Lignin is the main determinant of total dietary fiber differences between date fruit (Phoenix dactylifera L.) varieties

Date fruits (Phoenix dactylifera) of ten varieties, collected in the United Arab Emirates, were studied to determine their dietary fiber content and composition. Fourier transform infrared (FTIR) spectroscopy indicated that the dietary fiber components in all the date fruit varieties was similar. The major dietary fiber components, including cellulose, hemicellulosic components, lignin, and pectin, were analyzed by the Uppsala method. The total dietary fiber content in the date fruits analyzed (5.2%–8.3%) is comparable to commonly consumed dried fruits and is correlated with the content of lignin. The lignin was the main determinant of the total dietary fiber content in dates and its content was higher in semi-hard and hard fruit varieties.