Practicals are designed to understand the
physico-chemical processes involved in
food processing
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Practicals on pear canning, potato blanching and freezing, apple dehydration,
and onion pickles.
Effect of blanching – softening of texture, deactivation of enzymes, and loss of
water soluble components.
Effect of pH and acidity on microorganism survival and thermal processing
Effect of freezing – structural effects of freezing on texture
Effect of heat – Maillard browning reactions between proteins and sugars.
Effect of drying on microbiological stability of food
Effect of chemicals (ascorbic, citric and SO2) to prevent browning reactions.
Methods for monitoring food quality
Measurements to assess the quality of food and impact of food
processing conditions:
Rapid methods: pH, Brix, water activity.
Enzyme activity: peroxidase test
Reducing sugars: Fehlings test
Titratable acidity
Texture analyser: hardness or softness
Colour meter: determine extent of browning (Enzymic
or Maillard)
3
Sensory analysis of foods
4
Sensory assessment of appearance, texture, flavour
Relate sensory observations with objective measurements
Brix – sweetness
pH – acidity
Texture analyser – firmness
Colour meter – colour of food, extent of browning reactions
Mass Balance
Mass balance refers to the material balance of the process.
Includes the weights of raw materials, waste off cuts,
intermediate products and end products.
This weight data is used to calculate the Yield of the product,
and the Losses from the process.
This data should be collated and presented in clear format.
Don’t copy directly from the practical notes..
Systematically record experimental
data and maintain records.
6
Hardbound, pages dated,
Note experimental details/ variables
Record all results in detail
Interpret Scientific Data, Integrate Theoretical Knowledge &
Discuss Findings in a Scientific Report
Review relevant literature – theoretical background to the
objectives of the experiment. Use this to provide depth to
your interpretation of the experiments
Interpret your results in context of published literature,
demonstrating your understanding of the experiment
Preparation for report writing
Learning guide
Obtain background literature for your practical.
References listed in practical notes are the minimum
requirements, additional texts can be obtained from
the library.
Obtain your practical results as recorded in your
notebook during class, including shared results for
sensory evaluation of the product.
Style guide for report writing
The learning guide states the requirements for this report; including sections on:
Introduction
Method
Results
Discussion
Conclusions
References
Appendix
If you have never written a scientific report, you can take some inspiration
from the following style guide. http://services.unimelb.edu.au/__
data/assets/pdf_file/0010/489106/Scientific_Research_Reports_Update_051112.pdf
Presentation of results
Create well formatted comprehensively labelled tables and figures that
display your results in an accessible form for the reader. Don’t clutter with
calculations and raw data (e.g. tare weights, etc.).
The reported results should comprise the calculated result but not the
calculation.. Eg. Mean sensory rating, Titratable acidity, or Yield %.
Plan which results that should be grouped together in a table, which should
be in separate tables.. Use logic to decide. Plan how best collate and arrange
the results so they clearly show the experimental findings in an efficient
uncluttered table or graph.
The recorded results in the practical notes (comprising raw data and
calculations) should be placed into the Appendix to show the basis of your
results.
SI /Metric Units and abbreviations –
scientific report writing
Use the SI symbols for the units:
Use the symbol oC for degrees Celsius, ensure it is preceded by a space when
one expresses the value of temperatures, eg 25 oC
The symbol % should be used, not the name “percent”, and leave a space
between the symbol % and numeral.
The word “to” be used to indicate a range of values for a quantity instead of
a range dash ( – )
http://physics.nist.gov/cuu/Units/checklist.html
Sensory Rating scales
*Used in FS2
*Used in FS1
Line rating scales
Rating scales are used to describe the intensity of sensory attributes of a sample.
Panellist’s can mark their rating anywhere along the line to represent their assessment
15cm line rating scale
0 cm = no detectable amount of the attribute
15 cm = a very large amount of the attribute
Use a ruler to measure the rating (cm) based on location of rating on the scale.
Calculate the average rating for multiple panelists.
Extremely Extremely
Soft Firm
Reporting sensory results –
example
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Sensory parameter
Control
Milk powder
Test
Whey powder
Colour intensity 2.5 3.5
Texture – chewy 10 7.2
Texture – sandiness 0.9 2.4
Sweetness 4.7 5.3
Table 1. Sensory Analysis of Ice Cream made with milk powder compared
to whey powder, assessed using 15cm line rating scale (Average of 10
Tasters)
Discussion of results
Use the Marking criteria to guide the topics that should be covered in the
discussion.
Link your sensory results, and objective (physical and chemical) results, with
the variables tested in the experiment.
Explain your observations, using suggested literature readings to provide a
scientific explanation for the findings of the experiments.
Submission of report
Upload to the TURNITIN portal in vUWS, include the entire report,
references and appendix.
Assessment Item 2 – Laboratory Report
Due 27 April 2020 by Midnight
The report will be marked in TURNITIN, if sections are missing they
cannot be marked.
The body of your report needs to be relatively clear of matched
text, i.e. Introduction, Method, Results and Discussion will be
considered for matched text.
Appendix includes material direct from the practical notes, it will
boost the matched text score; but don’t worry about the matched
text in the Appendix.
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