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FCH621S - FOOD CHEMISTRY - 1ST OPP - NOVEMBER 2024 |
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f
nAm I BIA un IVERSITY
OF S(IEnCE Ano TECHnOLOGY
FacultyofHealthN, atural
ResourceasndApplied
Sciences
Schoool f HealthSciences
Departmenot fPreventative
HealthSciences
13JacksonKaujeuaStreet
Private Bag13388
Wlnohoel:
NAMIBIA
T: +264612072970
F: +264612079970
E: dphs@nust.na
W: www.nust.na
QUALIFICATION : BACHELOR OF HUMAN NUTRITION
QUALIFICATION CODE: 08BOHN
COURSE:FOOD CHEMISTRY
DATE: NOVEMBER 2024
DURATION: 3 HOURS
LEVEL: 6
COURSECODE: FCH621S
SESSION: 1
MARKS: 100
FIRST OPPORTUNITY EXAMINATION: QUESTION PAPER
EXAMINER:
MODERATOR:
MR. ERICK NATANGWE UUKULE
MS. FIINA K. NAMUKWAMBI
INSTRUCTIONS:
1. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIALS:
1. None
ATTACHMENTS
1. None
This question paper consists of 5 pages including this front page
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SECTION A: MULTIPLE CHOICE AND TRUE/ FALSE
[ 20 MARKS)
QUESTION 1: MULTIPLE CHOICE QUESTIONS
(10 MARKS)
Evaluate the statements in each numbered section and select the most appropriate answer or
phrase from the given possibilities. Fill in the appropriate letter next to the number of the
correct statement/phrase on your ANSWERSHEET.
[10]
1.1 Which of the following proteins is not a structural protein:
A.
Keratin.
B.
Collagen.
C.
Actin.
D.
Elastin.
1.2 Water activity is known to influence the rate of chemical reactions such as:
A.
Lipid oxidation.
B.
Non-enzymatic browning.
C.
Enzyme activity.
D.
All of the above.
1.3 Which of the following is not a type of non-polar lipids:
A.
Phospholipids.
B.
Waxes.
C.
Triacylglycerols.
D.
Cholesterols.
1.4 The disaccharide "maltose" is made up of the following sugar monomers:
A.
Glucose and Galactose.
B.
Glucose and Glucose.
C.
Glucose and Fructose.
D.
Glucose and Lactose.
1.5 Which of the following thermal processing technologies is not an example of moist heating:
A.
Frying.
B.
Steaming.
C.
Pasteurisation.
D.
Autoclaving.
1.6 From the list below, identify the pigment that serves as a precursor for Vitamin A:
A.
Carote noids.
B.
Chlorophylls.
C.
Anthocya nins.
D.
Beta lains.
Food Chemistry (FCH621S)
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1.7 Natural antioxidants include vitamins such as:
A.
Vitamins C and E
B.
Vitamins A and C
C.
Vitamins A and K
D.
Vitamins C and D
1.8 Hypervitaminosis is likely to be caused by:
A.
Vitamin A.
B.
Vitamin 83.
C.
Vitamin Bg.
D.
Vitamin C.
1.9 Globular proteins are known to be:
A.
Insoluble in water.
B.
Long and narrow.
C.
More sensitive to changes in temperature and pH.
D.
Structural proteins.
1.10 Which of the following fatty acids is likely to have the lowest melting point in °C:
A.
C4:0
B.
C 10:0
C.
C 16:1
D.
C 18:1
QUESTION 2: TRUE/FALSE QUESTIONS
[10 MARKS]
Evaluate the statements and select whether the statement is true or false. Write the word
'True' or 'False' next to the corresponding number on your ANSWERSHEET.
[10]
2.1 The degradation of pectin is known to positively modify the texture of fruits.
2.2 Iron, iodine and Vitamin A deficiencies are the most common around the world.
2.3 Hygroscopic foods are able to easily lose moisture to their immediate environment,
especially under humid conditions.
2.4 Physically entrapped water may result in a food product that has a high water activity.
2.5 Peptide, Ester and Glyosidic bonds are all formed through condensation reactions.
2.6 Enzymes speed up reactions by increasing a reaction's activation energy.
2.7 Minerals remain as ash after the combustion of plant and animal tissues.
2.8 A high moisture content is always indicative of high water activity.
2.9 Most bacterial species start thriving from a water activity of 0.91.
2.10 Stereoisomers have the same molecular formula but different structures.
Food Chemistry (FCH621S)
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Please answer ALL of the questions in this section.
QUESTION 3
[80 MARKS)
{30 MARKS)
3.1 Define the following terms:
a) Water activity.
(3)
b) Inte reste rificatio n.
(3)
c) Essential mineral.
(2)
d) Food additives
(3)
e) Gelatinisation
(3)
3.2 As nutritionists, which aspects of food chemistry are we required to understand for
effective dietary interventions.
(3)
3.3 State any four (4) major forces that stabilise protein structures.
(4)
3.4 Discuss the different mechanisms that contribute to the allergenic properties of proteins. (6)
3.5 Explain the impact of rapid denaturation on protein structure and function.
(3)
QUESTION 4
(25 MARKS)
4.1 Draw the aliphatic structures of the following fatty acids:
a) C18:2Li9•12
(3)
b) C16:0
(2)
c) C18:3 W-3
(3)
4.2 Hydrogenation makes lipids more solid at room temperature and improves their oxidative
stability. However, there are potential drawbacks. What health concerns should we keep
in mind when practicing hydrogenation and how can these concerns be mitigated?
(4)
4.3 After a good harvest, Mr Erick is left with a lot of spinach that he could not sell at the market.
As such, he gets the idea to can the leftover spinach. However, after his first three canning
attempts, Mr Erick realises that his canned spinach was no longer green but had a pale yellow
colour. Answer the following questions:
a) Why is colour an important quality attribute of foods?
(3)
b) What is the name of the pigment responsible for the colour of spinach?
(1)
c) Describe the role of thermal processing in the loss of the spinach's green colour.
(3)
Food Chemistry (FCH621S)
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d) Suggest three (3) ways by which Mr. Erick can retain the green colour of his canned
spinach.
(3)
4.4 Outline the conditions that must be met before a Maillard reaction can take place.
(3)
QUESTION 5
(25 MARKS)
5.1 The Ministry of Health intends to initiate a food fortification campaign, however they are
unsure on the type of food to include in this campaign. How would you advice the Ministry
of Health in this regard?
(3)
5.2 The presence of inhibitors may affect the rate at which enzymes work. Differentiate
between "competitive inhibitors" and "non-competitive inhibitors".
(4)
5.3 Highlight the four (4) main approaches to the study of food chemistry.
(4)
5.4 Name and describe the three categories used to classify starch based on its digestibility. (6)
5.5 Discuss the impact of sugar on starch gelatinisation.
(4)
5.6 Outline any four (4) strategies used to minimise the formation of acrylamide in food.
(4)
END OF QUESTION PAPER
Food Chemistry (FCH621S)
1st opportunity November 2024
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