English abstract
Date powder can be used as an alternative of sugar; however, fiber content could affect the
physicochemical characteristics of date powder negatively. Reducing the particle size of date
powder could potentially enhance the desirable characteristics of date powder as sugar
replacer. This study aims to investigates the effect of micronization of Mebsili date powder
on the structural, chemical composition, and physicochemical characteristics. Specifically,
the study aims to examine the effect of size reduction of date powder fraction on its moisture
content, solubility, absorption, hygroscopicity, crystallinity, sugar content, and dietary fiber
content by using FTIR, HPLC, DMTA, SEM, XRD, and DSC. Three sizes were produced
with particle sizes of 125μm, 50μm, and 25μm from Mabsli date powder using heavy duty
grinder and ball milling (BM). It was found that glucose and fructose content increased as
the size fraction of the powder decreases. This increase was followed by an increase in glass
transition temperature. As a consequence, date powder became more hygroscopic. Insoluble
dietary fiber constituents, such as cellulose and lignin, underwent breakdown during the
milling process, resulting in a decrease in their content that improves their solubility. In
contrast, pectin content showed an increase as sample fraction size reduced from 125μm to
50μm and 25μm (1.32 g/100 g, 1.50 g/100 g, and 2.92 g/100 g respectively). Fourier-
transform infrared (FTIR) analysis indicated that BM does not generate any new chemical
group bands. However, the results indicated that certain characteristic bands showed changes
in absorbance and/or wave number as the size of the powder was lowered. These changes
correlated to the increase in the hydroxyl group content. X-ray diffraction revealed a
decrease in crystallinity when fraction size was reduced. SEM images likely showed
alterations in the fraction size, and shape, implying that ball-grinding process has a significant
impact on their physical characteristics. These findings demonstrate that micronization
induces modifications in the dietary fiber composition of date powder, thereby expanding its
potential applications as a functional ingredient in the food industry.
