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Nowadays, resulting from disordered glucose and lipid metabolism, metabolic diseases (e.g., hyperglycemia, type 2 diabetes, and obesity) are among the most serious health issues facing humans worldwide. Increasing evidence has confirmed that dietary intervention (with healthy foods) is effective at regulating the metabolic syndrome. Whole grain rice (WGR) rich in dietary fiber and many bioactive compounds (e.g., γ‐amino butyric acid, γ‐oryzanol, and polyphenols) can not only inhibit starch digestion and prevent rapid increase in the blood glucose level, but also reduce oxidative stress and damage to the liver, thereby regulating glucose and lipid metabolism. The rate of starch digestion is directly related to the blood glucose level in the organism after WGR intake. Therefore, the effects of different factors (e.g., additives, cooking, germination, and physical treatments) on WGR starch digestibility are examined in this review. In addition, the mechanisms from human and animal experiments regarding the correlation between the intake of WGR or its products and the lowered blood glucose and lipid levels and the reduced incidence of diabetes and obesity are discussed. Moreover, information on developing WGR products with the health benefits is provided. [ABSTRACT FROM AUTHOR]

A novel method (dynamic water transfer–based water activity analyzer (DWT) method) based on Fick's law of diffusion for the accurate measurement of moisture sorption isotherm (MSI) has been developed and was compared with saturated salt solutions (SSS) method and dynamic vapor sorption (DVS) method. MSIs at 25 °C of sultana raisins obtained by the three methods were analyzed and compared, and four adsorption models (BET, Halsey, GAB, and Peleg) were used to fit the results. The MSI curves obtained by the three methods all showed the similar type III isotherm characteristic, but equilibrium moisture content at the same relative humidity (RH) showed some differences, and the repeatability and accuracy were different. Generally, results obtained by the SSS method may have relatively low accuracy due to the relatively high measurement error; results obtained by the DVS method may lack representativeness due to the small sample size; results obtained by the DWT method may have high representativeness and accuracy at the same time. The fitting results of adsorption models indicated that MSI results obtained by the DWT method had the highest fitting degree with the Peleg model. This study may contribute to deepened understandings on MSI measurement of semi-dried foods. [ABSTRACT FROM AUTHOR]

The cover image is based on the Review Article I Whole grain rice: Updated understanding of starch digestibility and the regulation of glucose and lipid metabolism i by Dongling Qiao et al., https://doi.org/10.1111/1541-4337.12985. [Extracted from the article]

The chain reorganization of cooked starch during storage plays an important role in the performance of starchy products such as rice foods. Here, different analytical techniques (such as small-angle X-ray scattering) were used to reveal how microwave cooking influences the chain assembly of cooked indica rice starch undergoing storage for 0, 24, or 48 h. While stored, more short-range double helices, long-range crystallites, and nanoscale orders emerged for the microwave-cooked starch than for its conventionally cooked counterpart. For instance, after storage for 24 h, the microwave-cooked starch contained 46.8% of double helices, while its conventionally cooked counterpart possessed 34.3% of double helices. This could be related to the fact that the microwave field caused high-frequency movements of polar groups such as hydroxyls, which strengthened the interactions between starch chains and water molecules and eventually their assembly into double helices, crystallites, and nanoscale orders. This work provides further insights into the chain reassembly of microwave-cooked starch undergoing storage, which is closely related to the quality attributes of starch-based products. [ABSTRACT FROM AUTHOR]

The effects of starch structures, in particular amylose content, on grafting reactions were investigated using thermal gravimetric analysis (TGA), nuclear magnetic resonance, X-ray diffraction (XRD). As a model system, corn starches with different amylose contents (0, 26, 50 and 80 %) were grafted onto acrylamide to produce superabsorbent polymers (SAPs). The weight loss measured by TGA at different temperature was used to analyze the grafting ratio in quantity. In general, the grafting ratio increased (about 10 %) with increasing starch amylose content, and graft chain segment lengths were much lower for the amylopectin-rich (waxy) starch. The high molecular weight and branched structure of the amylopectin reduced the mobility of the polymer chains and increased viscosity, which resulted in resistance to chain growth. The water absorption capability was increased with increasing amylose content for the starch-based SAPs. XRD detection showed that the crystalline structure of all starches was destroyed after grafting reactions. The thermal stability of the polyacrylamide grafted onto the starches increased by about 10 °C, which could be explained by the strong bonding between the grafted polymer chains and the starch matrices. [ABSTRACT FROM AUTHOR]

Microstructure and Mechanical/Hydrophilic Features of Agar-Based Films Incorporated with Konjac Glucomannan. The authors wish to make the following correction to this paper [[1]]: in the original version of the published article, there is a mistake in Equation (1) on Page 3. Reference 1 Qiao D., Tu W., Zhong L., Wang Z., Zhang B., Jiang F. Microstructure and mechanical/hydrophilic features of agar-based films incorporated with konjac glucomannan. [Extracted from the article]

Natural biopolymers, which are renewable, widely available, biodegradable, and biocompatible, have attracted huge interest in the development of biocomposite materials. Herein, formulation–property relationships for starch/agar composite films were investigated. First, rapid visco analysis was used to confirm the conditions needed for their gelation and to prepare filmogenic solutions. All the original crystalline and/or lamellar structures of starch and agar were destroyed, and films with cohesive and compact structures were formed, as shown by SEM, XRD, and SAXS. All the plasticized films were predominantly amorphous, and the polymorphs of the composite films were closer to that of the agar-only film. FTIR results suggest that the incorporation of agar restricted starch chain interaction and rearrangement. The addition of agar to starch increased both tensile strength and elongation at break, but the improvements were insignificant after the agar content was over 50 wt.%. Contact angle results indicate that compared with the other samples, the 4:6 (wt./wt.) starch/agar film was less hydrophilic. Thus, this work shows that agar dominates the structure and properties of starch/agar composites, and the best properties can be obtained with a certain starch/agar ratio. Such composite polysaccharide films with tailored mechanical properties and surface hydrophilicity could be useful in biodegradable packaging and biomedical applications (wound dressing and tissue scaffolding). [ABSTRACT FROM AUTHOR]

With abundant renewable resources and good biodegradability, bio-based aerogels are considered as promising insulating materials for replacing the conventional petroleum-based foam. In this study, konjac glucomannan (KGM)-based aerogels were prepared as thermal insulation materials via a convenient sol–gel and freeze-drying progress with different content of plant polysaccharides, proteins, and wheat straw. The morphology, thermal conductivity, and flame retardancy of KGM-based aerogels were determined. The KGM-based aerogels showed a uniform three-dimensional porous microstructure. The addition of wheat straw could significantly reduce the pore size of aerogels due to its special multi-cavity structure. KGM-based aerogels showed low densities (0.0234–0.0559 g/cm−3), low thermal conductivities (0.04573–0.05127 W/mK), low peak heat release rate (PHRR, 46.7–165.5 W/g), and low total heat release (THR, 5.7–16.2 kJ/g). Compared to the conventional expanded polystyrene (EPS) and polyurethane (PU) foam, the maximum limiting oxygen index (LOI) of KGM-based aerogels increased by 24.09% and 47.59%, the lowest PHRR decreased by 79.37% and 94.26%, and the lowest THR decreased by 76.54% and 89.25%, respectively. The results demonstrated that the KGM-based aerogels had better performance on flame retardancy than PU and EPS, indicating high potential applications as heat insulation in the green advanced engineering field. [ABSTRACT FROM AUTHOR]

Here, we tailored the multi-level structural and practical (mechanical/hydrophilic) features of gelatin films by varying the konjac glucomannan (KGM) content and the film-forming temperatures (25 and 40 °C). The addition of KGM apparently improved the mechanical properties and properly increased the hydrophilicity. With the lower temperature (25 °C), the increase in KGM reduced the gelatin crystallites of films, with detectable KGM–gelatin interactions, nanostructures, and micron-scale cracks. These structural features, with increased KGM and negligibly-occurred derivatizations, caused initially an insignificant decrease and then an increase in the strength, with a generally-increased elongation. The higher temperature (40 °C) could reduce the strength and slightly increase the elongation, related to the reduced crystallites of especially gelatin. With this higher temperature, the increase in KGM concurrently increased the strength and the elongation, mainly associated with the increased KGM and crystallites. Additionally, the increase in KGM made the film more hydrophilic; the multi-scale structural changes of films did not dominantly affect the changing trend of hydrophilicity. [ABSTRACT FROM AUTHOR]

Different characterization methods spanning length scales from molecular to micron scale were applied to inspect the microstructures and mechanical/hydrophilic features of agar/konjac glucomannan (KGM) films prepared under different drying temperatures (40 and 60 °C). Note that the lower preparation temperature (40 °C) could increase the strength and elongation of agar/KGM films at high KGM levels (18:82 wt/wt KGM-agar, or higher). This was related to the variations in the film multi-scale structures with the increment of KGM content: the reduced crystallinity, the increased perfection of nanoscale orders at some KGM amounts, and the negligibly-changed morphology and molecular chemical structure under 40 °C preparation temperature. These structural changes initially decreased the film tensile strength, and subsequently increased the film strength and elongation with increasing KGM content. Moreover, under the higher drying temperature (60 °C), the increased KGM content could concurrently reduce the strength and elongation for the films, associated with probable phase separations on nano and smaller scales. In addition, the increased KGM amount tended to make the film more hydrophilic, whereas the changes in the film structures did not dominantly affect the changing trend of hydrophilicity. [ABSTRACT FROM AUTHOR]