Impact of binding interaction characteristics on physicochemical, structural, and rheological properties of waxy rice flour

Investigation of self-assembly mechanism of gluten protein amyloid fibrils and molecular characterization of structure units

The mechanism of peptides self-assembly into gluten amyloid fibrils was explored through bond-breaking experiments and molecular dynamics (MD) simulations, verified through fibrillation experiments using synthetic peptides. The disruption of hydrogen bonds reduced thioflavin T fluorescence intensity and average particle size of gluten amyloid fibrils by 24 % and 81 %, respectively, causing a breakdown of internal structure. Disruption of electrostatic and hydrophobic forces induced further aggregation of fibrils. MD simulation revealed that peptides transitioned from a dispersed state to aggregation, followed by changes in secondary structure, culminating in the formation of stacked β-sheets structure units. Hydrogen bonding emerged as the primary driver of self-assembly with contributions from hydrophobic and electrostatic interactions. The synthetic single or hybrid peptide systems selected by MD formed ribbon- or fiber-like amyloid fibrils with inter-strand distance of 4.7 Å and respective inter-sheet distances of 10.2 Å and 10.8 Å, suggesting that the structure and morphology of eventual amyloid fibrils were affected by the peptide sequence and cross β-sheet structure units.

Differences in starch and protein composition, morphological and structure, and their impacts on eating quality of soft japonica rice under different light and nitrogen fertilizer conditions in southern China

This study explores the differences in starch and protein composition, morphological and structure, and their impacts on soft japonica rice eating quality under different light and nitrogen fertilizer conditions. Results showed that decreased light and applied panicle fertilize resulted in a decreased in total starch, accompanied by an increased in long-chain amylopectin, protein, particularly glutelin, and β-sheet, with these effects being more pronounced when panicle fertilizer was applied under 50 % light. RVA, LF-NMR and Rheometer date showed that aforementioned changes in starch and protein were detrimental to water migration and starch gelatinization during rice cooking, resulting in a high-strength rice gel network. Ultimately, cooked rice exhibited poor taste. In conclusion, decreased light and applied panicle fertilize both degrade rice eating quality, and the combined effect of these two factors further diminishes cooked rice taste. Furthermore, 50 % light had a greater impact on starch, protein and eating quality than panicle fertilize.

Analysis of the effects of light and panicle fertilizer on rice eating quality based on morphological structural changes in starch and protein during cooking

Light and panicle fertilizer are crucial environmental factors that influence rice eating quality. Currently, there is a lack of systematic research on how light and panicle fertilizer alter the morphological structures of starch and protein during cooking, subsequently affecting rice taste. To address this gap, field experiments were conducted under varying conditions of light (100 % light, L1; 50 % light, L2) and panicle fertilizer (no panicle fertilizer, N1; 81 kg/ha of panicle fertilizer, N2), followed by cooking after harvest. The results showed that, compared to L1N1, the water migration (low T2), starch and protein structural disruption (slow decline in 1047/1022 cm-1) were limited in L1N2, L2N1, and L2N2 during the cooking, making rice hard to cook. Eventually, compared to L1N1, L1N2, L2N1 and L2N2 exhibited lower peak viscosity but higher strength gel networks (higher G' and G''), leading to a decline in rice eating quality. In summary, reduced light intensity and applied panicle fertilizer restricted the disruption of starch and protein structures during rice cooking, which hindered rice cooking processes, ultimately leading to a decrease in rice eating quality. Furthermore, it is noteworthy that the combination of reduced light and applied panicle fertilizer further exacerbated the decline in rice eating quality.

Synthesis, characterization of thiolated hyaluronic acid and evaluation of its encapsulation effects on Limosilactobacillus reuteri HR7

Hyaluronic acid (HA) was thiol-modified by adding different concentrations of L-Cysteine (1 mmol, 2 mmol, 3 mmol, 4 mmol, 5 mmol and 6 mmol) and the resulting polymers (HA-SH) were characterized. The results of FTIR, 1H NMR, XRD, SEM and DSC all confirmed the success of thiol modification, accompanied by free thiol group content of 3169.51-3913.44 μmol/g. Sulfur element was only detected in HA-SH, accounting for 1.12 %-1.23 %. The Mw and particle size were decreased after thiol modification, representing a more uniform polysaccharide conformation, which was beneficial for the encapsulation of probiotics. Rheological analysis showed that the hydrogel prepared by HA displayed viscoelastic fluid properties, while the hydrogels prepared by HA-SH exhibited solid-like gel properties, indicating enhanced gelation properties after thiol modification. Subsequently, the hydrogels were applied to probiotics encapsulation to explore the effects on gastrointestinal tolerance. A higher encapsulation efficiency was observed in HA-SH hydrogel with enhanced gastrointestinal tolerance, increasing by 38.15 % on average. These results demonstrated that thiolation was a good strategy for polysaccharide modification and hydrogel formed by HA-SH was a more promising encapsulation and delivery system for probiotics compared with HA.

The interaction between starch and gluten and related wheat-based noodles quality, a review

Starch and gluten, the primary components of wheat, play critical roles in determining noodle quality through their synergistic interactions. To unveil the influence of starch-gluten protein interactions on the quality of noodles, further comprehensive exploration in this domain remains imperative. The current understanding of the interactions between gluten and starch in noodles processing was reviewed, with emphasis on water competition, space competition, and covalent and non-covalent interactions. In addition, the influencing factors that impact the starch-gluten interaction, including starch chain, starch granule size, damaged starch content, gluten subunits, processing technology, and additives were discussed. This review describes the interactions between starch and gluten and provides a reference for improving noodle quality.

The Effect of Protein-Starch Interaction on the Structure and Properties of Starch, and Its Application in Flour Products

Grains are an energy source for human beings, and the two main components-starch and protein-determine the application of grains in food. The structure and properties of starch play a decisive role in determining processing characteristics, nutritional properties, and application in grain-based foods. The interaction of proteins with starch greatly affects the structure, physicochemical, and digestive properties of the starch matrix. Scientists have tried to apply this effect to create foods tailored to specific needs. Therefore, studying the effect of protein on the structure and properties of starch in the starch-protein complexes will help in designing personalized and improved starch-based food. This paper reviews the latest research about the effects of endogenous and exogenous proteins on the structure and properties of starch, as well as factors influencing the interaction between protein and starch. This includes investigations of the chain and aggregation structure of proteins with starch, as well as assessments of impacts on thermal properties, rheology, gel texture properties, hydration properties, aging, and digestion. In addition, particular examples illustrating the effects of protein-starch interaction on starch properties in various foods are discussed, providing a reference for designing starch-protein foods that are rich in terms of nutrition and easier to process.

Improving physicochemical and nutritional attributes of rice starch through green modification techniques

Rice, has long been an inseparable part of the human diet all over the world. As one of the most rapidly growing crops, rice has played a key role in securing the food chain of low-income food-deficit countries. Starch is the main component in rice granules which other than its nutritional essence, plays a key role in defining the physicochemical attributes of rice-based products. However, rice starch suffers from weak techno-functional characteristics (e.g., retrogradability of pastes, opacity of gels, and low shear/temperature resistibility. Green modification techniques (i.e. Non-thermal methods, Novel thermal (e.g., microwave, and ohmic heating) and enzymatic approaches) were shown to be potent tools in modifying rice starch characteristics without the exertion of unfavorable chemical reagents. This study corroborated the potential of green techniques for rice starch modification and provided deep insight for their further application instead of unsafe chemical methods.

Property and quality of japonica rice cake prepared with Polygonatum cyrtonema powder

Rice cake is a common traditional food in China. In this study, the effect of Polygonatum cyrtonema (PC) on the qualities and characteristics of rice cake was investigated. The incorporation of PC powder in rice cakes endowed a light-yellow color and increased the water content and water absorption of products. Rheological analysis showed that the rice cake containing PC exhibited weak-gel properties. Additionally, PC (40%) inhibited the rice cake aging and lowered the hardness of rice cakes to 13.86 N after 4 h storage. In vitro starch digestion analysis showed that PC (40%) reduced the digestibility of rice cakes by decreasing the starch hydrolysis rate from 88.70 to 58.95%, displaying a low estimated glycemic index (eGI) of 52.14. The findings mentioned above indicated that the inclusion of PC powder in rice cakes enhanced their characteristics and attributes, which also provided an approach for the development of PC products.

Rheological properties of indica rice determined by starch structure related enzymatic activities during after-ripening

The processing quality of indica rice must undergo ripening after harvest to achieve stability and improvement. However, the mechanism underlying this process remains incompletely elucidated. Starch, the predominant component in indica rice, plays a crucial role in determining its properties. This study focused on analyzing the rheological properties and starch fine structure, as well as the related biosynthetic enzymes of indica rice during the after-ripening process. The results showed that after-ripened rice exhibited increased elastic modulus (G') and viscous modulus (G″), accompanied by a decrease in the loss tangent (Tan δ), indicating an enhancement in viscoelasticity and the gel network structure. Moreover, the proportions of amylopectin super long chains (DP 37-60) decreased, while those of medium chains (DP 13-24 and DP 25-36) or short chains (DP 6-12) of amylopectin increased. Additionally, the activities of starch branching enzyme (SBE) and starch debranching enzyme (DBE) declined over the after-ripening period. Pearson correlation analysis revealed that the rheological properties of after-ripened rice were correlated with the chain length distribution (CLD) of starch, which, in turn, was associated with its related endogenous enzymes. These findings provied new insights into understanding the quality changes of after-ripened indica rice.

Effect of starch and protein on eating quality of japonica rice in Yangtze River Delta

This study examined four types of japonica rice from Yangtze River Delta, categorized based on amylose content (AC) and protein content (PC): high AC with high PC, high AC with low PC, low AC with high PC, and low AC with low PC. It systematically explored the effect of starch, protein and their interactions on eating quality of japonica rice. Rheological analysis revealed that increased amylose, long chains amylopectin or protein levels during cooking strengthen starch-protein interactions (hydrogen bonding), forming a firm gel network. Scanning electron microscopy showed that increased amylose, long chains amylopectin or protein levels made protein and starch more stable in combination during cooking, limiting starch structure cleavage. Therefore, the eating quality of high AC in similar PC japonica rice and high PC in similar AC japonica rice were poor. Further, correlation and random-forest analysis (RFA) identified amylose as the most influential factor in starch-protein interactions affecting rice eating quality, followed by amylopectin and protein. RFA also revealed that in high AC japonica rice, the interactions of Fb3 and albumin with amylose were more conducive to forming good eating quality. In low AC japonica rice, the interactions of Fb2 and prolamin with amylose were more beneficial.

Effect and Mechanism of Soluble Starch on Bovine Serum Albumin Cold-Set Gel Induced by Microbial Transglutaminase: A Significantly Improved Carrier for Active Substances

Soluble starch (SS) could significantly accelerate the process of bovine serum albumin (BSA) cold-set gelation by glucono-δ-lactone (GDL) and microbial transglutaminase (MTGase) coupling inducers, and enhance the mechanical properties. Hardness, WHC, loss modulus (G″) and storage modulus (G') of the gel increased significantly, along with the addition of SS, and gelation time was also shortened from 41 min (SS free) to 9 min (containing 4.0% SS); the microstructure also became more and more dense. The results from FTIR, fluorescence quenching and circular dichroism (CD) suggested that SS could bind to BSA to form their composites, and the hydrogen bond was probably the dominant force. Moreover, the ability of SS to bind the original free water in BSA gel was relatively strong, thereby indirectly increasing the concentration of BSA and improving the texture properties of the gel. The acceleration of gelling could also be attributed to the fact that SS reduced the negative charge of BSA aggregates and further promoted the rapid formation of the gel. The embedding efficiency (EE) of quercetin in BSA-SS cold-set gel increased from 68.3% (SS free) to 87.45% (containing 4.0% SS), and a controlled-released effect was detected by simulated gastrointestinal digestion tests. The work could put forward new insights into protein gelation accelerated by polysaccharide, and provide a candidate for the structural design of new products in the food and pharmaceutical fields.

Understanding effects of glutelin on physicochemical and structural properties of extruded starch and the underlying mechanism

This work studied effects of different amounts of rice glutelin (RG) on physicochemical and structural properties of extruded rice starch (ERS) and explored the underlying mechanism of interaction between rice starch and RG upon extrusion processing. The results showed that the addition of RG altered the pasting properties, improved the viscoelastic, and increased the water mobility of ERS. The weight loss of ERS decreased from 71.40 % to 62.61 %, while the degradation temperature increased from 290.48 °C to 296.25 °C as the RG content increased from 0 % to 12 %. The complex index of extruded starch-glutelin complexes significantly elevated from 10.40 % to 35.81 % when RG content increased from 6 % to 12 %. Fourier-transform infrared spectra confirmed that RG interacted with starch via Maillard reactions, and the binding strength between RG and starch was enhanced at a higher RG content. Furthermore, results of rheological property and chemical interactions demonstrated that hydrogen bonding, hydrophobic, and electrostatic interaction were formed between RG and starch during extrusion. In summary, the obtained results of this study can further enrich the theory of starch-protein interactions and show the possibility of RG applied in the extruded starchy foods.

Physicochemical and functional properties of the protein-starch interaction in Chinese yam

Protein-starch interaction has an important impact on the properties of starchy foods rich in protein, but the contribution of the interaction to Chinese yam still remains unclear. This study aimed to characterize the physicochemical and functional properties related to the possible interaction between starch and protein in Chinese yam. Differential scanning calorimetry and rapid viscosity analyzer results revealed that the gelatinization temperature increased in protein and starch cross-linked powder, while the peak viscosity and the setback viscosity decreased. The swelling power and solubility at 80°C and 95°C decreased with increasing protein ratio in the powder. In vitro starch digestibility test indicated that a high protein ratio could rapidly reduce digestible starch, but increase both slowly digestible starch and resistant starch. Protein could act as the physical barrier toward starch against heating and digestion to exert the influence on starch properties. Fourier transform infrared spectroscopy test revealed the interaction between protein and starch. These results revealed the role of protein-starch interaction and provided beneficial information for the utilization of Chinese yam.

Effect of extrusion parameters on the interaction between rice starch and glutelin in the preparation of reconstituted rice

Reconstituted rice produced by extrusion has been attracted attention due to nutritional fortification and convenient production. Nevertheless, how to achieve desirable qualities and physicochemical properties of reconstituted rice nearly to natural rice by regulating extrusion process parameters is difficult. Herein, rice starch/glutelin mixture as raw material of reconstituted rice was extruded at varying extrusion conditions. Specific mechanical energy (SME) and sectional expansion index (SEI) dropped with rise in density (R² = 0.9117 and 0.8207). Solubility was enhanced with increase in product temperature (R² = 0.9085), color darkened and shifted to reddish and yellowish as extrusion temperature increased (R² = 0.8577). These trends were well fitted by sigmoid models. Furthermore, SME enhanced hydrophobic and electrostatic interactions between rice starch and glutelin and caused the reduction in crystallinity and thermal stability, promoting the formation of a bi-continuous matrix of protein aggregates with rice starch. The obtained results can be applied to guide the production of reconstituted rice with desirable qualities.

Effect of Maltodextrin on the Physicochemical Properties and Cooking Performance of Sweet Potato Starch Noodles

Maltodextrin (MD), the hydrolyzed starch product, is a promising alternative ingredient to improve the quality of starch-based foods. The effects of MD on the physicochemical, microstructural, and cooking properties of sweet potato starch (SPS) noodles, as well as the mechanism of SPS-MD interactions, are discussed. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results indicated that MD at a suitable concentration can improve the ordered structure of SPS-MD gels. The cooking loss showed lower values of 1.47−2.16% at 0.5−2.0 wt% MD. For the texture properties, an increase in hardness and chewiness occurred at first with the addition of MD, followed by a decreasing trend, showing a maximum value at 2.0 wt% of MD. The pasting and thermal results verified the increased stability of the starch granules with MD < 3 wt%. Additionally, SPS formed a solid-like gel with MD, and the main interaction forces between SPS and MD were hydrogen bonding. The scanning electron microscopy results revealed that the higher concentrations of MD (>3 wt%) loosened the gel structure and markedly increased the pore size. These results help us to better understand the interaction mechanism of the SPS-MD complex and facilitate the development of SPS-based gel products.

Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value (p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption (p < 0.05). Moreover, E-HBS had not only higher G′ and G″ values, but also the highest gel hardness value, reflecting its strong gel structure (p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.

Mechanisms Underlying the Formation of Amylose- Lauric Acid-β-Lactoglobulin Complexes: Experimental and Molecular Dynamics Studies

The aim of the present study was to reveal the mechanisms underlying the formation of ternary complexes with a model system of amylose (AM), lauric acid (LA), and β-lactoglobulin (βLG) using experimental studies and molecular dynamics (MD) simulations. Experimental analyses showed that hydrophobic interactions and hydrogen bonds contributed more than electrostatic forces to the formation of the AM-LA-βLG complex. MD simulations indicated that interactions between AM and βLG through electrostatic forces and hydrogen bonds, and to a less extent van der Waals forces, and interactions between AM and LA through van der Waals forces, were mostly responsible for complex formation. The combination of experimental results and MD simulations has provided new mechanistic insights and led us to conclude that hydrophobic interactions, van der Waals forces between AM and LA, and van der Waals forces and hydrogen bonds between AM and βLG were the main driving forces for the formation of the AM-LA-βLG complex.

Pasting Properties of Various Waxy Rice Flours: Effect of α-Amylase Activity, Protein, and Amylopectin

Waxy rice has a long history of being cultivated and consumed in China. In this study, the effect of different factors including α-amylase activity, protein, and amylopectin structure on the pasting properties of four waxy rice varieties were investigated. Rice flours were divided into four groups (Vietnam indica (VI), Jiangxi indica (JI), Anhui japonica (AJ), and Dongbei japonica (DJ) group) and treated with AgNO3 solution, DL-dithiothreitol (DTT), or protease (n = 3). Results suggested that both α-amylase activity and protein significantly decrease the pasting viscosity of waxy rice flours. Chain length distribution of amylopectin as measured by high performance ion exchange chromatography (HPAEC-PAD) showed that starch with a higher ratio of short chain leads to a higher pasting viscosity. X-Ray diffractograms showed that the crystal type of all the four varieties of rice starches were characteristic A-type. Relative crystallinity of each rice starch was further calculated, and higher crystallization resulted in a higher viscosity. Our study would provide a fundamental knowledge of the relationship between different factors and waxy starch pasting properties, as well as be a reference for controlling the quality of waxy rice starch-based food products.

Size Changeable Nanomedicines Assembled by Noncovalent Interactions of Responsive Small Molecules for Enhancing Tumor Therapy

The size of nanocarriers strongly affects their performance in biological systems, especially the capacity to overcome various barriers before delivering the payloads to destinations. However, the optimum size varies at different delivery stages in cancer therapy due to the complicated tumor microenvironment. Relatively large particles are favored for long-term circulation in vivo, while smaller particles contribute to deep penetration into tumor tissues. This dilemma in the size of particles stimulates the development of stimuli-responsive size-shrinking nanocarriers. Herein, we report a facile strategy to construct a tumor-triggered tannic acid (TA) nanoassembly with improved drug delivery efficiency. Cystamine (CA), a small molecule with a disulfide bond, is thus used to mediate TA assembling via cooperative noncovalent interactions, which endows the nanoassembly with intrinsic pH/GSH dual-responsiveness. The obtained TA nanoassemblies were systematically investigated. DOX encapsulated nanoassembly labeled TCFD NP shows high drug loading efficiency, pH/GSH-responsiveness and significant size shrinkage from 122 to 10 nm with simultaneous drug release. The in vitro and in vivo experimental results demonstrate the excellent biocompatibility, sufficient intracellular delivery, enhanced tumor retention/penetration, and superior anticancer efficacy of the small-molecule-mediated nanoassembly. This noncovalent strategy provides a simple method to fabricate a tumor-triggered size-changeable delivery platform to overcome biological barriers.

Selective adsorption of egg white hydrolysates onto activated carbon: Establishment of physicochemical mechanisms for removing phenylalanine

Previously, it was shown that activated carbon can remove phenylalanine from egg white hydrolysates to produce a low phenylalanine peptide ingredient that can be used by individuals suffering from phenylketonuria. However, the factors impacting the selective adsorption of phenylalanine and peptides to activated carbon is not fully understood, which is holding back the optimization of this process. In this research, two activated carbons with different morphologies and electrical characteristics were used to adsorb egg white hydrolysates with different degrees of hydrolysis. The selective adsorption behavior of the different constituents within the hydrolysates was studied to identify the nature of the adsorption mechanisms involved. The results showed that aromatic amino acids and components with higher molecular weight were preferentially adsorbed. Moreover, the main driving force for adsorption was hydrophobic attraction, followed by hydrogen bonding and electrostatic interactions. These results could facilitate the preparation of medical foods for patients with phenylketonuria.

Starch-protein interplay varies the multi-scale structures of starch undergoing thermal processing

This work concerns how starch-protein interplay affects the multi-scale structures (e.g., short- and long-range orders, nanoscale structure and morphology) of starch undergoing thermal processing (pasting) involving heating and cooling at high water content. An indica rice starch (IRS) and three proteins (whey protein isolate, WPI; soy protein isolate, SPI; casein, CS) were used. By inspecting rheological profiles of mixed systems before and after adding chemicals, IRS-WPI and IRS-CS showed mainly hydrophobic molecular interaction; and IRS-SPI exhibited hydrophobic, hydrogen bonding and electrostatic interactions. The RVA results revealed that, with starch and proteins as controls, starch-globular protein (WPI or SPI) interplay accelerated the swelling of starch granules (faster viscosity increase at initial pasting stage), and reduced the paste stability during heating (higher breakdown) and during cooling (higher setback); however, the starch-casein interactions resulted in opposed effects. Moreover, starch-protein interactions varied the multi-scale chain reassembly of starch into different structures during cooling. Observed could be fewer short- and long-range starch orders, and larger nonperiod structure (or colloidal clusters) on the nanoscale. On even larger scale to micron, IRS-globular protein molecules generated larger grids (with reduced number) in the gel network, and IRS-casein formed a more continuous gel network with less prominent tunnel-like features.

Effect of maltodextrin combination with gum arabic and whey protein isolate on the microencapsulation of gurum seed oil using a spray-drying method

This study aimed to evaluate the potential of maltodextrin (MD) combination with gum arabic (GA), and whey protein isolate (WPI) on the microencapsulation of gurum seeds oil by a spray-drying method. Three formulations of protein-based (PB) (WPI: MD, 2:1), carbohydrate-based (CHOB) (GA: MD, 2:1), and mixed (MIX) (WPI: GA: MD, 1:1:1) wall materials were designed. The moisture content and water activity were in the range of 1.65-3.67% and 0.17-0.31, respectively, which is suitable for long-term storage. The best results were achieved when gurum seed oil was microencapsulated with carbohydrate-based, where it had the highest microencapsulation yield (92.80%) and microencapsulation efficiency (97.38%). Carbohydrate-based showed the highest relative crystallinity (32.25%) and the temperature of the glass transition (58.20 °C). FT-IR revealed that the oil was well encapsulated in the microcapsules. SEM of microcapsules showed spherical shapes without any apparent cracking on the surfaces. During the oxidative stability study, carbohydrate-based microencapsulation was the wall material that best protected the active materials against lipid oxidation.

The thiolated chitosan: Synthesis, gelling and antibacterial capability

Chitosan-1-(mercaptomethyl)-cyclopropane acetic acid (CS-MCA) copolymer was synthesized by amino linkage. The obtained copolymer was characterized by FTIR, ¹H NMR, XRD, TGA and SEM. Porous and reticulate morphologies were found on the CS-MCA surface. The effects of pH on the rheological properties of CS-MCA were investigated. On the one hand, the apparent viscosity of CS-MCA indicated a shear-thinning behavior. The graft of MCA enhanced the moduli and the maximum elastic properties were observed at pH = 7.00. The addition of dithiothreitol reduced the viscosity and modulus of CS-MCA hydrogel, and the gelation time, temperature and frequency were obtained in dynamic oscillatory tests. The antibacterial effect of CS-MCA against E. coli was investigated for the inhibition zone and bacterial growth curve. These results showed that CS-MCA had better antibacterial ability than chitosan without modification. Therefore, the rheological behavior and functional activities can be applied for the hydrocolloid gels in food and pharmaceutical applications.