Dietary fiber components, microstructure, and texture of date fruits (Phoenix dactylifera, L.)

Date fruits vary widely in the hardness of their edible parts and they are classifed accordingly into soft, semi-dry, and dry varieties. Fruit texture, a signifcant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profle of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fber contents varied 5.2–7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profle analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the diferent fber constituents correlated variably with the diferent parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate signifcantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.