Starch in its pure form can be used as a functional component of numerous food products; however, much better results both in terms of technological and economical aspects are obtained with the use of modified starches. The aim of the work was to establish how chemical modification affects the molecular structure of potato starch and, as a consequence, its rheological properties as well as texture forming ability. Commercial food-grade potato starch preparations oxidized starch, acetylated starch, distarch phosphate, acetylated distarch phosphate and acetylated distarch adipate were the investigated material. The experimental methods included: viscographic analysis of pasting properties, flow rheometry, texture profile analysis, size exclusion chromatography with triple detection. The obtained data were further analyzed employing principal component and hierarchical cluster analysis. It was found that chemical modification leads to substantial changes in the molecular and functional properties of starch products. Oxidation process leads to depolymerization, which causes a substantial decrease in viscosity. Acetylation results mostly in stabilization of rheological properties during thermal processing. Crosslinking of starch leads to an improvement in thickening capabilities, while the type of crosslinking agent used for modification has a secondary effect. Sterilization of all types of modified potato starch pastes leads only to minor changes in their texture and rheological properties.
The paper presents the effect of replacing starch (at 2%, 6% and 10%) with cricket powder (CP) on the water behavior studied by the 1H NMR method, as well as the texture of gluten-free bread during 6-day storage. It was noticed that the bread crumb containing CP has lower water transport rate than the control bread crumb, while concluding that 2% CP stabilizes water transport throughout the entire staling time range. The NMR analyzes showed that the initial T21 values are the higher, the more starch has been replaced with the CP, however, after 6 days of storage, all tested samples are characterized by similar values of the T21 parameter. A decrease in long component of spin-spin relaxation time T22 during storage was also observed. It has been noted that the replacement of starch to 2% and 6% CP causes an increase in the molecular dynamics of water. The less starch present, the greater the potential for bulk molecules to move. The observed changes at the molecular level resulted in macroscopic changes in the texture of the bread. After analyzing the hardness parameter of the tested breads, it was found that on the day of baking, bread without the addition of CP had significantly higher values of this parameter than breads with CP. For the sample without CP, the highest increase in total hardness change (123.93%) was noted during storage, which indicates the fastest texture change process. Based on the results obtained, it can be concluded that the use of cricket powder to enrich gluten-free bread can not only improve the nutritional value, but also effectively delay the process of bread staling.
Industrial application of starch as a texture-forming agent is primarily limited to preparations obtained from waxy corn and potatoes. The main reason behind this is its functionality, which depends mostly on rheological properties. However, in food product matrices, these properties change. Despite the vast amount of information on the rheological properties of various starches, the rational choice of thickener appears to be an extremely difficult task. The aim of the work is to systemize the information on the rheological properties of most popular starches in matrices of various food products, applying principal component and cluster analyses. The investigated material is potato and corn starch of the normal and waxy varieties. Binary mixtures containing salts or sweetening agents, as well as four different food products (ketchup, mayonnaise, pudding, and jelly), are investigated. It was found that compared to normal varieties, waxy starches reveal many similar rheological properties in all investigated models and food systems. Furthermore, in most applications, one waxy starch variety may be substituted by another, with no significant impact on the rheological properties and texture of the food product. Moreover, waxy starch preparations are less altered by the presence of cosolutes, i.e., salts and sugar alcohols. Starch model systems were proven to be useful only for rapid thickener screening tests and cannot be recommended as a final reference for the quality design of food products.