ISO 6571:2008 pdf download – Spices, condiments and herbs -Determination of volatile oil content(hydrodistillation method).
5.2.2 Liquid detergent (used at the concentration recommended by the manufacturer) or a solution of sulfuflc acid and potassium dichromate (see the warning) prepared by slowly adding. wtiiie stirnng continuously, one volume of concentrated sulfuric acid to one volume of saturated potassium dictiromate solution and by passing the mixture, after coding, through a tntted glass filter.
WARNING — Avoid any contact of this solution with the skin and mucous membranes.
6 Apparatus
Usual laboratory equipment, and in particular the following.
6.1 Distillation apparatus, made of strong glass having a low coefficient of thermal expansionU.
The apparatus comprises the following components connected by ground glass joinls
6.1.1 Round-bottom flask, with a ground neck, of capacity 500 ml or 1 000 ml, according to the product concerned (see Annex A).
6.1.2 Condenser system, comprising Itie following components joined together (see Figure 1):
a) a vertical tube (AC). th base of wtiich has a ground joint to fit the flask (6.1.1);
b) a bent tube (CDE);
C) a vertical bulb condenser (FG);
d) an assembly consisting of a tube with a side-arm (K) provided with a ground stopper (K’), a pear-shaped enlargement (J), a tube graduated in divisions of 0,05 ml (JL), a spherical enlargement (L) and a three- way lap (M) connected to the vertical tube (AC) by an inclined tube (0) provided with a safely tube (N), if necessary topped by the steam trap (6.1.3).
8.3 Test portion
Weigh, to the nearest 0,01 g, on the filter paper (62), the specified quantity of test sample (see Annex A).
8.4 Determination
8.4.1 D.t.rmlnatlon of the volum. of xyl.n.
Using the measuring cylinder (6.6), transfer the specified quantity of water (see Annex A) to the flask (61.1) and add the anti-bumping granules or glass beads (65). Connect the flask to the condenser system (6.12) and fill the tube graduated in divisions of 0,05 ml (JL), the collector bulb (L) and the mclined tube (0) with water through the side-arm (K). Using the pipette (6,3), add 1 ml of the xylene (5.1) through the side-arm. Half fill the steam trap (6.1.3) with water and connect it to the condenser sy5tem. Heat the flask and regulate the rate of cstillation to 2 mI/mm or 3 mI/mm unless otherwise specified. Distil for about 30 mm and then remove the source of heat (6.4). By means of the three-way tap (M), allow the xylene to flow into the tube (JL) in such a way that the upper level coincides with the zero mark Allow to cool for at least 10 mm and measure the volume of xytene.
8.4.2 Determination of volume of organic phase (volatile oN and xylene)
Transfer the filter paper (6.2) with the test portion (8.3)10 the flask (6.1,1), and again connect the flask to the condenser system, Heat the flask and regulate the rate of distillation to 2 mI/mm or 3 mI/mm unless otherwise specified. Allow the distillation to continue for the specified time (see Annex A). (Record the distillation time for Inclusion In the test report.)
Remove the source of heat (6.4) and allow to cool. After 10 mm, read the volume of the organic phase (mixture of volatile oil and xylene) collected in the measurement tube.
8.4.3 DeterminatIon of moisture content
Determine the moisture content by the method specified in Iso 939,
9 Expression of results
The volatile oil content, , expressed in mililitres per 100 g of dry product, is given by the following equation.