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Edible films from the blending hydroxypropyl methylcellulose (HPMC) with hydroxypropyl starch (HPS) have been developed. This work focuses on the relationship between morphologies and mechanical properties of such systems. To aid understanding of blend morphology, a new technique used to identify the two phases through dying of the HPS by iodine has been developed, which provided a simple and convenient way to clearly distinguish between HPMC and HPS phases. It was found that the blend system is immiscible and there is phase transition point depending on blending ratio and solution concentration. The lower transparency point of the blend and phase transition reign of HPMC from continuous phase to separated phase correspond with the variation of tensile modulus. The modulus and elongation decreased with increased solution concentration, which is correlatable with the morphologies present, where it was found that the HPMC gradually changed from a continuous phase to a distinct phase. [ABSTRACT FROM AUTHOR]

Swelling behavior involves the process of starch granules absorbing enough water to swell and increase the viscosity of starch suspension under hydrothermal conditions, making it one of the important aspects in starch research. The changes that starch granules undergo during the swelling process are important factors in predicting their functional properties in food processing. However, the factors that affect starch swelling and how swelling, in turn, affects the texture and digestion characteristics of starch-based foods have not been systematically summarized. Compared to its long chains, the short chains of amylose easily interact with amylopectin chains to inhibit starch swelling. Generally, reducing the swelling of starch could increase the strength of the gel while limiting the accessibility of digestive enzymes to starch chains, resulting in a reduction in starch digestibility. This article aims to conduct a comprehensive review of the mechanism of starch swelling, its influencing factors, and the relationship between swelling and the pasting, gelling, and digestion characteristics of starch. The role of starch swelling in the edible quality and nutritional characteristics of starch-based foods is also discussed, and future research directions for starch swelling are proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

Although synthetic polymer hydrogels have excellent mechanical properties, they are not easily degraded, are toxic, and easily cause environmental pollution. Therefore, starch-based hydrogels have attracted great interest due to their biodegradability, biocompatibility, and non-toxicity. First of all, this review describes in detail the preparation of starch-based hydrogels by physical retrogradation method and chemical crosslinking methods, as well as the intrinsic and extrinsic factors that affect the performance of the hydrogels. Moreover, the commonly used methods to characterize starch-based hydrogels and the properties of responsive (thermo-, pH-, and enzyme-responsive) starch-based hydrogels have also attracted wide attention from researchers. In addition, the applications of starch-based hydrogels in starch noodles, treatment of sewage from the food industry, and food bioactive ingredient carriers are discussed. Furthermore, prospects and future directions of starch-based hydrogels are discussed. We believe that this review provides a valuable reference for the efficient preparation and application of starch-based hydrogels. [Display omitted] • Starch retrogradation is the most common method to prepare starch-based hydrogels. • Amylose content affects the mechanical properties of starch-based hydrogels. • The starch-based hydrogels showed thermo-, pH-, and enzyme-responsive properties. • The hydrogels are widely used in starch noodles and as food active substance carriers. [ABSTRACT FROM AUTHOR]

The development of environmentally friendly and transparent superhydrophilic food packaging materials is essential in our daily lives. The objective of this study was to develop a simple method of preparing a superhydrophilic, transparent, and biodegradable composite film. The composite film was obtained by soaking a chitosan-sodium phytate film in an ethanol solution of SiO 2 nanoparticles. The results showed that when the chitosan-sodium phytate film was coated with SiO 2 nanoparticles that were dissolved in 75% ethanol, its water contact angle (WCA) was reduced from 100° to 3°, and the film surface was changed from a hydrophobic to a superhydrophilic. Furthermore, the oxygen transmission rate (OTR) was significantly reduced, and the mechanical properties of the film were improved. The method is easy to carry out and can be used for the potential production of superhydrophilic materials. • A superhydrophilic chitosan film was prepared by an ethanol soaking process. • When ethanol concentration was 75%, the contact angle of the chitosan film was 3°. • The obtained film showed excellent water vapor and oxygen barrier properties. [ABSTRACT FROM AUTHOR]