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Perfumery Raw Material Odor Intensity Prediction with Olfaction Characteristics Database

This is an English translation of a news release in Japanese on December 19.

The Sensory Science Research Laboratory of Kao Corporation has developed a database containing details regarding 314 different types of perfumery raw materials (PRMs) regularly used for fragrance development in a variety of consumer products. In addition, a technological method with use of the database has been developed that enables prediction of odor intensity based on the concentration of PRMs present in a gas sample.
These research results were published in the Industrial & Engineering Chemistry Research journal of the American Chemical Society.*1


The gas concentration at which humans can perceive odor differs for each PRM, and the relationship between concentration in the gas phase and odor intensity is not uniform. For example, a characteristic of the PRM Pentalide is that its odor can be perceived even at a low concentration, while the intensity does not dramatically increase when the gas concentration is increased. Traditionally, such knowledge has been dependent on the experience of perfumers, while an objective method for determining the effects of a PRM on scent has not been developed.
Kao considers that such technology for determining individual PRM odor characteristics is important and would be beneficial for fragrance development, as well as more efficient PRM usage. Furthermore, consideration of environmental impact and sustainability is strongly required, as increases in the amounts of PRMs produced and used for fragrance development are anticipated. In order to address these issues, we developed an odor intensity prediction method.

Methods and Results

Kao researchers built a database of olfaction characteristics of 314 PRMs to develop an odor intensity prediction method. Data were obtained from evaluation testing performed by 18 perfumers and experienced researchers, who scored the intensity of samples*2 emitted from a fragrance diluter with different gas concentrations (Fig. 1).

  • * 2 Air containing PRM gas

Fig. 1. Odor intensity evaluation device

Based on evaluations of those results, visualization of the relationship between gas concentration and odor intensity, as well as prediction of odor intensity of an arbitrary gas concentration of a PRM became possible (Fig. 2).

Fig. 2. Olfaction characteristics

In order to verify the accuracy of this novel prediction technology based on the database records, evaluation scoring*3 and prediction scoring*4 were conducted using static analysis, and good prediction accuracy was confirmed (Fig. 3).

  • * 3 Odor intensity obtained by evaluating various concentrations of samples emitted from a fragrance diluter
  • * 4 Odor intensity predicted using gas concentration of a specific sample and the olfaction characteristics database

Fig. 3. Relationship between predicted and evaluated scores for odor intensity


Creation of a database containing PRM olfaction characteristics led to development of an effective odor intensity prediction method. With this novel technology it is possible to predict the odor intensity of an arbitrary PRM gas concentration. In future investigations, Kao will apply this expertise for more sophisticated control of odor intensity, such as diffusion and lasting scent in order to develop more attractive fragrance products for consumers. Furthermore, Kao researchers will continue to contribute to improving the environment by seeking to decrease greenhouse gases emitted during the process of fragrance production and transportation by more effective utilization of PRMs.

About Kao

Kao creates high-value-added products that enrich the lives of consumers around the world. Through its portfolio of over 20 leading brands, such as Attack, Bioré, Goldwell, Jergens, John Frieda, Kanebo, Laurier, Merries and Molton Brown, Kao is part of the everyday lives of people in Asia, Oceania, North America and Europe. Combined with its chemical division, which contributes to a wide range of industries, Kao generates about 1,500 billion yen in annual sales. Kao employs about 33,000 people worldwide and has 130 years of history in innovation. Please visit the Kao Group website for updated information.

Media inquiries should be directed to:

Corporate Communications
Kao Corporation

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