Food Chemistry Laboratory Guidelines

University of Kentucky, Department of Animal & Food Sciences, FSC 434


Laboratory Guidelines

Experiments will be done working in pairs, unless told otherwise. You are expected to have read the laboratory procedures for each experiment before coming to lab, and should be prepared to do the experiment. You should be prepared to follow the procedure given in the lab handout, and your notebook ready to record data.

All belongings except lab notebooks should be placed on the coat rack, or on the floor below the coat rack.

Wear lab coats while doing your experiments. You are required to wear glasses or safety goggles in the laboratory. Lab coats and safety glasses can be labeled with your name and left in boxes that will be returned to lab each week.

Report if any equipment breaks or is not working properly.

When finished with your experiment, clean up your workspace. Place all glassware on a cart for dirty glassware. All tape on dirty glassware should be removed. Glass pipettes should be placed in the pipette washer with the tips up. Return equipment to where you got it. Turn off balances after using, and clean up any mess that was made. Turn off spectrophotometers and pH meters when finished. Push in the chairs at your lab bench when you leave.

Laboratory Notebook

Laboratory results must be placed in a laboratory book as described below.

The notebook should have a table of contents designating the title of each experiment and page upon which it starts.

Your notebook may be a three-ring notebook (i.e. loose-leaf notebook) into which you can insert all lab preparation materials, data calculations, lab procedure handouts, and returned lab reports. Keep all materials for each experiment together. If your notebook is bound and it has holes, your lab procedure handouts and returned lab reports can be inserted and attached in the notebook. Pages in the notebook should be numbered.

All data, comments, calculations, timetable plans, etc. pertaining to the work done during an experiment should be entered directly into the notebook and not onto any other paper or book. THINK IN YOUR NOTEBOOK!

The form of each notebook entry should be a) title of experiment & date initiated, b) brief objective statement, c) methods, referring to the laboratory procedure handout (note any changes in standard procedures), d) results including all raw data and calculations used to get final, reportable data along with pertinent comments. (i.e. enter data as you go; don't recopy neatly).

NOTE: Occasionally firms or universities are involved in patent-litigation or for other reasons must be able to substantiate the validity and time of their laboratory work. Clarity and completeness of records contained in laboratory notebooks are vitally important in these cases. The notebooks in these cases must be bound books and all entries must be made in ink. The methods may be handouts taped into the book, or reference to published procedures is acceptable. Because the laboratory system for this class is not very conducive to the use of bound notebooks, loose-leaf notebooks are acceptable.

Laboratory Reports

 Laboratory partners will alternate reports so that every other laboratory reports will be done entirely by one member of a group and the other member will do the other half of the reports. Typed reports should be turned in during the laboratory sessions and are due by 5 p.m., 1 week after completion of the experiment unless otherwise specified. There is no set points assigned for each section of a laboratory report: however, errors that have resulted in substantial loss of points in the past include:

  1. Failure to provide a clear and descriptive title for figures and tables.  Each figure and table should make sense to someone not involved in the lab without consulting the text of your report.
  2. Failure to label the axis of figures.
  3. Failure to pay attention to what you are doing.  Generally an error in a calculation will not result in a substantial loss of points; however, reporting an absurd value as a result of an error (e.g., reporting that Coke contains 50% phosphoric acid) will result in a loss of as much as 10 points.  Think about what you are doing.
  4. Failure to use the appropriate units in a calculation.
  5. Omitting important segments of your report.
  6. Five (5) points will be deducted for each day a lab report is late. If a lab report is more than one week late, a grade of zero will be given. Any one lab report for a given student can be corrected and resubmitted for a change of grade within 2 weeks after the original is returned to the student (attach original with the resubmission).

The lab reports (see Sample Lab Report handed out in class) should be typed (typing of figures and tables is optional) and include the following:

Experiment Title
Your Name
Introduction/Background/Underlying Principles of the Methods Used 
Experimental Data
Results: calculations, tables and graphs
Discussion of results and conclusions
Answers to questions
References if applicable (use the Journal of Food Science format)


Experimental data will be requested in tabular or graphical form. When calculations are involved, show one example of each type of calculation for each question (except calculating the mean of multiple trials), including the equations used, below the table or figure. Provide the appropriate statistical analysis of your data.


Tables      

Number each table in sequence
Each table must have a clear & descriptive title so that the table can be understood without referring to the text.
Show units of measure in the headings
Use appropriate footnotes


Figures   

Number each figure in sequence
Each figure must have an explicit & descriptive title
Label each axis and give unit of measure
(x-axis = independent variable)
(y-axis = dependent variable)


Include in lab report answers to questions asked in laboratory handout. Read the questions carefully. Answer all parts of the questions completely and concisely.

Reminders Concerning Common Problems with Lab Reports

When asked to give your data, give a complete listing of data, not just a summary or part of the data.

Include appropriate information in footnotes to tables.

Show equations used and give sample calculation for each type of calculation, using your data. Make sure it is clear where the numbers come from in your calculations. Label each value used in the equation with the appropriate units (i.e., grams per milliliter) and give the units of the final value.

When you analyze unknown samples, give the # of sample analyzed in your lab report. When you analyze a specific type of sample (when given a choice of many types of samples), state the type of sample analyzed in your lab report.

Give results in the units requested.

Round off your final values to the appropriate number of significant figures.

Do not average duplicate or triplicate values (e.g. absorbency or titration values) until at the end of your calculations. (i.e. Do calculations with each of the duplicate or triplicate values, before calculating the average.) When question asks for concentration, e.g. sugar content of soft drink, do calculation for each trial, then give the average as the concentration.

When an analysis involves dilution, be sure to use the appropriate dilution factors in your calculation.

When working with standard curves, calculate the equation of the line(e.g., using a Microsoft Excel program), then use that equation to obtain the values for your samples. Do not get the value directly from the line on the graph. However, you should use that as a check of the value you get from the equation of the line. Also, to obtain the slope of the standard curve, use points from the best fit line; not actual data points used to get the line.