Effect of low temperature on the aging characteristics of a potato starch gel

Endogenous gliadin/glutenin fractions regulate the short/long-term retrogradation behavior of starch-gluten gels

This study explored composite gels' structural properties and short/long-term retrogradation behavior by varying ratios of wheat starch to gluten and gliadin to glutenin. The results showed that as the proportion of gluten increased, the degree of order and crystalline conformation was lost, manifested by an increase in the gel network's porosity and protein aggregation. The dilution effect of gluten on starch and the water competition significantly reduced the viscosity and elasticity of the system, and the ratio of glu75-gli25 had the most significant impact on the viscoelasticity. During 30 d of storage, the hydration of gliadin with glutenin resulted in tight binding of the gel with hydrogen protons, which reduced water migration, effectively retarded the retrogradation behavior, and maintained a suitable hardness (2.59 N-5.39 N) and acceptable color. The above findings indicated that gliadin demonstrated favorable water-locking ability and effectively prevented starch's long-term retrogradation.

Inhibition of starch retrogradation: Advances in physical, chemical, and biological methods

Starch retrogradation, especially post-gelatinization, is a prevalent storage-induced process wherein starch recrystallization causes starch-based products to harden and develop an inferior texture, thereby impacting digestibility. Consequently, inhibiting this retrogradation is imperative for sustaining product quality. This review presents a comprehensive overview of the key factors influencing starch retrogradation and an in-depth discussion of the physical, chemical, and biological methods used to mitigate this process. Additionally, the characteristics and efficacy of these approaches are explored, and potential future developments in starch retrogradation control are discussed. Overall, this review serves as a valuable reference for advancing research in the inhibition of starch retrogradation.

Large deformation of food gels: Influencing factors, theories, models, and applications-A review

Gels possess remarkable properties, and they hold particular importance in food science. After consumption, food gels undergo large deformation, which impacts the overall texture of the food. This process is influenced by various factors, including temperature, pressure, and presence of crosslinking agents. Comprehensive insights into the interplay among these factors and gel texture, combined with the theoretical exploration of gel deformation, enable the development of foods to meet consumer preferences. To bolster the development of food gels, in this review, we summarize the factors affecting the large deformation of gels Moreover, we discuss various mathematical models established by food scientists to explore the large deformation of food gels and explore applications thereof. We expect that these insights into the large deformation of gels can lead to their increased utilization in the food industry.

Factors and modification techniques enhancing starch gel structure and their applications in foods:A review

The formation of starch gel structure results from the gelatinization and retrogradation of starch in aqueous solutions, which plays a crucial role in determining the quality and functional properties of starchy foods. The gelation ability of many native starches is limited and their structure is weak, which restricts their application. Therefore, how to enhance the gel structure of starch is of great significance to food science and industry. In this paper, the mechanism of starch gel formation was reviewed, and the research progress of starch composition, retrogradation conditions, food composition and modification methods were reviewed. Meanwhile, the applications of enhanced starch gel structures in food quality, nutrition, packaging, and 3D printing were discussed. This review provides valuable references for researchers and producers to develop high-quality and nutritious starch-based foods and further expand the applications of starches.

Integrative experimental and computational analysis of the impact of KGM's polymerization degree on wheat starch's pasting and retrogradation characteristics

This study investigated the influence of Konjac Glucomannan (KGM) with varying degrees of polymerization (DKGMx) on the gelatinization and retrogradation characteristics of wheat starch, providing new insights into starch-polysaccharide interactions. This research uniquely focuses on the effects of DKGMx, utilizing multidisciplinary approaches including Rapid Visco Analysis (RVA), Differential Scanning Calorimetry (DSC), rheological testing, Low-Field Nuclear Magnetic Resonance (LF-NMR), and molecular simulations to assess the effects of DKGMx on gelatinization temperature, viscosity, structural changes post-retrogradation, and molecular interactions. Our findings revealed that higher degrees of polymerization (DP) of DKGMx significantly enhanced starch's pasting viscosity and stability, whereas lower DP reduced viscosity and interfered with retrogradation. High DP DKGMx promoted retrogradation by modifying moisture distribution. Molecular simulations revealed the interplay between low DP DKGMx and starch molecules. These interactions, characterized by increased hydrogen bonds and tighter binding to more starch chains, inhibited starch molecular rearrangement. Specifically, low DP DKGMx established a dense hydrogen bond network with starch, significantly restricting molecular mobility and rearrangement. This study provides new insights into the role of the DP of DKGMx in modulating wheat starch's properties, offering valuable implications for the functional improvement of starch-based foods and advancing starch science.

Crucial effect of ovomucin on alkali-induced egg white gel formation: Properties, structure and facilitation mechanism

Alkali-induced preserved egg gel formation is a dynamic process that involves complex protein changes. Ovomucin (OVM) is closely associated with the gel properties of egg white. In this study, the effect of OVM in alkali-induced egg white gel (AEWG) formation was investigated. The results suggested that OVM reduced the gel formation time by 15 %. The mechanical properties of the fully formed gel were also improved by OVM. Specifically, OVM increased the storage modulus (G') of the gel by 1.5-fold, while the hardness significantly increased from 78.90 ± 4.24 g to 99.80 ± 9.23 g. Low-field nuclear magnetic resonance (LF-NMR) demonstrated that OVM significantly shortened T23 relaxation time and reduced the water mobility, thus increasing the water holding capacity (WHC). Meanwhile, the presence of OVM resulted in a more homogeneous and denser microscopic morphology of the gel. Selective solubility experiments revealed that disulfide bonds are the primary force in gel formation. OVM promoted the formation of more disulfide bonds, which increased the strength and stability of the gel network. Overall, this research proved OVM plays a critical role in the performance improvement of AEWG, which provides a new insight into the quality control of preserved egg and protein gel foods.

Insights into the effect mechanism of freeze-thaw cycles on starch gel structure and quality characteristics of frozen extruded whole buckwheat noodles

The effects of freeze-thaw cycles (FTC) on starch gel structure and quality characteristics of frozen extruded whole buckwheat noodles (FEWBN) were studied. The repeated FTC treatments induced the retrogradation of amylose which increased the compactness, crystallinity, hardness, and cooking time of FEWBN. However, with the increasing number of freeze-thaw cycles, the larger volume of ice crystals formed in the noodles destroyed the starch gel network structure to a certain extent, and led to the dehydration and syneresis of the noodles, and the quality deterioration. However, moderate amylose retrogradation occurred during the FTC treatment was found to be beneficial for the quality of FEWBN. After one time of FTC treatment, the cooking loss of 3.53 % was even lower compared with that without FTC treatment (4.61 %). After seven times of FTC treatment, the cooking loss of FEWBN was 6.53 %, and the breaking rate was still 0, indicating that FEWBN could resist the damage caused by temperature fluctuations on the internal structure of frozen food to a certain extent, and maintain good quality. This study establishes a fundamental basis for the development of buckwheat noodles with good freeze-thaw stability and high cooking quality.

Impact of Rare Sugar D-Allulose on Hardening of Starch Gels during Refrigerated Storage

The rare sugar D-allulose (Alu), with ca. 10% calories of sucrose (Suc), is a promising alternative sugar that can be used to improve the quality of starch gels in storage. The effects of Alu (compared to Suc) on the hardening and microstructural and molecular order of amylopectin-rich (glutinous rice (GR) and corn amylopectin (CAP)) and amylose-rich (corn (C)) starch gels were investigated. Alu and Suc both suppressed hardening in C gels, while Alu but not Suc was effective in GR and CAP gels. SEM results showed that Alu-containing GR and CAP maintained a relatively large pore size compared to Suc-containing gels. The deconvolution of FTIR spectra revealed that Alu-containing GR and CAP gels had lower ratios of intermolecular hydrogen bonds and higher ratios of loose hydrogen bonds than Suc-containing gels. For amylose-rich C gels, on the other hand, such tendencies were not observed. The influence of Alu on amylopectin-rich gels could be because Alu reduced the ratio of intermolecular hydrogen bonds, which might be involved in amylopectin recrystallization, and increased that of loose hydrogen bonds. The results suggest that Alu is more effective than Suc in inhibiting the hardening of amylopectin-rich starch gels during refrigerated storage.

Enzymatic modification lowers syneresis in corn starch gels during freeze-thaw cycles through 1,4-α-glucan branching enzyme

The current research in the food industry regarding enzymatic modification to enhance the freeze-thaw (FT) stability of starch is limited. The present study aimed to investigate the FT stability of normal corn starch (NCS) modified using 1,4-α-glucan branching enzyme (GBE) derived from Geobacillus thermoglucosidans STB02. Comprehensive analyses, including syneresis, scanning electron microscopy, and low-field nuclear magnetic resonance, collectively demonstrated the enhanced FT stability of GBE-modified corn starch (GT-NCS-30) in comparison to its native form. Its syneresis was 66.4 % lower than that of NCS after three FT cycles. Notably, GBE treatment induced changes in the pasting properties and thermal resistance of corn starch, while simultaneously enhancing the mechanical strength of the starch gel. Moreover, X-ray diffractograms and microstructural assessments of freeze-thawed gels indicated that GBE treatment effectively hindered the association of corn starch molecules, particularly amylose retrogradation. The enhanced FT stability of GBE-modified starch can be attributed to alterations in the starch structure induced by GBE. This investigation establishes a foundation for further exploration into the influence of GBE treatment on the FT stability of starch and provides a theoretical basis for further research in this area.

Comparison of structural and in vitro digestive properties of autoclave-microwave treated maize starch under different retrogradation temperature conditions

Retrogradation is a critical step in the physical production of resistant starch. This study aimed to examine the effects of isothermal and temperature-cycled retrogradation on the structural, physicochemical properties, and digestibility of resistant starch type-III (RS3) under various thermal conditions. To create RS3, normal maize starch (NM) and Hylon VII (HAM) were treated by autoclave-microwave and then retrograded at isothermal (4 °C) or various temperature conditions (4/10 °C, 4/20 °C, 4/30 °C, 4/40 °C, and 4/50 °C). We found that temperature-cycled retrogradation possessed greater potential than isothermal retrogradation for producing short-range ordering and crystalline structures of RS3. Also, retrograded starch prepared via temperature cycling exhibited higher double helix content, lower amorphous content, reduced swelling power, and less amylose leaching in water. Furthermore, the starch digestibility was affected by structural alterations, which were more significant in HAM-retrograded starch. While, HAM-4-40 (39.27 %) displayed the highest level of resistant starch (RS).

Improvement of sorghum-wheat blended flours by E-beam irradiation: Physicochemical properties, rheological behavior, microstructure, and quality properties

To enhance the processing suitability of blended flours, this study used 4 kGy E-beam irradiated (EBI) sorghum flour in different ratios blended with wheat flour and further verified the improvement mechanism of the processed products under the optimal ratios. The results suggested that the EBI can mitigate the deterioration of the blend flour farinograph properties while enhancing the gas release during dough fermentation. Under the same addition ratio, the irradiated blend flours showed higher expansion height, gas release, cavitation time, and gas retention coefficient than the control flours. Also, irradiated blend flours retained a gluten network at a higher addition rate (20 %). Moreover, the irradiated blend flours were optimized at 10 % as its pasting and thermal properties were improved. Notably, this ameliorating effect promotes a decrease in hardness and chewiness and an increase in cohesion of the bread cores, presenting better textural attributes and delaying the aging rate during storage. The findings are instructive for applying EBI technology in the manufacture and quality improvement of mixed grain breads and open a new research avenue for processing sorghum staple foods.

Study on physicochemical properties and anti-aging mechanism of wheat starch by anionic polysaccharides

The anti-aging effects of two anionic polysaccharides AG (sodium alginate)/SSPS (soluble soybean polysaccharide) and WS (wheat starch) were evaluated, and their different mechanisms were explored. The rheological properties, gelatinization properties and aging properties were characterized. The addition of AG and SSPS changed the gelatinization parameters of WS, decreased the peak viscosity, breakdown viscosity and setback viscosity, and enhanced the fluidity of the gel system. Additionally, the starch molecular orderliness experiment showed that the relative crystallinity of starch gels decreased with the increase in AG and SSPS concentrations, indicating that the rearrangement of amylopectin was disturbed, which inhibited the cross-linking of starch molecules. The water state analysis showed that the hydrophilicity of AG and SSPS and their interactions with starch molecules influenced the relaxation behavior of water protons in the gel system in a concentration-dependent manner. In conclusion, the addition of AG and SSPS could significantly inhibit the aging of WS gels, probably due to the competition effect of AG and SSPS on water and the interaction with starch molecules. The present study results would provide new theoretical insights into WS-based food research.

Interpretation of the effects of hydroxypropyl starch and hydroxypropyl distarch phosphate on frozen raw noodles quality during frozen storage: Studies on water state and starch-gluten network properties

The impacts of both structural variations induced by low temperature and physiochemical changes induced by modified starch on the qualities of frozen raw noodles (FRNs) were investigated during long-term freezing storage. The addition of modified starch was a potentially effective method to delay the loss of FRNs qualities during storage. In this study, hydroxypropyl starch (HPS) and hydroxypropyl distarch phosphate (HPDSP) were added to improve the cooking and textural characteristics of FRNs. The cooking loss rate of FRNs with the addition of 12%HPS was consistent with that of the control (4.39 % and 4.37 %, respectively), while after 8 weeks of storage showed the significant decrease effect (5.01 % and 5.78 %, respectively). In addition, adding HPS or HPDSP could change the colour and lustre of FRNs to that preferred by consumers. When 6 % HPS or HPDSP were added, the FRNs showed the lowest of freezable water content during storage. The test results of FTIR showed the secondary structure of FRNs was maintained with the introduction of HPS or HPDSP during refrigeration, and the microstructure was improved during the frozen storage period. Consequently, the results provided a theoretical basis and new insight for the production and transportation of FRNs.

Effects of different storage temperatures and time on frozen storage stability of steamed bread

BACKGROUNDS

This research intended to explore the effects of different frozen storage temperatures and time on the stability of steamed bread. The quality characteristics, moisture content and microstructure of steamed bread were determined after quick-frozen for 30 min at -32 °C and frozen storage at -6, -12, -18, -24 and -30 °C for 1-4 weeks.

RESULTS

When the frozen storage temperature is lower, the moisture content, specific volume, pH and the strong bound water in the steamed bread increase, the water loss rate and the contents of freezable water, the weak bound water and free water decreased. With the extension of frozen storage time, the pH value and water loss of steamed bread first increased and then decreased, while the trend of water content was opposite. The specific volume, cohesion and elasticity of steamed bread decreased, while the freezable water content, hardness and chewiness increased. The bound water of steamed bread gradually migrated to free water. In addition, the longer the frozen storage time and the higher the temperature, and the more serious the damage to the microstructure was.

CONCLUSION

The shelf life of steamed bread frozen storage at -12 °C could be up to 3 weeks, and the quality of steamed bread stored at -30 °C for more than 3 weeks was the best. © 2022 Society of Chemical Industry.

The modulatory roles and regulatory strategy of starch in the textural and rehydration attributes of dried noodle products

Noodles are popular staple foods globally, and dried noodle products (DNPs) have gained increasing attention due to recent changes in consumer diet behavior. Rapid rehydration and excellent texture quality are the two major demands consumers make of dried noodle products. Unfortunately, these two qualities conflict with each other: the rapid rehydration of DNPs generally requires a loose structure, which is disadvantageous for good texture qualities. This contradiction limits further development of the noodle industry, and overcoming this limitation remains challenging. Starch is the major component of noodles, and it has two main roles in DNPs. It serves as a skeleton for the noodle in gel networks form or acts as a noodle network filler in granule form. In this review, we comprehensively investigate the different roles of starch in DNPs, and propose strategies for balancing the conflicts between texture and rehydration qualities of DNPs by regulating the gel network and granule structure of starch. Current strategies in regulating the gel network mainly focused on the hydrogen bond strength, the orientation degree, and the porosity; while regulating granule structure was generally performed by adjusting the integrity and the gelatinization degree of starch. This review assists in the production of instant dried noodle products with desired qualities, and provides insights into promising enhancements in the quality of starch-based products by manipulating starch structure.

Preparation of corn starch/rock bean protein edible film loaded with d-limonene particles and their application in glutinous rice cake preservation

Glycerol hydrogenated rosin (GEHR) and d-limonene were prepared for micro-particles by electrostatic spray method. When the GEHR/d-limonene ratio is 5.5:4.5 and the electrostatic spray extrusion speed is 1 mL/h, the best particle size (177.24 ± 17.09 μm) and embedding rate of d-limonene (41.74 ± 9.88%) are achieved. Then, rock bean protein (RP) was extracted from wild rock beans and combined with GEHR/d-limonene particles and corn starch (CS) to prepare a new type of edible film. The prepared film was characterized using Fourier transform infrared spectroscopy in terms of structural changes and physical, optical, mechanical, and thermal properties. The results show that the edible film with a ratio of 1:1 exhibited more optimized thermal (179.2 °C) and mechanical properties (TS 0.88 MPa, EAB 54.36%). Studies on freshly prepared glutinous rice cake as an object for preservation using edible film show that the films can prolong shelf life by ~2-4 d. Through this experiment, it can serve as a reference for the development of a new type of edible film.

Study of starch aging characteristics based on Terahertz technology

Traditional methods for the determination of starch aging indicators often have a series of shortcomings such as time-consuming, high cost, large human error, damage to samples, environmental pollution, and high requirements for inspectors. Therefore, it is meaningful to find or establish a dynamic fingerprint identification pattern that can detect the aging degree of starch during the process of processing or storage quickly and accurately. It not only provides guidance for starch food processing but also saves a lot of human, material resources, and time. Terahertz technology is an emerging molecular spectroscopy technology in the 21st century. It is with low energy and basically harmless to the human body. It can also realize nondestructive testing of samples. In the experiment, the samples were prepared by the tableting method and the samples containing 20% of 50 mg samples were prepared with polyethylene as the diluent. The thickness of the samples was 1 mm and the diameter was 13 mm. The terahertz time-domain spectrometer was used to obtain the spectral information of aging starch at different aging times. After the pretreatment of the spectrum by vector normalization, first derivative, and multiple scattering correction, the prediction models of aging days, crystallinity, and resilience of aging starch were established, respectively. The determination coefficient (R 2) of the established models is all greater than 95%, indicating that the established models are highly reliable and can be used to predict the aging days, crystallinity, and retrogradation degree of starch. And the R 2 of the prediction model based on the refractive index spectrum is greater than that of the absorption coefficient spectrum. The experimental method obtains the dynamic fingerprint identification map of starch in the aging process, realizes the real-time monitoring and detection of the starch aging process, and provides an effective means for the production and processing of starch-related industries.