(QC/SENSORY) Flashcards
In the twentieth century, attention was given to
the selection and training of quality assessors
to utilize of formal sensory methods including:
- Use of reference standards.
- Use of formal data analysis methods to
summarize and interpret the quality data.
Over time, QC/sensory evolved in two important paths:
a) Focused on the challenges of initiating and maintaining a QC/sensory program in an organization.
b) Focused on sensory methods that were practical and effective for an in-plant QC function.
- Method used for QC/sensory function:
o Attribute descriptive method
o Different from control method
o In-out method
ATTRIBUTE DESCRIPTIVE METHOD
Focus on a small number of sensory attributes that have been
demonstrated to impact consumer acceptance.
ATTRIBUTE DESCRIPTIVE METHOD-sensory specifications are based on
consumer acceptance and the attributes descriptive methods are typically applied only to finished products.
Objective of Attribute descriptive method is to provide detailed information on :
Ø What is varying perceptibly/ detectable in the product?
Ø The magnitude of the variability.
Ø The direction of variability relative to the product’s sensory specifications.
Major drawback of attribute descriptive methods:
Ø High level of resources.
Ø Need significant resources to identify the sensory attributes.
Ø Involve parallel descriptive and consumer evaluations of many production samples.
Ø Requires QC program maintenance
Implementing an attribute descriptive QC
program:
- Establish sensory specifications
* Initial sample screening
* Sensory descriptive evaluation and sample selection for consumer testing
* Consumer testing production samples
* Establishing the sensory specifications - Implementing the in-plant QC/sensory function
- Product sampling, data analysis and reporting
Objective Establishing sensory specifications
To develop a set of relevant sensory specifications.
Establishing sensory specifications Involve 2 steps:
- Identification of a small number of sensory attributes (5-15) that influence the consumer’s acceptability of the product.
- Establish of ranges of intensities for each of these attributes (using 15-unit scale).
Initial sample screening
Collection and screening of many production samples.
Number of units of production that need to be collected at this stage must be adequate for
subsequent formal sensory descriptive evaluations and consumer testing
Things to be considered:
- Logistical issue
- Space available to store the sample
- How quick the sample can be evaluated
- Shelf-life issue
b. Sensory Descriptive Evaluations and Sample Selection for Consumer Testing
- To obtain a comprehensive description of all the sensory properties of each sample and to fully characterize the ranges of
variability.
Sensory Descriptive Evaluations and Sample Selection for Consumer Testing- goal:
to identify the smallest number of samples
that fully represent the total sensory variability of the product.
Familiarity with the product and sound sensory judgment should
be used in combination with
the statistical results to decide
which attributes should remain.
Consumer testing production samples
The questionnaire for the consumer test can be relatively short, consisting of acceptability questions- overall (aroma, appearance, texture, flavor etc.) and of specific attribute intensity questions.
- The key consumer acceptance measures will be combined with
the sensory descriptive ratings of the test samples to
o identify the
attributes that affect consumer acceptance
Establishing the sensory specifications
The relationship between consumer acceptance and the intensities of the sensory attributes lead to the sensory specifications for the product.
Correlation analysis can be used to
identify attributes that have a strong straight-line relationship with acceptance
Three key patterns are likely to emerge
on the charts:
- There may be no systematic relationship between acceptance and the intensity of the sensory attribute
- There may be a strong linear trend , either increasing or decreasing
- There may be a strong curvilinear trend where intermediate intensities of the attribute have higher acceptability than extreme.
No systematic relationship between acceptability and the intensity of an attribute means
no sensory specification is needed
for that attribute.
- Linear relationships with acceptability, one side specification apply.
Lower specification limits are set for
attributes with increasing trends; upper specification limits are set for attributes with decreasing trends
Curvilinear relationships with acceptance,
both lower and upper specification limits may be needed.
Develop the in-plant resources that will be used to
monitor the sensory quality of the products
how to develop the resources
i. Identify an in-plant sensory coordinator who will oversee the operation of the in-plant QC/ sensory panel and coordinate with the other QC functions to communicate the results of the panel’s evaluation.
ii. Candidates for QC/sensory assessors need to be identified, screened, trained and put to work.
QC/ sensory assessors can be drawn from
company employees or from non-employees who are willing to work part time as a panel.
Once a pool of assessors is identified, the QC/sensory panel
screening and training on the attributes that will be evaluated as part of the QC/sensory evaluation and to be calibrated to the
intensity scales that will be used
Step 3: Product sampling, data analysis and
reporting
For each attribute, the panel’s average intensity rating is
calculated for each sample collecte
The most common QC summary measures are
the sample
mean and the sample range
