LAB REPORT 4: LIPID

BIOCHEMISTRY SBK3013

LAB REPORT 4: LIPID

MAUREEN SANTIH ANAK AMBANG	D20141067070
SHARIFAH AWANIS BINTI SYED MOHD ASWAD	D20141067053
HEIDI AMELDA ANAK LAGAT	D20141067086

DATE OF EXPERIMENT: 26 APRIL 2017

LECTURER: ASSOCIATE PROFESSOR ROSMILAH BINTI MISNAN

INSTRUCTOR: NUR ATIEKAH BINTI AZAHARI

TITLE :  LIPID (SAPONIFICATION OF TRIGLYCERIDES)

OBJECTIVES:

1.To study the saponification of triglycerides

2. To calculate the saponification number

INTRODUCTION

            Triglycerides is one type of lipid. Lipid is a diverse group of organic compounds including fats, oils, hormones, and certain components of membranes that are grouped together because they do not interact appreciably with water. In organisms, triglycerides is sequestered as fat in adipose cells, which serve as the energy-storage depot for organisms and also provide thermal insulation.

Triglycerides consist of a three carbon chain (glycerol backbone) with a fatty acid bonded to each of the three carbon atoms. The bond between the fatty acid and the glycerol backbone is referred to as an ester linkage. In the saponification process, the ester linkage is broken to form glycerol and soap.

Saponification is an organic chemical reaction that utilizes an alkali to cleave an ester into a carboxylic acid and alcohol. The saponification number is the number of milligrams of potassium hydroxide  required to neutralize the fatty acids  resulting from the complete hydrolysis of 1g of fat. The saponification number shows  the character of the fatty acids of the fat. The longer the carbon chain, the less acid is liberated per gram of fat hydrolysed. It is also show the average molecular weight (or chain length) of all the fatty acids present. 

MATERIALS :

1. Triglyceride sample: e.g. Coconut oil, corn oil, palm oil, margarine, butter

2. Solvent (1:1 ethanol/ether)

3. 0.5M KOH/ethanol solution

4. Phenolphtalein

5. 0.5M HCL

WARNING: KOH is a very strong corrosive agent and can cause serious burns on contact. Use appropriate eye / hand protection during this procedure.

PROCEDURE

The sample/control is boiled for 30 minutes

                                                    a) Sample after being boiled 

    b) Control after being boiled

Titration of sample/control using 3 drops of phenolphthalein and 0.5M of HCL

A) SAMPLE

 

B) CONTROL

RESULTS

The following information is used to calculate the saponification number

Saponification number = (B − T) × M of KOH x MW KOH

Sample weight (g)

Note:

o   Saponification number: The mass of KOH in milligram (mg) that is required to saponify 1 gram of fat.

o   B = volume (ml) of 0.5 mol/l HCl consumed in the blank test (Initial volume HCl-final volume HCl)

o   T = volume (ml) of 0.5 mol/l HCl consumed in the sample test (Initial volume HCl-final volume HCl)

o   Molecular weight of KOH (MW KOH)= 56.11 g/mol

o    Molar of KOH (M) = 0.5 mol/L

o    Sample weight (g) = 1 g

SAMPLE	B(ml)	T(ml)	SAPONIFICATION NUMBER
Sunflower Oil	22.2	21	33.67
Butter	25	21.5	98.19
Corn Oil	23	22	28.06
Margerine	23	20	84.17
Palm oil	23	22	28.06
Sunflower Oil	22.2	21	33.67
Butter	28	25	84.17
Butter	22.5	22	13.03

DISCUSSION

The saponification number is the number of milligrams of potassium hydroxide required to neutralize the fatty acids  resulting from the complete hydrolysis of 1g of fat . The principle that is used for this experiment is that the oil sample is saponified by refluxing with a known excess of potassium hydroxide solution. The alkali required for saponification is determined by titration of the excess potassium hydroxide with standard hydrochloric acid. By measuring saponification value, mean molecular mass can be obtained. Saponification value is inversely related to mean molecular mass. During saponification,each carboxyl group of fatty acid reacts with one mole of KOH. Therefore, the amount of KOH needed to saponify certain  fat depends in the number of fatty acid presents in the fats.

 Fats containing short-chain of fatty acid have more carboxyl groups per gram and consume more alkali to saponify it therefore have higher saponification number.  Fats that contain long chain of fatty acid have less carboxyl group per gram that consume less alkali to saponify it therefore have lower saponification number.

In this experiment, butter has the highest saponification number,followed by margarine and sunflower oil. Corn oil and palm oil has the lowest  saponification number. This showed that the margarine has shortest chain of fatty acid compare to the other sample and they require more alkali(KOH) to saponify them. The lowest  saponification number goes to corn oil and palm oil which showed to us that they have longest fatty acid compare to the other sample and they require less alkali(KOH) to saponify them.There is different value for saponification of butter. This happen due to the error during the experiment as it is carried out by different groups.

FATS	ACTUAL SAPONIFICATION NUMBER
Butter	220-233
Corn Oil	188-193
Palm Oil	196-205
Sunflower Oil	191

Actual saponification number of fats

            According to the actual saponification number, butter has the highest saponification number followed by palm oil, sunflower oil and corn oil. Compare to our results, butter has the most saponification number, followed by margarine and sunflower oil. Corn oil and palm oil has the lowest saponification number. The result that we obtained from this experiment is differ from the theory due to several error that occurred during the experiment. One of the sources of the error is during the titration process as the volume of HCL used in the titration might be excess after the indicator pink colour turn to colourless. The actual saponification number of margarine is not shown in the table because we can’t find it through the internet.

CONCLUSION

Different triglyceride sample has different saponification value. The longer the chain length of the fatty acid , the lower the saponification value. The shorter the chain length of the fatty acid , the higher the saponification value. In this experiment, butter has the most saponification number, followed by margarine and sunflower oil. Corn oil and palm oil has the lowest saponification number.

 REFERENCES

amrita.olabs.edu.in,. (2013). Saponification-The process of Making Soap. Retrieved 30 April 2017, from amrita.olabs.edu.in/?sub=73&brch=3&sim=119&cnt=1

Thomas E. Thompson (2005). Lipid | Biochemistry | Britannica.com. Retrieved 30 April 2017. from https://global.britannica.com/science/lipid

vlab.amrita.edu,. (2011). Estimation of Saponification Value of Fats/Oils.  Retrieved 1 May 2017, from vlab.amrita.edu/?sub=3&brch=63&sim=688&cnt=1

Helmenstine, P. A. (2015). Definition of Saponification. Retrieved May 01, 2017, from https://www.thoughtco.com/definition-of-saponification-605959

REFLECTIONS

Maureen-  From this experiment, I get to know that different triglyceride sample has different saponification number. I also learn that, the chain length of the fatty acid affected the saponification value. Besides, I also found that the blank sample required more HCL to neutralize it than the triglyceride sample. This is due to the amount of KOH left in both sample. For me, this experiment quite simple but required patience because we need to wait for 30 minutes to boiled the sample.

Awanis-  In this experiment, we used butter as a sample to make the soap. However, due to the error that we make during the experiment, the soap that we obtained from the experiment become “detergent-like” because of the overheating during the experiment.This experiment also required patience because we need to constantly stirring it to avoid spattering for several minutes. From this experiment, I learned new skills that is to make soap creatively.

Heidi- In this experiment we are able to determine the saponification number for every samples which are corn oil, margarine, butter, palm oil and sunflower oil. We conducted the experiment smoothly because each member gave a great teamwork.