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1.0

INTRODUCTION AND OBJECTIVES

1.1

Objectives

This objective of this experiment was:   1.2

To determine the crude fat content in food product using Soxhlet method To familiarize with the Soxhlet method Introduction Fats are the substance that are soluble in organic solvent such as ether, hexane and

chloroform but insoluble in water. Fat consists of triacylglycerol, monoacylglycerol and several fatty acids. Fat may be exist in the form of liquid or solid in the room temperature, depending on their structure and composition. Fat is one of the example of lipids that play a crucial role in determining the overall physical characteristics of food. The importance of lipids can be varied but the most important functions of lipids are culinary, physiological and nutritional. There are several ways used in order to determine the fat content in sample and one of it is solvent extraction method. In this experiment, Soxhlet extraction method was used to determine the fat content in the sample. Soxhlet extraction method is a continuous solvent that is usually used to remove fats from the sample. Other than that, the determination of crude fats in the food sample can also be determined by using the Soxhlet extraction. The experiment was done by weighing 2g the sample, Brand B Cream Cracker (SiangSiang), into an extraction thimble and then being transferred in Soxhlet extraction. A 125 ml of petroleum ether was added in the solvent beaker. After 2 hours and 30 minutes, the fat content was determined by weigh the fat extracted. At the end of the experiment, the mean total fat (%) was 24.27%. Besides, the fat weight determined in this experiment was 0.4866g per 2g of cream crackers which is slightly higher than the fat the content stated at the nutritional fact on the packaging which is 0.3857g per 2g of cream crackers.

2.0

MATERIALS AND PROCEDURES

2.1

Equipment and Supplies

Soxhlet extraction unit and its apparatus, analytical balance, cotton wool, filter paper, samples; Brand B’s cream crackers (Siang Siang), chemical solution; petroleum ether. 2.2

Test Procedures First step was, two empty solvent beakers were weighed to record the initial weight of

container. Approximately 2 grams of samples on filter papers were then weighed and this was done twice, as duplicate; Replicate 1 and Replicate 2 with respective to Solvent Beaker 1 and Solvent Beaker 2. The filter papers containing the samples were put into the thimble and covered with cotton wool, before being transferred in the Soxhlet extraction. An amount of 125 ml of petroleum ether was added in the solvent beakers. After that, the process was started up. After 2 hours and 30 minutes of process completion, the solvent beakers containing the extracted fat were dried in a preheated oven of 100°C for another 30 minutes. Then, the beakers were allowed to cool in the dessicator’s for another 10 minutes before the final weight was taken.

3.0

RESULT AND DISCUSSION

3.1

Result

TABLE 1: Test Data Test Data Sample Data Empty Solvent beaker, A (g) Sample weight, B (g) Solvent beaker + Fat after drying, C (g) Fat weight, D = [ C – A] (g) Average fat weight (g)

Replicate 1 86.0723 2.0023 86.5377 0.4654 0.4866

Replicate 2 87.5213 2.0065 88.0029 0.5077

Replicate 1

Replicate 2

TABLE 2: Test Result Test Result Test Data Total Fat (%) =

23.24%

Mean of Total Fat (%)

25.30% 24.27%

Table 3: Comparison Weight of Fat Brand A B

Mean weight of fat (g) 0.4576 0.4866

3.2

Discussion Fat is an important ingredient in cream cracker as it’s add structure, eating quality and

flavor to the product. Fat may also be presented in a generic form such as shortening which is a term used to describe one of the key functions of fat in cream cracker which is to shorten the dough that is, to give it the ‘melt in mouth’ feels to the consumer, and crumbly texture which a characteristic of cream cracker. The Soxhlet extraction method, semi continuous extraction method, used for determine crude fat content in cream cracker. The Soxhlet allows one to extract fats from a solid sample into a liquid, leaving behind any impurities. It also used small volume of solvent over and over again. [Classic Kit: Soxhlet Extractor. (2007) Royal Society of Chemistry. [Online].

[Accessed

on

10

October,

2015].

Available

from

World

Wide

Web:

http://www.rsc.org/chemistryworld/Issues/2007/September/ClassicKitSoxhletExtractor.asp] During this process, the solvent builds up in the extraction chamber for 5-10 minutes and completely surrounds the 2g cream cracker sample of Brand B, and then siphons back to the boiling flask. Fat content is measured by weigh loss of the sample or by weigh of the fat removed. Based on Table 1: Test Data, the total fat content in the cream cracker sample for Replicate 1 and Replicate 2 is 0.4654g and 0.5077g respectively with a mean of 0.4866g. The fat content was measured by weigh loss of the sample after extracting using a Soxhlet extractor. Next, the percentage of the fat content in the cream cracker sample used also was calculated using a formula given;

Total Fat =

fat weight ×100 sample weight

The fat content percentage for each sample were recorded in Table 2; Test Result. Based on Table 2, for Replicate 1, the fat content percentage of the sample is 23.24%, for and Replicate 2, 25.30%. The mean of fat content percentage of the three replicates is 24.27%.

Furthermore, the result obtained is compared with another brand which is Brand A. Brand A has extracted 0.4576g of fat from 2g of cream cracker sample. The weight of fat from Brand A is slightly lower than Brand B which is 0.4866g. This slight difference is may be due to the raw material used by the manufacturer to produce the cream cracker. Manufacturer of Brand B might has used more butter to make the product to meet consumer demands.

4.0

CONCLUSION By the end of the experiment of fat determination by Soxhlet method, the average of the

fat content per serving packet in Hwa Tai biscuit is lower compared to fat ingredient stated at the nutritional facts. The percentage of the fat per serving in the experiment is not accurate and not significant as with the nutrition facts given. One of the error was the extraction method that was Soxhlet method which used petroleum ether. In the experiment, petroleum ether was used as nonpolar and as the greater molarity, the more the yield of specific extraction. Due to that, in the experiment, the petroleum ether could not be able to break some of the polar shells that surrounded some of the lipid and could reach the complete extraction of lipid inside the sample of biscuit in the food packaging. Soxhlet method only gives the free fatty acid amount of the sample. Due to the error during the experiment that was the sample was not been extracted properly by using Soxhlet method as the method only give the free fatty acid amount of the sample. For the recommendation, the total fat extraction method result can be used for the result in both free and bound fat for the higher value in total fat extraction.

5.0

REFERENCES

Internet: 

[Classic Kit: Soxhlet Extractor. (2007) Royal Society of Chemistry. [Online]. [Accessed on 10 October, 2015]. Available from World Wide Web: http://www.rsc.org/chemistryworld/Issues/2007/September/ClassicKitSoxhletExtractor.as p

Journal: 

MEAT TECHNOLOGY- INFORMATION SHEET. (1998), Reprinted November (2006), Crude Fat Determination-Soxhlet Method. Meat and Live Stock Australia.

Book: 

Stanley C., Linda Y. (2009) The ICC Handbook of Cereals, Flour, Dough & Product Testing: Methods and Application. Lancaster, PA. DEStech Publications Inc.p158