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Three types of inulin with different degree of polymerization (average DP < 10, DP ≥ 10, and DP > 23) were used to improve the freeze-thaw stability of rice starch gel. The gels with or without addition of inulin were subjected to seven freeze-thaw cycles (FTC). Inulin enhanced the water holding capacity and reduced the amount of freezable water of the gels, thereby decreasing the syneresis of the gels during seven FTC. In addition, the amylose and amylopectin retrogradation of the gels were retarded. By adding inulin, the microstructure of gel network was stabilized, and the deterioration in viscoelastic properties of the gels during seven FTC was reversed. Therefore, inulin was an effective additive for preserving the quality of freeze-thawed rice starch gels. Furthermore, low DP inulin had higher water holding capacity than high DP one, as a result the inulin with lower DP was more effective. [ABSTRACT FROM AUTHOR]

The rate and extent of starch hydrolysis in the digestive tract impacts blood glucose levels, which may influence an individual's susceptibility to diabetes and obesity. Strategies for decreasing starch digestibility are therefore useful for developing healthier foods. β-amylase is an exo -hydrolase that specifically cleaves α-1,4 glycosidic linkages of gelatinized starches. In this study, starch granules were disrupted by extrusion under different feed moisture conditions, and then subjected to β-amylolysis. The degree of starch gelatinization increased with increasing feed moisture content during extrusion, leading to faster β-amylolysis. The hydrolysis of in vitro starch digestion study was reduced for extruded samples treated with β-amylase, which was attributed to an increase in resistant starch (RS) after β-amylase treatment. Indeed, X-ray diffraction (XRD) indicated that the crystalline structure in the extruded starch was either partially or fully lost after β-amylase treatment. Similarly, Fourier transform infrared (FTIR) analysis indicated there was a higher level of amorphous regions in the starch after β-amylase treatment. Overall, our results suggest that enzymatic treatment of extruded starch with β-amylolysis reduces the ratio of crystalline-to-amorphous regions, which increases the level of resistant starch, thereby slowing down digestion. These results have important implications for the development of healthier starch-based foods. [ABSTRACT FROM AUTHOR]

The edible quality of starch paste formed by direct dispersion in boiling water is crucial to the design and production of instant starch-based products. In the present study, the kudzu powder was complexed with different chain-length fatty acids to improve its instant properties. The formation of V6-type kudzu powder-fatty acid complexes was initially characterized. Then, the impact of different chain-length fatty acids on instant properties of kudzu powder was characterized by measuring agglomeration rate and viscoelasticity. The agglomeration rate was decreased from 42.31% (native kudzu powder) to 0.08% (kudzu powder-myristic acid complex). Moreover, the viscoelasticity of the kudzu powder complexed with fatty acids (except for stearic acid) was stronger than that of native kudzu powder. These improvements were related to the formation of kudzu powder-fatty acid complexes with high thermal stability existed on the surface of complexed kudzu powder and extending the time for water to enter into complexed kudzu powder. Thus, all of kudzu powder could absorb sufficient water to avoid aggregating together that was involved into the formation of kudzu paste. This research had important implication for the preparation of instant starchy products that could be directly dispersed in hot water with high edible quality. • The instant properties of kudzu powder was improved by complexing with fatty acid. • Crystallinity and complexing index decreased with increasing fatty acid chain length. • The complexes with V-type crystalline enhanced thermal properties of kudzu powder. • The formed complexes decreased the agglomeration rate and maintained the viscosity. • The formed complexes extended time for water to penetrate into kudzu powder. [ABSTRACT FROM AUTHOR]

There is considerable interest in preparing high-quality gluten-free bread. The effect of the molecular structure of extruded pregelatinization starch on the dough's rheological properties and the brown rice bread's quality was investigated. Extruded rice starch (ERS) was prepared with various added moisture contents of 20 % (ERS20), 30 % (ERS30), and 40 % (ERS40), respectively. ERS had smaller molecular weight and more short branched chains as the moisture content decreased. The dough elasticity and deformation resistance were improved with the ERS supplementation and in the order of ERS40 > ERS30 > ERS20 at the same level. Fortification with ERS improved the gluten-free brown rice bread quality. Compared to the control group, breadcrumbs supplemented with ERS20 at the 10 % level showed an increase in cell density from 17.87 cm-2 to 28.32 cm-2, a decrease in mean cell size from 1.22 mm2 to 0.81 mm2, and no significant change in cell area fraction. In addition, the specific volume increased from 1.50 cm3/g to 2.04 cm3/g, the hardness decreased from 14.34 N to 6.28 N, and the springiness increased from 0.56 to 0.74. The addition of extruded pregelatinization starches with smaller molecular weights and higher proportions of short chains is promising for preparing high-quality gluten-free bread. • Extruded rice starch (ERS) was prepared by extruding in different moisture content. • ERS with lower moisture had smaller molecules and a higher ratio of short chains. • Specific structure ERS improved dough elasticity and resistance to deformation. • Specific structure ERS enhanced the gluten-free bread characteristics. [ABSTRACT FROM AUTHOR]

The digestibility of starch in cooked ordinary rice grains and cooked texturized rice grains was compared using an in vitro gastrointestinal tract (GIT), which involved sequentially exposing samples to simulated oral, gastric, and small intestinal regions. The total extent of starch hydrolysis (%) of texturized rice was slightly lower than that of ordinary rice by the end of the GIT, probably because of its higher resistant starch content. Furthermore, the rate of starch hydrolysis in the small intestine was much slower for texturized rice than ordinary rice. Gel electrophoresis and microstructure analysis suggested that the proteins in the texturized rice formed a cross-linked network around the starch molecules. This network may have retarded the ability of digestive enzymes to access the starch, thereby reducing the hydrolysis rate. These results have important implications for the design of starch-based foods with a lower glycemic index, and therefore improved nutritional profiles. Image 1 • The simulated gastrointestinal tract was first used to evaluate the digestibility of texturized rice grains. • Texturized rice grains had a slower starch digestibility in simulated gastrointestinal tract digestion. • Proteins formed cross-linked structure in texturized rice. • Texturized rice had a compact structure. [ABSTRACT FROM AUTHOR]

Food extrusion has evolved over the past decades and is now a unique research area. Starch is a primary ingredient of raw materials that are widely used in food extrusion. Extrusion is a thermomechanical process that can break the bonds of starch, leading to starch gelatinization, melting, and degradation. This article reviews the effects of extrusion on structure (crystallinity, morphology, molecular weight) and physico‐chemical properties (expansion ratio, water absorption index, water soluble index, texture, pasting property, and digestion) of starch. In addition, some applications of extruded starches are described. This review is of significance as it provides an overview of the effects of extrusion on starch properties and indicates the potential of extrusion applications in the food industry. Starches are the primary raw materials widely used in extrusion processing. Extrusion is a thermo‐mechanical process that significantly changes the morphology and fine structure of the starches, thereby giving new physicochemical properties to the starches. The properties of starches after extrusion may be varied with the processing parameters. In this review, the applications of extruded starches are also introduced. [ABSTRACT FROM AUTHOR]

Regulating particle size and shape of starch nanoparticles (SNPs) is imperative to producing natural nanomaterials with controllable physicochemical properties enabling novel applications. In this study, natural deep eutectic solvents (NADES) based on lactic acid and glucose were obtained and used for the self-assembly of SNPs with different shapes and sizes. The size of fabricated SNPs ranged from 406.7 to 104.6 nm, and the shape of SNPs changed from spherical to rice-like with increasing proportion of NADES. X-ray diffraction was shown that SNPs were in B + V crystalline structure, and the relative crystallinity was decreased with the increase of NADES content, indicating that the NADES disrupted the recrystallization of starch molecules. DSC and TGA analysis demonstrated that the longer starch chains self-assembled in NADES system to form SNPs with less ordered crystallization structure. Fourier transform infrared spectra exhibited a shift of O–H stretching band at 3500-3300 cm−1 towards higher wavenumber values due to the weakened hydrogen bond strength of SNPs. In addition, turbidity analysis indicated that the formation of rice-like and smaller size SNPs was related to the inhibition of nucleation and growth of starch by NADES, which was confirmed with the results of yield results. This study has significant implications for the preparation of SNPs with various size and shape in a completely new and highly effective approaches. [Display omitted] • SNPs were prepared via self-assembly in NADES for the first time. • Rice-like and tiny-size SNPs were prepared by regulating the NADES concentration. • NADES controlled the self-assembly of starch chains through hydrogen bond interaction. [ABSTRACT FROM AUTHOR]

At present, the primary solvents in nanocarrier systems for curcumin encounter challenges related to rapid degradation, and biosafety of organic reagents, surfactants and lipids, which are not suitable for food applications. Therefore, this research proposed an eco-friendly method for the first time, using choline chloride-lactic acid deep eutectic solvent as a solvent for curcumin and a self-assembly medium for short-chain amylose to prepare curcumin-loaded starch nanoparticles. This study investigated the interactions between curcumin and short-chain amylose as well as improved stability. Curcumin was successfully loaded into starch nanoparticles as demonstrated by scanning electron microscopy and confocal laser scanning microscopy analyses. The loading capacity of curcumin-loaded starch nanoparticles on curcumin reached up to 7.99 mg/g, with an encapsulation efficiency of 56.18%. 13C nuclear magnetic resonance spectroscopy peaks at 93–107 ppm and Fourier transform-infrared spectroscopy signals at 3386 cm−1 indicated the formation of a non-inclusion complex through hydrogen bond interactions between curcumin and short-chain amylose. While A-type crystalline pattern and weakening ordered crystallization structure were also probed. Additionally, the formation of non-inclusion complex improved the pH stability and photostability of curcumin through physical barrier of starch nanoparticles and the hydrogen bond interaction between curcumin and starch. Overall, this study established a novel and eco-friendly technique for loading and stabilizing curcumin with nanoscale dimensions, offering potential applications in edible packaging and functional foods. [Display omitted] • Curcumin-loaded starch nanoparticle was firstly prepared via self-assembly in NADES. • Encapsulation by starch nanoparticles enhanced the stability of curcumin. • Curcumin-loaded starch nanoparticle (CSNP) was non-inclusion complex. • CSNP formed by hydrogen bond interaction between curcumin and short-chain amylose. [ABSTRACT FROM AUTHOR]

During home cooking or industrial food processing operations, starch granules usually undergo a process known as gelatinization. The starch gelatinization degree (DG) influences the structural organization and properties of starch, which in turn alters the physicochemical, organoleptic, and gastrointestinal properties of starchy foods. This review summarizes methods for measuring DG, as well as the impact of DG on the starch structure, properties, and applications. Enzymatic digestion, iodine colorimetry, and differential scanning calorimetry are the most common methods for evaluating the DG. As the DG increases, the structural organization of the molecules within starch granules is progressively disrupted, the particle size of the granules is altered due to swelling and then disruption, the crystallinity is decreased, the molecular weight is reduced, and the starch-lipid complexes are formed. The impact of DG on the starch structure and properties depends on the processing method, operating conditions, and starch source. The starch DG affects the quality of many foods, including baked goods, fried foods, alcoholic beverages, emulsified foods, and edible inks. Thus, a better understanding of the changes in starch structure and function caused by gelatinization could facilitate the development of foods with novel or improved properties. [Display omitted] • The quantification of starch gelatinization degree (DG) methods is compared. • The multiscale structure and functional property related to starch DG are concluded. • The impact of starch DG on the quality of various foods and beverages is reviewed. [ABSTRACT FROM AUTHOR]

In this study, starch citrates were synthesized by superheated steam (SS) treatment without changing the granule structure of starch. The degree of substitution (DS) of starch citrates prepared in present study was ranged from 0.015 to 0.064. Fourier transform infrared spectroscopy confirmed that citric acid (CA) and starch were successfully esterified with an absorption peak appeared at 1735 cm−1. In vitro digestion results revealed that the content of resistant starch (RS) was significantly increased by citric acid esterification, which was attributed to the cross-linked structure of starch and the inhibition of gelatinization and swelling. According to the physicochemical properties analysis, the pasting temperature of rice starch citrates were significantly increased by citric acid treatment, while the swelling power and gelatinization enthalpy were significantly decreased and the short- and long-range molecular order of the starch was disrupted after the esterification reaction. These results indicated that it is a feasible method to synthesize starch citrate by superheated steam to increase resistant starch, and it could be used as an alternative approach for preparing starch citrate to conventional hot air treatment. • A superheated steam technology was adopted to synthesize starch citrates. • The starch citrates were maintaining the granule structure of starch. • The resistant starch content was increased by the formation of starch citrates. • The esterified and cross-linked structure was formed in starch citrates. • The inhibition of gelatinization and swelling was found in starch citrates. [ABSTRACT FROM AUTHOR]