1. Chemical composition of HS
Table 1 shows the chemical composition of HS. According to the results, total dietary fibre was the major component, amounting to a mean of 55%. A mean of 86% of the fibre was composed of insoluble fibre, with significant differences among the varieties. The lipid content ranged from 109.96 ± 1.68 g/Kg for Georgia samples to 187.55 g/kg for San Giovanni samples. The values were similar to those reported by Anil (2007) as well as Turhan, Sagir, and Ustun (2005) for other varieties.
The TPC values assessed in hazelnut skin extracts significantly characterized the varieties. The highest values were measured in the Georgia skin extracts, and the lowest values were found in the San Giovanni skin extracts; nevertheless, there were no significant difference for TGT.
The results of the RSA assays revealed a different trend - the RSA had the highest values reported for the Georgia sample, followed by San Giovanni and TGT.
The use of different extraction methods and/or different data expression methods prevented the comparison of our TPC and RSA results with those published by other authors.