HIRANUMA APPLICATION DATA

Data No.

Automatic Titrator

A9Apr. 19,
2018

Saponification value of cooking oil

FOOD

1. Abstract
When potassium hydroxide ethanolic solution is added to fats and oils and heated, glyceride produces fatty acidpotassium salt and glycerin by saponification (Formula (1)), and free fatty acid produces fatty acid potassium salt and water(Formula (2)).
RCOOR′ ＋ KOH
RCOOH＋ KOH→→

RCOOK ＋ R′OH・・・(1)RCOOK ＋ H2O・・・(2)Saponification value is defined as “amount (mg) of potassium hydroxide required to react with heating in 1 g of fats
and oils sample”. This method is described in a variety of official standards such as “Japan Agricultural Standards” andPharmacopoeias. Example of titration for saponification value in cooking oil is introduced here.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition

2. Configuration of instruments and Reagents(1) Instruments
Main unit： Hiranuma Automatic Titrator

COM series

Electrode： Glass reference combination electrodeGR-522BZ, Connect to IE-1.

Components： Buret tip (Tube Type), tubing accessories(2) Reagents
Titrant： 0.5 mol/L Hydrochloric acid standard solution

Additive solution： 0.5 mol/L Potassium hydroxide ethanolic standard solution

3. Measurement procedure(1) Take 1.5 – 2.0 g* of sample into 200 ml Erlenmeyer flask and weigh it exactly.
(2) Add 25 ml of 0.5 mol/L potassium hydroxide ethanolic standard solution with volumetric pipet.
(3) Fit reflux condenser on the Erlenmeyer flask and heat to 80 C for 30 minutes in water bath.
(4) Wash inside of reflux condenser with small amount of DI water and detach the condenser.
(5) Add 100 mL of DI water.
(6) Immerse the electrode and start titration with 0.5 mol/L hydrochloric acid standard solution.
(7) Blank measurement is also performed with procedure (2) – (6).
※ Sample size depend on expected value, and it’s described in a standard method.

4. Measurement conditions and results
Examples of titration conditions
Measurement of blankCondition No. 1
MethodAutoConstant No.

1Mode No.

4Buret No.

1Size0 g

Pre Int

0 sec

Amp No.

1Blank0 mL

Del K9D.UnitpHMolality

0 mol/LDel Sens

0 mV

S-Timer

5 sec

Factor0Int time

3 sec

CP mL

24 mL

K0Int Sens

3 mV

T Timer

0 sec

L0Buret Speed

20 mL

UnitmL

FormulaD
3D.P. mLEnd Sens

1000

Over mL

0.2 mL

DigitsMax. Vol.

30 mL

Auto input Parameter

Pulse

40
0.050 mL

None

Measurement of sample
Condition No. 2Method
Buret No.

Auto

Constant No.

2Mode No.

41Size1.613 gPre Int

0 sec

Amp No.

1Blank

26.44 mL

Del K

9D.Unit

pHMolality

Del Sens

0 mV

S-Timer

5 sec

Factor1.004

Int time

3 sec

CP mL

0 mL

K

56.1

Int Sens3 mV

T Timer

0 sec

L

D.P. mL

0.1 mL

UnitEnd Sens

500

FormulaOver mL

0.2 mL

DigitsMax. Vol.

30 mL

Auto input Parameter

0.5 mol/L

0mg/g(B-D)*K*F*M/S
4None

Buret Speed

2Pulse400.050 mL

Measurement results
SampleBLANK

SAMPLE

Measurement

Size

Titrant

Saponification

No.

(g)

volume (mL)value (mg/g)

1-26.407

-

Avg.

26.44

mL2-

26.457

-SD

0.029

mL3-

26.457

-

RSD

0.109

%

1

1.613

15.732186.956

Avg.

186.9

mg/g

2

1.650

15.449187.594

SD0.738

mg/g

3

1.514

16.434186.123

RSD

0.395

%

Measurement of blankStatisticalresult

Measurement of sample

Examples of measurement curves

5. Note(1) Tips of measurement.
Note the sample loss during reflux condensation for pretreatment. In order to prevent loss due to volatile matter, thecondenser needs to be cooled adequately. After pretreatment, add DI water immediately and start titration.
Keywords：Cooking oil, Saponification value, Pharmacopoeia* Some measurement would not be possible depending on optional configuration of system.