Evaluation of Unsaturated Alkanoic Acid Amides as
Maskers of Epigallocatechin Gallate Astringency
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Abstract
Some
foods, beverages, and food ingredients show characteristic
long-lasting aftertastes. The sweet, lingering taste of high intensity
sweeteners or the astringency of tea catechins are typical examples.
Epigallocatechin-3-gallate (EGCG), the most abundant catechin in green
tea, causes a long-lasting astringency and bitterness. These sensations
are mostly perceived as aversive and are only accepted in a few foods
(e.g., tea and red wine). For the evaluation of the aftertaste of
such constituents over a certain period of time, Intensity Variation
Descriptive Methodology (IVDM) was used. The approach allows the measurement
of different descriptors in parallel in one panel session. IVDM was
evaluated concerning the inter- and intraindividual differences of
panelists for bitterness and astringency of EGCG. Subsequently, the
test method was used as a screening tool for the identification of
potential modality-selective masking compounds. In particular, the
intensity of the astringency of EGCG (750 mg kg<sup>–1</sup>) could be significantly lowered by 18–33% during the time
course by adding the trigeminal-active compound <i>trans</i>-pellitorine (2<i>E</i>,4<i>E</i>-decadienoic
acid <i>N</i>-isobutyl amide <b>1</b>, 5 mg kg<sup>–1</sup>) without significantly affecting bitterness perception.
Further, structurally related compounds were evaluated on EGCG to
gain evidence for possible structure–activity relationships.
A more polar derivative of <b>1</b>, (2<i>S</i>)-2-[[(2<i>E</i>,4<i>E</i>)-deca-2,4-dienoyl]amino]propanoic
acid <b>9</b>, was also able to reduce the astringency of EGCG
similar to <i>trans</i>-pellitorine but without showing
the strong tingling effect