Addition Of Κ-carrageenan Research Articles

Evaluation of physicochemical, textural, and sensory properties of reduced-fat chicken patties produced with chia flour and κ-carrageenan

The effects of chia flour and κ-carrageenan on the physicochemical, textural, and sensory properties of reduced-fat chicken patties were investigated. Usage of chia flour decreased pH, while addition of κ-carrageenan increased it. Chicken patties with chia flour had higher thiobarbituric acid reactive substances (TBARS) and lower L*, a*, and b* values. Production stages significantly affected pH, TBARS, and color of the samples (p < 0.01); while pH, TBARS, a*, and b* values increased and L* value decreased after cooking. Adding chia flour and Kappa-carrageenan (κ-carrageenan) to reduced-fat chicken patties increased cooking yield and moisture retention while decreasing the shrinkage. Chia flour and κ-carrageenan increased hardness of samples and the highest mean value was found to be 68.70 ± 1.40 N in the group containing 8% beef fat + 4% chia flour + 5% breadcrumbs + 1% κ-carrageenan. However, adhesiveness and cohesiveness decreased by addition of chia flour and κ-carrageenan. Among the sensory properties, flavor, texture, and general acceptability were significantly affected by the addition of chia flour and κ-carrageenan (p < 0.01). Sensory properties were studied by panelist, and it was found that usage of 2% chia flour and 1% κ-carrageenan in reduced-fat chicken patties could be effective regarding product quality, health benefits, and consumer acceptance.

Elucidating the mechanisms of ultrasound treatment combined with κ-carrageenan addition enhancing the gelling properties of heat-induced myofibrillar protein gel

This work investigated the effect of ultrasound (US) treatment synergized with κ-carrageenan (KC) on the gel properties, structural characteristics and microstructures of myofibrillar protein (MP) gel. The results demonstrated that simply adding KC enhanced the gel strength and water holding capacity (WHC) of MP gels. Moreover, the gel strength and WHC of MP gels were increased by 56.67 % and 76.19 % via 20 min US treatment synergized with KC, which was mainly attributed to the changes in sulfhydryl content, surface hydrophobicity, and fluorescence intensity of MP gels. Based on the results of molecular docking and secondary structure, it can be hypothesized that the synergistic effect resulted in the rearrangement of the proteins, which altered the interaction site between MP gels and KC, accompanied by stronger binding. Furthermore, the microstructural results indicated that moderate US treatment (20 min) facilitated the production of a more compact and denser MP gels matrix with uniformly sized and distributed pores. However, excessive US treatment (40 and 50 min) caused the MP gels to form looser and disordered gel structure, which reduced the gel strength and WHC. This study suggested that combining of US and KC was a potential tactic to enhance the gelling properties of heat-induced MP gels.

Gelation of crocodile myofibrillar protein – κ-carrageenan mixtures in two low-NaCl solution

Crocodile meat is a novel reptile meat source, but its processing method is rare. This study investigated the effect of κ-carrageenan addition and partial substitution of NaCl on the gel properties of crocodile myofibrillar protein (CMP). Result showed that CMP formed gel when temperature above 60 ℃. The water-holding capacity, gel strength, denaturation degree, sulfhydryl content covalent bond and hydrophobic bond of gel in KCl solution were significantly higher than those in CaCl2 solution (P < 0.05). K+ induced CMP to form a tight network structure with uniform small pores though covalent and hydrophobic bonds, but the gel properties were reduced by κ-carrageenan. In CaCl2 solution, κ-carrageenan improved the gel structure by filling the protein network through hydrogen bonding. Therefore, it can be concluded that KCl is better than CaCl2 in the manufacturing of low-sodium crocodile foods. Moreover, κ-carrageenan was only beneficial to gel quality in CaCl2 solution.

Combined effect of ultrasound treatment and κ-carrageenan addition on the enhancement of gelling properties and rheological behavior of myofibrillar protein: An underlying mechanisms study

This work aimed to investigate the combined effect of ultrasound (US) treatment and κ-carrageenan (KC) addition on the gelling properties and rheological behaviors of myofibrillar protein (MP). Without US treatment, the KC incorporation promoted the gel strength and water-holding capacity (WHC) of MP gels. These properties were further improved by 20 min US treatment with gel strength of 98.61 g and WHC of 79.87 %, which was mainly attributed to changes associated with hydrophobic interactions and disulfide bonds and the transformation from α-helix to β-sheet in MP gels. In addition, US treatment for 20 min effectively resulted in a more homogeneous polymer distribution of the MP-KC mixed system, leading to lower particle size and the largest G′ and G″ values of the MP-KC mixed gels. However, longer US treatment times (30, 40 and 50 min) rendered lower gel strength, WHC, storage modulus and loss modulus of MP-KC mixed gels, which was mainly due to the formation of loose and disordered gel structures. Our present results indicated that the application of US to MP for an intermediate treatment time (20 min) combined with KC provides a potential and novel strategy to promote the gel qualities of heat-induced MP gels.

In vitro gastrointestinal digestibility and peptidomic analysis of frankfurters as influenced by different forms of κ-carrageenan

We used peptide profiling to investigate the effects of different forms of κ-carrageenan (a typical hydrocolloid) on the in vitro gastrointestinal digestibility of frankfurters. All incorporated forms of κ-carrageenan were found to decrease the digestibility of meat proteins in the frankfurters, although the effects varied for some peptide fragments. Particle size analysis and super-resolution microscopy revealed that addition of κ-carrageenan in a water suspension resulted in the lowest protein digestibility for frankfurters, followed by κ-carrageenan in a powder form and in a brine suspension. Peptide profiling identified 63 peptides common to all frankfurters after gastrointestinal digestion. In addition, 9 new peptide fragments related to myofibrillar proteins and sarcoplasmic proteins were observed in digestion products from frankfurters that contained κ-carrageenan. Addition of the κ-carrageenan water suspension resulted in a unique pattern of peptide abundance after gastrointestinal digestion of the frankfurters. This pattern was not observed with the powder or brine suspension, both of which contained higher abundances of myosin peptides. However, it is still unclear how different forms of κ-carrageenan caused changes in specific digestion sites, and further investigation is needed to understand this phenomenon. These findings provide novel insights into the effects of various forms of κ-carrageenan on the digestibility of meat proteins in emulsified meat products.

The synergistic effect of κ-carrageenan and l-lysine on the 3D printability of yellow flesh peach gels: The importance of material elasticity in the printing process

This study investigated the effect of κ-carrageenan and l-lysine on the physical, chemical and textural properties of yellow flesh peaches and their suitability for 3D printing. The addition of κ-carrageenan and l-lysine was found to improve the apparent viscosity, elasticity, gel strength, and Young's modulus of the yellow flesh peach with κ-carrageenan and l-lysine gels (PCLG) and increase the minimum piston pressure required for 3D printing, thereby improving the printing performance.Optimum levels of κ-carrageenan and l-lysine (0.1 mmol/mL and 3.42 × 10−2 mmol/mL, respectively) were found to enhance mechanical strength, viscoelasticity and print fidelity. On the other hand, when the addition of κ-carrageenan is 0.1 mmol/mL, the addition of l-lysine causes an increase in the G0 value and a decrease in the η0 value of the PCLG according to Burger's model, indicating a transition from viscosity to elasticity and an increase in maximum extrusion force, while the apparent viscosity does not change significantly. The results of 3D printing showed that when the addition of κ-carrageenan and l-lysine reached 0.1 mmol/mL and 6.84 × 10−2 mmol/mL, respectively, the PCLG could not be smoothly extruded, indicating that elasticity also plays an important role during the extrusion process of the mixed gel.

Bioactive interpenetrating hybrids of poly(hydroxyethyl methacrylate-co-glycidyl methacrylate): Effect of polysaccharide types on structural peculiarities and multifunctionality

Crosslinked poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) hybrids prepared in the same experimental condition by adding various polysaccharides of different chemical types; inulin, Na-alginate, starch and κ-Carrageenan were qualitatively compared. The results are presented to extract relevant physicochemical properties for qualitative comparison of structures within the same synthesis batch. Elastic properties and swelling degree of hybrids can be tightly regulated using different types of polysaccharides and by controlling effective cross-linking density. Addition of κ-Carrageenan to copolymer network increased elastic modulus by 6.2-fold in as-prepared state, but greatest increase in effective cross-link density through swelling was observed in alginate-doped gels. An overshooting effect was observed for alginate-doped hybrids; swelling first to a maximum, followed by a gradual deswelling until equilibrium was reached. Compressive elasticity of hybrids is mainly controlled by type of polysaccharides and cross-linking density but also depends on polymerization temperature. The obtained hybrid gels displayed excellent adsorption performance for methyl orange (MO). The highest adsorption capacity was reached with inulin-doped hybrids. The rate of adsorption was very fast and reached equilibrium with 98.9 % efficiency at about 90 min. This approach to modify the properties of hybrid gels with various types of polysaccharides may find wide use in biomaterials and water purification applications.

Insight into the Mechanism of Porcine Myofibrillar Protein Gel Properties Modulated by κ-Carrageenan

The purpose of this study is to explain the mechanism of porcine myofibrillar protein gel properties modulated by κ-carrageenan. The textural properties results showed that the stress at fracture of the composite gel with 0.4% κ-carrageenan had the highest value (91.33 g), which suggested that the 0.4% κ-carrageenan addition was the limitation. The strain at fracture was significantly reduced with κ-carrageenan addition. The composite gel with 0.4% κ-carrageenan had the lowest proportion of T22 (7.85%) and the shortest T21 relaxation time (252.81 ms). The paraffin section showed that the phase separation behavior of the composite gel transformed from single-phase behavior to dispersed phase behavior to bi-continuous phase behavior, and the ratio of CG/MP phase area significantly increased from 0.06 to 1.73. The SEM showed that the three-dimensional network of myofibrillar protein transformed from a loose structure to a compact structure to an unaggregated structure with κ-carrageenan addition. The myofibrillar protein network of the treatment with 0.4% κ-carrageenan had the highest DF value (1.7858) and lowest lacunary value (0.452). The principal component analysis was performed on the data of microstructure and textural properties, and the results showed that the dispersed phase behavior and moisture stabilization promoted the aggregation of myofibrillar protein and the composite gel had better water holding capacity and textural properties, while bi-continuous phase behavior hindered the aggregation of myofibrillar protein and the composite gel had worse water holding capacity and textural properties.

Physicochemical properties and microstructure of bigels formed with gelatin and κ-carrageenan hydrogels and monoglycerides in olive oil oleogels

The preparation and properties of novel edible bigel systems based on olive oil oleogels structured with 15% monoglycerides and different hydrogels formed with 8, 10 or 12% gelatin or gelatin plus 1% κ-carrageenan were studied. The effect of hydrogel composition and oleogel/hydrogel ratio on physicochemical characteristics and microstructure, as well as mechanical and thermal properties of the resultant bigels was examined. An increased proportion of oleogel led to a decrease in hardness (10.34–43.95 N) and an increase in the cohesiveness of bigels (0.13–0.36). Addition of κ-carrageenan to the bigel system increased hardness (25.47–89.00 N) and decreased cohesiveness (0.12–0.16). Microscopy revealed the formation of an oleogel-in-hydrogel bigel system with significantly smaller oil droplets when only gelatin was used as a hydrogelator. Bigels containing gelatin and κ-carrageenan had the lowest swelling capacity, possibly due to formation of hydrogen bonds and electrostatic interactions between gelatin and κ-carrageenan resulting in an inelastic structure that could not absorb water. Differential scanning calorimetry revealed an increase in the melting enthalpy of the monoglycerides from 5.35 mJ/mg to 8.85 mJ/mg with increasing oleogel proportion in bigels, while the incorporation of κ-carrageenan improved the thermal stability of the biphasic system. Fourier transform infrared spectroscopy documented the existence of a complex between gelatin and κ-carrageenan and confirmed that the mechanism of bigels formation is based on the physical interactions of the two structured phases. These results provide a comprehensive overview regarding the structure and functional properties of bigels with potential applications in foods.

Rheological properties and microstructure of rennet-induced casein micelle/κ-carrageenan composite gels

This study aimed to investigate effects of kappa-carrageenan (κ-carrageenan) concentration and storage temperature on the rheological and texture properties of casein micelle/κ-carrageenan composite gels. The particle size, zeta potential, Fourier transform infrared spectroscopy of the mixture, and microstructure of the composite gels were measured. The movement of κ-carrageenan characteristic bond showed that the casein micelle and κ-carrageenan formed a complex with larger particle size through electrostatic adsorption. The electrostatic repulsion between molecules increased with the increase of κ-carrageenan concentration, which stabilized the mixed system. It was found that both κ-carrageenan concentration and storage conditions affected the gel's rheological properties and microstructure. As the concentration of κ-carrageenan increased, the storage modulus (G′) of the composite gels increased, the rennet coagulation time (RCT) decreased, and the water holding capacity (WHC) increased at 25 °C. Microstructure results showed that a more uniform and denser gel network structure with smaller pore sizes was formed after the addition of κ-carrageenan compared with the control. G′ and RCT were reduced and microscopic phase separation occurred after storage at 4 °C, resulting in a porous structure with large pore sizes. Thus, the addition of κ-carrageenan could enrich the diversity of food gel structure to obtain an ideal gel.

Effects of κ-carrageenan addition and chlorogenic acid covalent crosslinking on protein conformation and gelling properties of soy protein hydrogels

This paper reports the effects of κ-carrageenan (KC) additions (0.6% w/v) and covalent crosslinking by chlorogenic acid (CA) on the protein conformation and gelling properties of soybean protein isolate (SPI) hydrogels. Treatment with KC and CA changed the conformation of the SPI and improved the antioxidant capacity and gel properties, as confirmed by fluorescence spectroscopy, Fourier-transform infrared spectroscopy, antioxidant capacity analysis, and rheology measurements. The addition of CA (0.01 g/g-SPI) decreased the number of free amino groups, free sulfhydryl content, tryptophan fluorescence intensity, and surface hydrophobicity of SPI by 44.22%, 10.05%, 30.47%, and 44.61%, respectively, and increased the DPPH and ABTS radical scavenging activities by 30.29% and 40.69%, respectively. The addition of KC (0.6% w/v) enhanced the DPPH radical scavenging activities of the SPI-CA (0.002 and 0.01 g/g-SPI) conjugates by 11.29–16.50%, and improved the viscoelasticity, water immobilization, density, and thermal stability of the SPI–CA gels.

Incorporation of κ-carrageenan improves the practical features of agar/konjac glucomannan/κ-carrageenan ternary system

Three materials (agar, konjac glucomannan (KGM) and κ-carrageenan) were used to prepare ternary systems, i.e., sol-gels and their dried composites conditioned at varied relative humidity (RH) (33 %, 54 % and 75 %). Combined methods, e.g., scanning electron microscopy, small-angle X-ray scattering, infrared spectroscopy (IR) and X-ray diffraction (XRD), were used to disclose how κ-carrageenan addition tailors the features of agar/KGM/κ-carrageenan ternary system. As affirmed by IR and XRD, the ternary systems with κ-carrageenan below 25 % (agar/KGM/carrageenan, 50:25:25, m/m) displayed proper component interactions, which increased the sol-gel transition temperature and the hardness of obtained gels. For instance, the ternary composites could show hardness about 3 to 4 times higher than that for binary counterpart. These gels were dehydrated to acquire ternary composites. Compared to agar/KGM composite, the ternary composites showed fewer crystallites and nanoscale orders, and newly-formed nanoscale structures from chain assembly. Such multi-scale structures, for composites with κ-carrageenan below 25 %, showed weaker changes with RH, as revealed by especially morphologic and crystalline features. Consequently, the ternary composites with less κ-carrageenan (below 25 %) exhibited stabilized elongation at break and hydrophilicity at different RHs. This hints to us that agar/KGM/κ-carrageenan composite systems can display series applications with improved features, e.g., increased sol-gel transition point.

Comparative physicochemical characteristics and in vitro protein digestibility of alginate/calcium salt restructured pork steak hydrolyzed with bromelain and addition of various hydrocolloids (low acyl gellan, low methoxy pectin and κ-carrageenan)

Physicochemical and in vitro protein digestibility of alginate/calcium (AC) restructured pork steak hydrolyzed with bromelain with addition of LA gellan, LM pectin and κ-carrageenan at various concentrations (0.5, 1.0, 1.5 and 2% w/w) was evaluated for masticatory dysfunction people. The AC samples with κ-carrageenan showed the lowest cooking losses and highest water holding capacity (WHC). Moreover, addition of κ-carrageenan showed the highest Kramer shear force (KSF) and higher hardness, cohesiveness, springiness, chewiness, and gumminess, but the adhesiveness value was lower than those of the other treatments. According to SEM, the gel network of AC samples with κ-carrageenan was more clearly than those with the other treatments. FTIR demonstrated that the addition of polysaccharides to AC sample enhanced the hydrogen bonds in the gel system. For in vitro protein digestibility results, addition of 0.5% (w/w) LA gellan and κ-carrageenan samples showed the highest pepsin (73–74%) and trypsin (79–80%) digestibility.

Utilization of κ-carrageenan as stabilizer and thickener of honey pineapple (Ananas comosus [L. Merr]) jam

Honey pineapple jam is an intermediate moisture food that often has low stability; hence it is not strong enough to hold the fruit tissue sugar in position during storage. Therefore, it is necessary to add hydrocolloid in fruit jam processing to increase stability and consistency, one of which is κ-carrageenan. The purpose of this study was to determine the effect of adding κ-carrageenan towards stability and preference for honey pineapple jam. The κ-carrageenan concentrations used were 0%, 0.5%, 1%, and 1.5% (w/w) of total ingredients. The ratio of honey pineapple pulp and sugar was 4:1 (w/w). The results showed that the addition of κ-carrageenan had a significant effect (p&lt;0.05) on the hedonic evaluation of colour, smearing ability, and texture; moisture content, water activity (Aw), syneresis and texture (hardness, cohesiveness, and adhesiveness). The addition of κcarrageenan had no significant effect (p&gt;0.05) on the hedonic evaluation (preference) of aroma and taste. Increasing the κ-carrageenan concentration can increase the hedonic value for colour and decrease the hedonic value for smearing ability and texture. Increasing the concentration of κ-carrageenan can also increase the value of hardness and cohesiveness but decrease water activity, syneresis, and adhesiveness. The addition of κcarrageenan 0.5% was more efficient in shortening the cooking time until 25%, inhibiting syneresis by 30%, and improving the colour of honey pineapple jam.

The Use of κ-Carrageenan in Egg Yolk Free Extender Improves the Efficiency of Canine Semen Cryopreservation.

Simple SummarySemen cryopreservation generates sperm damage and reduces fertilization capacity as a consequence of reactive oxygen species formation, a known trigger of the apoptosis cascade. The present study aimed to examine the effects of κ-carrageenan supplementation to the freezing medium on canine sperm cryo-survival. To this end, the sperm was frozen in egg-yolk-free diluent containing different κ-carrageenan concentrations (0.0%, 0.1%, 0.2%, 0.3%, and 0.5%). The addition of κ-carrageenan to the extender at a 0.2% concentration resulted in a significant increase in the total motility and rapid progressive motility. Increasing levels of κ-carrageenan increased the spermatozoa acrosome integrity (p < 0.05). Apoptosis levels were significantly lower in the 0.1% and 0.2% κ-carrageenan treatment. Moreover, the κ-carrageenan supplemented group exhibited an upregulation of the relative expression of anti-apoptotic and down-regulation of oxidative state-related genes (p < 0.05). Overall, the introduction of κ-carrageenan as a component of egg-yolk-free freezing diluent could be useful for defining the cryopreservation media and improving the overall efficiency of cryopreserved canine semen.κ-Carrageenan is a plant polysaccharide derived from red seaweeds reported to possess potential medicinal and antioxidants activities. The present study aimed to identify the cryoprotective effects of κ-carrageenan on the quality of frozen-thawed canine semen. Twenty-eight ejaculates were collected and diluted in a Tris egg-yolk-free extender supplemented with various concentrations of κ-carrageenan (0.0%, 0.1%, 0.2%, 0.3%, and 0.5%). The addition of κ-carrageenan to the extender at a 0.2% concentration induced a significant increase in the total motility (TM) and the rapid progressive motility (RPM) of canine sperm. Among the experimental groups, the highest percentage of sperms with intact acrosomes was found in the 0.5% κ-carrageenan group (p < 0.05). Apoptosis levels were significantly lower in the 0.1% and 0.2% κ-carrageenan treatment. Moreover, sperm in the κ-carrageenan supplemented group showed a significantly higher expression of antiapoptotic (Bcl-2) and lower expression of NADPH oxidase (NOX5), spermine synthase (SMS), and spermine oxidase (SMOX) genes than those in the control group. In conclusion, the addition of κ-carrageenan to the freezing extender improved the overall efficiency of frozen-thawed dog spermatozoa.

EFFECT OF K-CARRAGEENAN ON MECHANICAL, THERMAL AND BIODEGRADABLE PROPERTIES OF STARCH–CARBOXYMETHYL CELLULOSE (CMC) BIOPLASTIC

Starch–carboxymethyl cellulose (CMC) bioplastics have limited mechanical properties. Carrageenan from seaweed is a potential reinforcement material for improving the mechanical properties of bioplastics. This study aimed to determine the effect of Kappa (κ)-carrageenan on the mechanical and thermal properties and biodegradability of starch–CMC bioplastics. In this study, carrageenan at concentrations of 0%, 10%, 15%, 20%, 25% and 30% was used. The melt-mixing process was conducted at 130 °C for 4 min, using a mixer and then hot-pressing (30 kgf/cm2) at 150 °C for 5 min. The results indicated that the higher κ-carrageenan concentration increased the strength of bioplastics up to 15.7 MPa. The fracture analysis via scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated the distribution of sulfur (S) elements that described the dispersion of κ-carrageenan. The Fourier transform infrared spectroscopy spectra revealed that the interaction between the starch–CMC matrix and κ-carrageenan formed a tight hydrogen bond network. The lowest mass reduction observed by thermogravimetric analysis occurred in bioplastics with 25% carrageenan, decreasing by 48% compared with bioplastics without κ-carrageenan. The addition of κ-carrageenan was identified as not affecting the biodegradability of the bioplastics.

Effect of κ-carrageenan on quality improvement of 3D printed Hypophthalmichthys molitrix-sea cucumber compound surimi product

In this study, κ-carrageenan was used as an additive to improve the quality of Hypophthalmichthys molitrix-sea cucumbers (HM-SC) compound surimi gel. The effects of κ-carrageenan on rheological properties, gel strength, textural and moisture characteristics, as well as microstructure of the HM-SC surimi gel were investigated, alongside with Fourier transform infrared (FT-IR) spectroscopic characterization and SDS-PAGE analyses of the compound materials. Rheological tests showed that addition of κ-carrageenan increased the storage modulus of the HM-SC compound materials in a dosage-dependent way, which led to superior shape-forming and shape-keeping abilities in 3D printed products. The best gel strength of 1236.04 g mm was obtained in samples with κ-carrageenan addition at 1.5% (w/w). The microstructure of the HM-SC compound surimi gel became more compact and denser, with improved connectivity. These samples also had reduced cooking loss and improved water holding capacity, confirmed by changes in water mobility characterized through Low-field nuclear magnetic resonance (LF-NMR). Moreover, κ-carrageenan addition did not change protein configuration much, neither was it contributed to the aggregation and degradation of proteins. These results showed that the quality of the HM-SC compound material could be improved with the κ-carrageenan addition, which could make it suitable for 3D printing based novel product development.

The effect of furcellaran or κ-carrageenan addition on the textural, rheological and mechanical vibration damping properties of restructured chicken breast ham

The aim of the study was to investigate the dependence of selected textural, rheological and mechanical vibration damping properties of restructured chicken breast ham (RCBH) on the concentration of furcellaran (FRC1 or FRC2) or κ-carrageenan (KC) during a 14-days storage period (at 4 ± 2 °C). The above-mentioned polysaccharides were used in concentrations of 0.25 g/100 g, 0.50 g/100 g, 0.75 g/100 g and 1.00 g/100 g. Control sample (CS) without any polysaccharide addition was also produced. The textural, rheological and mechanical vibration damping properties of RCBH samples were affected by the type and concentration of the polysaccharide used (p < 0.05) and the storage period (p < 0.05). Samples prepared with KC and FRC1 at a concentration level of 1.00 (g/100 g) presented the highest values of hardness, G′, G″ and G*. Values of G* and δ (in all tested frequency ranges) indicated a solid-like behavior for all the samples over the experimental range. It was found that the first resonance frequency peak position increased with an increase in the RCBH stiffness leading to lower vibration damping properties of the samples (p < 0.05).

Effect of κ-carrageenan addition on protein structure and gel properties of salted duck egg white.

Salted duck egg white (SDEW) is a major by-product during salted egg yolk manufacturing. Due to the high salt concentration, SDEW has not been efficiently utilized. Moreover, functional properties of SDEW are altered by salt during pickling. To improve the functional properties, the effect of κ-carrageenan (κ-CAR) addition on the protein structure and gel properties of SDEW was investigated in this study. The surface hydrophobicity and free sulfhydryl content of SDEW protein increased, while total sulfhydryl content decreased significantly with the addition of κ-CAR (0.02-0.10%). Fourier-transform infrared spectroscopy analysis revealed that the relative content of α-helix and β-turn decreased, β-sheet and random coil increased, indicating the variation tendency of protein structure from order to disorder. As κ-CAR addition increased, the texture profiles including hardness, gumminess, chewiness, springiness, cohesiveness and resilience of SDEW gel were all improved. Water holding capacity increased significantly by 32.33% in the presence of 0.10% κ-CAR addition. The scanning electron microscopy indicated that the microstructure of SDEW/κ-CAR mixed gel was more smooth and compact. The results suggested that adding κ-CAR can be an effective method to improve gel quality of SDEW. This study is expected to provide theoretical basis for modification of SDEW protein, as well as preparation of food ingredients with better gel properties from SDEW. © 2020 Society of Chemical Industry.

Inhibitory effect of selected hydrocolloids on 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) formation in chemical models and beef patties

2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a mutagen and a rodent carcinogen mainly formed in thermally processed muscle foods. Hydrocolloids are widely used as thickeners, gelling agents and stabilizers to improve food quality in the food industry. In this study, the inhibitory effects of eight hydrocolloids on the formation of PhIP were investigated in both chemical models and beef patties. 1% (w/w) of carboxymethylcellulose V, κ-carrageenan, alginic acid, and pectin significantly reduced PhIP formation by 53 %, 54 %, 48 %, and 47 %, respectively in chemical models. In fried beef patties, κ-carrageenan appeared to be most capable of inhibiting PhIP formation among the eight tested hydrocolloids. 1% (w/w) of κ-carrageenan caused a decreased formation of PhIP by 90 %. 1% (w/w) of κ-carrageenan also significantly reduced the formation of other heterocyclic aromatic amines including MeIQx and 4,8-DiMeIQx by 64 % and 48 %, respectively in fried beef patties. Further mechanism study showed that κ-carrageenan addition decreased the PhIP precursor creatinine residue and reduced the content of Maillard reaction intermediates including phenylacetaldehyde and aldol condensation product in the chemical model. κ-Carrageenan may inhibit PhIP formation via trapping both creatinine and phenylacetaldehyde. The structures of adducts formed between κ-carrageenan and creatinine and κ-carrageenan and phenylacetaldehyde merits further study.