Characterisation of amylose and amylopectin with various moisture contents after frying process: effect of starch–lipid complex formation

Effects of starch-fatty acid complexes with different fatty acid chain lengths and degrees of saturation on the rheological and 3D printing properties of corn starch

The effect of corn starch-fatty (CS-FA) complexes from varying carbon chain length and degree of unsaturation on the rheological and 3D printing properties of corn CS-FA complex gels. The CS-FA complexes with longer carbon chain lengths and lower saturation enhanced the ability of gels to bind water, promoting the formation of intermolecular hydrogen bonds. The CS-FA complexes inhibit retrogradation and increase the amount of bound water, thereby reducing the structural integrity and transforming the original skeleton structure into a flake-like structure. These changes in gel structure led to lower flow stress and storage modulus for CS-FA gels containing FAs with shorter carbon chain lengths and lower saturation, resulting in reduced "extrusion swelling" of the material and facilitating its extrusion. The decreased "extrusion swelling" of gel improved print line width and printing performance. The CS-FA complex gel-printed product with a 12-carbon chain FA has the greatest printing accuracy, thanks to its moderate G', flow stress, and viscosity. This study provides important information for the CS-FA complexes for the preparation of starch-based 3D printing materials.

Effects of Incorporated Emulsifiers Into Noodles on V-amylose Formation, Digestibility, and Structural Characteristics

There is growing interest in developing low glycemic alternatives to starchy foods. In this study, two emulsifiers, namely sodium stearoyl lactylate and egg yolk, were incorporated into the formulation of noodles (EYN and SSLN), and their effects on V-amylose formation, digestibility and structural characteristics of the noodles were investigated. The emulsifiers facilitated V-amylose formation in the noodles, indicated by the complexing indices. The EYN and SSLN exhibited markedly high resistant starch contents compared to the control noodle. The logarithm of slope plot analysis showed that the EYN and SSLN had low first-phase rate constants compared to the control noodles, suggesting a barrier effect to digestive enzymes exerted by V-amylose. The SSLN and EYN displayed a mixture of B- and V-type patterns with higher crystallinities and two distinct spectral features of the bands at 2854 cm- 1 and 1746 cm- 1 compared to the control noodles. Polarized light micrographs of the SSLN and EYN exhibited vague contours of numerous irregularly shaped starch fragments with strong birefringence. These results suggest that forming V-amylose crystals in the SSLN and EYN was responsible for their increased resistance to digestion through reformulating emulsifiers in modifying their nutritional functionalities.

The Fluorescence Response of Four Crystalline Starches According to Ultrasound-Assisted Starch-Salicylic Acid Inclusions

Fluorescence has shown its superior performance in the fields of starch physicochemical properties, starch–based materials, and the interactions of starch with small molecules. However, it has not been well explored in the fluorescence characteristics of starch. Herein, the fluorescence properties of four crystalline starches (A–type tapioca starch, B–type potato starch, C–type pea starch, and V–type starch, prepared with corn starch and stearic acid) were investigated using salicylic acid (SA) as an indicator. The results of inverted fluorescence microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis indicated that SA could be included by starch. X–ray diffraction analysis further demonstrated that the inclusion of SA did not change the crystalline of the four crystal types of starches, which could provide a prerequisite for comparing the different fluorescence properties of the four crystal types of starches. Fluorescence enhancements of the four inclusions were 264.5 (B–type), 206 (C–type), 51.2 (V–type), and 28 (A–type). These results provide new insights for analyzing the fluorescence response of starch.

Formation of Starch-Lipid Complexes during the Deep-Frying Process and Its Effects on Lipid Oxidation

In the present study, maize starch (MS), potato starch (PS), high-amylose maize starch (HAMS), and wheat starch (WS) were deep-fried in soybean oil that was continuously heated for 40 h under 180 °C. The thermodynamic and pasting properties of deep-fried starch samples were determined. The results suggested that starch−lipid complexes formed with the extension of frying oils’ usage; however, their number was not dependent on the frying oils’ life cycle. Importantly, the results of pasting properties revealed the following strength of intermolecular force in deep-fried starch samples: PS > MS > HAMS > WS. The results of XRD and FTIR analysis confirmed the formation of starch−lipid complexes during the deep-frying process. Furthermore, the results of the in vitro digestibility of deep-fried starch revealed that the formation of starch−lipid complexes inhibited the swelling of starch granules and prevented the entrance of amylase into the interior. Additionally, the results of the oxidation stability of deep-frying oil indicated that the formation of starch−lipid complexes did not alter the trend of lipid oxidation as an effect of the limited number of starch−lipid complexes. These results could have critical implications for the development of healthier deep-fried foods.

Effect of stearic acid on the microstructural, rheological and 3D printing characteristics of rice starch

The aim of this study was to investigate the changes of the microstructural, rheological and printing properties of rice starch-stearic acid (SA) paste during the hot-extrusion 3D printing (HE-3DP). The results showed that starch chains could complex with SA to form V-type crystalline structure and its molecular kinematic behaviors were changed under shear force, and crystalline structure were then embedded and rearranged to constitute an ordered sea-island structure, thus improving the rigidity and dynamic storage modulus of network structure, leading to the increased layer number. Interestingly, with the increase of SA addition, the network structure became weakened and the viscosity decreased which might due to the destroyed continuity and the breaking of entanglement and hydrogen bonding between starch chains, and finally impairing the printing accuracy of objects. Overall, this study provided important information for the application of lipid in the preparation of starch-based food by HE-3DP.