Understanding of the residual odour of fatty esters used as emollient in cosmetic products

Abstract

Objective: Fatty esters are known for their versatility, but in addition to their performance as emollients, emulsifiers, solubilizers, or dispersing agents, they have to meet more and more criteria to be used in cosmetic products. Thus, their olfactory characteristics are expected to be as neutral as possible. However, despite a step of deodorization during the synthesis of fatty esters, a residual odour is currently still perceived at the end of the process. Methods:In this study, a specific analytical methodology combining sensory with chemical analyses was implemented to characterize the residual odour of two fatty esters and to determine its origin. Ethyl oleate and isononyl isononanoate were selected and underwent a sensory analysis to evaluate their odour intensity and odour profile. Volatile compounds released by these esters were assessed by GC-MS after solid-phase microextraction and among them, odouractive compounds were brought into light using gas chromatography coupled with mass spectrometry and olfactometry analyses.Results: On the isononyl isononanoate chromatogram, only peaks corresponding to the different isomeric ester forms were evidenced while around 70 volatile compounds were detected in the ethyl oleate headspace, including esters, aldehydes, hydrocarbons, and ketones. Isononyl alcohol used as raw material in the synthesis was proven to be responsible for isononyl isononanoate final odour.As for ethyl oleate, of the 23 odour-active compounds perceived, 14 have been identified; they are mainly esters and saturated as well as unsaturated aldehydes. Conclusion:A novel measurement approach was presented to analyse trace odours of fatty esters and the results will be useful to control their deodorization by targeting appropriate strategies with the aim to either avoid the formation or remove the identified odorant compounds. This study may be further expanded by investigating the impact of deodorization on odour-active compounds for a complete understanding of their contribution to the fatty ester global odour.

Comprehensive Phytochemical Analysis and Bioactivity Evaluation of Padina boergesenii: Unveiling Its Prospects as a Promising Cosmetic Component

“…These individual compounds found in P. boergesenii present various opportunities for formulators to develop skincare products with targeted benefits. The saturated and unsaturated fatty acids contribute to moisturization and skin barrier support, while the fatty aldehydes, fatty alcohols, and other compounds offer sensory enhancements and specific skincare properties [60,61]. By harnessing the potential of these compounds, cosmetic formulations can be tailored to address specific skin concerns and provide an enjoyable and effective skincare experience.…”