Source: CORNELL UNIVERSITY submitted to
SENSORY EVALUATION METHODS RESEARCH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0198143
Grant No.
(N/A)
Project No.
NYC-143411
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Sep 30, 2007
Grant Year
(N/A)
Project Director
Lawless, H. T.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
FOOD SCIENCE
Non Technical Summary
Sensory methods are used to test new and existing food products. Better methods would help to make better products. We are studying ways to make improved test methods. This work examines ways to choose people for testing who will be good at it. It also looks at ways to obtain more accurate judgments from them.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5027220309050%
5037220309050%
Goals / Objectives
Our overall objective is to develop sensory evaluation methods that are accurate, reliable and sensitive in order to facilitate development of successful new products. Better test methods will increase the rate of product success and improve management decision making in the industrial setting. Our objectives are the following: (1) to compare panelist selection criteria with prediction of performance, since traditional methods for the selection of panelists for descriptive panels are irrelevant to the actual tasks performed by the panelists; (2) to examine methods for training panelists to stabilize their judgments against contextual drifting (tendency of panelists to shift their rating from test to test); and (3) to improve methods for testing acceptance over time, through the use of reference products and new category-ratio scales, since acceptability tests are usually a single test, while repurchase decisions of consumers are based on multiple experiences.
Project Methods
Our first approach will compare screening methods including sensory discrimination tests, traditional threshold tests, and psychological predictors from the current literature. Panelist performance and reproducibility will be tracked during training and correlated with the screening tests as predictors. Next, we will examine whether contextual shifts can be minimized by training, using intensity scales with fixed reference products. This will be tracked longitudinally and compared between groups that vary in training methods. Our third approach will measure drift on acceptance scales with consumers who will undergo repeated testing. We will compare the use of reference products to the new hedonic labeled magnitude scale that has been purported to stabilize panelists' frame of reference.

Progress 10/01/03 to 09/30/07

Outputs
OUTPUTS: A series of experiments were conducted on food preference testing and results were reported in two journal publications and one presentation at the annual meeting of the Institute of Food Technologists. The results were also discussed in our extension workshops which are held for food industry professionals every summer. A presentation of the main findings was also made the U. S. Army Natick laboratories food testing staff. The results were also presented in Food Science courses at Cornell, Sensory Evaluation of Foods and also Advanced Concepts in Sensory Evaluation, both attended by undergraduates and graduate students. A second line of inquiry was begun during this funding period which investigated methods for consumer product surveys and multivariate statistical analysis of data. Results were presented at the Seventh Pangborn Symposium on Sensory Science in 2007, and since have been accepted for publication in a peer reviewed journal. This was an independent study project for a food science undergraduate who had recently made transfer from culinary school (the CIA) to CALS. As a result the student has begun a second project as a Cornell Food Science Summer Scholar and has applied for admission to our PhD program. Outputs in general include additions to the knowledge base concerning practical test methods for sensory evaluation of foods. These will be incorporated into the revision of my textbook, Sensory Evaluation of Foods, which is the worldwide standard text for university-level instruction in this field. PARTICIPANTS: P.I.: Harry Lawless, Cornell Food Science. Collaborator: Kathryn Chapman, Research Support Specialist, Cornell Food Science. Student: Michael Nestrud, undergraduate, was involved in independent research for course credit during 2006 and was a food science summer scholar in 2007. TARGET AUDIENCES: The primary target audience is food industry professionals. Cornell students (most of whom will find employment in the food industry) were also an audience. Efforts included publications, presentations, extension workshops, lectures in Cornell classes. One student was mentored in an independent study (research) project.

Impacts
These studies added to our knowledge concerning practical test methods for assessing food preferences. Food preference tests are widely used in developing new food products, but human biases and judgment behaviors limit their accuracy and reliability. The food industry needs better sensory testing methods to insure the delivery of food products with good acceptability and consumer appeal. Our results will alert food industry professionals to potential problems in what seem to be intuitively simple consumer tests, and suggest ways to avoid the inherent pitfalls. It is difficult to determine how reported results actually change behavior or strategy in a food company because their techniques are carefully guarded and often confidential in a highly competitive environment. However, in the past some effects we have documented later became part of the everyday language and thinking of practitioners in sensory test methods, judging from later presentations at subsequent scientific meetings.

Publications

  • Chapman, K. W. and Lawless, H. T. 2005. Sources of error and the no preference option in dairy product testing. Journal of Sensory Studies, 20, 454-468.
  • Chapman, K. W. and Lawless, H. T. 2006. Expectations and stability of preference choice Journal of Sensory Studies, 21, 441-455.
  • Nestrud, M. and Lawless, H. T. 2007. Perceptual Mapping of Citrus Juices using Nappe and Profiling Data from Culinary Professionals and Consumers. Food Quality and Preference (in press).


Progress 10/01/03 to 09/30/06

Outputs
Studies continued on methods for assessing consumer preference for dairy products. Use of the no-preference option remains problematic. Studies determined that judges' expectations to a large extent determine their responses, rather than their sensory information. We further found that although group averaged results are very repeatable, individual testers are likely to shift in their judgments over repeated tests. Application of logistic regression methods was a valuable tool in this work.

Impacts
Determining better sensory test methods and understanding the foibles of humans participating in taste tests will help us design better test methods, leading to more efficient development of new foods and consumer products

Publications

  • Chapman, K. W. and Lawless, H. T. 2006. Expectations and stability of preference choice. Journal of Sensory Studies, 21, 441-455.


Progress 01/01/05 to 12/31/05

Outputs
Studies continue on methods for assessing consumer preference for dairy products. Use of the no-preference option remains problematic. Consumers fail to choose this option most of the time even when products are identical. Part of the problem arises due to people's inability to discriminate products (like skim milk from 2 percent, an obvious difference to dairy judges) as well as lack of repeatability of their choices. Results suggest a baseline of error or random noise in the data of about 25 percent. Studies continue to determine whether the judges' expectations determine their responses, rather than their sensory information.

Impacts
Results will help food companies to better assess consumer acceptance of their products.

Publications

  • Chapman, K. W. and Lawless, H. T. 2005. Sources of error and the no preference option in dairy product testing. Journal of Sensory Studies, 20, 454-486.


Progress 01/01/04 to 12/31/04

Outputs
Studies were conducted on the frequency of consumer's choice of the 'No-preference' option in evaluation of dairy products (milk and yogurt). Surprisingly, only 30 percent of consumers choose the no preference response when samples were physically identical. When samples were easily discriminable, the proportion was less. Discrimination errors may contribute to this effect. Only 75 percent of consumers were able to discriminate skim milk from milk with 2 percent fat. Error variance is also contributed by a lack of repeatability. Only about 55 percent of consumers choose the same preference response on repeated trials. This work has been submitted for presentation at the 2005 IFT meeting.

Impacts
Improved sensory test methods should aid in the development of nutritious foods with consumer appeal.

Publications

  • No publications reported this period


Progress 01/01/03 to 12/31/03

Outputs
This project recently began. At this time we are examining personality tests and variables that might be expected to predict performance in sensory tests of foods with trained panelists.

Impacts
Improved sensory test methods should aid in the development of nutritious foods with consumer appeal.

Publications

  • No publications reported this period