Project Details Recommended Methods for the Structural Identification of Biologically Active Compounds in Food and Flavor Chemistry

Project No.:
Start Date:
01 October 2013
End Date:
12 August 2019
Division Name:
Chemistry and the Environment Division
Division No.:


The objectives of this proposal are to develop standards for the unequivocal structural identification of biologically active organic compounds occurring in foods and agricultural products. In this context “biological activity” is defined in the broadest terms, including for example: odor and taste; nutrients and anti-nutrients; plant and fungal toxins; insect pheromones; allelopathic compounds; contaminants; antioxidants, etc.

The rationale for the proposal is that without adequate identification, reports of biological activity for specific components are suspect or meaningless.

The intended outcome is to produce a document setting down standards for compound identification that must be adhered to by authors publishing original research.


The increasing reliance on instrumental methods for establishing the structure of compounds in food chemistry has often resulted in improper or incomplete characterization of chemical constituents. For example, many examples exist in the literature where compounds have been defined solely by comparison with mass spectrometric databases. Similarly, compounds isolated by preparative chromatography are frequently described as “amorphous solid” with no attempt being made to recrystallize to a constant melting point as a criterion of purity. Another problem is the failure to report optical activity data or to define the stereochemistry of compounds that possess chiral centers.

In the context of food chemistry, these deficiencies are a serious problem since the rationale for isolating and identifying constituents is almost always to elucidate their biological activity. Such activity may define, for example, odor and taste, nutritional properties, toxicity, insect attractants or repellents, plant competition, endogenous substances and exogenous contaminants, quality descriptors, etc.

The rationale for this proposal is that without adequate identification, reports of biological activity for specific components are suspect or meaningless. It is well understood that biological activity is highly dependent on subtle changes in structure. A classic example is the odor of R-(-)- and S-(+)-carvone, which smell of spearmint and caraway, respectively, because olfactory receptors can distinguish between these enantiomers. If a biological detection system is capable of such discrimination then it is essential that the structural power of chemistry be applied in a way that matches this capability. This project proposes to define the appropriate standards to be applied.


July 2014 – Project announcement published in Chem. Int. Jul-Aug 2014, p. 14; DOI: 10.1515/ci.2014.36.4.14a

Sep 2016 update – A draft of the document is been reviewed by the task group and suggestions for changes are being incorporated. Five members of the task group had the opportunity to meet at the American Chemical Society meeting in Philadelphia in August and go through the document point-by-point to ensure consistency between sections. A final report is expected early 2017.

August 2019 – A Technical Report prepared by Molyneux, R., Beck, J., Colegate, S., et al., titled “Guidelines for unequivocal structural identification of compounds with biological activity of significance in food chemistry” is published in Pure and Applied Chemistry 2019, 91(8), pp. 1417-1437;

Last update: 6 August 2019