代写NUT106 Lab 1: Sensory Evaluation代写留学生Matlab语言

NUT106

Lab 1: Sensory Evaluation

Lab Report Guidelines

Every week you will be writing a full laboratory report. By the end of the quarter, you should be able to present and analyze data, critically think about the data you generated, and write a report that has a format similar to a scientific manuscript. Presenting and critically thinking about data, as well as writing are important skills for working either in academia or in industry. Practicing these skills, will help you when you join the workforce.

Below in bold are the sections of the laboratory report that you must write each week. Pay careful attention to the instructions, as they will change from week to week. If you are unsure about what to do, contact any of the TA’s for the course.

Introduction

An  introduction  is  the  place  in  a  manuscript. where  the  reasoning  behind  an  experiment  is introduced. It often contains a brief synopsis of what is currently known about the subject, which segues into the purpose of the experiment and the hypothesis you had before performing the experiment. Your hypothesis does not need to be correct – it just needs to be testable. You describe whether your hypothesis was correct or not in the Discussion.

For this week, you do not need to write a formal introduction in paragraph format. We will discuss how to do that later. For the introduction to this week’s laboratory report, please copy the questions below and answer them in full sentences. As you are writing your introduction, think about how you could have organized it into paragraphs.

a)   Why would someone perform. a sensory test?

b)  Describe each of the sensory tests that were performed, and under what circumstances you might use that particular sensory test.

c)  What will the results of each of the sensory tests tell you about the particular products you are testing?

d)  Acidity and sweetness are two important characteristics of food. Explain why these are important, and how they maybe measured.

e)   What is the relationship between acidity and sweetness, and how can that help a food producer ensure a pleasurable experience for the consumer.

Purpose, and Hypothesis

Based on your introduction, write the purpose of this lab. You can start the sentence with the following: The purpose of this experiment is to …..

Based on what is being tested in this lab, write a sentence describing what you think the outcome will be. You can start the sentence with the following: Ihypothesize that …..

Note that there is more than one purpose and hypothesis for this (and most) labs. For the purpose, it is helpful to think about how you can describe the overall purpose concisely.

Note that for this lab, you will have 3 purposes, and for each purpose you will have a hypothesis.

Methods

Re-read the Procedure for the experiment this week. The guidelines provide you with a set of instructions. A methods section is a description in sentences of what was actually done during the experiment, such that someone could read it and be able to repeat what you did on their own. The methods section contains the essential information for reproducing the results, but is not meant to be an instruction manual or recipe.

Write a methods section for this week’slab. You should break it up into sections. The first section should describe the sensory tests you performed.

An example of how you might phrase your sensory methods could be:  To determine whether subjects could distinguish between Tropicana and Minute Maid orange juices …..

The second section should describe how the analytical measurements (i.e. 。Brix and acidity) were measured.

An example of how you might phrase this could be: To determine acidity of each of the juices, the pH was measured as 0.1 N NaOH was added stepwise using ….

The last section for this week will be the calculations and statistical analysis section. Here you will describe how you calculated %acidity, if you performed repeated measurements, then how those will be presented (for example, if you calculated  average and standard deviation for the Brix measurements). You will also describe any statistical tests and how those were performed.

An example of how you might phrase this could be: To determine whether there was a statistical difference in liking in the preference test, … .

For this (and subsequent labs), you will need to show the equation you used for each calculation as well as show one example calculation. Here, you will need to perform. an example calculation for the percent acidity of orange juice.  See Appendix  1 for information on calculating percent acidity.

Results

The results section is one of the most important sections of any scientific paper or laboratory report. It is in this section that you present and describe your data objectively.

Each week we will provide for you the data you will analyze as well as a list of the Tables and Figures that you need to include in your laboratory report. Once you have made all of your Tables and Figures, you need to refer to them and describe them to the reader in this section.

For this week, you need to create the following tables and figures for your report: Tables:

1.   For the triangle test, make a table showing the number of judges, the number of correct identifications, and the significance level.

2.   For the preference test, make a table showing the number of judges, the number of judges that preferred each soda, and the significance level.

3.   For the ranking test, make a table showing the number of judges, the rank sum of each of the juices based on acidity and sweetness, the absolute value of the rank sum difference when comparing each of the juices (note that there should be three comparisons), the significance level, as well as your calculations for %acidity, average Brix, as well as Brix/Acid.

Figures:

1.   pH and derivative plot for apple juice. Using the data provided for the titration of apple juice and the information in Appendix 1, create a scatterplot of the pH (y- axis) against volume of NaOH added (x-axis). On the same plot, also add the scaled derivative (y-axis) against the volume added (x-axis). Clearly label the equivalence point on your figure. Don’t forget to add appropriate axis labels, and a figure caption.

2.   pH and first derivative plot for grape juice. Use the data provided for the titration of grape juice to create the same plot as is described for Figure 1.

3.   pH and derivative plot for orange juice. Use the data provided for the titration of orange juice to create the same plot as is described for Figure 1.

Note: Include an appropriate title for each of your tables and caption for each of your figures. You will need to reference the document titled “Week 1-Statistical Tables” to determine significance levels for the various sensory tests.

Discussion

The discussion section is the section where you will interpret your results. For this week, you do not need to write a formal discussion in paragraph format. We will discuss how to do that later. For the discussion for this week’s laboratory report, please copy the questions below and answer them in full sentences. The questions below are provided to guide you to thinking about the data that was collected and its meaning. As you are writing your discussion, think about how you could have organized it into paragraphs to interpret the results of the experiment.

1.   Did the results of the triangle test indicate that there is a difference between the two different orange juices? What could lead to sources of bias in the experimental design?

2.   Did the preference test indicate an overall preference for either soda? Discuss.

3.   Did the judge’s ranking of the samples in the ranking test indicate differences in acidic taste of the juices? What about the sweet taste of the juices? If so, which juices differed and how did they differ?

4.   Which juice actually had the most acid? Does the acid data agree with what the judges indicated with regard to taste? Why or why not?

5.   Describe potential sources of bias in the ranking evaluation.

6.   Provide an example of something you might change in a recipe to make it healthier or accommodate  a  specific  dietary  need.  What  test  would  you  use  to  evaluate  the acceptability of the modification? Justify your answer based on the conclusions that can be drawn from the test.

7.   Include an anecdote (~2 sentences) about a food that you have eaten that didn’t conform. to your sensory perceptions of that food. Describe which sensory aspects of that food that you liked or disliked.