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FCA621S-FOOD COMPOSITION AN ANALYSIS- JAN 2020 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
Faculty of Health and Applied Sciences
Department of Health Sciences
QUALIFICATION: BACHELOR OF HUMAN NUTRITION
QUALIFICATION CODE: O8BOHN
LEVEL: 6
COURSE CODE: FCA 621S
COURSE NAME: FOOD COMPOSITION AND ANALYSIS
SESSION: JANUARY 2020
PAPER: THEORY
DURATION: 3 HOURS
MARKS: 100
SUPPLEMENTARY/SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) | Mr. Waliomuzibu Mukisa George William
MoperatTor: | Ms. Fiina Namukwambi
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLE MATERIALS
CALCULATOR
THIS QUESTION PAPER CONSISTS OF 4 PAGES (Including this front page)
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SECTION A
QUESTION 1
(42 MARKS)
1.1 Explain the major changes that may occur in food sample before analysis and
may result in wrong results.
(8)
1.2 Explain the following terms used in establishment of research project.
1.2.1 Sampling Plan.
(2)
1.2.2 Compartmentalised population.
(2)
1.2.3. Continuous population.
(2)
1.3 Outline three (3) major types of chromatographic methods used in analysis of
carbohydrates.
(3)
1.4 In the experiment to determine the concentration of reducing sugars in a food sample
using the Thin Layer Chromatography, the solvent moved a distance 1 cm on the
stationary phase and the two categories of reducing sugars (A and B) in the sample,
each moved 0.3 cm and 0.6 cm respectively.
1.4.1 Calculate the retention factor (Rr) of the sample.
(4)
1.4.2 Using the Rr value explain the difference between A and B.
(5)
1.5 A found sample was weighed in crucible and the weight recorded as 30 kg. It was
dried in the oven over 24 hrs period and weight of the dried sample was 25 g. If the
weight of the crucible before oven drying was 1.8 g.
1.5.1 Determine the moisture content (%) of the sample.
(3)
1.5.2 Determine the total solids (%) of the sample.
(3)
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1.6 Briefly explain the difference between following terms in food analysis.
1.6.4.
Reproducibility and Specificity.
(2)
1.6.2
Free water and chemically bound water.
(2)
1.6.3
Homogenous and heterogeneous population.
(2)
1.6.4
Direct and indirect methods of moisture determination.
(2)
1.6.5
Random errors and systematic errors.
(2)
SECTION B
QUESTION 2
2.1 Explain the principle behind the forced oven drying.
(44 MARKS)
(2)
2.2 Describe the process for determination of total solids in food using a forced
draft oven.
(6)
20S Explain the importance of sample dimension and water type in drying a food
sample by forced draft oven.
(4)
2.4 Describe the Karl-Fisher method for the determination of moisture content
in food samples.
2.5 Explain five reasons (5) why it is important for nutritionists and food
Manufacturers to know the moisture content of food product.
(10)
2.6 Explain the principle for determination of mineral content of food sample
by atomic absorption spectroscopy.
(4)
2.7
Outline two (2) types of spectroscopic methods used in food analysis.
2.8 Explain the Beer-Lambert law.
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2.9
Describe the Munson and Walker method for determination of carbohydrate
content of a food sample.
(6)
QUESTION 3
(14 MARKS)
| Outline four (4) disadvantages of the Munson and Walker method.
(4)
3.2 Explain the spattering in relation to drying of food by gravimetric methods.
(2)
3.3 Describe the dry ashing method used in determination of ash content of food. (5)
3.4 Explain three (3) reasons for determination of ash and mineral content of foods. (3)
GOOD LUCK