Gel Textural Properties Research Articles

Rheology and Texture Properties of Surimi Gels of Northern Snakehead (Channa Argus) as Affected by Angelica Sinensis (Oliv.) Diels. (Danggui) Powder

ABSTRACTNorthern snakehead (Channa argus) is very popular freshwater fish in China and is expected to become a new surimi material with therapeutic efficacy. The Angelica sinensis powder is a type of famous Chinese medicine that helps to regulate metabolism and enhance the immune function. Therefore, an upmarket medicated surimi product with hygienic qualities was designed to adapt to the stressful current lifestyle using snakehead and Angelica sinensis powder. The texture, whiteness, rheological properties, and sensory properties were studied to further optimize the dosage of the Angelica sinensis powder used in the surimi processing. The results indicated that the maximum breaking force and breaking distance were obtained at a concentration of 4 g/kg, and the whiteness value and driage were significantly decreased with the increase of the amount of the Angelica sinensis powder. Ultimately, the highest total sensory evaluation score was obtained for samples with the addition of 2 g/kg Angelica sinensis powder. This study shows that the Angelica sinensis powder has the potentiality to become an added ingredient to snakehead surimi products in order to improve the health status of sub-health population.

Genetic diversity of potato genotypes estimated by starch physicochemical properties and microsatellite markers

Genetic diversity of 29 potato genotypes was estimated by their starch physicochemical properties and microsatellite markers. The apparent amylose content (AAC) of potato starches averaged 25.3%, ranging from 18.9 to 29.4%. Significance differences were observed in pasting and gel texture properties among potato accessions. Wide genetic diversity was also found in the gelatinization temperatures (To, Tp, Tc), enthalpies of gelatinization, enthalpies of retrogradation and retrogradation percentage, which had ranges of 62.2–67.6 °C, 66.1–71.1 °C, 73.5–77.4 °C, 17.5–21.0 J/g, 1.95–4.41 J/g, and 10.6–21.4%, respectively. AAC had significant correlation with pasting viscosities and gel hardness, but had no correlation with thermal and retrogradation properties. The grouping of the potato genotypes using 30 microsatellite markers did not correspond to that drawn using the starch physicochemical properties. Molecular analysis revealed that genotypes with interesting starch properties were distributed among three clusters. Potato starches exhibited interesting physiochemical properties could be applied in food and industrial applications.

Aloe vera gel influence on the micellization behavior of copolymer Pluronic F127: A potential photosensitizer carrier for topical application

ABSTRACTThis work describes the influence of aloe vera gel on Pluronic F127 triblock copolymer (F127) micellization behavior. Aloe vera gel was obtained from aloe vera mucilage found in leaf pulp. F127 (20% w/w) gel and the aloe vera/F127 blend gel were obtained by using the cold method. Fourier transform infrared spectroscopy and X‐ray diffraction analyses of lyophilized samples did not show any important copolymer interaction between aloe vera gel and F127. However, in aqueous medium, the dynamic light scattering data showed that there was an important reduction in micelle size with increasing temperature of the aloe vera/F127 blend hydrogel. The differential scanning calorimetry results indicate that the aloe vera/F127 blend has a higher micellization temperature, affected by the lower dehydrating effect of the poly(propylene oxide) blocks during the micelle formation in comparison to F127 gel. The texture analyses (hardness and adhesiveness) showed that the addition of aloe vera gel did not change the Pluronic F127 gel texture properties. The photosensitizer zinc phthalocyanine (ZnPC) was incorporated into the aloe vera/F127 blend, and the results suggest that this formulation is suitable as a ZnPC delivery system for photodynamic therapy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46191.

Combination effects of NaOH and NaCl on the rheology and gel characteristics of hen egg white proteins

The effects of NaOH and NaCl on the rheology and gel properties of hen egg white were investigated. As the concentration of NaOH increased, egg white gel exhibited lower opacity and particle turbidity with coincidental increase in zeta potential, while the addition of NaCl resulted in the formation of opaque egg white gel and increase of surface hydrophobicity, particle turbidity and zeta potential. Rheological tests showed that alkali treatment will affect the unfolding state of egg white proteins during the heat stage while NaCl addition can inhibit the unfolding of egg white proteins. The results of correlation analysis indicated that random coil and α-helix were in good correlation with gel textural properties. Therefore, the rheology and gel properties of alkali/salt-induced egg white dispersions were closely related to the changes in surface hydrophobicity, molecule surface charge, and protein secondary structure.

The addition of hydrolyzed whey protein fractions to raw pork patties with subsequent chilled storage and its effect on oxidation and gel properties

ABSTRACTThis experiment was conducted to elucidate the protein oxidation and gel properties of whey protein hydrolysates that were mixed into raw pork patties with subsequent chilled storage. Whey protein polypeptides of different size classes (Fraction I, MW > 10 k; Fraction II, MW 3–10 k; Fraction III, MW < 3 k) were separated by ultrafiltration and the pork patties were stored for 0, 2, 4, 6, and 8 days at 4°C. The contents of thiobarbituric acid-reactive substances (TBARS), carbonyl groups, and gel textural properties were determined. The results showed that there was no significant difference at the beginning of the storage period between the treatment groups that contained whey polypeptides or BHA and the control group (P > 0.05). After 2 days of storage, Fraction III (F3) was superior to Fraction I (F1), Fraction II (F2), and the control in inhibiting the oxidation of pork patties and improving gel quality. In addition, F3 also had a higher water-holding capacity and storage modulus, which was similar to the 0.02% butylated hydroxyanisole (BHA) group. The amino acid compositions showed that F3 had relatively higher contents of histidine, arginine, and proline, demonstrating a strong potential for F3 to be used as a natural antioxidant in raw pork preservation.

Rheological properties and gel characteristics of polysaccharides from fruit-bodies of Sparassis crispa

ABSTRACTRheological properties and gel characteristics of Sparassis crispa polysaccharides (SCPs) were investigated under various concentrations, temperature, pH, salt concentrations, and sucrose concentrations. SCP solutions behaved as shear thinning pseudoplastic fluids; apparent viscosity increased with concentrations but decreased with extreme conditions and was highest for 1% SCPs at 80 ℃ under neutral conditions; 5% SCPs solutions formed a hysteresis loop and exhibited thixotropic properties. By oscillatory measurements, SCPs were viscoelastic materials. 0.5% and 1% SCPs solutions exhibited viscous behavior at low frequency and enhanced elastic property with the oscillation frequency increased. With the concentration increased to 3% and 5%, the elastic property was predominant in solutions and exhibited gel-like behavior. SCPs gel textural properties and water holding capacity increased with concentration (to 20%) and decreased with salinity, extreme sucrose, and pH. 10% SCPs gels were optimized at 10% sucrose in neutral conditions. Thus, these results implied SCPs had the potential utilization as a new hydrocolloid source in food industries.

Textural behavior of gels formed by rice starch and whey protein isolate: Concentration and crosshead velocities

ABSTRACT Fabricated food gels involving the use of hydrocolloids are gaining polpularity as confectionery/convenience foods. Starch is commonly combined with a hydrocolloid (protein our polyssacharides), particularly in the food industry, since native starches generally do not have ideal properties for the preparation of food products. Therefore the texture studies of starch-protein mixtures could provide a new approach in producing starch-based food products, being thus acritical attribute that needs to be carefully adjusted to the consumer liking. This work investigated the texture and rheological properties of mixed gels of different concentrations of rice starch (15%, 17.5%, and 20%) and whey protein isolate (0%, 3%, and 6%) with different crosshead velocities (0.05, 5.0, and 10.0 mm/s) using a Box-Behnken experimental design. The samples were submitted to uniaxial compression tests with 80% deformation in order to determinate the following rheological parameters: Young’s modulus, fracture stress, fracture deformation, recoverable energy, and apparent biaxial elongational viscosity. Gels with a higher rice starch concentration that were submitted to higher test velocities were more rigid and resistant, while the whey protein isolate concentration had little influence on these properties. The gels showed a higher recoverable energy when the crosshead velocity was higher, and the apparent biaxial elongational viscosity was also influenced by this factor. Therefore, mixed gels exhibit different properties depending on the rice starch concentration and crosshead velocity.

Retrogradation, gel texture properties, intrinsic viscosity and degradation mechanism of potato starch paste under ultrasonic irradiation

The effects of sonication on the retrogradation, gel texture properties, intrinsic viscosity and degradation of potato starch paste (PSP) were investigated using a specially designed reactor to study changes in molecular structure and functional properties. The retrogradation was analyzed by an x-ray diffractometry. The gel texture properties were analyzed by texture profile analysis (TPA) and the intrinsic viscosity was analyzed using a Cannon-Ubbelohde viscometer at different sonication times, intensities and PSP concentrations. The molecular weight of PSP was determined using gel permeation chromatography (GPC). The results showed that retrogradation of PSP occurred when it was placed in a high density ultrasonic field, and was accompanied by a transition from crystalline type B to type VH. The TPA results indicated remarkable decreases in gel texture properties (hardness, fracture ability, adhesiveness, gumminess, and chewiness) when the sonication time was prolonged, the intensity was increased and when the PSP concentration was reduced. Intrinsic viscosity decreased with extended sonication time and at higher intensity, but increased as the PSP concentration increased. The GPC results showed that the average molecular weight of PSP decreased significantly upon ultrasonic irradiation and the sample had a narrower distribution of molecular weight. The degradation kinetics were adequately described by the Baramboim models. Radical trapping by 2,2-diphenylpicrylhydrazyl was used to assess the radical-attack mechanism in PSP subjected to ultrasound. Under the reaction conditions, degradation of PSP in the ultrasound field is caused by OH radicals and mechanochemical effects. Mechanochemical effects were the main cause of bond scission.

Effect of high pressure on rheological and thermal properties of quinoa and maize starches

Quinoa starch has small granules with relatively low gelatinization temperatures and amylose content. High hydrostatic pressure (HHP) is a non-thermal technique for food processing. In this study, effects of HHP up to 600MPa on physical properties of quinoa starch were studied and compared with those of a normal maize starch. Both starches gelatinized at 500 and 600MPa. The pressure of 600MPa completely gelatinized quinoa starch as revealed by thermal analysis. Dynamic rheological analysis showed that HHP improved the gel stability of both starches during cooling. HHP had little effects on amylopectin recrystallization and gel textural properties of starch. Overall, quinoa starch was more susceptible to HHP than maize starch. The effects of HHP on some rheological properties such as frequency dependence were different between these two types of starches. The differences could be attributed to the different composition, granular and chemical structures of starch, and the presence of granule remnants.

Effect of Amylose Content on the Physicochemical Properties of Proso Millet Starch

The influence of amylose content (AC) on gel texture, thermal, pasting, rheological and morphologic properties, short-range order, X-ray diffraction pattern, solubility and swelling power of starches from nine proso millet cultivars was investigated. The solubility, swelling power, conclusion gelatinization temperature (Tc), gelatinization temperature range (Tc-To), gelatinization enthalpy (ΔH) and cohesiveness showed a negative correlation to the AC of millet starch. Whereas the pasting temperature (PT), peak viscosity (PV), trough viscosity (TV), final viscosity (FV), setback value (SB), gel hardness, and chewiness showed a positive correlation to the AC of millet starch. The R1047/1022 values of starches ranged in 0.7−0.9, and all starches showed similar morphology features (irregular, polygonal, and spherical shape) and crystal type, which showed no correlation to the AC.

Effects of high amylose corn starch and microbial transglutaminase on the textural and microstructural properties of wheat flour composite gels at high temperatures.

Although, transglutaminase was practically used in the production of noodles and pasta in Japan, but there is little academic and industrial knowledge concerning its utilization in the pasta or noodles. Moreover, long shelf-life noodle/pasta products have become popular in the Japanese market and in the emergency conditions like as floods or earthquake, but they can be stored for at least 5 months by applying heat treatment at 95C. Here, high amylose corn starch as a resistant starch, wheat flour, and microbial transglutaminase (MTGase) were selected as the main components in the composite gel (CG) systems to elucidate the effects of MTGase and Hylon on the texture, microstructure, and pasting behavior of CGs at high temperatures to produce long-life noodle/pasta products (about 2 years) through retort processing.

The Effects of Grass Carp Skin Gelatin and Whey Protein Interactions on Rheological and Textural Properties and Nanostructure

ABSTRACTThe physical properties and nanostructure of fish skin gelatin with and without whey protein isolate (WPI) were investigated. The addition of low concentrations of WPI (1 and 3%, w/v) into fish gelatin decreased the gel strength and textural properties. The addition of 5% WPI did not significantly influence textural properties but increased the melting and gelling temperatures of fish skin gelatin and improved the appearance of gelatin gels. X-ray diffraction indicated that a higher degree of crystallinity with an ordered structure or ordered structure snippets occurred with increasing WPI concentrations in line with the slight decrease in the loss factor (tan δ) with time sweeps. Fish gelatin had a spherical nanostructure, and a homogeneous nanostructure was observed in gelatin with 3% WPI. The addition of 5% WPI led to large aggregates in gelatin gels. The results indicated that whey protein could affect the nanostructure of fish skin gelatin gels and thus change their gelation properties and texture in food and pharmaceutical applications.

Effect of Vaccinium bracteatum Thunb. leaf pigment on the thermal, pasting, and textural properties and microstructure characterization of rice starch.

In this study, the thermal, pasting and gel textural properties of japonica rice starch (JRS) and glutinous rice starch (GRS) fortified with Vaccinium bracteatum Thunb. leaf pigment (VBTLP) were investigated. The results showed that VBTLP facilitated the gelatinization of JRS and GRS with earlier onsets of onset temperature (To), peak temperature (Tp), conclusion temperature (Tc), and lower values of gelatinization enthalpy (ΔHg), and retrogradation enthalpy (ΔHr), as the VBTLP level increased. For JRS, VBTLP increased the peak viscosity and breakdown, reduced the final viscosity and setback, but for GRS it increased the peak viscosity, final viscosity, breakdown and setback. VBTLP also reduced the hardness and adhesiveness of the JRS gel. The values of lightness (L∗) for JRS and GRS with VBTLP decreased by 47.60 and 49.56%, respectively. Scanning electron microscopy (SEM) revealed that VBTLP caused looser matrices in dried JRS and GRS gels which had lower crystallinities compared with the control.

Textural properties and morphology of soy 7S globulin-corn starch (amylose, amylopectin)

ABSTRACTThe texture properties (hardness, adhesiveness, cohesion, elasticity) of composite gels with different ratios (0:100, 6:94, 8:92, 10:90, 12:88, and 14:86, respectively) of soy 7S globulin to corn starch (amylose, amylopectin) were studied. Furthermore, the morphology and crystal structure of the mixed gels were investigated. The results showed: the addition of soy 7S globulin could weaken the hardness of corn starch (amylose, amylopectin) and increased the adhesiveness of corn amylose significantly (p < 0.05). Generally, when the additive amount of soy 7S globulin was 10%, the composite gels of soy 7S globulin and corn starch (amylose, amylopectin) appeared to have the best consistency, cohesion, and elasticity.

Physicochemical properties of quinoa flour as affected by starch interactions

There has been growing interest in whole grain quinoa flour for new product development due to the unique nutritional benefits. The quality of quinoa flour is much determined by the properties of its major component starch as well as non-starch components. In this study, composition and physicochemical properties of whole grain flour from 7 quinoa samples have been analyzed. Flour properties have been correlated to the flour composition and the properties of isolated quinoa starches through chemometrics. Great variations in chemical composition, swelling power, water soluble index, enzyme susceptibility, pasting, gel texture, and thermal properties of the flour have been observed. Correlation analysis showed that thermal properties and enzyme susceptibility of quinoa flour are highly influenced by the starch. Interactions of starch with non-starch components, including lipids, protein, dietary fibre, phenolics, and minerals, greatly impacted the flour properties. For example, peak gelatinization temperature of the flour is positively correlated to that of the starch (r=0.948, p<0.01) and negatively correlated to the lipid content (r=-0.951, p<0.01). Understanding the roles of starch and other components in physicochemical properties of quinoa flour provides a basis for better utilization of this specialty crop.

Study on Influential Factor of Texture Property of Sweet Potato Starch Gel

Sweet potato starch gel was prepared with thermal induction and the gel formation conditions were obtained by investigating the effects of starch concentration, pH value, heating temperature and time on gel hardness and elasticity. Furthermore, the effects of metal ions, such as K+, Mg2+, Ca2+ and Zn2+, on gel texture properties were explored. The result revealed that the formation conditions of sweet potato starch gel were listed as following: starch concentration of 8.0 g/100 mL, pH value of 8.0 and heating for 20 min at 90°. Low concentration of K+, Mg2+ and Ca2+ could promote the gel formation. Within the concentration range of 0.15-0.45 mol/L, the gel hardness and elasticity would enhance with the increase of Zn2+ concentration.

Effect of heat-moisture and acid treatment on physicochemical, pasting, thermal and morphological properties of Horse Chestnut (Aesculus indica) starch

The present work was carried out to study the effect of heat-moisture and acid modification on the structural, physicochemical, pasting, gel texture, morphological and thermal properties of Indian Horse Chestnut (HCN) starch. Starch isolated from seeds of HCN was subjected to heat moisture treatment (HMT) at 20% (HMT-20), 25% (HMT-25) and 30% (HMT-30) moisture levels and acid treatment (AT) with hydrochloric acid (HCl) at three different concentrations of 0.25M (AT-1), 0.5M (AT-2) and 1M (AT-3), respectively. XRD results showed a similar X-ray pattern with increased relative crystallinity in acid modification and decreased crystallinity in heat-moisture treatment. The IR-spectra also showed a similar pattern in both the modifications with increase in intensities of the band at 1016 cm−1 in heat moisture treatment and decreased intensities of the band in acid treatment. HMT showed negligible effect on amylose content while acid treatment significantly decreased the amylose content. Both the modifications significantly decreased the swelling power of the starch. Moreover, the solubility of HMT was decreased and in acid was increased. HMT resulted in increased water binding and oil binding capacity while reverse was found in acid treatment. Pasting characteristics of native starch were largely affected by both the treatments with a significant reduction in peak viscosity. Moreover, the HMT showed no breakdown in the treatments with higher moisture content. The gel firmness of the starch was increased in heat moisture and decreased in acid treatment. HMT of native HCN starch at higher levels caused few dents or cracks on the granule surface while acid treated starch showed rough surface with cracks and cavities, respectively. DSC revealed that both the treatments increased the gelatinisation temperature with reduced gelatinisation enthalpy (ΔH) in heat moisture treated starch while increased ΔH of acid modified starch.

Potato starch oxidation induced by sodium hypochlorite and its effect on functional properties and digestibility

The effects of different concentrations of sodium hypochlorite (active chlorine content at 0.1, 0.2, 1.0, 2.0, 3.0, and 4.0g/100g) on the properties of potato starch (PS) were investigated by determining the morphological, physicochemical, crystallinity, pasting, gel texture and digestive properties. The starch granules of PS oxidized with high oxidant concentrations caused cracks and pores, and oxidation mainly acts on the amorphous regions of the starch granules. As the sodium hypochlorite concentration increases, the carbonyl content, carboxyl content, solubility, and pasting temperature of PS increased, as measured using a Rapid Visco Analyser (RVA). The swelling power, breakdown, setback, and peak and final viscosities decreased according to the RVA (P<0.05). The gel strength increased under low-intensity oxidative treatments and decreased under high-intensity oxidative treatments. Oxidative treatment decreased the digestibility of gelatinized potato starch. The slowly digestible starch and resistant starch contents increased significantly, while the rapidly digestible starch content decreased after the oxidation modification (P<0.05). Overall, PS oxidation with sodium hypochlorite improved the functional characteristics of starch and decreased starch digestibility.

Rheological and textural properties of goat and cow milk set type yoghurts

Yoghurts were made from pasteurised and homogenised goat milk (2.5% protein), goat milk fortified with a milk protein isolate (5% protein) and cow milk (3% protein), by acidification with a starter culture at 43 °C until a pH of 4.6 was reached. The rheological and textural properties of gels and yoghurts were analysed using dynamic low amplitude oscillatory rheology and back extrusion texture analysis. Gelation and fermentation times of goat milk were longer, while gelation pH, storage moduli (G′) and yield stress values were lower, compared with those of cow milk. Textural properties of goat milk yoghurts such as firmness, consistency, cohesiveness and viscosity index were very poor. Consequently, the products could not be classified as set type yoghurts. Fortification of goat milk with a milk protein isolate contributed to a significant improvement of the rheological and textural properties of yoghurt.

Textural Properties of Acid Milk Gels: Effects of Dairy Protein Powder Rehydration State

In this study, the effect of dried dairy ingredient rehydration state on the textural properties and microstructure of acid milk gels was investigated. The control acid gel samples were made with 12% w/w of reconstituted skim milk powder. Milk base was enriched with whey protein isolates and/or micellar casein powders. Different rehydration times (5, 120, 240, 1,440 min) were considered before studying gel textural properties. This study showed that acid milk gels made with whey instead of casein resulted in an increase in firmness, gel strength, graininess but a decrease in syneresis susceptibility. Nevertheless, rehydration duration of casein powder in contrast to that of whey powder strongly altered the physical properties of the obtained acid milk gels. Moreover, prolonged hydration resulted in enhanced textural properties and decreased syneresis. Practical Applications Commercial preparation of yogurt involves different processing steps. Among them, protein fortification of the milk appears as a crucial step that attributes toward the change in textural properties. Milk protein powders are frequently dried in order to stabilize and transport. This is the reason why rehydration is an essential quality attribute of the powder. Consequently, rehydration is often realized by the industry before use and for a long time. This study showed that acid milk gels made with whey instead of casein resulted in an increase in firmness, gel strength, graininess but a decrease in syneresis susceptibility. Rehydration duration of casein powder in contrast to that of whey powder strongly altered the physical properties of the obtained acid milk gels. Prolonged hydration resulted in enhanced textural properties and decreased syneresis. These aspects are of high significance in the preparation of dairy products, i.e., different types of set and stirred yogurts.