Sugar Types, Phenolic Contents, and Antioxidant Activities for 17 Saudi Arabian Date Cultivars and Their Relations with Glycemic Indices

Abstract

Sugar types, sugar amounts, phenolic contents constituents were determined in fresh fruits of 17 Saudi date cultivars and the obtained values were correlated with the corresponding vales of glycemic index. Glucose and fructose were presented in all tested cultivars in the range 104–395 g kg−1 and 82–361 g kg−1, respectively. Glucose/fructose ratio constituted between 1.03–1.27. Sucrose was considered the main sugar in four date cultivars. Total phenolics presented in the range 2.15–3.86 g kg−1. Antioxidant activities varied between tested cultivars and ranged from 2.46 to 9.80 µmol Trolox g−1 as assayed by DPPH method and from 5.90 to 17.78 µmol Trolox g−1 as assayed by FRAP method. No significant correlation was found between the levels of glucose, fructose, sucrose, total phenolics and antioxidant activity with the corresponding glycemic index values.