Search

Highlights • Hydroxypropylmethylcellulose (HPMC) were hybridised with hydroxypropyl starch (HPS). • The rheological, gel and film properties were tailored by HPMC/HPS contents. • HPS displayed reduced viscosity and increased compatibility with HPMC. • HPS exhibited less chain rearrangement and lower film crystallinity and rigidity. • Starch hydroxypropylation reduced film density and oxygen permeability in blends. Abstract This work investigates the rheology, structure, and properties of novel thermal/cooling-gel biphasic systems formed by hybridization of hydroxypropyl methylcellulose (HPMC) as a thermal gel and hydroxypropyl starch (HPS) as a cooling gel. Due to the different gelation properties, HPS became the dispersed phase in the other continuous phase at low temperatures, and so did HPMC at high temperatures. However, the dispersed phase could play a dominant role in the viscosity, thixotropy, and gel properties of the blends, and subsequently affect the crystalline structure, fractal structure, mechanical properties, oxygen permeability, and thermal stability of the blend films. Moreover, the rheological properties and the film structure and performance could also be varied by the chemical modification of starch. Hydroxypropylation could break the starch intermolecular hydrogen bonding, disrupt its ordered structure, inhibit the molecular rearrangement, and result in a softer gel texture that was more compatible with HPMC. With a higher degree of hydroxypropyl substitution, the resultant blend films were more amorphous and flexible but exhibited decreased mechanical properties and oxygen permeability. The knowledge obtained from this work could provide guidance to further developing various thermal/cooling-gel multi-phasic systems with desired properties and functionality. [ABSTRACT FROM AUTHOR]

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]

• Hydroxypropyl methylcellulose (HPMC) was blended with hydroxypropyl starch (HPS) • The continuous phase of HPMC-HPS mixed hydrocolloid changed with HPMC/HPS ratio. • Hydroxypropylation promoted HPMC gelation. • Good compatibility between HPMC and HPS enhanced the HPMC-HPS gel strength. • HPMC hydroxypropylation improved the oxygen barrier effect of HPMC-HPS film. This work investigates the structure, processability, and film performance of hydroxypropyl methylcellulose (HPMC) hydrocolloids affected by hydroxypropy substitution degree and blending with hydroxypropyl starch (HPS). The hydroxypropylation of HPMC could increase inter-chain hydrogen bonding, thereby promoting its gelation, and improve film-forming, but reduce the mechanical properties of the films. HPMC-HPS mixed hydrocolloid system showed a typical "sea-island" morphology with the continuous phase changing with blend ratio. The content of hydroxypropy groups of HPMC affected the compatibility between HPMC and HPS, the morphology of the discrete phase, and the rheological properties of the blends. The fluid-like HPS enhanced the gel strength of HPMC when they had better compatibility. With a higher degree of hydroxypropy substitution, blend films exhibited a much denser structure, better oxygen barrier property, and appropriate mechanical properties. The knowledge obtained from this work could guide the development of edible packaging materials with desired properties and functionality. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hydroxypropylene grafted on both cellulose and starch improved their compatibility. [•] PEG acted as both a plasticizer and a compatibilizer for the blends. [•] Viscosity of starch at lower temperature improved viscosity balance of the system. [ABSTRACT FROM AUTHOR]

It is common to hybridize biopolymers for developing materials with combined properties or functionality. However, biopolymers are usually not fully compatible despite their chemical similarity, posing challenges to create mixed systems. Herein, we investigated how the gelation behavior and rheological properties of hydroxypropyl methylcellulose (HPMC), a thermal gel, and hydroxypropyl starch (HPS), a cooling gel, affect their miscibility and the phase structure of their mixed system. The dependence of the zero-shear viscosity for HPMC/HPS paste on biopolymer concentration in a double-logarithmic coordinate can be divided into two parts with the slopes being 11.9 and 2.8 respectively, indicating different degrees of intermolecular entanglement. A typical "sea-island" morphology was shown in the blends, and the phase structure (continuous or discrete) changed with varying HPMC/HPS blend ratio and temperature. This phase structure change can be well correlated to rheological parameters such as zero-shear viscosity, loss tangent, complex viscosity, and the Arrhenius equation correction coefficient (α). Biopolymer concentration, HPMC/HPS ratio, and temperature together controlled rheological properties and phase distribution for the mixed system. The relationship between rheological behavior and phase structure for HPMC/HPS understood from this work provides an insight into designing mixed biopolymer systems with desirable processability, structure, and properties. Image 1 • Hydroxypropyl methylcellulose (HPMC) and hydroxypropyl starch (HPS) mixture studied. • Strong rheological and gelation effects on the phase structure of HPMC/HPS shown. • HPMC/HPS blend ratio and temperature controls continuous/discrete phase change. • Phase structure correlated to zero-shear viscosity and Arrhenius coefficient α. • A schematic model to describe the temperature-induced conformational change. [ABSTRACT FROM AUTHOR]

Starch-based films are degradable, renewable, cost effective, and can be used as a foodstuff packaging material. Functional starch-based films have attracted extensive attention from researchers in recent years. Bioactive starch-based films with antibacterial, anti-oxidation, UV, oxygen, and water vapor barriers can reduce the reproduction of microorganisms and prolong the shelf life of packaged foods. Intelligent starch-based films with pH-, temperature-, magnetic field-, glucose-, and enzyme-responsive characteristics can be used to monitor the freshness of foods and control the delivery of functional ingredients and drugs. Therefore, the development of biodegradable bioactive and intelligent starch-based films is particularly important. In this review, we first introduce three common methods for preparing starch-based films and their advantages and disadvantages. Then, the bioactive and intelligent properties of starch-based films are discussed. Finally, examples are used to illustrate the application of active and intelligent starch-based films in food packaging and other areas. The addition of plant extracts, plant essential oils, and nanoparticles to starch films can improve their antibacterial, antioxidant, and barrier properties. The addition of anthocyanins to starch films can make the films pH-responsive, indicating the degree of spoilage in fish products and achieving the purpose of warning consumers. In the future, it is necessary to study other biologically active starch-based films, such as anti-fatigue, enzyme-responsive, and salt-responsive starch-based films. • Three preparation methods of starch-based films are introduced. • The bioactive films have antibacterial, anti-oxidation, and barrier properties. • The smart films have pH-, magnetic field-, and enzyme-responsive characteristics. • The films are widely used in food packaging, drug delivery and other aspects. [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]

• Retrogradation of short linear glucan debranched from amylopectin was investigated. • The retrogradation process of debranched starch (DBS) takes only 0–120 min. • The retrogradation of DBS is an ultra-short-term process. • The retrogradation enthalpy increased with increase in degree of polymerization. • The retrogradation enthalpy of DBS increased as storage time increased. Retrogradation is inevitable during the storage of starchy products. Retrogradation behavior of starches (e.g., amylopectin and amylose) has been widely investigated. We firstly studied the retrogradation behavior of short linear glucan debranched from amylopectin with different degrees of polymerization (DP). With increasing DP, the retrogradation enthalpy change (ΔH) of debranched starch (DBS) increased. At a DBS to water ratio of 1:2 and a storage time of 0 min, the retrogradation ΔH of DBS samples (DP 11.96, 12.62, and 13.36) reached up to 6.03 ± 0.41, 8.03 ± 0.53, and 12.80 ± 1.57 J/g, respectively. The greater the short-chain length, the more rapid the retrogradation of DBS. The peak temperature of retrograded DBS (101.95–111.53 °C) with a DBS to water ratio of 1:2 stored at 50 °C was greater than that stored at 4 °C. The retrogradation of DBS was rapid, taking only 0–120 min, corresponding to ultra-short-term retrogradation. [ABSTRACT FROM AUTHOR]

Debranching modifications of waxy corn starch with pullulanase can generate short-chain amylose or debranched starch (DBS), which is easy to recrystallize. Herein, we firstly investigated the regulation of recrystallization behaviors of DBS by studying the interactions between DBS and emulsifiers, polyphenols, and fatty acids. Sodium dodecyl sulfate at the 3.0% level had strong interactions with DBS. When the concentration of epigallocatechin gallate was 15%, the enthalpy change (ΔH) of DBS was close to 0 J/g and the relative crystallinity of DBS was 0, clearly indicating the strong interactions between epigallocatechin gallate and DBS. When the concentration of caproic acid, caprylic acid, and capric acid increased from 0 to 20.0%, the ΔH of DBS decreased from 11.38 ± 0.01 to 3.90 ± 0.63, 1.39 ± 0.21, and 3.98 ± 0.83 J/g, respectively. The interactions between emulsifiers, polyphenols, and fatty acids and DBS could affect physiochemical properties of DBS in varying degrees. Unlabelled Image • Regulation of recrystallization behaviors of debranched starch (DBS) was studied. • The enthalpy change of DBS decreased as contents of food additives increased. • Adding sodium dodecyl sulfate at 3.0% had a strong interaction with DBS. • There were interactions between DBS and emulsifiers, polyphenols, and fatty acids. [ABSTRACT FROM AUTHOR]

Abstract Edible starch film reinforced by laver was developed and characterized. The relationship between processing technologies, microstructures and performances was established. When the laver was added into cold starch suspension, the laver flack (fiber) simply act as reinforcing agent to improve the mechanical properties of the starch matrix, which results in increasing modulus and tensile strength. When the laver was added into hot starch suspension and mixed under shear stress, the protein containing in laver will release out and mix with starch, which results in a starch-protein-laver fiber hybrid composites. In the hybrids system, fiber improves the mechanical properties of the starch-based film about 25%, while the protein reduces the moisture sensitivity and gas permeability about 45%. Scanning electron microscopic observation indicated good compatibility between starch matrix and laver. The cellulose containing in laver kept its semi-crystalline structure after processing, which was used to explain the reinforcing mechanism. Some chemical bounds between starch and protein containing in laver was detected by FTIR. Since all the components used in this work are from food sources, the prepared films are safe for food packaging and application as edible films. Highlights • Laver improved tensile properties, decreased moisture sensitivity and permeability. • Laver and starch have good compatibility and interface. • Laver protein played key role to reduce moisture sensitive and achieve better interface. [ABSTRACT FROM AUTHOR]

Abstract Polymer film blends of hydroxypropyl methylcellulose (HPMC) and hydroxypropyl starch (HPS) were produced with an incorporation of three different plasticizers, including polyethylene glycol (PEG), glycerol and 1, 2-propylene glycol (PG) respectively, and the influence of these plasticizers were compared and studied by X-ray Diffraction (XRD), small angel X-ray Scattering (SAXS), optical microscope and dynamic mechanical analysis (DMA). Results showed that multi-scale structure of the blends were greatly affected by the plasticizers and therefore caused significant changes in mechanical properties. In the course, blends with glycerol presented lamellar structure rather than self-similar structure. Moreover, crystalline degree was increased with an order of glycerol > PEG > PG, whereas the compactness of amorphous region of all samples was decreased by PEG and PG. [ABSTRACT FROM AUTHOR]

Debranched starch (DBS) has attracted immense interest from the food, pharmaceutical, and cosmetic industries as a versatile ingredient. Herein, we firstly developed a simple fractionation method using an edible alcohol solution to separate DBS of different degrees of polymerization (DP). These DBSs were separated from debranched waxy corn starch on the basis of their differential solubility in aqueous/ethanol solutions of different volumetric ratios (1:1.5 and 1:3). Four DBS products were obtained with DP values of 23.53, 20.04, 9.14, and 6.75. The DBS (DP 23.53) exhibited higher iodine staining index values compared to DBSs of lower DPs. The thermograms of DBSs (DP 9.14 and DP 6.75) displayed no apparent peak, indicating their amorphous nature. Compared to freeze-drying, oven-dried DBS (DP 23.53) exhibited a higher relative crystallinity (72.0%). Therefore, the ethanol precipitation method developed here serves as a simple, scalable, and green approach for preparing DBS fractions of different molecular weights. [ABSTRACT FROM AUTHOR]

Effect of pressure with shear stress on the gelatinization of cornstarch with different amylose/amylopectin ratios (waxy 0/100; maze 23/77; G50 50/50; G80 80/20) was systematically investigated using a high-pressure rheometer. Onset and peak temperature of starch gelatinization as well as the peak viscosity were used to discuss the influence of pressure together with shear stress on the gelatinization of starch granules. The results showed that without shear stress, pressure could resist the gelatinization process due to weak swelling of starch granules and lower quantity of amylose released. However, the shear stress can simply counteract the influence of the pressure since its impact is much high on gelatinization. Under certain pressure and shear stress, both onset and peak temperatures of gelatinization were increased with increasing amylose content, which is in correspondence with the results from differential scanning calorimeter measurement, while the overall viscosity was lower when starches with a higher amylose content was used because part of its granular was not fully dissolved during the measurement. SAXS measurements were used to study the gel structure and stability of starch suspensions. It was found that the scattering intensity of starches in the measured range (0.1–1.0 nm −1 ) is G80 > waxy, indicating the amount of ordered semi-crystalline structures in amylose is higher. Peak values, q = 0.4 nm −1 and q = 0.2 nm −1 , detected for waxy starch under different shear rates, indicates that higher shear stress which plays a dominant role compared with pressure, resulted in more degradation in amylopectin, inhibiting the formation of aggregate structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rice noodles were prepared by indica rice flour containing hydroxypropyl starch (HPS). • Cooking loss of dried rice noodles with 3% HPS reduced 31.7%. • Tensile strain of the rice noodles with 3% HPS was 1.83 times that of the control. • The recommended addition of HPS in rice noodles was 3%. The convenient preparation of rice noodles with excellent mechanical and cooking properties remains a challenge for the food industry. The purpose of this study was to investigate the effect of different hydroxypropyl starch additions on the quality, performance, and structural characteristics of rice flours and noodles by mechanical property testing, cooking characteristic analysis, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), low-field nuclear magnetic resonance (LF-NMR), and other methods. SEM evaluation revealed that the addition of hydroxypropyl starch created rice noodles with a denser network structure. XRD analysis indicated a decrease in the noodle crystallinity from 11.37 % (control noodles) to 3.94 % (noodles containing 10 % hydroxypropyl starch). LF-NMR characterization confirmed an enhanced water-holding capacity of noodles containing hydroxypropyl starch. The noodle tensile strain increased from 54.97 ± 0.45 % in control noodles to 100.63 ± 1.58 % in noodles containing 3 % hydroxypropyl starch. The cooking loss of dried noodles decreased from 8.30 ± 0.57 % (control noodles) to 5.67 ± 0.16 % (noodles containing 3 % hydroxypropyl starch), and the broken rates were reduced from 77.50 ± 1.54 % of the control noodles to 12.50 ± 1.54 % of the noodles containing 3 % hydroxypropyl starch. The addition of 3 % hydroxypropyl starch can improve the quality of rice noodles and promote the development of the rice industry. [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]

This study aimed to develop a rapid ethanol annealing method by incubating pea starch and potato starch in 60% and 75% ethanol solutions at 95 °C for 0.5–3 h (to improve their heat, shear, and acid stability). The peak viscosities of the annealed starches decreased, the breakdown values declined to 0 cP, and the trough and final viscosities decreased remarkably. Furthermore, the pea starch transformed from a C-type to an A-type crystalline form, while the potato starch remained a B-type. Ethanol annealing also increased the pasting temperatures and decreased the enthalpy change values of the starches. When annealed in the 60% ethanol solution for 3 h, the pea starch showed the highest peak gelatinization temperature at 80.97 °C, which was 15.55 °C higher than the native starch. Moreover, the annealed starches showed remarkable decreases in swelling and solubility. Compared to traditional water annealing, this method could reduce the incubation period and lead to a higher gelatinization temperature of starch, which would have applications for thickening and stabilizing in the food system, for example, in the production of soups, puddings, and deep-fried foods. [Display omitted] • A new strategy for annealing starch in ethanol solution was studied. • The progress of ethanol annealing starch was shorter than that of water annealing. • Ethanol solution annealing treatment formed a complex between ethanol and amylose. • The thermal stability of starch was enhanced by ethanol annealing treatment. [ABSTRACT FROM AUTHOR]

• Hollow starch nanoparticles were obtained in an oil-in-water nanoemulsion system. • Nanoparticles were prepared by heterogeneous crystallization of debranched starch. • Nanoparticles with 0.5% debranched starch had uniform shells and globular shapes. • Thickness of their shells can be regulated by debranched starch concentration. The development of hollow nanoparticles has attracted widespread interest due to their potential commercial applications. This work aimed to prepare a novel hollow starch nanoparticles (HSNPs) from debranched waxy corn starch (DBS) via an oil-in-water (O/W) emulsion templating method. The effects of different concentrations of DBS on the formation of HSNPs at 4 °C and 25 °C were investigated. The monodispersed HSNPs obtained with 0.5% concentrations of DBS at 25 °C had spherical shapes, ranging between 200 and 800 nm. HSNPs with relative crystallinities of 16.9%–29.7% exhibited V-type or B + V-type structures, which indicated that DBS at low concentrations (0.5%–2.0%) could recrystallize and concomitantly form starch–lipid complexes around emulsion droplets. This novel approach of preparing HSNPs is viable and simple. The developed HSNPs could have great potential for delivering drugs or active ingredients. [ABSTRACT FROM AUTHOR]