F&F Literature Review: Value-Added Materials

Contact Author Rachel Grabenhofer, Managing Editor, Cosmetics & Toiletries
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  • A watermelon beverage
    Combining headspace and solvent extraction methods can provide a more comprehensive approach to extracting watermelon aroma compounds.
  • Testing on skin
    An integrated skin sensitization testing method (as opposed to the lymph node assay in mice) that includes reactivity data and KeratinoSens assay results among others make animal-free testing a possibility.

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Emulsions for Dual Flavor Delivery

U.S. Patent Application 20180077942, Assigned to: Givaudan, S.A. (Mar 22, 2018), Accessed on Aug 2, 2018

Flavors are both added to the bulk of an edible product, e.g., mixed into dough, and added topically to allow for greater versatility and variety. Topical flavors, however, are often provided as solids, which according to these inventors, can complicate the application process. For example, slurries are sometimes unstable or can cause blockages in application systems over time. Further, the chemical structures of flavor compounds vary widely, so their solubilities in aqueous and non-aqueous media differ. Such incompatibilities hinder the potential creativity of the flavorist, especially with regard to using oils.

Here, the inventors have discovered an approach to topically apply both hydrophilic and lipophilic flavor compounds via an emulsion format. Specifically, a topical flavor composition is disclosed comprising at least one hydrophilic flavor compound and one lipophilic flavor compound in a water-in-oil emulsion. The emulsion consists of a continuous non-aqueous phase and a disperse aqueous phase. The lipophilic flavor compound is dissolved or dispersed in the continuous phase, whereas the hydrophilic flavor compound is dissolved or dispersed in the disperse phase.

Watermelon Flavor Focus

L Ye, H Congcong and S HuanLu, Food Analytical Methods 11 1677 (2018)

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This study compared headspace vs. solvent extraction methods to produce watermelon juice flavor. Specifically, solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) techniques were used to collect watermelon aroma compounds, which were then separated and analyzed by gas chromatography-olfactometry-mass spectrometry (GC-MS/O).

SPME and SAFE identified 47 compounds, including 7 aldehydes, 10 olefinic aldehydes, 14 alcohols, 7 sulfur compounds, 5 ketones and 4 miscellaneous compounds. SPME more effectively extracted the saturated aldehydes, olefinic aldehydes, alcohols and ketones, whereas SAFE more effectively derived sulfur compounds. The authors note the techniques could be combined to more comprehensively extract the aroma compounds.

1,3-Propanediol for Natural Flavor Retention

U.S. Patent 9883691, Assigned to: Kraft Foods Group Brands LLC (Feb 6, 2018), Accessed on Aug 2, 2018

According to this invention, 1,3-propanediol has been used in personal care but is not known to be commonly used in the food industry. This polar compound can be prepared from corn sugar, and since it has a similar structure, molecular weight and polarity to propylene glycol, 1,3-propanediol was expected to provide similar properties and taste characteristics. However, it was unexpectedly found to uniquely impact the flavor of foods or beverages—significantly different from propylene glycol.

Specifically, certain classes of flavor compounds were better suppressed in the presence of 1,3-propanediol, including: unsaturated and saturated aldehydes (C2-C12), saturated and unsaturated acids (C6-C12), saturated and unsaturated alcohols (C6-C12), ketones (C7-C10), ethyl esters, butyl esters and aromatic hydrocarbons. Examples include decanoic acid, caprylic acid, propionaldehyde, hexanal, citral, ethyl butyrate, methyl butyrate, ethanol, octanol, benzaldehyde, nonanone and octanone, among others. As such, this patent discloses methods and compositions with improved flavor retention thanks to 1,3-propanediol.


Aggregate Limonene Exposure

N Dornic, AC Roudot, A Batardière, AS Nedelec, P Bourgeois, N Hornez, F LeCaer and AS Ficheaux, Food and Chem Tox 116(B) 77-85 (June 2018)

As these authors emphasize, knowing the aggregate exposure to materials in different types of products is paramount to risk assessment. As such, this study used limonene as a case study to, for the first time, compare the relative contribution of essential oils vs cosmetics in daily aggregate exposure levels. A panel of volunteers used essential oils and cosmetics on four body sites and exposure calculations were made using the Monte Carlo method for probability and sensitivity analysis. Essential oils appeared to be significant contributors to limonene exposure, particularly on the face. The authors note this work is a first step toward determining the aggregate exposure levels of users to other fragrance compounds with sensitizing potential.

Animal-free Fragrance Sensitization Test

A Natsch, R Emter, T Haupt and G Ellis, Toxicol Sci (Jun 1, 2008), available at

Most cosmetic regulations prohibit the use of animal testing for safety assessments, although the local lymph node assay (LLNA) in mice is allowed where in vitro data is insufficient. And according to these authors, to quantitatively assess fragrance risk, a “no expected sensitization induction level” (NESIL) is required; i.e., a dose not expected to cause sensitization in humans. This is challenging to derive from nonanimal data, so the LLNA is typically used.

The present work offers an alternative. It describes a workflow based on a material’s structural information, reactivity data, KeratinoSens assay results and more to predict LLNA results. In vitro and in vivo data on close analogues was then used to estimate the certainty of predictions. The authors concluded that, in data-rich fragrance ingredient domains, sensitization risk assessment without animal testing is possible in most cases by this integrated approach.

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