How to Determine Ash Content
RESULT: SampleReading | 4A | 4B | 4C | AVERAGE | Weight of crucible (g) | 53.8242 | 60.9377 | 56.7898 | 57.1869 | Weight of crucible+ sample (g) | 56.0800 | 63.0159 | 59.3516 | 59.4825 | Weight of sample (g) | 2.2558 | 2.0782 | 2.5527 | 2.2956 | Weight of crucible + sample after 1 day (g) | 53.8813 | 60.9910 | 56.8657 | 57.2460 | Weight of ash (g) | 2.1987 | 2.0249 | 2.4859 | 2.2365 | Percentage of ash (%) | 2.5313 | 2.5647 | 2.6168 | 2.5709 |
CALCULATION:
% of ash = weight of sample (g) – weight of ash (g) X 100 weight of sample (g)
For sample A:
% of ash = 2.2558 g-2.1987 g X 100 = 2.5313% 2.2558 g
For sample B:
% of ash = 2.0782 g-2.0249 g X 100 = 2.5647% 2.0782 g
For sample C:
% of ash = 2.5527 g-2.4859 g X 100 = 2.5709% 2.5527 g For average:
% of ash = 2.2956 g-2.2365 g X 100 = 2.5745% 2.2956 g
Variance of Ash:
s2 = ∑ x2 – (∑x)2 n n-1
= 15.1142 g – (45.0174 g/3) = 0.0542 2
Standard Deviation of Ash: s= √s2
=√0.0542
=0.2328
DISCUSSION:
Ash is the inorganic residue remaining after the water and organic matter have been removed by heating in the presence of oxidizing agents, which provides a measure of the total amount of minerals within a food. Analytical techniques for providing information about the total mineral content are based on the fact that the minerals (the “analyte”) can be distinguished from all the other components (the “matrix”) within a food in some measurable way. The most widely used methods are based on the fact that minerals are not destroyed by heating, and that they have a low volatility compared to other food components. The three main types of analytical procedure used to determine the ash content of foods are based on this principle: dry ashing, wet ashing and
CALCULATION:
% of ash = weight of sample (g) – weight of ash (g) X 100 weight of sample (g)
For sample A:
% of ash = 2.2558 g-2.1987 g X 100 = 2.5313% 2.2558 g
For sample B:
% of ash = 2.0782 g-2.0249 g X 100 = 2.5647% 2.0782 g
For sample C:
% of ash = 2.5527 g-2.4859 g X 100 = 2.5709% 2.5527 g For average:
% of ash = 2.2956 g-2.2365 g X 100 = 2.5745% 2.2956 g
Variance of Ash:
s2 = ∑ x2 – (∑x)2 n n-1
= 15.1142 g – (45.0174 g/3) = 0.0542 2
Standard Deviation of Ash: s= √s2
=√0.0542
=0.2328
DISCUSSION:
Ash is the inorganic residue remaining after the water and organic matter have been removed by heating in the presence of oxidizing agents, which provides a measure of the total amount of minerals within a food. Analytical techniques for providing information about the total mineral content are based on the fact that the minerals (the “analyte”) can be distinguished from all the other components (the “matrix”) within a food in some measurable way. The most widely used methods are based on the fact that minerals are not destroyed by heating, and that they have a low volatility compared to other food components. The three main types of analytical procedure used to determine the ash content of foods are based on this principle: dry ashing, wet ashing and
References: 1)S.Suzanne Nielsen.Food Analysis Third Edition.Chapter 7,in Ash Analysis.Purdue University.pages 105-111. 2)R.Lees 1968.Laboratory Handbook of Methods of Food Analysis.Leonard Hill Book.page 14. 3)http://www.sciencedirected/ash/analysis/mineral%20%food (14 January 2010)