Justyna Rosicka-Kaczmarek

Characterization of Amylose-lipid Complexes Derived from Different Wheat Varieties and their Susceptibility to Enzymatic Hydrolysis

Starches from eight wheat varieties were analyzed for contents of dry matter, protein, pentosans, apparent and total amylose, total lipids, starch lipids, phosphorus, lysophospholipids and amylose-lipid complex (AML). Processes of starch gelatinization, reversible dissociation of AMLs and its susceptibility to degradation by α-amylase were monitored by differential scanning calorimetry (DSC). Degree of crystallinity of starches were evaluated based on X-ray diffraction pattern. Starches from different wheat varieties show some slight differences in terms of chemical composition, thermal properties and susceptibility to enzymatic hydrolysis. Endotherms and exotherms of most starch samples obtained by DSC contained single peaks, which indicated that AML complexes existed in one polymorphic form. Only AMLs formed by amylose from Symfonia cultivar was reflected by the double-peak exotherm on cooling of starch gel. Our studies showed that there was no correlation between AML content and enthalpy of its degradation in native starch. During enzymatic hydrolysis of starch AML complex in all examined starches underwent considerable degradation. Enthalpies of dissociation of AMLs, which remained after amylolysis were significantly lowered (80—90%) as compared to that of undigested starch. The susceptibility of AMLs to degradation by α-amylase did not depend on its amount (based on calculation from LPLs), but probably on its structure.

The influence of arabinoxylans on the quality of grain industry products

Arabinoxylans (AX) are the major components of cell walls of cereal grains and play a significant role in shaping the physical and chemical properties of products obtained from this raw material. Thanks to their properties, such as high capacity to absorb water, they show a tendency to form high viscosity solutions. This determines their directions of use. The physicochemical properties of AX depend primarily on their molecular structure, i.e., the degree and profile of substitution, as well as the xylose-to-arabinose ratio. This article presents the most important information on the topic of AX, such as the occurrence in cereal grains, chemical structure as well as physicochemical and prebiotic properties. Moreover, particular attention has been paid to the role of these polysaccharides in major biotechnological processes associated with the processing of cereals, such as baking, brewing, production of glucose hydrolysates and animal feed, and how it is reflected in the quality of products derived from cereal grains.

The Functionality of Wheat Starch

Abstract Starch constitutes the major carbohydrate in the endosperm of wheat grains and serves as a multifunctional ingredient for the food or nonfood industries. The functional properties of starch are important for their use in food products and industrial applications, especially the pasting properties and gelatinization and retrogradation characteristics. These properties in respect to wheat starch are characterized in this chapter. Furthermore, the chapter discusses the methods of wheat starch isolation, its molecular structure, and the resulting functional properties. The influence of its components, protein, lipids, and nonstarch polysaccharides, present both on the surface and inside wheat starch granule, on shaping its properties has been characterized. The important role of starch interactions with bioactive compounds on the formation of its functional properties has been indicated as one of the most intensively developing research area concerning starch. The positive impact of resistant starch (RS) on the improvement of human health is also stressed.