Transcript Department of Bioengineering BE210-101B2

BE210-101B2
A COMPARATIVE STUDY OF
THE HEAT OF COMBUSTION OF
SUGAR AND FAT
Elizabeth Hines (Background & Hypothesis)
Edward Swanson (Methods & Protocol)
Karishma Mehta (Deliverables)
Lorraine Chua (Pitfalls)
Bo Zeng (Equipment & Budget)
BE210-101B2
Background
Bioenergetics- The study of the
transformation of energy in living organisms.
 Bomb Calorimeter used to find the Heat of
combustion(∆cH0) of a compound
Glucose- A simple sugar that is an important energy
source in living organisms and is a component of many
carbohydrates.
Palmitic Acid- a solid saturated fatty acid obtained from
palm oil and other vegetable and animal fats CH3 (CH2)14
COOH
This study would perpetuate the importance of a well
balanced diet coupled with an appropriate exercise routine.
QuickTime™ and a
TIFF (Uncomp resse d) de com press or
are nee ded to s ee this picture.
Quic kTime™ and a
TIFF (Unc ompres sed) dec ompres sor
are needed to see this pic ture.
Hypothesis, Aim and Objective:
We hypothesize that the heat of combustion of Palmitic
acid will be higher than that of glucose.
Department of Bioengineering
Elizabeth Hines
BE210-101B2
Methods & Protocol
2.
3.
4.
5.
6.
7.
1.Make a 1.000 gram pellet of Benzoic Acid in a bomb
crucible, with a 10 cm fuse wire just above the pellet.
Pressurize the bomb with 25 atm of pure oxygen
Place the bomb in a calorimeter filled with 2000 grams of diwater and begin the rotation of the stirrer.
After a five minute wait, start logging the thermistor data. After
five minutes of pre-period data, ignite the bomb with the ignition
unit. Keep recording data until more that 5 minutes after
temperature stabilization has been reached.
Repeat Steps 1-4 twice and analyze the temperature versus
time graphs to restandardize W.
Repeat Steps 1-4 three times with palmitic acid and analyze the
temperature versus time graphs to calculate ∆cH0.
Repeat Step 6 with Glucose.
Department of Bioengineering
Edward Swanson
BE210-101B2
Proposed Deliverables and Findings
Macronutrient
Heat of Combustion (kcal/g)
Starch
4.18
Sucrose
3.94
Glucose (Carbohydrate)
3.72
Palmitic Acid (Fatty acid)
9.44
Heat of Combustion of different macronutrients. Source: Dietary
Reference Intakes for Energy, Carbohydrate, Fibre, Fat, Fatty Acids,
Cholesterol, Protein, And Amino Acid; Institute of Medicine; National
Academies Press; Aug 1, 2005
• The DH calculated from
data in the lab should
correspond to the literature
values of DH for the sugar
and the fat.
• The DH of sugar will be
statistically lower than the
DH of fat (p-value < 0.05).
• The temperature rise of water for
the fat will be statistically higher than
for the carbohydrate after ignition of
the bomb calorimeter. Therefore, the
temperature-time graphs for the two
substances will differ, as shown on
the right.
Department of Bioengineering
Karishma Mehta
BE210-101B2
Potential Pitfalls
Methods Pitfall
•Difficulty in pressing the pellets of benzoic acid, palmatic
acid and glucose resulting in inconsistent pellet masses
•Placement of the fuse wire and handling of the bomb
resulting in misfiring
•Loss of water mass via evaporation
•Inaccuracy in acid correction due to incomplete removal
of nitirc acid and sulfuric acid from calorimeter
Statistical Pitfall
•Difficulty in the determination of points of the start of the
temperature rise and the points of the temperature
leveling after the rise from temperature-time graph
Department of Bioengineering
Lorraine Chua
BE210-101B2
Equipment/Materials, Budget
& Justification
Materials:
-Par Instrument Model 1341
Oxygen Calorimeter w/ Stirrer
and associated components
-Par Instrument Model 1108
Oxygen Combustion Inner
Container
-Precision Temperature
Sensor (LM135)
-Biopac System, Biopac Pro
Software
-Par Model 2901 Ignition Unit
-Parr Pellet Press
-Sample crucible, ignition
wire, stands and other
associated components
Additional Equipment:
-10 grams Palmitic Acid (Sigma-Aldrich) - $25.20
-30 grams Benzoic Acid (Sigma-Aldrich) - $12.40
-1 grams (D+) Glucose (Sigma – Aldrich) -$15.20
Justification:
The two additional compounds from Sigma-Aldrich
are used to compare the similarities and
differences between milk fat (Palmitic Acid) and
glucose . Benzoic Acid is used as a test standard.
Palmitic Acid is the most common source of
saturated fatty acids found in animals and plants.
Department of Bioengineering
Bo Zeng