Viscoelastic behavior, gelation properties and structural characterization of Deccan hemp seed (Hibiscus cannabinus) protein: Influence of protein and ionic concentrations, pH, and temperature.

This study investigates the viscoelastic behavior, gelling properties, and structural characteristics of Deccan hemp seed protein (DHSP) to overcome limitations in its application in food formulations. Small amplitude oscillatory shear measurements were employed to investigate the impact of protein concentration, pH, ionic concentration, and temperature on DHSP's rheological features. The study revealed that the 20 % protein dispersion had the highest storage modulus (G') and yield stress at 63.96 ± 0.23 Pa and 0.61 Pa, respectively. DHSP dispersion exhibited pseudo-plastic behavior across various conditions. The gelling performance was higher at pH 4 and 8 and at ionic concentration in the range of 0.1 M - 0.5 M. Gelation time and temperature were observed from the temperature ramp test. Structural characterizations, including fluorescence spectroscopy, circular dichroism spectra, FTIR spectra, SEM, AFM images, zeta potential analysis, and DSC, provided insights into DHSP's tertiary and secondary conformation, surface characteristics, and thermal properties. Notably, the study highlighted DHSP's exceptional rheological properties, making it a promising gelling material for the food and nutraceutical industries. The findings also offer new insights into DHSP's structural characteristics, suggesting potential applications in food packaging and product development within the food industry.

Gelled Liquid Crystal Nanocarriers for Improved Antioxidant Activity of Resveratrol.

As many natural origin antioxidants, resveratrol is characterized by non-suitable physicochemical properties for its topical application. To allow its benefits to manifest on human skin, resveratrol has been entrapped within liquid crystal nanocarriers (LCNs) made up of glyceryl monooleate, a penetration enhancer, and DSPE-PEG 750. The nanosystems have been more deeply characterized by using dynamic light scattering and Turbiscan Lab® Expert optical analyzer, and they have been tested in vitro on NCTC 2544. The improved antioxidant activity of entrapped resveratrol was evaluated on keratinocyte cells as a function of its concentration. Finally, to really propose the resveratrol-loaded LCNs for topical use, the systems were gelled by using two different gelling agents, poloxamer P407 and carboxymethyl cellulose, to improve the contact time between skin and formulation. The rheological features of obtained gels were evaluated using two important methods (microrheology at rest and dynamic rheology), before testing their safety profile on human healthy volunteers. The obtained results showed the ability of LCNs to improve antioxidant activity of RSV and the gelled LCNs showed good rheological profiles. In conclusion, the results confirmed the potentiality of gelled resveratrol-loaded nanosystems for skin disease, mainly related to their antioxidant effects.

Polyurethane Degradable Hydrogels Based on Cyclodextrin-Oligocaprolactone Derivatives.

Polymer networks based on cyclodextrin and polyethylene glycol were prepared through polyaddition crosslinking using isophorone diisocyanate. The envisaged material properties are the hydrophilic character, specific to PEG and cyclodextrins, and the capacity to encapsulate guest molecules in the cyclodextrin cavity through physical interactions. The cyclodextrin was custom-modified with oligocaprolactone to endow the crosslinked material with a hydrolytically degradable character. SEM, DTG, and FTIR characterization methods have confirmed the morphology and structure of the prepared hydrogels. The influence of the crosslinking reaction feed was investigated through dynamic rheology. Further, thermal water swelling and hydrolytic degradation in basic conditions revealed the connectivity of the polymer network and the particular influence of the cyclodextrin amount in the crosslinking reaction feed on the material properties. Also, levofloxacin was employed as a model drug to investigate the drug loading and release capacity of the prepared hydrogels.

Changes in Gel Characteristics, Rheological Properties, and Water Migration of PSE Meat Myofibrillar Proteins with Different Amounts of Sodium Bicarbonate.

The changes in the gel and rheological properties and water-holding capacity of PSE meat myofibrillar proteins with different amounts of sodium bicarbonate (SC, 0−0.6/100 g) were studied. Compared to the PSE meat myofibrillar proteins with 0/100 g SC, the texture properties and cooking yield significantly increased (p < 0.05) with increasing SC; meanwhile, adding SC caused the gel color to darken. All samples had similar curves with three phases, and the storage modulus (G') values significantly increased with the increasing SC. The thermal stability of the PSE meat myofibrillar proteins was enhanced, and the G' value at 80 °C increased with the increasing SC. Because water was bound more tightly to the protein matrix, the initial relaxation times of T21 and T22 shortened, the peak ratio of P21 significantly increased (p < 0.05), and the P22 significantly decreased (p < 0.05), which implied that the mobility of the water was reduced. Overall, SC could improve the thermal stability of the PSE meat myofibrillar proteins and increase the water-holding capacity and textural properties of the cooked PSE meat myofibrillar protein gels.

Use of Dynamic Shear Rheology to Understand Soy Protein Dispersion Properties.

Soy flour dispersions are used as adhesives for bonding interior wood laminates, but the high viscosity of these dispersions requires low solids in the adhesive formulations; the greater water content causes excessive steam pressure during hot press manufacturing. This limits the utility of soy adhesives in replacing urea-formaldehyde adhesives; thus, understanding the cause of high soy viscosities is important. Lack of literature on aqueous soy flour dispersion rheology led to our dynamic rheology studies of these dispersions to understand high viscosity and the effect of various additives. Even at low soy solids, the elastic nature outweighs the viscous properties at low shear, although increasing the shear results in shear-thinning behavior after the yield point. At even higher shear, beyond the flow point where the storage and loss moduli cross, some of the dispersions show an additional shear thinning transition. The comparison of the rheological properties of aqueous dispersions of the soy flour and protein isolate, and another natural protein, ovalbumin from egg whites, led to a better understanding of different types of rheological behaviors. The experimental observations of two observed shear thinning events for soy are consistent with the model of dispersed particles, forming clusters that then form large scale flocculants.

A review on octenyl succinic anhydride modified starch-based Pickering-emulsion: Instabilities and ingredients interactions.

Pickering emulsions endow attractive features and a wide versatility in both food and nonfood fields. In the last decades, a noticeable interest has emerged toward the use of octenyl succinic anhydride (OSA)-starch to improve the long-term stability in such systems. In this review, instabilities were pointed out, where a new kinetic equilibrium was observed in Pickering emulsions assigned to migration and size variations of particles. These features were monitored using rheological measurements to understand microstructure and droplets mobility. The elastic modulus (G'), the viscous modulus (G″), and tan(δ) values were attributed to the transition from solid to fluid and assigned to the instability of the formulation regardless of the type of the system configuration. The novelties in using OSA-modified starch, were also exposed. The chemical modification of starch decreased creaming for months. Interaction between OSA-modified starches and some ionic components (potassium, magnesium, and calcium) as well as hydrocolloids and proteins reduced creaming and coalescence due to dense interfacial film. Furthermore, the key parameters (oil fraction, fatty acids composition, oxidative stress oil polarity, and oil viscosity) that govern oil phase in Pickering emulsion, were analyzed. These parameters were found to be positively correlated to the stability of Pickering emulsions.

Advances in rheological study of topical preparations for skin / 中国药科大学学报

@#Topical preparations for skin, including the commonly used dosage forms of ointments, creams, gels, patches and plasters, are convenient and can avoid the first-pass effect of drugs.Rheological study, which describes the flow characteristics and mechanical properties of products relevant to their Critical Quality Attributes, has become the main focus for topical preparations.Liquid and solid behaviors of products are usually investigated via steady rheology as well as dynamic rheology.This article reviews the research on topical preparations for skin and the data analysis models based on two rheological methods, aiming to provide some references for the rheological evaluation of topical preparations.

Physicochemical, rheological, and emulsification properties of nonenyl succinic anhydride (NSA) modified quinoa starch.

Nonenyl succinic anhydride (NSA) modification could be an alternative to octenyl succinic anhydride (OSA) modification of starch to obtain a range of physicochemical and rheological properties and for emulsification applications. A series of NSA-modified quinoa starches in granular form with different degrees of substitution (DS) (0.0080, 0.0175, 0.0359, and 0.0548) were prepared. The NSA modifications reduced the gelatinization temperatures and frequency dependence of storage modulus (G'), while increasing the peak viscosity, gel hardness, and G'. The NSA-modified quinoa starches with medium DS were the most effective in stabilising Pickering emulsions. The droplet size of Pickering emulsions decreased first with increasing DS before increasing at the highest DS. Modified starch with a DS of 0.0359 had the highest emulsifying capacity. Apart from the commonly used octenyl succinic anhydride (OSA) modification, the NSA-modified starches could be potential candidates as efficient Pickering emulsion stabilizers.

Evaluation of Properties and Micro-Characteristics of Waste Polyurethane/Styrene-Butadiene-Styrene Composite Modified Asphalt.

In order to solve the problems caused by asphalt diseases and prolong the life cycle of asphalt pavement, many studies on the properties of modified asphalt have been conducted, especially polyurethane (PU) modified asphalt. This study is to replace part of the styrene-butadiene-styrene (SBS) modifier with waste polyurethane (WP), for preparing WP/SBS composite modified asphalt, as well as exploring its properties and microstructure. On this basis, this paper studied the basic performance of WP/SBS composite modified asphalt with a conventional performance test, to analyze the high- and low-temperature rheological properties, permanent deformation resistance and storage stability of WP/SBS composite modified asphalt by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The microstructure of WP/SBS composite modified asphalt was also observed by fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR), as well as the reaction between WP and asphalt. According to the results of this study, WP can replace SBS as a modifier to prepare WP/SBS composite modified asphalt with good low-temperature resistance, whose high-temperature performance will be lower than that of SBS modified asphalt. After comprehensive consideration, 4% SBS content and 15% WPU content (4 S/15 W) are determined as the suitable types of WPU/SBS composite modified asphalt.

Cryotropic gel-forming capacity of alfalfa (Medicago sativa L.) and fenugreek (Trigonella foenum graecum) seed galactomannans.

Cryotropic gelation is one of the most common approaches to design novel hydrogels with multifaceted technological and biological functionalities. In the present paper, we studied the ability of highly galactosyl-substituted galactomannans, i.e. fenugreek and alfalfa gum, to form physically crosslinked hydrogels via cryogenic processing. Cycling of the galactomannan solutions (0.25 to 4% wt) from 25 to -20 to 25 °C induced the physical crosslinking of the galactomannan chains leading to the formation of different cryogel structures, i.e. filamentous aggregates (c* < c < 1%), cellular-like gel networks (1 ≤ c < 4%) or a homogeneously swollen gel (c ≥ 4%), depending on the total biopolymer content. Alfalfa gum-based cryogels exhibited higher elasticity and stiffness, better uniformity of the structure and a lower macropore size than their fenugreek counterparts. The physical blending of alfalfa or fenugreek gum with locust bean gum (2% total biopolymer) led to the reinforcement of the mechanical properties of the cryogels without significantly altering their microstructural aspects.

Protein extraction pH and cross-linking affect physicochemical and textural properties of protein gels made from channel catfish by-products.

BACKGROUND: Channel catfish farming is very important aquaculture industry in the southern states of the USA. However, huge amounts of by-products are generated from catfish fillet-processing. The by-products (mostly heads and bone frames) are excellent sources of proteins. Currently, catfish by-product has little value, and is regarded as a 'waste', which if not utilized properly could cause serious environmental pollution. Therefore, to find a way to utilize those by-products is critical for the economy of aquaculture. METHOD: Protein isolates were extracted from the mixture of catfish by-products (heads and frames) under different alkaline conditions (pH 7.5-11) and made into protein gels. Secondary structures of extracted protein isolates were studied. Microbial transglutaminase (MTGase, 0-4 U g-1 proteins) was incorporated to improve gel structure. Gelling, physicochemical, textural and thermal properties of protein gels treated with/without MTGase were investigated. Protein pattern changes of MTGase-treated protein gels were studied and the microstructure of the protein gels was analyzed. RESULTS: Alpha-helicity of protein isolates made at pH 11 was 21.5% lower than that extracted at pH 8.5. Storage modulus (G') of protein gel decreased with increasing extraction pH (pH > 9) of the corresponding protein isolate. MTGase treatment exhibited significant effects on denaturation temperature and enthalpy of protein gels. Excessive MTGase (>2 U g-1 ) could weaken the gel structure. CONCLUSION: Protein isolates can be extracted from catfish by-products and made into protein gels, which are a value-added product. © 2021 Society of Chemical Industry.

Perennial halophyte Salicornia neei Lag.: Cell wall composition and functional properties of its biopolymers.

Salicornia neei halophyte extends in Argentina seashores. To envisage potential applications, cell wall sequential extraction performed on dry plant yielded 1.1, 2.4, 0.3 and 0.9% of pectin fractions respectively extracted by room temperature water, 90 °C-water, CDTA and Na2CO3. They contained 21-33% uronic acids (UA) with low degree of methylation and 0.5-1.2 M ratios of neutral sugars to UA. High arabinose level suggests that long arabinan side-chains maintain cell wall flexibility in water deficit. Fractions also contained 10-36% of proteins. The KOH-soluble fractions (4.3%) were mainly arabinoxylans. At 2.0% w/v, pectin fractions developed "weak gel"-type networks with Ca2+, while arabinoxylans generated "dilute solutions". Cellulose (28%) and lignin (45.1%) were the main biopolymers in the final residue, which showed low water swelling capacity (3.6 mL/g) due to lignin, increasing when arabinoxylans were also present. Phenolics (9.8%) were mainly water-extractable. Salicornia is a source of biopolymers and antioxidants potentially useful for food applications.

Energetic neutral atoms assisted development of kithul (Caryota urens) starch-lauric acid complexes: A characterisation study.

Kithul starch was treated by EN (energetic neutral nitrogen) atoms at 6 W,12 W and 18 W for 15 min and incorporated lauric acid for the development of starch-lauric acid inclusion complexes. EN atoms treatment significantly (p ≤ 0.05) increased the complex index (CI). Severe morphological alterations on the kithul starch granules by EN atoms treatment enhanced starch-lauric acid complex formation. Relative crystallinity of EN atoms treated lauric acid incorporated kithul starch samples increased with plasma power. Moreover, lower pasting property, storage modulus (G'), loss modulus (G''), hardness and higher Tanδ indicated decrease in gelation and retrogradation property. ENL-18 W showed the lowest complex viscosity (È *). Lauric acid incorporation in EN atoms treated kithul starch reduced in vitro digestibility and significantly (p ≤ 0.05) increased RS (resistant starch). Hence, EN atoms treatment on the kithul starch granules prior to fatty acid incorporation is an effective technique for the development of starch-fatty acid complexes.

Effect of laver powder on textual, rheological properties and water distribution of squid (Dosidicus gigas) surimi gel.

In order to ameliorate the gel quality of Dosidicus gigas surimi, the effects of laver powder on gel properties, rheological properties, and water-holding capacity (WHC) were investigated. Results indicated that the addition of laver powder could significantly increase the hardness, chewiness, and breaking force of surimi gels. However, the texture indexes and gel strength began to decline when additional amount exceeded 0.6%. Rheological results demonstrated that the addition of laver powder increased the storage modulus (G') and viscosity of surimi, prolonged protein denaturation temperature in surimi gels. Moreover, the WHC of surimi gel was improved with the increase of laver powder. Further analyses in low-field nuclear magnetic resonance revealed that laver powder could shorten the transverse relaxation time, enhanced the combination with water, and altered the distribution of different water categories. The proportion of bound water and immobilized water reached its maximum and minimum at 0.6% of laver powder, respectively. Correlation analyses showed that WHC of surimi gel was negatively correlated well with the proportion of loose-bound water, but positively correlated with the strong-bound water and free water. In conclusion, the results supported that 0.6% was the optimal additional amount of laver powder for the squid-based surimi production based on the current ingredients of surimi products.

Barley ß-glucan concentrate and its acid hydrolysate for the modification of dough making and rheological properties of water chestnut flour.

ß-Glucans are known for their beneficial physiological roles but can be used as potential food hydrocolloid. The present study was performed to assess the potential of barley ß-glucan concentrates (native and partially hydrolyzed) in altering the functional properties of water chestnut flour dough. The ß-glucan concentrate was subjected to partial hydrolysis to prepare a low molecular weight polymer. The WAC, swelling behavior, and pasting properties were significantly modified after the addition of ß-glucan concentrates. The water chestnut dough incorporated with ß-glucan concentrates displayed enhanced viscoelastic and creep characteristics and the efficacy of ß-glucans in providing strength to water chestnut dough depended on its molecular weight. Hydrolyzed ß-glucan concentrates increased the elasticity of dough to the greater magnitude in comparison to its native counterpart.

Effect of processing temperature on dynamic rheological properties and color degradation kinetics of bael fruit pulp.

BACKGROUND: A lack of knowledge about the dynamic rheological properties and color degradation of bael fruit pulp gives rise to many problems during thermal processing for the preparation of bael fruit products. In this research, the effects of processing temperature (30-75 °C) on dynamic rheology and color degradation kinetics of bael fruit pulp were studied and analyzed. RESULTS: Bael fruit pulp showed more elastic behavior than viscous behavior by analyzing the storage modulus, loss modulus and phase angle over oscillatory frequency range 0.06-300 rad s-1 . The dynamic rheological study classified the bael fruit pulp as a weak gel (G' > G″). The values of first-order degradation rate constant (k) were determined to be 0.07, 0.011, 0.018 and 0.023 for 30, 45, 60 and 75 °C, respectively. The first-order color degradation kinetics of bael fruit pulp has given a higher value of activation energy (Ea = 23.83 kJ mol-1 ) with coefficient of determination (R2 ) of 0.99, which indicated a higher sensitivity for treatment temperature and time during processing. CONCLUSIONS: The results obtained would allow simplification of processes for easier formulation of quality products from bael fruit pulp. This study has the potential to increase the processing ability of bael fruit, which will encourage a greater production of bael fruits. © 2020 Society of Chemical Industry.

Characterization of partial acid hydrolysates of citrus pectin for their pasting, rheological and thermal properties.

Pectin was subjected to acid hydrolysis with hydrochloric acid for 30 and 60 min to prepare partial hydrolysates (PH30 and PH 60). The influence of acid hydrolysis on the physico-chemical and functional properties were assessed for their potential applications in foods. Acid hydrolysis significantly reduced the molecular weight and viscosity of pectin in a time dependent manner. Steady shear properties revealed a shear-thinning behavior for NP and PH 30 while Newtonian behavior was observed for PH 60. Oscillatory measurements revealed a viscoelastic behavior for NP while a viscous liquid like behavior was observed for PH30. DSC measurements also revealed reduced thermal stability of pectin hydrolysates in comparison to native pectin. The results of the present study suggested that pectin hydrolysates with improved solubility can be used in various food products as a source of dietary fiber without modifying the texture and palatability of food products.

Pasting, rheological, and dough mixing behavior of rice flour as affected by the addition of native and partially hydrolyzed ß-glucan concentrate.

This study was aimed at evaluating the potential of barley ß-glucan concentrates (native and partially hydrolyzed) in modifying the techno-functionality of rice flour dough. ß-Glucan concentrate was partially hydrolyzed to obtain a low molecular weight polymer and their influence on the pasting, rheological, and thermal properties of rice dough were assessed. Hydration, thermal, and pasting properties were significantly modified with the added ß-glucans. The rice dough supplemented with ß-glucan concentrates showed improved viscoelastic and creep behavior and the effectiveness of ß-glucans in imparting strength to rice dough depended on its molecular weight. Hydrolyzed ß-glucan concentrates having low molecular weight increased dough elasticity to the greater extent in comparison to native ß-glucan concentrates. The micrographs of supplemented dough showed a strong and dense network indicating improved structure and strength.

Pectin and its acid hydrolysate for the modification of hydration, pasting, thermal and rheological properties of barley starch.

The influence of native pectin (NP) and its hydrolysate (PH) in modifying hydration, thermal, pasting, rheological and textural properties of barley starch was assessed. The addition of NP and PH significantly modified the hydration properties of barley starch. The swelling and solubility of barley starch increased in the presence of NP while PH decreased it in a concentration dependent manner. The differential scanning calorimetry results showed that gelatinization temperatures increased in the presence of NP/PH whereas decrease in enthalpy was observed. In addition, only NP was found effective in increasing peak viscosity of the barley starch during pasting while PH decreased it. PH was observed to be more efficient in terms of reducing setback and final viscosity. Moreover, the NP addition caused an increase in magnitude of G' and G" while lower values were obtained with PH suggesting an increase in the elasticity of barley starch pastes with NP and an increased viscous behavior in case of PH. This was further confirmed by scanning electron microscopy which revealed interconnected flakes network in starch pastes containing NP. Overall these results revealed that molecular weight and concentration of pectin played an important role in modifying starch functional properties.

Structural modification of quinoa seed protein isolates (QPIs) by variable time sonification for improving its physicochemical and functional characteristics.

High intensity ultrasound treatment (HIUS) by probe method is a novel technique to impart desirable physical, structural and functional characteristics to the native proteins structures. In this concern, effect of HIUS treatment at variable intervals from 5 to 35 min on quinoa seed protein isolates (QPIs) characteristics was analyzed. A typical dynamic rheological characteristic curve of QPIs had been obtained as a result of HIUS treatments at variable time intervals. Higher sonication resulted in the formation of large protein aggregates with higher particle size which increased QPIs turbidity. Temperature and frequency sweep tests had shown dominance of storage modulus over loss modulus, thus described strong gelling behavior of treated QPIs. HIUS treatment reduced particle size of QPIs with improved its flow properties. No splitting of bands had occurred due to sonication, whereas, more intensity of bands of treated QPIs depicted its greater water solubility. HIUS treatment decreased fluorescence intensity of QPIs whereas, no significant changes in Amide-II & III regions of QPIs occurred except decrease in wave number. The effects of HIUS on QIPs isolates had shown completely different response than those of results of quinoa protein extracts. Moreover, the studies conducted on quinoa protein extracts provided detailed information about the effect of HIUS on structural changes and its impact on physicochemical, functional and rheological characteristics.