HNF 300 - LABORATORY REPORTS
FORMAT
I.MECHANICS
Laboratory reports should be typed, written in the third person, past tense, with correct grammar and spelling. Refer to scientific journals for examples of scientific writing. See pg. 19 (18) of Text, textbook Table 2-1 for example of journals.
II.TITLE
A.Provide a title page. USE ALL CAPITAL LETTERS.
B.A title should also be at the top of the experiment. The titles used in the lab manual are not specific. Therefore, the student should write a very specific title for each experiment.
III.PURPOSE
In the introduction, state WHY the experiment was performed. What was it designed to determine? This information can be short in length, but must be concise.
IV.METHODOLOGY
A.The methodology section includes HOW the experiment was performed. Use the past tense.
B.Include the source and page numbers for the basic recipe or procedures. List all the variables and the number of times tested.
C.Include any changes or additions in the procedure, sources of ingredients, etc.
V.RESULTS
A.Summarize the results of the experiment. Tell what happened in writing.
B.Include all completed charts or tables that apply to the experiment. Make sure that tables have detailed descriptive titles and are complete. Don’t try to put all data into one table if two or three, etc. tables would be more appropriate. Put related data in the same table.
VI.DISCUSSION
A.Provide a brief introduction to the topic. What are the characteristics of an ideal control?
B.Discuss what happened in the experiment, answering the questions:
1.What happened?
2.What didn’t happen?
3.What should have happened?
4.Why didn’t it happen?
C.Back the discussion with information (principles, facts, etc.) available in textbooks citing the author and date of publication. (McWilliams)
D.Compare the results with previously done experiments. Discuss variability in the experiment; i.e. different students subjectively determining the end point, different sized bowls used to whip foam, etc.
E.Were the results of the experiment consistent with known information or not? Make sure that you compare the control results to that from the literature i.e. ideally what should have happened.
F.Bring examples of the data from you report into the discussion. Example: "The percent increase of the foam was only 275% vs 400% increase for the control.
VII.SUMMARY & CONCLUSIONS
A.Summarize the results of the experiment.
B.Give the value or lack of value for each variable.
VIII.REFERENCES - Use lecture, text and one outside source (check food books in the Human Ecology library)
A.Provide references for books and material used for your report.
B.Be consistent in style. Use the format used in text (McWillliams).
POINTERS ON WRITING LABORATORY REPORTS
1.Read the textbook, paying particular attention to information relating to the experiment.
2.Read the laboratory manual before going to the lab class.
3.Listen carefully and critically to presentation, comments of lab instructor. Ask questions of the experimenters of types of ingredients used, techniques, and changes in procedure. Ask them to clarify or to further explain any information that is not completely concise or clear to you.
4.Read the text again, plus other foods textbooks, lecture notes, and other resource materials over thoroughly before writing the report to see if results are accurate and if not, why not. This step is crucial to writing the Results, Discussion, and Summary and Conclusions.
5.Write in the third person, past tense. Avoid using the first person (i.e., I or we).
6.Use the provided format when writing the report.
7.Also use the following Checklist to make sure your report includes all vital information.
LABORATORY REPORT CHECKLIST
Before turning in your lab report, make sure the following items have been included depending upon which lab report assignment you are completing.
I.MECHANICS
______typewritten
______typing errors corrected (pen acceptable)
______title page
______title concisely describes experiment
______each section identified by headings
_____ I.Title
_____ II.Purpose
_____ III.Methodology
_____ IV.Results
_____ V.Discussion
_____ VI.Summary & Conclusions
_____ VII.References
______words spelled correctly
______graphs, charts and/or product evaluations included
______references cited and footnoted
II.TITLE
_____all in capital letters
_____title sheet and on top of first page of report
III.PURPOSE
______explanation of the objectives of the experiment
IV.METHODOLOGY
______explanation of how the experiment was concluded (brief and concise)
______any changes in procedure mentioned
V.RESULTS
______results given for each variable
______charts and/or product evaluation completed and included
VI.DISCUSSION
______explanation of results
______comparison with previously documented results (use reference materials)
______explanation of differences between class results and expected results
______food principles that apply are included
______mention of any known or suspected experimental errors or variability
VII.SUMMARY AND CONCLUSIONS
______what did the experiment demonstrate
______summarize the results including every variable
______value of this information
VIII. REFERENCES
______use of lecture, lab notebook, text, at least one outside source
______style consistent (see text, McWilliams)
AN EXAMPLE OF A LAB REPORT AND ITS SECTIONS IS GIVEN HERE SEE CHECK OFF SHEET AND SYLLABUS FOR ADDITIONAL REQUIREMENTS:
TITLE PAGE
TITLE: AN EVALUATION OF THE QUALITY CHARACTERISTICS IN A BASIC CREAM PIE FORMULA, VARYING THE AMOUNTS OF EGGS AND MILK.
PURPOSE: This experiment was conducted to identify the quality characteristics of a basic
cream pie formula, increasing and decreasing the eggs, and increasing and decreasing
the milk compared to the standard formula.
METHODOLOGY: The basic cream pie filling formula included 2 eggs, one quarter teaspoon
vanilla, three tablespoons cornstarch, 1 cup brown sugar, four cups milk, and a standard graham
cracker crust using 1 cup graham cracker crumbs, one tablespoon sugar and one pound fat free
margarine.
The variables included decreasing the eggs to one, increasing the eggs to three,
decreasing the milk to one cup, and increasing the milk to eight cups. Line spread tests were
conducted prior to cooking the filling mixture, after cooking the mixture, and after the
completed pies were chilled. This method is described on page xx of the laboratory
manual (Mook, 1998). Sensory evaluation of the cream pie fillings were also completed by 18 HNF 300 students, one replication. Characteristics evaluated were appearance and mouthfeel.
RESULTS: The linespread values are shown in Table 1, and the sensory evaluations are shown
in Table 2. The control pie filling gave linespread values of 27 for the uncooked filling, 12 for the cooked filling, and 10 for the chilled filling (Table 1). The mixture was pale tan in color and
very smooth (Table 2).
The variable with decreased egg gave linespread values of 29 for the uncooked filling, 22
for the cooked filling, and 20 for the chilled filling (Table 1). This mixture was dark brown in
color with streaks of light blue. There were lumps of cornstarch through the mixture (Table 2)
The variable with increased egg gave linespread values of 25 for the cooked filling, eight for the
cooked filling, and four for the chilled filling (Table 1). The mixture was light green in color
and thicker than the control (Table 2).
With a decreased amount of milk, the linespread values were 28 for the uncooked filling,
11 for the cooked filling, and four for the chilled filling Table 1). The color was medium purple
with streaks of pale pink. The mouthfeel of the variable was generally firmer than the control,
and there were some lumps of overcooked egg throughout the mixture (Table 2).
An increased amount of milk gave linespread values that decreased from the value of 30
for the uncooked filling to samples that were cooked (23) then chilled (20) (Table 1) Fillings
were creamy white in appearance and had a thin and runny appearance and mouthfeel (Table 2).
TABLE 1. LINESPREAD VALUES OF CREAM PIE FILLINGS PREPARED WITH VARYING AMOUNTS OF EGG AND MILK.
VARIABLE / Linespread Uncooked(number of 1/8 inch units) / Linespread Cooked
(number of 1/8 inch units) / Linespread Chilled
(number of 1/8 inch units)
Control / 27 / 12 / 10
Decreased Egg / 29 / 22 / 20
Increased Egg / 25 / 8 / 4
Decreased Milk / 28 / 11 / 8
Increased Milk / 30 / 23 / 20
-3-
TABLE 2. SENSORY EVALUATION OF COLOR AND MOUTHFEEL OF CREAM PIE FILLINGS PREPARED WITH VARYING AMOUNTS OF EGG AND MILK*.
VARIABLE-CHILLED / Mouthfeel / ColorControl / smooth, medium creamy / tan
Decreased Egg / thin, lumpy / brown/blue
Increased Egg / firm gel, thicker than control / light green
Decreased Milk / firmer gel than control, some lumps / purple/pink
Increased Milk / thin, runny / creamy white
* one evaluation by 18 HNF 300 students (number of 1/8 inch units)
DISCUSSION:
PUT IN AN INTRODUCTION THAT INCLUDES THE QUALITY CHARACTERISTICS OF A DESIRABLE BASIC CREAM PIE. COMPARE YOUR CONTROL TO THE IDEAL BASED ON THE LITERATURE. ALSO PROVIDE BACKGROUND OF THE THEORY INVOLVED IN PRODUCING THIS PRODUCT. EXAMPLE- SUCH AS IMPORTANCE OF GELATINIZATION AND GELATION IN STARCH MIXTURES, IMPORTANCE OF MIXING THE STARCH AND SUGAR, ETC.
Decreased egg protein inn a cream pie filling should result in increased linespread values as compared with the control. Less egg protein for gel formation should give a thinner product and softer mouthfeel (McWilliams, 1997). Results in this experiment agreed with this information. For all variables, the linespread values for the cooked samples should be slightly higher than for the chilled samples. The gel formation in the pie filling is due to the heat-gelling of the egg proteins. There is also thickening due to loss of heat during preparation which causes the starch to gelatinize (or thicken with heat). Cornstarch will form gels when chilled, thus contributing to the thickness of the mixture (Harte lecture, 1998). Any change in color should be a lightening of the filling due to less egg. The egg yolk functions to produce the tan/yellow color of the filling. The brown and blue color of the mixture was not expected.
Someone may have erroneously used food coloring in the samples. Lumps due to uncooked
cornstarch may be the result of poor preparation methods where the cornstarch was not dispersed
with the sugar during the initial mixing of the ingredients.
Increased egg should result in slightly lower linespread values as more egg protein
increases gelling ability and the protein traps additional liquid, giving a firmer texture
(McWilliams, 1997). Linespread results from this variable agreed with what was expected. The
only difference in color, if any, would be a slight increase in yellow. The light green color was
not expected nor is it easily explained. Use of food coloring may be the reason for the odd color.
With increased milk, linespread values should increase as there is more liquid than the
egg protein can trap into a gel. Increased milk will also decrease the relative concentration of
the cornstarch, resulting in a thinner mouthfeel. Results from this variable agreed with what
was expected for the linespread data. the purple and pink colors were not expected nor easily
explained. Once again, the use of food coloring may have caused the unexpected color.
Decreased milk, conversely, provides less liquid, thus giving a thicker, firmer product
with lower linespread values. By decreasing the milk, the egg protein concentration is
effectively increased, thus increasing the firmness of the filling (McWilliams, 1997). This is
also true for the cornstarch. Eggs are sensitive to high heat. However, there should have been
some browning of the mixture in addition to this if it were the explanation. The only color
difference with increasing milk may be dilution of the egg yolk yellow color. The creamy white
color is the more typical color expected in the mixtures.
MAKE SURE TO INCLUDE A DISCUSSION OF SOURCES OF ERROR, VARIABILITY, WITH ANY OF THE SAMPLES, ESPECIALLY WHEN RESULTS ARE NOT WHAT IS EXPECTED. WHAT SHOULD HAVE BEEN DONE TO HAVE BETTER CONTROL OF THE EXPERIMENT AND DECREASE THE VARIABILITY IN THE RESULTS?
SUMMARY:
BRIEFLY SUMMARIZE WHAT HAPPENED. WHAT DID THE EXPERIMENT DEMONSTRATE? WHAT WAS THE VALUE OF THIS INFORMATION?
REFERENCES:
Harte, J. B. Lecture, HNF 300, date.
McWilliams, Margaret. Foods: Experimental Perspectives. Third Edition. Prentice Hall, New Jersey. 1997
Mook, M. Laboratory Manual for HNF 300. Michigan State University. Publication date.
At least one outside source