Analyzis of the bioactive compounds and antioxidant capacity of fruit Cydonia oblonga

The authors compared Cydonia oblonga fruits from two regions of Transylvania with regard to their polyphenol content, total acidity, and vitamin C levels. The polyphenol content was determined using the Folin-Ciocalteu method, which is based on a redox reaction involving electron transfer from phenolic compounds to the Folin-Ciocalteu reagent. The results ranged from 365.96 ± 1.7 to 422.93 ± 2.3 mg GAE/100 g dry weight in aqueous extracts and from 397.50 ± 1.9 to 998.78 ± 4.5 mg GAE/100 g dry weight in methanolic extracts. These values are in agreement with those previously reported in the literature. No significant differences in polyphenol content were observed either between the harvested samples or between the solvents used. However, the analytical method and storage duration of the fruits may influence the measured polyphenol content. The flavonoid content of the fruits was determined using the method described in the 10th edition of the Romanian Pharmacopoeia. The results ranged from 30.9 ± 1.02 to 34.0 ± 1.05 mg QE/100 g dry weight for aqueous extracts and from 19.2 ± 0.98 to 20.7 ± 0.87 mg QE/100 g dry weight for methanolic extracts. The total acidity of the fruit extracts was measured by acid-base titration with potentiometric endpoint detection. The samples showed slight differences depending on the harvesting location and the extraction solvent (methanol or water). The vitamin C content was determined by bromatometric titration using p-ethoxychrysoidine as the endpoint indicator. The ascorbic acid content was found to depend on both the geographical origin of the samples and the nature of the extraction solvent.