Validated Method for the characterization and quantification of extractable and non-extractable ellagitannins after acid hydrolysis in pomegranate fruits, juices, and extracts


Rocio Garcia-Villalba and colleagues from CEBAS-CSIC (ES) have developed a new method for the analysis of the extractable and non-extractable ellagitannins, based on the quantification of acid hydrolysis products.

Despite the interest and potential health benefits (antioxidant, anti-inflammatory, antimicrobial, and anti-carcinogenic activities) of ellagitannins, reliable data on content in pomegranates and derived extracts as well as food products is lacking. Often content is under-estimated because of their complexity, diversity and the absence of commercially available standards. Thus a method for their correct quantification and characterisation is important.

Garcia-Villalba et al. found ellagitannin content and type were highly variable in the the 11 pomegranate extracts studied, including ellagic acid, gallic acid, sanguisorbic acid dilactone, valoneic acid dilactone, and gallagic acid dilactone. The method was optimised using a pomegranate peel extract and, to quantify non-extractable ellagitannins, freeze-dried pomegranate fruit washydrolyzeddirectly prior to extraction.

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  1. Ellagitannin C-glycosides are present in pomegranates.
  2. The method was validated with high reproducibility across six laboratories (standard deviations less than15%).
  3. Applicability was demonstrated using several pomegranate extracts, different parts of pomegranate fruit (husk, peels, and mesocarp) and commercial juices.