Joke Putseys

Functionality of short chain amylose-lipid complexes in starch-water systems and their impact on in vitro starch degradation.

Monodisperse short-chain amorphous or semicrystalline amylose-glycerol monostearate (GMS) complexes, or, as a reference, pure GMS, were added to starch dispersions which were gelatinized and allowed to cool. The largest impacts on rheological properties were observed when GMS or amorphous GMS complexes were added. The controlled release of the short amylose chains of the latter induced double helix and, thus, network formation, resulting in higher viscosity readings. As the lipid is set free after starch gelatinization, it is assumed that it complexes with amylose leached outside the granule, whereas additional pure GMS can probably to a greater extent complex inside the granule. Semicrystalline complexes could be considered as inert mass in the starch systems as their melting temperature exceeded the temperature reached during the experiment. The additives also impacted starchs sensitivity to enzymatic degradation. GMS addition reduced the resistant starch (RS) content of the gels and increased their hydrolysis index (HI). Added amorphous or semicrystalline complexes, on the other hand, yielded gels with a higher RS content and a lower HI. Addition of amylose-lipid complexes to starch suspensions impacts starch gel characteristics and decreases its digestion rate, possibly by releasing short amylose chains in a controlled way that then participate in amylose crystallization and, hence, RS formation.

Fate of Starch in Food Processing: From Raw Materials to Final Food Products

Starch, an essential component of an equilibrated diet, is present in cereals such as common and durum wheat, maize, rice, and rye, in roots and tubers such as potato and cassava, and in legumes such as peas. During food processing, starch mainly undergoes nonchemical transformations. Here, we focus on the occurrence of starch in food raw materials, its composition and properties, and its transformations from raw material to final products. We therefore describe a number of predominant food processes and identify research needs. Nonchemical transformations that are dealt with include physical damage to starch, gelatinization, amylose-lipid complex formation, amylose crystallization, and amylopectin retrogradation. A main focus is on wheat-based processes. (Bio)chemical modifications of starch by amylolytic enzymes are dealt with only in the context of understanding the starch component in bread making.