ISO/TC 34/SC 2 - Oleaginous seeds and fruits and oilseed meals

This document specifies a method for the determination of the content of the total glucosinolates in rapeseeds (colza) using visible spectrometry to determine the glucose released from glucosinolates by hydrolysis.

This document specifies a method for the determination of the moisture and volatile matter content of oilseed meals obtained by the extraction of oil from oilseeds by pressure and/or solvent.

This document specifies a method for the determination of the moisture and volatile matter content of oilseeds.

This document specifies a rapid method for extraction of oil and for preparation of the methyl esters of fatty acids. The methyl esters thus obtained can be used for gas chromatography. This document is applicable to the following oilseeds: rape and mustard with low erucic acid content ( NOTE Applying this rapid method to high erucic acid content rapeseed leads to an overestimation of erucic acid content by approximately a mass fraction of 1 %. This difference was observed in Reference [6] and could be due to the partial extraction of the oil from the sample (yield around 70 %). High content of erucic acid in triglycerides could increase their solubility in hexane because of the lipophilic effect of the carbon long-chain (C22). However, as this effect was not checked on a large set of high erucic rapeseed samples, it is not appropriate to apply a correction factor to the erucic acid content when analysing high erucic acid rapeseed.

This document specifies a method for the determination of the individual glucosinolates content in rapeseeds and rapeseed meals using high-performance liquid chromatography with gradient elution. This method was tested on rapeseeds and rapeseed meals (Brassica rapa, Brassica napus and Brassica juncea) but is applicable to other plant materials, on the condition that the occurring glucosinolates previously identified are described in this document. On the contrary, the quantitative analysis of the concerned glucosinolate(s) is not carried out. NOTE This method does not determine glucosinolates that are substituted on the glucose molecule, but these compounds are of little importance in commercial rapeseed and rapeseed meal. Annex A presents the results of the interlaboratory trials for the gradient elution HPLC method. Annex B presents how to check the titre of the prepared internal standard solution. Annex C presents how to prepare and test the purified sulfatase solution and how to check the desulphation step on the ion exchange column. Annex D presents the HPLC and column performance criteria qualification. The analysis of glucosinolates content in rapeseed can also be done using an isocratic elution mode. This requires some modifications of the method (internal, standard, HPLC column and HPLC buffers), as described in Annex E.

This document specifies a method of determining the urease activity of products derived from soya beans. The method allows inadequate cooking of these products to be detected. It is applicable to products having a urease activity of less than 1 mg of nitrogen per gram of product as received, under the conditions specified. For more active products, the method is applicable provided that the mass of the test portion is reduced (see 9.1).

ISO 21294:2017 specifies the requirements for discontinuous sampling of oilseeds, using the manual or automatic method, for the purpose of assessing their quality and condition. NOTE An example of "condition" is an odour due to a treatment product.

ISO 734:2015 specifies a method for the determination of the hexane extract (or light-petroleum extract), called "oil content", of meals (excluding compounded products) obtained by the extraction of oil from oilseeds by pressure or solvents.

ISO 22630:2015 specifies an extraction method which may be used to assess the efficiency of a de-oiling process by comparing the oil content of the oilseed with the residual oil content of the corresponding extraction meals, pellets and expeller cakes. It is not applicable to disputed cases, for which ISO 734 is applicable. It is applicable to oilseed meals obtained from oilseeds by expelling or by extraction with a solvent, as well as to the pellets made from the residues.

ISO 10519:2015 specifies a spectrometric method for the determination of the chlorophyll content of rapeseed. It is not applicable to the determination of chlorophyll in oils.

ISO 14244:2014 specifies a method for the determination of soluble proteins in potassium hydroxide solution in soya meals, rapeseed meals and sunflower pellets, which are then assayed using the Kjeldahl method as specified in ISO 5983-1 and ISO 5983-2.

ISO 7700-2:2011 specifies a method of checking the performance of moisture meters in service for measuring the moisture content of oilseeds. It is not applicable to either cases of pattern approval or for initial calibration of moisture meters. The results of the verification described in ISO 7700-2:2011 are used to evaluate whether to check fully or to repair the moisture meter.

ISO 659:2009 specifies a reference method for the determination of the hexane extract (or light petroleum extract), called the “oil content”, of oilseeds used as industrial raw materials. The procedure for sunflower seed is different from those for other seeds as it includes an additional moisture content determination after the seed has been ground to prepare the test sample. The method has been tested on rapeseed, soya beans and sunflower seed. This does not, however, preclude its applicability to other commercial seeds. If required, the pure seeds and the impurities can be analysed separately. In the case of groundnuts, the pure seeds, the total fines, the non-oleaginous impurities and the oleaginous impurities can be analysed separately.

ISO 664:2008 specifies the procedure for obtaining a test sample from a laboratory sample of oilseeds.

This International Standard specifies a method for the determination of the impurities content in oilseeds used as primary industrial materials. It also defines the various categories of what are usually understood to be impurities.

This International Standard specifies a rapid method using nuclear magnetic resonance (NMR) for the determination of the oil and water contents of oilseed residues obtained after oil extraction by pressure or solvents (excluding mixed products). It is applicable to oilseed residues as flour, plates or agglomerates, provided that the particles are smaller than 2 mm and that the water content is not higher than the conversion threshold.

This International Standard specifies a rapid method for the determination of the oil and water contents of commercial oilseeds using pulsed nuclear magnetic resonance (NMR). It is applicable to rapeseeds, soya beans, linseeds and sunflower seeds with a water content less than 10 %. For seeds with higher water contents, drying is necessary before the oil content can be determined by pulsed NMR. NOTE 1 This method has been tested with rapeseeds, soya beans, linseeds and sunflower seeds. This does not, however, preclude its applicability to other commercial seeds whose oil is liquid at the temperature of measurement. NOTE 2 The reproducibility values are generally higher than those obtained by the drying method (ISO 665)

Specifies a method for the determination of the content of the different glucosinolates in crucifer oilseeds. Does not allow to determine glucosinolates which are substituted on the glucose molekule.

The principle of the method is grinding of the laboratory sample, with or without preliminary breaking, crushing, grinding or drying, division of the sample by suitable means, taking care that the test sample thus obtained, from which the test portion(s) will be taken, truly represents the totality of the laboratory sample.

Specifies a method for the determination of hexane content after extraction with hydrocarbon-based solvents. Describes the principle, the reagents and materials, the apparatus, the sampling, the test procedure, the expression of results, and the contents of the test report.

Specifies general conditions relating to the sampling for the assessment of quality of oilseeds purchased as industrial raw materials. Nine figures show exemples of suitable apparatus. There is specified the limitationof the size of lot, methods of taking samples, packaging and labelling of samples, the dispatch of samples and the sampling report.

The method consists in dissolving in a mixture of diethyl ether and ethanol of the oil extracted for the determination of the "oil contend" of the seeds (see ISO 659), and then titrating of the free fatty acids present using an ethanolic potassium hydroxide solution. It is not applicable to cotton seeds with adherent cotton linters, or to palm or olive fruits.

The method consists in treating of the total ash (see ISO 749) with hydrochloric acid, to remove the portion soluble in this reagent, then incinerating and weighing of the residue and replaces ISO Recommendation R 735-1968.

The method consists in incinerating of a test portion at 550 + 15 C in an electrically heated muffle furnace, until practically constant mass is reached. It isnot applicable to compounded products. It cancels and replaces ISO Recommandation R 749.1968.

ISO 734-2:2008 specifies an extraction method which may be used to assess the efficiency of a de-oiling process by comparing the oil content of the oilseed with the residual oil content of the corresponding extraction meals, pellets and expeller cakes. It is not applicable to disputed cases, for which ISO 734-1 is applicable. It is applicable to oilseed meals obtained from oilseeds by expelling or by extraction with a solvent, as well as to the pellets made from the residues.

ISO 17059:2007 specifies a rapid method for extraction of oil and for preparation of the methyl esters of fatty acids. The methyl esters thus obtained can be used for gas chromatography. ISO 17059:2007 is applicable to the following oilseeds: rape, sunflower, soya beans, mustard, linseed.

ISO 734-1:2006 specifies a method for the determination of the hexane extract (or light-petroleum extract), called "oil content", of meals (excluding compounded products) obtained by the extraction of oil from oilseeds by pressure or solvents.

The method specified is based on extraction by methanol, purification and enzymatic desulfatation, determination using reversed-phase chromatography. Does not determine glucosinolates which are substituted on the glucose molecule. A rapid method for the determination of glucosinolates content using X-ray fluorescence spectrometry is the subject of ISO 9167-2.

Under normal conditions of use, it does not apply to oilseeds which do not yield oil which is completely liquid at 20 °C (e.g. shea, palm, illipe, cocoa, etc.). The method has been successfully tested on the following oilseeds: rapeseed, soya, sunflower seed and groundnuts. The reference method for the determination of the oil content of oilseeds is specified in ISO 659.

The principle of the method consists in dividing of the contract sample (see ISO 542) by suitable means, if necessary after removal of impurities of large size, using one or other of the dividing instruments specified and taking care that the final analysis sample thruly represents the bulk of the contract for sample. A table gives the minimum mass of each analysis sample for 17 species of seed.

The method allows inadequate cookingof the products to be detected. It applies to products having a urease activity of less than 1 mg of nitrogen per gram of product as received. For more active products the mass of test may be reduced. The principle consists in mixing of a ground test portion with a buffered urea solution, after keeping the mixture for 30 min at 30 C, neutralization of the ammonia liberated, with an exess of hydrochloric acid solution, and back-titration with standard volumetric hydroxide solution.

The method consists in separating of the impurities, by sieving and sorting, into three categories as follows: -fines, -non-oleaginous impurities, - oleaginous impurities, followed by determing of the mass of total impurities or, on request, of the mass of each category of impurity.

For each specien to be tested using the meter, the methods consist in preparing of several test samples, or a range of test samples, with different moisture contents, under specified conditions, determining of their moisture contents by a reference method, and measuring with the meter to be checked. Information concerning the maximum permitted errors is given in an annex.