# Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis, Division Note 2: MONITORING LIPASE ACTIVITY

Extent: E+W+S+N.I.

Prepare an olive oil emulsion as follows:
In a mixer stir for 10 minutes a mixture of 165 ml of a 100 g/l gum arabic solution, 15 g of crushed ice and 20 ml of a previously neutralised olive oil.
Pour 10 ml of the emulsion into a 50 ml beaker, then 0,3 ml of a 0,2 g/ml sodium cholate solution and then 20 ml of distilled water.
Put the beaker in a thermostat set at 37 °C; introduce the electrodes of the pH meter and the screw agitator.
Using a burette, add a 0,1 N sodium hydroxide solution drop by drop until a pH of 8,3 is obtained.
Add an aliquot of the lipase powder suspension in water (0,1 g/ml of lipase). As soon as the pH meter reads 8,3, start the chronometer and add the sodium hydroxide solution drop by drop at a rate which maintains the pH at 8,3. Note every minute the volume of solution consumed.
Record the data on an x/y graph with the time on the x-axis and millilitres of 0,1 N alkaline solution consumed to keep a constant pH on the y-axis. A linear graph should be obtained.
Lipase activity, expressed in lipase units per mg, is given by the following formula:
A = V × N × 100 m
where:
A is activity in lipase units/mg
V is the number of millilitres of 0,1 N sodium hydroxide solution per minute (calculated on the basis of the graph)
N is the titre of the sodium hydroxide solution
m is the mass in mg of the test lipase.
A lipase unit is defined as the quantity of enzyme which releases 10 micro-equivalents of acid per minute.

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Source: https://www.legislation.gov.uk/eur/1991/2568/annex/VII/division/8/division/2 (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-VII/division-8/division-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.