Insights into the interaction of CaCl2 and potato starch: Rheological, structural and gel properties

Modulation of the properties of starch gels by a one-step extrusion modification method based on Ca2+-citric acid synergistic crosslinking

Citric acid (CA) is a green and safe food-grade crosslinking agent for starch, but its high crosslinking temperature limits its application. In this study, a "one-step" extrusion modification method based on Ca2+-esterification synergistic crosslinking was proposed for the preparation of high gel performance crosslinked starch at low temperatures (90 °C). The linear and nonlinear rheological properties of crosslinked starch were comprehensively characterized, and the enhancement effect of synergistic crosslinking reactions on starch gel properties was quantitatively studied. The results show that the elastic modulus of the synergistically crosslinked starch (SC-0.5Ca2+, G' = 3116 ± 36) was significantly increased by 879 % compared to the elastic modulus of starch without synergistically crosslinked modification (SC, G' = 318 ± 9). The elastic modulus of starch gels can be adjusted by changing the ion concentration. Nonlinear rheological Lissajous curve analysis results show that the synergistic crosslinked gel system has a stronger anti-deformation ability. In addition, the honeycomb porous structure and smaller pore size distribution of the synergistic crosslinked gels were characterized using scanning SEM. The XPS, FTIR and XRD results suggest that the synergistic crosslinking enhancement effect may involve various molecular forces such as electrostatic attraction, hydrogen bonding and ester bonding.

Rheological properties and microstructure of wheat flour dough systems with enzyme-hydrolyzed mashed potatoes

The interest in incorporating potatoes into wheat dough is increasing. However, potatoes exhibit significant viscosity during thermal processing, affecting product processing and quality. This study aims to find an effective method to reduce the viscosity of mashed potatoes. We aimed to compare the effects of different enzymes (α-amylase, β-amylase, and flavourzyme) and concentrations (0.01%, 0.05%, and 0.1%) on the micromorphology and rheological properties of mashed potatoes and potato-wheat dough. The impact of flavourzyme was the most significant (p<0.05). When enzyme concentration increased, viscosity decreased, and the degree of structural damage, indicated by increased porosity. Notably, the addition of flavourzyme can increase the content of sweet and umami free amino acids, improving the flavor of mashed potatoes. The scanning electron microscopy and confocal laser scanning microscopy images of potato-wheat dough revealed that enzyme-hydrolyzed mashed potatoes had improved homogeneity, reestablished the dough continuity, and strengthened the three-dimensional structure comprising proteins and starch. Notably, flavourzyme demonstrated the most significant effect on enhancing the protein-starch network structure. This was attributed to the exposure of functional groups resulting from protein hydrolysis, facilitating interaction with starch molecules. Our findings indicate that the addition of 0.1% flavourzyme (500 LAPU/g, pH 5.5, 55 ± 2°C, 30 min treated) was the most effective in reducing viscosity and reconstructing the gluten network. Enzymatic hydrolysis plays a vital role in the production of high-quality potato products, with particular importance in the baking industry, where flavourzyme exhibits significant potential. PRACTICAL APPLICATION: Enzymatic hydrolysis plays a vital role in the production of high-quality potato products, with particular importance in the baking industry, where flavourzyme exhibits significant potential.

Preparation of crosslinked starches with enhanced and tunable gel properties by the cooperative crosslinking-extrusion combined modification

Due to its safety and palatability, the citric acid crosslinking modification is an excellent way to modify the properties of starch gels. However, the application of this method is restricted by the low degree of crosslinking of gels produced by this method in the hydrogel system. To produce citric acid-crosslinked starch with improved strength and tunable gel characteristics, a novel ion-esterification cooperative crosslinking-extrusion combined (CCEC) modification approach is presented in this study. The linear and nonlinear rheological characteristics of the samples were measured to evaluate the effectiveness of CCEC modification. Findings disclosed that at 0.1 % strain, the elastic modulus of the CCEC-modified starch (SC-0.5Zn2+, G' = 1522.29 ± 36.31) exhibited a significant rise of 387.27 % as compared to the elastic modulus of citric acid-crosslinked starch (SC, G' = 318.29 ± 11.62). Furthermore, changing the cation concentration allowed for efficient control of the gel's rheological characteristics. The samples were characterized by SEM, FTIR, XRD, and XPS. The CCEC-modified gels had a smaller pore size distribution and a denser honeycomb porous structure. The CCEC modification reaction involves ester bonds and electrostatic attraction. This research is essential to elucidate how coupled physicochemical modification techniques affect the manipulation of starch gel characteristics.

Enhancement of Starch Gel Properties Using Ionic Synergistic Multiple Crosslinking Extrusion Modification

Crosslinking is a promising method to modulate the gel properties of food-grade starch gels. Still, the poor crosslinking effect of a single type of crosslinker limits the application of this method in starch gel modification. In this study, an Ca2+ synergistic multiple crosslinking modification method was proposed to prepare crosslinked starches with good gel properties and setting. The rheological properties of the samples were tested. The modified sample (SC-Ca-N3, G' = 1347 ± 27) showed a 79% improvement compared to the starch without synergistic crosslinking modification (SC-N, G' = 752 ± 6). The elastic modulus of starch gels can be adjusted by changing the degree of the crosslinking reaction. The results of nonlinear rheological Lissajous curve analysis showed that the synergistically crosslinked gel system strongly resisted deformation. In addition, the microstructure of the modified samples was characterized using scanning electron microscopy. The XPS, FTIR, and XRD results indicated that multiple molecular forces participate in the synergistic crosslinking reaction.