Effects of sucrose addition on the rheological properties of citrus peel fiber suspensions before and after drying

In this study we investigated the impact of sucrose on the rheological properties of high pressure homogenized citrus peel fiber suspensions before and after drying. Drying of such cellulose-rich microfibrillated systems often goes paired with structural collapse which leads to a product with sub-optimal functional properties (e.g. swelling, water holding ...) upon reconstitution. The purpose was to better understand the role of sucrose on preventing structural collapse during drying and consequently identify the optimum fiber/sucrose mixing ratio allowing optimal recovery of the functional properties upon reconstitution. High pressure homogenized samples were prepared by fixing the fiber concentration at 1% w/w while varying sucrose content from 0% to similar to 60% w/w. Through these investigations, we demonstrated that the presence of sucrose (at the given concentrations) seems to have a negative impact on the functionalized fiber properties prior drying, whereas a positive effect could be observed for the dried functionalized fibers when they were co-dried in presence of 30% w/w sucrose. This sucrose concentration allowed recovery of the functionalized fiber properties prior drying. The initial fiber properties recovery suggests that sucrose can act as a hydrogen bond blocker or a spacer that limits the irreversible aggregation effect usually observed for plant cell wall-derived fibers upon drying.