Deciphering the structure and properties of wheat starch-based paste through a multi-response factorial design experiment

Abstract

Wheat starch-based pastes, including wheat starch paste and wheat flour paste containing wheat protein, are extensively employed in the conservation of paper-based heritage objects. This study investigated the effects of mass fraction, protein, and gelatinization temperature on the key properties of the pastes using a 23 factorial experimental design. Characterization confirmed the absence of long-range ordered structures and the presence of short-range ordered features in the prepared pastes. Results demonstrated that protein predominantly affects pH variation. Gelatinization temperature was identified as the dominant factor for water holding capacity, whereas both gelatinization temperature and mass fraction, along with their interaction, governed the apparent viscosity, a conclusion directly supported by SEM observations showing that these conditions promote a denser and honeycomb-like network structure. Furthermore, mass fraction influences relative crystallinity, while both gelatinization temperature and protein collectively enhance thermal stability. These findings provide scientific basis for wheat starch-based paste in paper heritage conservation.