Methyl anthranilate, grape

The principal aroma and flavor agent of Concord grapes, methyl anthranilate, provides a related example ... 

Sour Grapes Methyl Anthranilate as Feeding Repellent for Birds... 

Fortunately, such sophistication is not always necessary to compare containers. For example, a few days after the gas chromatography tests were completed, we opened the jars and were able to detect by sniffing that the grape odor from one container was noticeably more distinct than from the other. The methyl anthranilate, which had eluded the gas chromatograph, could be detected qualitatively and, for comparative purposes, quantitatively by the human nose. 

Feeding repellents for pest birds are the most important application of chemical stimuli to manipulate bird behavior. Methyl anthranilate (Fig. 13.1) and dimethyl anthranilate, esters of benzoic acid, are found in concord grapes and are used as artificial flavorings. Starlings, Sturnus vulgaris, have an aversion to methyl anthranilate, which irritates the trigeminal nerve, and they feed less on food flavored with a variety of anthranilates. They avoid the more volatile anthranilates most. The odor is partly responsible for the effect contact is not necessary. In one particular experiment, only volatile compounds were aversive (Mason and Clark, 1987). If only anthranilate-treated food is offered, the birds will accept more of the flavored food than they do if they offered a choice between... 

C8H9NO2, Mr 151.16, bp2w 135.5 °C, df 1.1682, ng 1.5815, occurs in a large number of blossom essential oils (e.g., neroli, ylang-ylang, and jasmin oils), grapes, and citrus oils. It occurs as white crystals mp 24-25 °C), or a yellowish liquid, that show blue fluorescence and have an orange blossom odor. Methyl anthranilate is prepared by esterification of anthranilic acid with methanol or by reaction of isatoic anhydride with methanol [163]. 

The development of methyl anthranilate in Concord grapes was reported by Robinson et al. (43) to occur during the last stages of maturity and within the four week period from mid-September to mid-... 

Table VII. Methyl Anthranilate Content of Commercial Eastern Grape Musts, 1972...

The Ives grape is of special interest both from the aspect of pigmentation (classed as teinturier) and its unusual flavor. Although it has a significant concentration of methyl anthranilate, other components distinguish its flavor from that of Concord. 

The Scuppemong grape has a distinctive flavor characteristic. Kep-ner and Webb (47) analyzed the volatile essence of this grape and identified six alcohols, including 0-phenylethyl alcohol, five aldehydes, and five esters. No nitrogen or sulfur containing compounds were found which indicated the absence of methyl anthranilate. 

Amine and Aminophenol Derivatives. Amines and aminophenols (Table VIII) react with the F-C reagent about as predicted considering the aromatic amino groups equivalent to phenolic hydroxyls. This would be an important interference with total phenol assay in samples with appreciable aromatic amine content. Fortunately, for this and other reasons as well, the major wine grapes and most other fruit and vegetable products are free of significant concentrations of aromatic amines which would interfere. Correction might be made for methyl anthranilate... 

Quantify peaks of interest (e.g., methyl anthranilate in Concord grape samples). 

Figure G1.1.3 FID gas chromatogram of a direct injection of the headspace above concentrated extract of Concord grape essence using OV101 substrate. Note the size of the methyl anthranilate peak and the absence of a convincing peak for p-damascenone.

Figure G1.1.3 shows a chromatogram of the headspace of Concord grape essence prepared by direct injection. At retention index 1320 is the peak caused by methyl anthranilate, one of the strongest odorants characterizing Concord grapes however, (i-damascenone, the second most potent odorant in Concord grapes, elutes at 1360 but is not visible. This is because P-damascenone is lOOOx more potent (i.e., its odor threshold is lOOOx lower than methyl anthranilate). This is typical result for the direct injection of headspace from natural products. Figure Gl.1.4, on the other hand, shows the injection of an extract of Concord grape essence concentrated 500-fold with the fi-damascenone peak large enough for quantitation.

Figured.1.4 An FID chromatogram of concentrated extract of the same Concord grape essence shown Figure G1.1.3, drawn to display the data on a linear retention index scale. By simply comparing the index of a peak with the data listed in the flavornet, the odorants that have similar retention indices can be determined. Notice how large the methyl anthranilate peak is, but still no convincing peak for p-damascenone, even though both compounds have the same odor activity (intensity).

Figure G 1.8.4 shows a graphical display of dilution analysis data and Table Gl.8.1 shows the data in tabular form. Notice that, as also shown for concord grapes in Figure G1.1.3, the methyl anthranilate peak in the FID is ten times...

If you carefully smell the original Kool Aid sample and carefully smell the collected fractions, where does the grape smell elute Does it elute The smell is due to another organic compound, methyl anthranilate, whose structure is shown below. 

Birds such as starlings attack Concord grapes less than other grape varieties. Concord grapes contain comparatively high levels of methyl anthranilate (MA) ... 

Methyl anthranilate Methyl N-methyl anthranilate Trametes versicolor Mosty-fruity, Concord grapes... 

CIC The basic Muscat note is produced from linalool, balanced with further terpene alcohols, geraniol and linalool oxides. The catty odour of the concord grape is based on methyl anthranilate, combined with ethyl-3-mercapto propionate, benzaldehyde adds the touch of a seedy character. 

The observation that birds do not eat Concord grapes led to the isolation of methyl anthranilate (11.27), which is now used to keep gulls off airports and Canada geese off of lawns.146 Before this use, 15,000 gulls had to be shot in 1991 at John F. Kennedy Airport in New York City. 

Very few esters are present in grapes. Odoriferous molecules such as methyl anthranilate are responsible for the foxy odor in Vitis labrusca grapes and wines made from them. There are also methoxyl groups in pectins that release methanol by hydrolysis (Section 2.2.1). 

Methyl anthranilate was long considered to be solely responsible for the foxy smell of Vitis labrusca and Vitis rotundifolia grapes (Power and Chesnnt, 1921). It is now known that other compounds are involved in the aromas of these varieties (Fignre 7.17). 

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