قدرت تورم

This study aimed to investigate the effect of chemical modification with adipic acid/acetic anhydride mixture (1:30) on the physicochemical and functional properties of amaranth starch and also to determine the optimal conditions for amaranth starch chemical modification with the mentioned mixture. Amaranth starch was isolated and then modified under nine different treatments designed by the Taguchi method using three main chemical modification factors, including the mixture of adipic acid /acetic anhydride concentration (4%, 6%, and 8%), reaction time (60, 90 and 120 min) and suspension pH (8, 8.5 and 9). Swelling power, solubility, color, paste clarity, thermal properties, freeze-thaw stability, and apparent viscosity of starch samples were investigated. Modification optimal conditions were determined using Taguchi analysis and the related percentage deviation (RPD) method. The result obtained from this study showed that the chemical modification significantly changed the physicochemical and functional properties of amaranth starch. Adipic acid/ acetic anhydride mixture improved the swelling power, solubility, viscosity, and paste clarity of modified starch than native. Modified starch powders showed more lightness, less yellowness, and redness in color. Chemical modification reduced gelatinization temperatures, gelatinization enthalpy, and freeze-thaw stability. However, since other food components such as sugars, salt, hydrocolloids, etc., influence the freeze-thaw stability of starch, the possibility of modified amaranth starch utilization as a stabilizer, thickener, or fat replacer in food products with the mentioned mixture needs additional research is required to be conducted. The optimum modification conditions were a concentration of 6%, a reaction time of 120 minutes, and a pH of 9.

Rice is a food product that provides meals for more than half of the world's population. Rice varieties and cultivated areas are factors that affect on the rice cooking properties and cooking behavior. In this study, the effect of various cultivated areas on chemical properties, swelling power, solubility and rheological and textural properties of Tarom Mahali was investigated. The results showed that Tarom Mahali of northern Iran consists of average amylose content (20-25%) and appropriate gelatinization degree (3-5), which represents high quality of Tarom Mahali. On the other hand, rice of Fereydunkenar region has the lowest protein, fat, amylose content and the gelatinization degree and highest content of swelling power and solubility (P

Chemical modification of starch is of the prevalent used methods in order to improve its physicochemical attributes. In this study phosphorylated and hydroxypropylated wheat starches were produced with 0.096 and 2.106% degree of substitution, respectively; and then some of their physicochemical and rheological attributes were studied. The implemented chemical changes due to hydroxypropylation and phosphorylation on native wheat starch were exhibited by FT-IR. X-ray diffraction (XRD) results showed that the native and phosphorylated wheat starches had the most and least amount of crystallinity with 17.34 and 16.14%, respectively. The influence of temperature on swelling power revealed that the native (Ea=46.111) and hydroxypropylated (Ea=26.603) wheat starches had the most and least thermal sensitivity, respectively. Besides, in the case of solubility index, it was observed that native (Ea=77.674) and phosphorylated (Ea=44.478) starches had the most and least thermal sensitivity, in the order given. The high value of determination coefficient (0.895-0.979) attained from the modeling results of the solubility changes with temperature using two power law equations, demonstrated the high capability of these models in prediction. It was seen that hydroxypropylation and phosphorylation of wheat starch resulted in 2.65 times increase and 17.58 times decrease in paste clarity compared to native starch (p

In this study، variations of the pasting properties، swelling power and solubility of two rice starches، low amylose (8. 7%) and high amylose (26%) at two citric acid concentrations (0 and 0. 01 M) was investigated. The results showed that the peak viscosity and breakdown viscosity of rice starch decreased significantly.