Despite its uniquely sweet flavour and intense aroma, wild strawberries are far more prized than their store-bought cousins. Nonetheless, some companies manufacture a synthetic version of this flavor since it is hard to find in the wild. An edible fungus made from waste from black currant juice production has now been used by researchers to make a naturally derived wild strawberry aroma reported in ACS’ Journal of Agricultural and Food Chemistry.
These small, flavored wild strawberries grow in forests, but they are usually smaller than cultivated strawberries. The combination of their distinctive aroma and taste makes a natural wild strawberry flavor hard to get into foods because of its rarity and size. Interestingly, some species of fungi have the ability to synthesize pleasant odor compounds from plant material, including vanillin, raspberry ketone, and benzaldehyde, which has an almond-like scent.
Foods such as tea, carrot peels, and even tea leaves can break down and release fruity and floral aromas when exposed to Wolfiporia cocos, a specific brown-rot fungus. It is likely that the black currant juice industry provides a particularly plentiful and nutrient-rich substrate for the fungus, since it produces so many pulp, seeds, and skins that are usually discarded as waste products.
To achieve a unique aroma associated with wild strawberries, Holger Zorn and colleagues grew W. cocos on black currant pomace and tweaked the conditions to naturally generate the aroma associated with wild strawberries.
Initially, scientists fed black currant pomace to W. cocos as its primary source of nutrition, creating aromatic scents that were both fruity and floral. In addition to the ammonium nitrate and monopotassium phosphate, the team added sodium L-aspartate monohydrate and other substances to the medium. The culture then emitted a scent similar to wild strawberries. A GC-MS-O analytical technique and 10 trained panelists helped the researchers determine the compounds that contributed to the scent.
It was (R)-linalool, methyl anthranilate, geraniol and 2-aminobenzaldehyde that emitted the most intense odors, as perceived by the sensory panel. Using artificial versions of these compounds, the researchers found that sensory experts rated the odor of the model wild strawberry as being very similar to the odor of the cultivated fungus.
Therefore, researchers say they’ve created a sustainable and cost-effective way to produce a flavoring ingredient that could be used industrially as a natural flavoring agent by growing W. cocos on food waste.
Funding for the study was provided by the Hessian initiative for scientific and economic excellence (LOEWE) within the Hessian Ministry of Higher Education, Research and the Arts.
Source: Svenja Sommer et al. Wild Strawberry-like Flavor Produced by the Fungus Wolfiporia cocos─Identification of Character Impact Compounds by Aroma Dilution Analysis after Dynamic Headspace Extraction. Journal of Agricultural and Food Chemistry, 2021; DOI: 10.1021/acs.jafc.1c05770