Long underestimated, olfaction is now often at the heart of the sensorial experience of consumer products. As a result, more and more products make claims relating to olfactory efficacy. These olfactory claims can be of two main types:

Fragrance performance:

In the cosmetics and personal care products sector, the scent of the product is a major lever for triggering the act of purchase and re-purchase. Two main criteria are studied: the perception of the fragrance of a cosmetic on application and the long-lasting of the fragrance. The latter criterion is essential for certain product segments such as shampoos and shower gels.

Effectiveness in reducing unpleasant odours:

In cosmetics, this type of claim is used in particular for deodorants. To support such claims, an in-vivo test can be used to assess the product’s effectiveness in reducing the smell of perspiration. Other products now offer odour-masking or odour-neutralising properties. This is particularly true of hair products designed to eliminate pollution, cooking or cigarette odours from the hair.

In the laboratory, protocols for assessing the olfactory properties of cosmetic products are based on 2 key stages:

• Firstly, sampling:

The sampling technique used depends very much on the product segment targeted, the product itself and the objective of the study. Standards exist for certain types of product. Where this is not the case, personalised sampling strategies adapted to the product to be tested should be implemented. For example, it is important that the test environment is as close as possible to the consumer’s actual behaviour when using the product. To this end, in-vitro or in-vivo protocols can be set up depending on the claim being sought.

• Secondly, analysis:

To assess the odour of a product, sensory analysis techniques, molecular analysis methods or a combination of the two can be used. Evaluating the olfactory properties of samples using a sensory analysis panel requires appropriate panelist selection and training protocols to be put in place, enabling a common and appropriate olfactory vocabulary to be defined, as well as reproducibility and repeatability of the tests. The intensity of the odour, the hedonic character and the description of the odour are, in particular, parameters of interest for evaluating an odour, comparing samples or justifying a significant improvement in perception. These evaluations make it possible to rapidly obtain information based on human perception and therefore close to the end consumer’s experience. Nevertheless, additional molecular analyses can be relevant to understanding the mode of action of an ingredient or a formula and thus support the results obtained sensorially.

GCMS/TOF type instruments can be used to qualitatively and quantitatively analyse the volatile emanations of the products to be tested, at concentration levels 100 times lower than those of standard GC-MS instruments. By establishing a link between the molecular information obtained by GCMS/TOF and the perceived odour, it is possible to understand in detail which molecules have an impact on the overall odour of a product.

Contact

Charlotte Tournier

Head of Sensenet

ctournier@sensenet.net

https://www.sensenet.net/