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November/December 2010

Science for the Senses

ASTM’s E18 Marks 50 Years of Standards and Education

When a manufacturer changes the vanilla in a chocolate chip cookie, develops a new body lotion or tries a different sweetener in a beverage, there’s a whole lot of testing going on.

The testing is sensory, to determine the flavor of the treat, the feel of the formula and the lasting sweetness of the soft drink, among other attributes.

And the testing to appraise the flavor, the feel and the sweetness can tap into standards from ASTM Committee E18 on Sensory Evaluation to determine and describe these attributes.

The E18 committee develops standards for specific sensory tests and standards that provide guidance about performing sensory tests, and it manages an active, related education program.

“E18 is the one place where all contributors, people from all parts of the profession, can come and learn and grow, and become better contributors whatever their professional endeavors,” says Christine Van Dongen, Ph.D., chairman of Committee E18 and manager, Sensory and Consumer Preference, at Nestlé Nutrition R&D Center in Minnetonka, Minn. “The work we do is for the good of all.”

E18 Sets the Standard

Committee E18 is responsible for standard test methods for those cookies, lotions and sweet beverages, and more.

To check the vanilla flavor in the cookie, a triangle test, which involves choosing the one that’s different among three samples, can be performed with E1885, Test Method for Sensory Analysis — Triangle Test.

For the lotion, expressing how one feels compared with another can be aided with E1490, Practice for Descriptive Skinfeel Analysis of Creams and Lotions.

And to assess how the beverage sweetness changes? There’s E1909, Guide for Time-Intensity Evaluation of Sensory Attributes, which guides the understanding of how long it takes a taste to build up or go away.

With such methods, “you’re trying to discover how people respond to products,” says Gail Vance Civille, president of Sensory Spectrum, New Providence, N.J., and a veteran E18 member. A company then can analyze the data, make conclusions about a particular product attribute and decide to change it — or not.

E18’s standards also include E1958, Guide for Sensory Claim Substantiation, which covers how to design and implement sensory tests that will validate product claims — how it tastes or smells or looks, and so on. Edgar Chambers IV, Ph.D., says that E1958 is the only voluntary standard in the world on the topic. Chambers is distinguished professor of sensory analysis and consumer behavior and director, Sensory Analysis Center, Department of Human Nutrition, at Kansas State University, Manhattan, Kan.; he has been an ASTM International member since 1981. Van Dongen adds, “The claims standard is the most comprehensive guide to what you need to do to have a defensible sensory claim.” To that end, E1958 delineates sampling; consumer and laboratory test design; and statistical analysis. Plus, an appendix answers commonly asked questions on the topic.

Chambers notes that E18 has produced significant standards other than those for foods and fragrances; the committee is responsible for standards having industrial purposes. For example, in addition to the scientific understanding of odor transference, a chemical company or plastics manufacturer might want to understand the perception of such transference. To that end, E460, Practice for Determining Effect of Packaging on Food and Beverage Products During Storage, can be used to evaluate experimental materials or alternative storage conditions against a known control, such as potato sticks in plastic bags versus coated paper bags. E18 standards also address odor and taste transfer from polymer packaging (E1870 and E2609) and odor evaluation in paper packaging (E619).

Also useful, though unrelated to testing the items already in your local grocery store, is an E18 standard that is being adapted for use in the wake of the Gulf of Mexico oil spill: E1810, Practice for Evaluating Effects of Contaminants on Odor and Taste of Exposed Fish, which is helping to determine when fishing areas can reopen.

In addition to maintaining its existing standards, Committee E18 is also developing standards on several topics: measuring sensory descriptive panel and assessor performance; design and execution of instrumental correlation studies; assessing drinking water flavor; and developing, selecting and using appropriate sensory scales.

Particularly notable among E18’s proposed standards is WK22268, Guide for Two-Sample Acceptance and Preference Testing with Consumers, which Van Dongen anticipates going out to ballot soon. WK22268 covers methods for measuring hedonic responses in unbranded two-sample tests, focusing on using the nine-point hedonic scale to measure liking and choice as measured by preference. According to its scope, no standard guide for hedonic product testing issues currently exists; WK22268 will, Van Dongen says, cover the fundamentals of the questions that sensory professionals ask about liking and preference testing — key subjective consumer response measures.

Early Beginnings

Although founded in 1960, Committee E18 has roots that go back even further. In 1945, ASTM appointed an administrative committee to consider possible engineering test methods for consumer groups. Under that committee, a joint subcommittee on natural science and social science began work, and one result was a 1951 symposium and the resulting Special Technical Publication: STP 117, Symposium on Measurement of Consumer Wants. Closing remarks from that program show that government, academia and industry were grappling at that time with how to measure opinion and attitudes. Sensory science was coming together as a field of study and ASTM members recognized a role for standards.

The administrative committee recommended “a permanent committee to develop standards in the area of preference testing, psychophysical aspects and other matters where human factors play a part in tests on materials.” That recommendation preceded an E18 organizational meeting on Jan. 14, 1960. In addition to standards development, the E18 scope included the dissemination of information by technical publications and symposia.

W.H. Danker, then chairman of E18 Subcommittee II on Principles of Psychophysical Test Methods, noted these events in an essay, “Historical Background for ASTM Committee E-18.” “Production of STP’s to serve as basic references was deemed the wisest first step [for the committee],” Danker commented in the essay, which appears in STP 433, Basic Principles of Sensory Evaluation. The volume, published in 1968, addresses the senses, their inter-relationships and methods to measure subjective response. Also published that year was a companion reference work, STP 434, Manual on Sensory Testing Methods, intended “to guide the technical man who is not an expert” on performing such procedures.

That dual approach of standards and education continues now, 50 years later. The standards detail the intricacies of many sensory procedures, and the manuals and STPs provide additional practical and technical guidance.

“At one time, it [E18] was almost the only way that sensory people really had access to the latest and greatest information,” says Chambers. “It was, and still is, a major source for information in the field.”

Education Beyond Standards

In addition to its standards work, Committee E18 still emphasizes its ongoing educational component with publications and technical programs.

Civille explains: “We tend to be practitioners who are practical.” And for E18, practical includes manuals that cover testing from setup to conclusions as well as how to develop descriptive vocabulary, lexicons and data series, and more. “How do I test, with consumers or with experts, to find out whether the change that I made in a formulation [for example] is detectable?,” Civille says of the manuals’ uses. “Those types of things are universally used by sensory practitioners. There’s rarely a sensory practitioner who does not have [manual] copies on his or her desk.”

Chambers says, “Some of the most interesting documents that have come out of E18 are not standards at all. They are either the data series or the manuals, and we’ve published a lot of those.”

One landmark work from E18 is Manual 26, Sensory Testing Methods. In this revision to STP 434, Chambers and Mona Baker Wolf of the Wolf Group, Cincinnati, Ohio, build on existing knowledge about practical sensory study techniques and controls. Complete with case studies for the various sensory methods covered in its chapters, the manual also discusses, complete with example charts, statistical procedures to examine resulting data.

Committee E18 has added to its array of publications most recently with Manual 63, Just About Right (JAR) Scales: Design, Usage, Benefits and Risks. It’s a manual about scales where the endpoints are essentially opposite, such as “not nearly sweet enough” versus “much too sweet,” with “just about right” in the middle. The reference covers how to construct and use JAR scales, which are often used with other sensory scales during product development, and how to analyze and interpret the resulting data.

Upcoming, among other planned works, is an updated software tool that consists of a database and related manual to develop and define terms (beyond definitions found in E253, Terminology Relating to Sensory Evaluation of Materials and Products) describing perceived properties for an array of products from foods and personal care to fabrics and household cleaners. One part of the update is DS69, Lexicon for Sensory Attributes Relating to Texture and Appearance; the other is DS66, Aroma and Flavor Lexicon for Sensory Evaluation: Terms, Definitions, References and Examples.

The other component of E18’s educational program consists of workshops, seminars and discussions on topics of particular interest to professionals involved in sensory science. Earlier this year, for example, the committee held an interactive program on Using Technology to Transform Sensory and Consumer Research, with sessions addressing how the technology is best used, and techniques and ideas for using technology in research.

Also to further education — and networking — E18 meets every other year in conjunction with the Society of Sensory Professionals. Chambers, who is immediate past co-chairman of SSP, says that the organization actually grew out of discussions by the E18 committee. SSP, which brings standards development needs to E18, provides further educational opportunities as well as skill and career development; its mission is to advance the field of sensory evaluation and those working in the field.

Participation Welcome

Committee E18 looks forward to continuing its standards and education work at the next of its twice-yearly meetings. The committee will meet April 12-14, 2011, in Anaheim, Calif., during the April 2011 committee week. All those interested are welcome to participate.

For more information, contact Scott Orthey, E18 staff manager, ASTM International (phone: 610-832-9730).