careful mixing of the sample, take 15 to 20g and grind it. A.4.2 Test portion Take about 2g of the ground sample and weigh it to the nearest 0.001g. A.4.3 Determination Transfer the test portion to the pear-shaped flask of the distillation apparatus, add 80ml of water previously heated to 70 ± 2 O C, close the flask with its ground glass stopper and leave to stand for 15min. Then add 20ml of the ethanol and allow to soak for 45 min. After the soaking, connect the flask quickly to the distillation apparatus. Distil, and collect the distillate in a conical flask containing a mixture of 5ml of the ammonium hydroxide solution and 10ml of the ethanol. (Entrainment distillation lasts, on average, for 5min.). The quantity of the distillate should be at least 100ml. Add to the distillate 10ml of the standard volumetric silver nitrate solution and leave for 12hours at ambient temperature (the operation will be faster if the conical flask is placed for 1h in a water bath heated to 70 to 80 O C). Filter through a fine filter paper, rinse the flask and residue several times with hot water (approximately 90 O C). To the bulked filtrate and washings add 10ml of the nitric acid and then titrate with the standard volumetric potassium, or ammonium, thiocyanate solution using the ammonium iron(lll) sulphate solution as indicator, until a persistent pink colour is obtained. A.4.4 Number of determinations Carry out two determinations on the same prepared sample. A.5 Expression of results A.5.1 Method of calculation and formula The allyl isothiocyanate content, expressed as a percentage by mass on the dry basis, is equal to: 4.95(10-V) X 100 X m 100-H Where m is the mass, in grams, of the test portion; 7

8 V is the volume, in millilitres, of the standard volumetric potassium, or ammonium, thiocyanate solution used in the titration; H is the moisture content of the sample, expressed as a percentage by mass, Take as the result the arithmetic mean of the two determinations provided that the requirement for repeatability is satisfied. A.5.2 Repeatability The difference between the results of the two determinations carried out simultaneously or in rapid succession by the same analyst, shall not exceed 1% of the mean value. Notes During the analysis, any contact with copper or rubber shall be avoided, especially in the distillation apparatus. Use cork or, preferably, ground glass stoppers. The enzymic activity of the mustard seed diminishes with age; thus, it may be necessary to modify the analytical method in the case of old seed. After a preliminary determination giving particularly low figures for allyl isothiocyanate, add to the distillation residue 5g of Sinapis alba (take care to check that sulphurcontaining volatile substances are not present in it) and then proceed to a second determination. The addition of the two results will give the real figure of allyl isothiocyanate that may be formed in the sample. However, the actual quality of the sample should be considered as very reduced and it is recommended that the two figures, found before and after the addition of Sinapis alba, should be given in the test report. The enzymic activity of the seeds increases during certain periods of the year (particularly in spring); thus, identical results are not always found with a given lot of seed, according to the season in which the analysis is carried out. 8

9 Figure 1: Entrainment distillation 9