Effects of different harvesting seasons on antioxidant activity and phenolic content of prickly pear cladode juice

The study was carried out to evaluate the effect of environmental conditions on the phenolic content and antioxidant activity of two distinct cladode genotypes under three sampling dates (spring, summer, and winter). The juice extracted from Opuntia ficus-indica (spineless) and Opuntia megacantha (spiny) genotypes was analyzed for their phenolics content and antioxidant activity using DPPH, ABTS, and FRAP methods. The composition of major phenolics substances of cladode juice harvested in March was determined by HPLC analysis. The average of the total phenolics content ranged from 455.65 to 542.70 μg GAE mL−1. The antioxidant activity varied from 1.78 to 4.10 μmol TE mL−1 by DPPH assay, 12.78–23.10 μmol TE mL−1 by ABTS assay and 1.74–3.33 μmol TE mL−1 by FRAP assay. Higher values of antioxidant activity and polyphenols content were registered in summer. O. ficus-indica recorded significantly higher values for the parameters compared to O. megacantha. Keywords: Prickly pear cactus, Opuntia ficus-indica, Opuntia megacantha, Cladode juice, Antioxidant activity, Polyphenol

Study of pomological traits and physico-chemical quality of pomegranate (Punica granatum L.) genotypes grown in Italy

Pomegranate is considered a functional food but several local accessions and cultivars are widespread in different countries. The characterization of local germoplasm allows to identify genotypes that possess the highest nutraceutical value compared to standard cultivars (cvs.) and that are well-adapted to local climatic conditions and could be used in the breeding programs. The aim of this study was the characterization of pomological and physico-chemical traits as well as antioxidant system in local pomegranate accessions (‘Mondrone Dolce’, ‘San Pietro’, ‘Granato’ and ‘Roce’), comparing to an Italian (‘Dente di Cavallo’) and international cvs. (‘Wonderful’). A high variability of the pomological traits resulted among the cultivars. ‘Wonderful’ showed the highest value of anthocyanins (554.99 ± 0.05 mg C3gE L−1), total phenols (1494.00 ± 116.20 mg GAE L−1) and antioxidant activity (EC50values 21.21 ± 0.05 µL mL−1), whereas ‘Granato’ had the highest values among local accessions. Furthermore, the antioxidant enzymes activities varied with genotypes. Principal component analysis revealed great differences in all investigated parameters among pomegranate genotypes. ‘Mondrone Dolce’, ‘San Pietro’ and ‘Dente di Cavallo’ showed similar pomological and nutraceutical traits compared to ‘Granato’ and ‘Roce’. Conversely, ‘Wonderful’, due to its peculiar traits, revealed significant differences with respect to other genotypes