PHENOLICS IN WALNUT LIQUEUR

Traditional walnut liqueur is made from green walnuts just prior to hardening of the endocarp.
Fruits are left to steep in food-grade ethanol (40%). This drink is commonly used in folk medicine.
For improving the amount of phenolic extraction, 3 different concentrations of alcohol (40%, 60% and 96% ethanol) were used.
Two different cultivars (‘Elit’ and ‘Franquette’) were utilized in preparing the liqueur.
Several groups of phenolics were identified by high performance liquid chromatography (HPLC) with diode array detection.
Commonly analysed phenolics in liqueur were: gallic, ellagic, vanillic, protocatechuic, syringic and p-coumaric acid, juglone and 1,4-naphthoquinone.
Extraction of some phenolics increased with higher concentration of ethanol and vice versa.
Interestingly, total analysed phenolics were highest using 40% ethanol for extraction.
Phenolics were extracted in similar amounts compared to the traditional method of preparing the liqueur.

I International Symposium on Human Health Effects of Fruits and Vegetables

F. Stampar, A. Solar, M. Hudina, R. Veberic, M. Colaric, J. Fabcic

walnut, Juglans regia L., green fruits, phenolic compounds

https://doi.org/10.17660/ActaHortic.2007.744.54