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The chemistry of Strawberry

Giuseppe Coglienti

THE CHEMISTRY OF STRAWBERRY

The vital problem of strawberry-flavored products when you find yourself unable to use the fruit derivative has led to the search for the best solution of imitating the aroma of strawberry since the classic types of wild strawberry and strawberry were more or less set up like this:

  • 7,14% Yara Yara (20% sol in Benzyl Benzoate) [nowadays it won’t make many sense but I’m reporting the original preparations for you to see]

  • 4,08% Bulgarian rose or imitation

  • 2,04% Methyl Benzoate

  • 8,16% Ethyl nitrate

  • 30,61% Ethyl acetate

  • 4,08% Ethyl butyrate

  • 25,51% Amyl acetate 

  • 7,14% Amyl valerianate 

  • 1,02% Methyl cinnamate

  • 10,2% Phenylethyl alcohol

🛒 Buy Strawberry Base HERE!

At the same time as the discovery of ethyl methylphenylglycidate (pseudo aldehyde C16, a product not identified among the natural constituents), hundreds of strawberry bases were marketed in which, in addition to this product and those mentioned at the beginning, many of these flavorings were used in various proportions:

Nerolin Bromelia, amyl butyrate, heliotropin, ethyl propionate, isobutyl butyrate, rum ether, vanillin, butyric acid, alpha ionone, raspberry bases, neroli essential oil, lemon, mint, enanthic ether, ethyl cinnamate, methyl salicylate, butter, and Iris. 

The Maltol (corps pralines, palatone, veltol), a product identified in 1964 in the natural aroma of strawberry and prepared by synthesis, became available. The formulations acquired a different physiognomy because the massive quantities of aliphatic esters previously used gave way to more complex products making compounds with even higher yield than the previous bases. 

And for example, it turned out formulas with the following constituents:

1. anethole, diacetyl, gamma undecalactone, beta-ionone, methyl salicylate, Methyl heptine carbonate, methyl anthranilate, methyl cinnamate, vanillin, benzyl acetate, methyl phenyl glycidate, acetic acid, maltol. 

2. Ethyl lactate, ethyl methylphenylglycidate, ethyl valerianate, diacetyl, methyl amyl ketone, dipropyl ketone, cinnamyl isovalerate, maltol, ethyl vanillin, cinnamyl isobutyrate, gamma undecalactone, ethyl enanthate, and others. 

These interesting formulations also use products not present in nature. 

Other flavoring substances could however be used in such compositions and precisely the natural constituents: cuminic alcohol and anisyl formate. 

Those are probably present in nature but so far not confirmed:

  • isobutyl anthranilate, 

  • benzyl isobutyrate, 

  • neryl isobutyrate, 

Those not found in nature: 

  • Methyl naphthyl ketone

  • 4-methyllacerophenone

  • 3-phenylglycidate ethyl 

The importance of the aroma of strawberries, as it is logical, sensitized research chemists to the need to know what flavoring principles could actually be present in fruits.

On the basis of the results of the surveys, we can make the following list which, despite being drawn up on the basis of precise bibliographic information that makes us raise doubts about some due to attendance given the discrepancy between different authors.

Alcohols

  • Methanol *

  • Ethanol *

  • N-propanol

  • Butanol *

  • Butan-2-olo 

  • Isobutanol

  • Pentan-1-olo 

  • Isoamyl alcohol

  • Hexanol *

  • Trans 2 hexenol *

  • D, L-alpha-terpineol

  • L-(+)-borneol 

  • Terpine

  • Cis-terpinol-hydrate

  • Phenyl-2-ethanol

  • P-hydroxyphenyl-2-ethanol

  • Isophenyl alcohol

  • Pent-1-en-3-ol *

  • Heptan-2-ol *

  • Benzyl alcohol

Carbonyl compounds 

  • Acetic aldehyde

  • N butanal

  • hexanal

  • Hexen-2-al

  • Acetone

  • Methyl-3-butanone

  • Acetophenone 

  • Diacetyl

  • Propanal

  • Acrolein

  • Crotonal 

  • Pent-2-enal 

  • Cis-3-hexenal 

  • Pentan-2-one

  • Eptan-2-one

Esters 

Methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, hexyl acetate, trans-Hexen-2-yl acetate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl isobutyrate, ethyl isobutyrate, ethyl valerianate, ethyl isvalerianate,  ethyl born goat, we love ethyl, ethyl salicylate, ethyl acetate, propyl acetate, methyl caproate, hexyl butyrate, isopropyl butyrate, hexyl crotonate, butyrate di trans-es-2-en-1-yl, alpha-methyl butyrate, alpha-methyl butyrate. 

Free acids

Formic, acetic, propionic, butyric, isobutyric, n-valerianic, isovaleric, caproic, benzoic, cinnamic, salicylic, succinic, (+) alpha-methyl butyric. 

Other products

Vinegar, various acetal, dimethoxy methane, dimethoxy 1,1-ethane, methoxy-1-ethoxy-1-ethane, dimethoxy-1,1-ethane, Ethoxy-1-propoxy-1-ethane, Hydrogen sulfide, metilsolfuro, Dimethyl sulfide, Maltol, Decalactones.

At the end of this long list of products we can say that, according to more recent discussions, 

that the number of alcohols indicated on the bibliography, in reality, should be less but that certainly there are those marked with (*)

That many esters made evident by gas chromatography have not yet been identified, that the characteristic aroma of the strawberry is certainly 85% more due to carbonyl compounds,  esters, and some of the different products than to alcohols. 

The studies for complete identification of the constituents of strawberry aroma continue and so does our reserve for a more faithful reconstruction in the light of the information provided to us by the same research of natural constituents. 

See this product in the original post

Sources:

  • Original publication from Professor G Fenaroli 1969 in italian

  • Revosed formulations and ingredients from Fulvio Ciccolo, 2022

  • Photo by Lewis Fagg, Allec Gomes on Unsplash