Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
Coversheet
HSN 104 The Science of Food
Laboratory report 2- Fibre and Energy Analysis
Natalie Harris*/Caitlyn Hack
Laboratory Class: Wednesday 3pm-6pm, Lab #3 and #4
Word Count (excluding text in table and graphs): 908 words
Abstract
Fibre and energy content was measured using the enzymatic gravimetic method and bomb
calorimeter. The outcomes were compared to the product package nutrition label. The final
Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
product showed that fibre was 8.8g/100g and 18.6 kJ/g of energy, which were compared to the
claims on packaging. The results found coincided with that which was claimed, representing
accuracy on the labeling.
1. Introduction
Manufacturers are enforced by the Australian Food Guidelines to provide accurate food
nutritional panels for their consumers, the lab will focus on legitimizing these claims. This was
completed through the analysis of the enzymatic gravimetric method, the AOAC method, and
use of a bomb calorimeter. The enzymatic gravimetric method is responsible for analyzing fibre
content. It is completed by the sample being repeatedly heated and cooled, whilst adjusting the
pH and adding the given enzyme, being either alpha amylase, protease or amylogluctoidase.
The addition of the three enzymes represents the digestion of starch and protein. (Redono A,
Garcia B, 1992) Alpha amylase is commonly found in saliva, its main roll is to digest
carbohydrates. Protease, used for digestion of proteins to alpha amylase, and amylogluctoidase
digest carbohydrates into glucose. The three enzymes used break down the given macronutrient
and must be kept at 60C, this increases the rate of digestion. Ethanol is the final substance added
before settling overnight, at this point one is able to calculate the dietary fibre content.
To determine energy by a bomb calorimeter, a sample is added to the crucible, weighed, and
placed in the bomb calorimeter, which is ran by the demonstrator. Once it has fired the maximum
deflect was recorded and calculation were made to determine the energy and overall calorie
content. (Faculty of Health, 2012) The aim of the laboratory is to compare claimed and
calculated results using the enzymatic gravimeter method and bomb calorimeter method.
2. Results and discussion
(i) Total dietary fibre content of biscuits
Figure 1, Personal data** and class mean of dietary fibre (g/100g)
Dry,
fat-free
sample
weight
(g)
Blank
Biscuit
1.011
Celite +
crucible
weight
(g)
67.800
69.731
Residue
weight
(g)
Nutritio
n Panel
Fibre
Conten
t
(g/100g
)
Total
dietary
fibre, fatfree
(g/100g)
Total
dietary
fibre in
original
sample
(g/100g)
Class
Average
(g/100g)
-
-
-
-
3.24966
7
0.0952
2.857
9.5
8.8
The class mean (3.25 g/100g) and the calculated (8.8 g/100g) are much higher then the packaged
claimed (2.857 g/100g). This can be caused by experimental error, including incorrect
measurements, directions or calculation errors. When comparing the biscuits to the
recommended fibre content by the Australian and New Zealand Food Standards, it shows the
biscuits meet criteria for fibre content. The standards claim fibre must be greater then 1.5 g/100g
Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
and the biscuits claim to be 2.857 g/100g, with a even higher class average being 3.24967
g/100g. (Australian and New Zealand Food Standards, 2012)
(ii) Energy by bomb calorimetry
Figure 3, Personal data***
Food
Biscuit
Estimated
energy of fresh
sample
(kJ/100g) on
label
1860
Actual
Moisture
(%)
2.7%
Dry matter
coefficient
0.973
Estimated
energy on
dry basis
(kcal/g)
4.57
Estimated
sample size
(g) of dry
sample
containing
4 kcal
0.875
The bomb calorimetry is considered a old-fashioned and unreliable method. This is because it
poorly coincides with the human bodies digestion, it is ironically too efficient. (Nutrition Facts
and Basics, 2007). Generally, humans can harvest energy in 97% of carbohydrates, 95% of fats
and 92% of proteins. This data can be used to adjust the bomb calorimetry to be more accurate.
These differences are known as Atwater general factors. Recently, energy is calculated through
the analysis of chemical composition of foods. This is done by determining the concentrations of
macronutrients and the addition of energy value to determine the total value. Although, this is a
on-going area of research. (Mullan, 2006)
(iii) Determination of sugar, sodium and saturated fat content using indirect data
Macronutrient
Content in food (g/100g)
Sugar
21.4
Sodium
192 (mg)
Saturated fat
5.7
Proper labeling on nutrition labels, including sugar, sodium and saturated fat, is extremely
important from a health perspective. Not only can foods high in any of those can contribute to
obesity, it can also put a consumer’s life at risk by increasing the probability of developing
diabetes or high cholesterol. These foods are energy dense, and can have too much fat and not
enough good nutrients, such as fiber. (Putatunda) A general view at these biscuits shows that
they are not healthy. There is 21.4% sugar, which is higher for a biscuit that does not taste
sugary. The fat content although is not that high, normally 15-20% fat is considered a high fat
food and it claims to only be 5.7%. (Nutrition Labeling, 2012)
(iv) Calculation of total carbohydrate of food
Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
This can be determines using the equation:
=100- [water, protein, total lipids, alcohol, in g/100g]
(Food Standards Australia and New Zealand, 2012)
(v) Calculation of energy content of food
This is determined through the addition of energy from protein, fat, carbohydrates, dietary fibre,
alcohol and organic acids.
The equation is as followed:
Energy (kJ) = protein (g)*17 + sugars (g)*16 + other available carbohydrate (g)*17 + fat (g)*37
+ dietary fibre (g)*8 + alcohol (g)*29 + sorbitol (g)*16 + citric/malic/quinic acids (g)*10 +
lactic/acetic acids (g)*15)
(Food Standards Australia and New Zealand, 2012)
Using the calculation above is generally more accurate then using the bomb calorimetry. This is
because it is more accurate because bomb calorimetry does not harvest the amount of energy the
human body will.
(vi) Preparation of a nutrition information panel
Class Mean and Individual Results Nutritional Table
Marie Biscuits
Calculated
Energy
4.57 kcal/1g or 19.13
g/100g
Total dietary Fibre*
8.8 g/100g
Marie Biscuits Nutritional Panel
Marie Biscuits
Claimed
Energy
18.60 g/100g
Total dietary Fibre
2.8 g/100g
The class and claimed nutritional panels are a bit different but claims are relatively close. It can
be predicted that differences in the claims are due to error. As one can see, the total fibre
contents are very different, this is assumed to be due to misusing methods and incorrect
Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
calculations. The enzymatic gravimetric method is recommended to be completed for a second
time to obtain more accurate results.
3. Conclusion
In conclusion, the laboratory session gave a great insight to how to use methods to determine
fibre content and energy content. The calculated fibre content (8.8 g/100g) was much higher then
the class and nutrition label content. Again, this can be due to extensive experimental error. The
total energy content outcomes were fairly similar, the calculated being 19.13 g/100g and the
claimed being 18.60 g/100g, this shows that there was accuracy when it came to the bomb
calorimetry method.
4. References
1. Faculty of Health (2012), The Science of Food [Laboratory one and two HSN 104]. Burwood:
Deakin University.
2. Cohen, Juliet. "Nutrition Facts and Basics." Articlesbase.com. Articlesbase.com, n.d. Web. 17
Sept. 2012. <http://www.articlesbase.com/nutrition-articles/nutrition-facts-and-basics177403.html>.
3. Mullan, W.M.A. (2006) . Labelling-Determination of the energy content of food. [On-line].
Available from: http://www.dairyscience.info/packaging-/119-labelling-determination-of-theenergy-content-of-food.html . Accessed: 17 September, 2012. Updated March 2012
4.Putatunda, Rita. "Fast Food Nutrition Facts." Buzzle. N.p., n.d. Web. 17 Sept. 2012.
<http://www.buzzle.com/articles/fast-food-nutrition-facts.html>.
Natalie Harris
HSN 104 Fibre and Energy Methods
212375709
5 ) Williams, P., H. Yeatman, S. Zakrzewski, B. Aboozaid, and S. Henshaw. "Nutrition and
Related Claims Made on Packaged Australian Foods." (2003): 1-32. Research Online. University
of Wollongong, 2003. Web. 15 Sept. 2012.
<http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1019&context=hbspapers&seiredir=1&referer=http%3A%2F%2Fwww.google.com.au%2Furl%3Fsa%3Dt%26rct%3Dj%26q
%3Daustralian%2520food%2520regulations%2520for%2520fibre%26source%3Dweb%26cd%3
D6%26ved%3D0CEkQFjAF%26url%3Dhttp%253A%252F%252Fro.uow.edu.au%252Fcgi%25
2Fviewcontent.cgi%253Farticle%253D1019%2526context%253Dhbspapers%26ei%3DQhFXUJ
H9EfGQiQeM7oCIDg%26usg%3DAFQjCNHfeWrHusABFpdrAGYlyJU_M4p5A%26sig2%3DAX6hy9thyBg_P7_MF54dQw#search=%22australian%2
0food%20regulations%20fibre%22>.
6) "Nutrition Labelling." NSW Food Authority: Safer Food, Clearer Choices. NSW Nutrition
Labelling, n.d. Web. 17 Sept. 2012. <http://www.foodauthority.nsw.gov.au/consumers/foodlabels/label-facts/nutrition-labelling/>.
7) Redondo, A, Villanmva, M J, Garcia, B . (1992). Determination of Dietary Fibre by the
AOAC method in raw and processed vegetables:peas samples. Fresenius' Journal of
Analytical Chemistry. 4 (4), 1-8.
8) "Food Standards Australia New Zealand." Labelling of Food -. Food Standards Australian
New Zealand, 2012. Web. 14 Sept. 2012.
<http://www.foodstandards.gov.au/consumerinformation/labellingoffood/>.