Decrease In Water Holding Capacity Research Articles

Impact of Probiotic Fermentation on the Physicochemical Properties of Hemp Seed Protein Gels.

Hemp seed protein isolates (HPI) were used to produce a gel through probiotic fermentation. This study assessed how fermentation time (ranging from 0 to 16 h) affected the physicochemical properties of the HPI gel. The results indicated that gel formation began after 8 h of fermentation, as demonstrated by a pH decrease, an increase in particle size, and the development of aggregation observed through fluorescence and scanning electron microscopy. The gel produced after 16 h of fermentation showed the highest viscosity, storage modulus, and gel strength, attributed to stronger molecular interactions, including non-covalent and covalent crosslinking. However, the gel produced after 12 h of fermentation showed the highest water-holding capacity, and extending the fermentation beyond 12 h caused a decrease in water-holding capacity. Additionally, the subunits tended to form polymers after fermentation, suggesting that gel formation was influenced by both acidification and specific covalent crosslinking. These findings propose that HPI could serve as a viable alternative for developing plant-based gel products.

Cryoprotective effect of epigallocatechin gallate replacing sucrose on Hypophythalmichthys molitrix surimi during frozen storage.

The present study aimed to investigate the cryoprotective effect of epigallocatechin gallate (EGCG) replacing sucrose on surimi during frozen storage. Substitution or partial substitution of 0.1% EGCG for sucrose (1.5%) was added to surimi, and the surimi samples without and with commercial cryoprotectants (4% sucrose and 4% sorbitol) were used as the control group. The results obtained suggest that, with the increase in frozen storage time, the structural performance of surimi protein gradually weakened (e.g. the decrease in the surface hydrophobicity, the increase in the total sulfhydryl and solubility, and the protein myosin heavy chain bands became shallow) and surimi gel quality gradually deteriorated (e.g. the decrease in water-holding capacity, gel strength and all texture profile attributes). However, compared with the other three group surimi samples during the frozen period, the surimi proteins with partial replacement of sucrose by EGCG had a higher total sulfhydryl group content and solubility of proteins, as well as lower surface hydrophobicity of protein, suggesting that the addition of EGCG as a partial substitute for sucrose can enhance the antifreeze ability of surimi. Meanwhile, the surimi gel with the partial replacement of sucrose by EGCG had a higher water retention capacity, gel strength and texture attributes (e.g. hardness, springiness, cohesiveness, chewiness, and resilience), indicating that the addition of EGCG as a partial substitute for sucrose can inhibit the deterioration of surimi gel quality. Overall, EGCG partially replacing sucrose can play an alternative cryoprotectant with a lower sweetness to prevent the quality of surimi from deteriorating. © 2024 Society of Chemical Industry.

Effect of boiling on texture of scallop adductor muscles and its mechanism based on label-free quantitative proteomic technique

The mechanism behind textural changes in scallop adductor muscle during boiling was investigated through proteomic analysis, determination of water holding capacity (WHC) and oxidative indices, as well as observation with scanning electron microscopy and multiphoton nonlinear optical microscopy. The hardness and shear force showed the trend of first rising and then falling in 45 min-boiling time. The results suggested that short-time boiling caused the oxidation, denaturation and aggregation of proteins, resulting in the transverse contraction of myofibers and lateral cross-linked aggregation of muscle fibers and a rise in WHC, which led to the increase in hardness and shear force. While long-time boiling caused the progressive degradation of structural proteins such as fibrillin-1, collagen alpha-2(I) chain, myosin heavy chain, basement membrane-specific heparan sulfate proteoglycan core protein, and paramyosin, resulting in a loose myofibril network and the decrease in WHC, which led to the decrease in hardness and shear force.

PENGGUNAAN TEPUNG TALAS SEBAGAI SUBSTITUSI TEPUNG TAPIOKA TERHADAP KARAKTERISTIK FISIKOKIMIA DAN ORGANOLEPTIK BAKSO DOMBA (Using of taro flour as a substitute of tapioca flour on physicochemistryl and organoleptic characteristics of lamb meatballs)

Lamb meatballs are rarely found in the market, because lamb meat has a distinctive aroma. One way to reduce the distinctive aroma of lamb meatballs is to use various types of flour in combination with tapioca flour. The purpose of this study was to determine the quality of meatballs processed from lamb and given taro flour as a substitute for tapioca flour. A completely randomized design (CRD) 5 x 4 was used in this experiment. The five treatments used were: T0 = no taro flour (control); T25=25% taro flour 25%; T50 = 50% taro flour; T75 = 75% taro flour; T100 = 100% taro flour, and each unit was tested four times. Parameters measured were: pH, water holding capacity (WHC), cooking loss, water and fat content, aroma, color, elasticity and taste. The parametric data was analyzed using ANOVA, while the nonparametric data was analyzed using the Kruskal-Wallis test. The statistical analysis result showed that a balanced mixture of tapioca and taro (50%) caused a decrease in pH (P<0.01). The higher the percentage of taro to substitute tapioca, caused a decrease in WHC and an increase in cooking loss (P<0.05), decreased water content, increased fat content (P<0.01), but did not affect aroma, color, elasticity and taste (P>0.05). The results of this study concluded that the use of taro flour as a substitute for tapioca flour in processing lamb meatballs do not change the organoleptic value of meatballs. Taro flour can be used to replace tapioca flour in processing lamb meatballs as much as 50%.

Dynamics of Chernozem’s self-cleaning from oil pollution over two years

ABSTRACT This work investigates the natural self-cleaning capacity of Chernozem soil in the face of oil pollution. A field experiment in 2019–21 on heavy loam Haplic Chernozem confirmed that after oil pollution up to 1.6 l/m2, Chernozem can clean itself to an acceptable level in 2 years. With contamination of 6.4 and 25.6 l/m2, petroleum hydrocarbon content decreased by more than half by the 24th month, but not enough to support rye and mustard for bioremediation. The oil also caused water repellence and a decrease in water-holding capacity, nitrification, and available phosphorus. Lack of available nitrogen limits the rate of petroleum biodegradation; therefore, application of nitrogen fertilisers should be part of the bioremediation.

Effect of protein oxidation in meat and exudates on the water holding capacity in bighead carp (Hypophthalmichthys nobilis) subjected to frozen storage

This study aimed to investigate the effect of myofiber changes and protein oxidation on water holding capacity (WHC) of bighead carp fillets stored at −20 °C. WHC, microstructure, protein oxidation parameters, and specific modifications of oxidized amino acids were analyzed during 9 months of frozen storage. Results indicated that WHC decreased accompanied by myofibers’ structural changes (including the formation of cavities among myofibers, breakage of myofibrils and myofibers, and shortening of sarcomeres) and protein oxidation. SDS-PAGE and carbonyl and sulfhydryl content determination of myofibrillar proteins and exudates gave a detailed description of the protein oxidation. LC-MS/MS analysis demonstrated that oxidation, di-oxidation, and 4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA) adduction were the top four oxidative modifications of proteins. Oxidative modifications impaired configuration and polarity of proteins, which may further affect WHC. This study provides plausible explanations to support the role of protein oxidation in the decrease of WHC in frozen fillets.

Impact of Ultra-High-Pressure Homogenization of Buttermilk for the Production of Yogurt.

Despite its nutritional properties, buttermilk (BM) is still poorly valorized due to its high phospholipid (PL) concentration, impairing its techno-functional performance in dairy products. Therefore, the objective of this study was to investigate the impact of ultra-high-pressure homogenization (UHPH) on the techno-functional properties of BM in set and stirred yogurts. BM and skimmed milk (SM) were pretreated by conventional homogenization (15 MPa), high-pressure homogenization (HPH) (150 MPa), and UHPH (300 MPa) prior to yogurt production. Polyacrylamide gel electrophoresis (PAGE) analysis showed that UHPH promoted the formation of large covalently linked aggregates in BM. A more particulate gel microstructure was observed for set SM, while BM gels were finer and more homogeneous. These differences affected the water holding capacity (WHC), which was higher for BM, while a decrease in WHC was observed for SM yogurts with an increase in homogenization pressure. In stirred yogurts, the apparent viscosity was significantly higher for SM, and the pretreatment of BM with UHPH further reduced its viscosity. Overall, our results showed that UHPH could be used for modulating BM and SM yogurt texture properties. The use of UHPH on BM has great potential for lower-viscosity dairy applications (e.g., ready-to-drink yogurts) to deliver its health-promoting properties.

Effect of sonication pretreatment on physicochemical, surface, thermal, and functional properties of fibro‐proteic extracts from male date palm flowers

This study aims to investigate the effect of the application of an ultrasound pretreatment on physicochemical, surface, thermal, and functional properties of two extracts from male date palm flowers. The obtained extracts were compared based on their structural and functional properties. It was proved that the application of sonication pretreatment has modified significantly (p < .05) the extract's characteristics. The protein yield, the essential amino acid content and the protein solubility were improved (29.61%, 29.22 g/100 g protein, and 91.1% for native sample against 35.26%, 41.04 g/100 g protein, and 100% for treated sample, respectively), while the protein content and the surfactant behavior at 1% were decreased due to the liberation of other compounds than protein. Moreover, the sonication has engendered some structural modifications such as the dissociation of some intermolecular bonds (FTIR) and the increase of crystalline region (X-ray), which influenced the protein unfolding and have led to the decrease of enthalpy (DSC) (272.2 against 228.6 J/g) and the decrease of water-holding capacity (11.62 against 9.51 g water/g of dry sample). Practical applications The male date palm flowers (MDPF) present a rich matrix composed mainly of dietary fiber, protein, and minerals. The protein fraction of MDPF was considered as an excellent source of amino acids supplying the human requirements. The dietary fiber fraction was composed essentially of insoluble dietary fibers which contribute to a balanced diet by creating satiety feeling and facilitating the intestinal transit. The fibro-proteic extract (FPE) of MDPF could be a potential functional ingredient for food applications. The physicochemical and functional properties of the FPE was changed by ultrasound pretreatment, which was beneficial to improve the protein yield, the amino acid profile, and the protein solubility. Nevertheless, both treated and non-treated samples showed promising nutritional and functional characteristics that could be used in the food industry to ameliorate food quality.

Changes in Soil Properties after Soil Washing of Metal-contaminated Soil near the former Janghang Smelter

Objectives : Changes in soil properties after washing of metal-contaminated soil near the former Janghang Smelter were investigated in this study. Contaminated input soils and remediated output soils were sampled from three different soil washing plants and analyzed for soil physical and chemical properties. Soil quality was evaluated by the soil fertilization guideline suggested by the Korea Rural Development Administration (KRDA). This study revealed the necessity of soil quality management for the remediated soil as an ecosystem member.Methods : Three soil washing plants (1OU, 2OU, 3OU) were commonly divided into the five steps: 1) the particle separation (crushing and grinding etc.) → 2) soil particle classification (big stone, fine soil, minimal fine soil) → 3) chemical washing (fine soil) → 4) neutralization of washed soil (lime) → 5) return-back to the original position. The separating minimum particle diameters of the 1OU, 2OU, and 3OU washing processes were 5 µm, 20 µm, and 10 µm, respectively, and the chemical washing solutions used were respectively 0.1 M H2SO4, 0.5 M H2SO4/0.5 M H3PO4, and 0.1 N NaOH-Na2CO3 (alkali reduction). Soils were collected before and after washing, air-dried, sieved with &lt; 2 mm and analyzed for soil texture, bulk density, aggregate stability (AS), water holding capacity (WHC), pH, electrical conductivity (EC), organic matter content (OM), total nitrogen (TN), available phosphate (AvP), cation exchange capacity (CEC), exchangeable cations (potassium, calcium, magnesium, sodium).Results and Discussion : Sandy soil showed a big change in soil texture before and after soil washing, while there was no change in soil texture for fine soil. Sandy soil showed an increase in bulk density, a decrease in WHC, and a decrease in AS. The pH of remediated soil was affected by the type of washing chemical. The acidic washing processes (1OU, 2OU) resulted in low pH soils, while an alkali reduction process (3OU) showed high pH soil. The soil OM, TN, AvP and CEC decreased after soil washing. In the case of silty paddy soil, OM and TN were significantly reduced by washing. The most important change in soil property after washing was EC. After soil washing, the soil electrical conductivity increased sharply in all OUs : 1OU 0.51 → 6.21 ds/m, 2OU 1.09 → 3.73 ds/m, 3OU 0.99 → 9.30 ds/m. The EC values of the contaminated soil before washing were all less than 2 ds/m, which is an appropriate agricultural level. However, EC was significantly increased after washing, implying a strong salty soil level. The soil quality evaluation results before and after washing showed that the soil quality of heavy-metal contaminated soil was apparently degraded by washing. The number of soil property in the optimal range before washing (contaminated soil) was 10, but the number decreased to 5 after washing (remediated soil).Conclusions : Soil quality may be significantly changed after soil washing. The most noticeable change was the significant increase in the EC of soil and the soil health should be restored first to recycle the remediated soil. The important causes of changes in the soil quality were the separation of fine soil particles containing relatively high heavy metals from the bulk soil, soil disturbance by chemical washing solution and addition of high salts such as coagulants and pH adjust. Soil management schemes considering soil health should be soon prepared to restore the remediated soil back as an ecosystem member.

Impact of chicken wooden breast on quality and oxidative stability of raw and cooked sausages subjected to frozen storage.

Considering (i) the increased incidence of wooden breast (WB) myopathy in broilers, (ii) the poor meat quality in such breasts and (iii) the lack of studies on the industrial use of WBs; the objective of this study was to investigate the quality of chicken sausages made with WB under frozen conditions. Three formulations of chicken sausage [100% normal (N) breast, 100% WB, and 50% N breast + 50% WB] were considered and raw and cooked (70 °C/10 min) sausages were frozen for 180 days and evaluated for their quality and oxidative stability. WB formulations exhibited higher pH, moisture (%), and shear force (SF), associated with lower water holding capacity (WHC) and fat (%). During the freezing period, there was a decrease in WHC and redness (a*) and an increase in cooking loss (CL) and SF for all formulations. Additionally, during freezing, thiobarbituric acid-reactive substances values were higher in raw sausages made with N breast than in sausage made with WB probably due to the higher fat content in the former. Results showed that the products did not reach noticeable rancid levels (<2 mg malondialdehyde/kg) and that WB sausage presented great resistance to oxidation, which suggests that WB sausage can be kept frozen at -20 °C for up to 198 days. Using WBs for the manufacture of chicken sausages subjected to freezing is a viable option given their overall quality and resistance to oxidation. © 2020 Society of Chemical Industry.

FEATURES WATER-HOLDING CAPACITY LEAF APPARATUS DENDROPHITES IN URBAN ENVIRONMENT

In the article the results of studies to identify general trends in water-holding capacity of foliagefrom the eight most common types that are used for the needs of landscaping in the city of Lubny. Themost intensively studied parameters identified in july and august, which is probably due to a complex ofnegative factors such as high air temperature, the maximum level of air pollution and etc.Revealed a more intense decrease in water-holding capacity of dendrophites: small-leaved lime (Tiliacordata Mill.), silver birch (Betula pendula Roth.), norway maple (Acer platanoides L.), horse chestnut(Aesculus hippocastanum L.), blue spruce (Picea pungens Engelm.), common pine (Pinus sylvestris L.),common lilac (Syringa vulgaris L.) that grew in unfavorable conditions. This trend is characteristic forall species with the exception of estelito maple (Acer negundo L.), which has a water holding capacityincreased during the growing season.Identified species with high rates of water-holding capacity during the whole period of vegetation, inparticular common pine (Pinus sylvestris L.), blue spruce (Picea pungens Engelm.), silver birch (Betulapendula Roth.), small-leaved lime (Tilia cordata Mill.) and the like, which testifies to their high adaptabilityto the conditions of arboreta. These types of dendrophites, their forms and varieties are promisingfor expanding the range that is used for the needs of landscaping, especially in areas with high anthropogenictension.

The Effect of Long-Term Frozen Storage on the Quality of Meat (Longissimus thoracis et Lumborum) from Female Roe Deer (Capreolus capreolus L.)

The objective of this study was to determine the quality of meat (Longissimus thoracis et lumborum) from 10 female roe deer (Capreolus capreolus L.), which was vacuum-packaged, frozen-stored (−26°C) for 6, 10, and 12 months, and compared with fresh, nonfrozen meat. Roe deer (aged 3 to 5 years) were hunter-harvested in north-eastern Poland in December and January during the same hunting season. Frozen storage did not affect the proximate chemical composition of meat (except for ash content). An analysis of the physicochemical properties of meat revealed that frozen-stored meat was characterized by a darker color, a higher hue angle, lower ability to bind its own and added water, and lower cooking loss compared with nonfrozen meat. The values noted for meat samples that were stored in the freezer for 12 months (increase in pH, considerable decrease in water-holding capacity, and first symptoms of flavor deterioration) indicate that frozen roe deer meat should be stored for no more than 10 to 12 months to maintain its high quality.

Changes in the quality of meat (Longissimus thoracis et lumborum) from Kamieniec lambs during long-term freezer storage.

The aim of this study was to determine changes in the quality of lamb meat (Longissimus thoracis et lumborum), which was vacuum-packaged and freezer-stored (-26°C) for 6 and 12months. The experiment was performed on 12 male lambs of the Kamieniec Longwool breed, raised to 106days of age. In comparison with fresh meat, thawed meat was characterized by lower ash content, higher pH, greater natural drip loss and cooking loss, and lower scores for taste intensity. Vacuum packaging and low-temperature storage protected lamb meat against oxidative changes, and alleviated the adverse effects of oxidation on the color, aroma and taste of meat. It can be concluded that freezer storage (-26°C) of vacuum-packaged meat can help meet consumer demand for lamb meat products in periods when fresh meat is unavailable. However, it should be noted that long-term frozen storage induces undesirable changes in meat quality, including a decrease in water-holding capacity and taste intensity.

A family 30 glucurono-xylanase from Bacillus subtilis LC9: Expression, characterization and its application in Chinese bread making

A GH30-8 endoxylanase was identified from an environmental Bacillus subtilis isolate following growth selection on aspen wood glucuronoxylan. The putative endoxylanase was cloned for protein expression and characterization in the Gram-positive protease deficient protein expression host B. subtilis WB800. The extracellular activity obtained was 55 U/mL, which was 14.5-fold higher than that obtained with the native species. The apparent molecular mass of BsXyn30 was estimated as 43 kDa by SDS-PAGE. BsXyn30 showed an optimal activity at pH 7.0 and 60 °C. Recombinant BsXyn30 displayed maximum activity against aspen wood xylan, followed by beechwood xylan but showed no catalytic activity on arabinose-substituted xylans. Analysis of hydrolyzed products of beechwood xylan by thin-layer chromatography and mass spectroscopy revealed the presence of xylooligosaccharides with a single methyl-glucuronic acid residue. BsXyn30 exhibited very low activity for hydrolysis xylotetraose and xylopentaose, but had no detectable activity against xylobiose and xylotriose. Using BsXyn30 as an additive in breadmaking, a decrease in water-holding capacity, an increase in dough expansion as well as improvements in volume and specific volume of the bread were recorded. Thus, the present study provided the basis for the application of GH30 xylanase in breadmaking.

Effects of hydrocolloids as fat replacers on the physicochemical properties of produced Labneh

Carbohydrate-based fat replacers are of growing interest because of their physicochemical, sensorial properties, and health characteristics. The used hydrocolloids suggest plausible texture and sensory attributes solution in low or reduced fat content products including dairy products.

The effects of calcium chloride on the gel properties of porcine myosin–κ-carrageenan mixtures

Calcium chloride (CaCl2) is used in low-fat meat products containing κ-carrageenan to improve their functional properties. However, the mechanism of how CaCl2 affects these meat systems has not been clearly elucidated. The aim of this study was to investigate the effects of adding CaCl2 with different concentrations (0.02 M, 0.04 M, 0.06 M, 0.08 M, 0.10 M and 0.12 M) on the gel properties of porcine myosin–κ-carrageenan mixtures. The usage of CaCl2 improved the water-holding capacity (WHC) and gel strength, but higher concentrations (0.10 M and 0.12 M) of CaCl2 led to decreased WHC. The low-field nuclear magnetic resonance results demonstrated that the addition of CaCl2 decreased the position of T22 and increased the proportion of T22, which indicated that the percentage of the water trapped within the gel matrix increased. Scanning electron microscopy was used to explain the above results. The addition of CaCl2 caused the formation of a compact gel phase. However, higher concentrations of CaCl2 induced the formation of large aggregates and cavities, which could cause the decrease in WHC. Furthermore, Raman analysis revealed that the addition of CaCl2 induced more hydrophobic residues to be exposed and an increased percentage of the β-sheet structure. However, higher concentrations of CaCl2 induced fewer hydrophobic residues to be exposed, indicating an excessive aggregation of myosin. In conclusion, a suitable concentration of CaCl2 could improve gel properties by inducing stronger hydrophobic interactions and forming more β-sheet structures, while excessive additions of CaCl2 induced extensive myosin aggregation, leading to a reduction in gel properties.

Hydrothermal carbonization of biomass from landscape management – Influence of process parameters on soil properties of hydrochars

Besides pyrolysis the technology of hydrothermal carbonization (HTC) is tested to produce hydrochars for soil improvement. The chemical and physical properties of the hydrochars mainly depend on the feedstock and the process parameters reaction time and process temperature. Systematic investigations on the influences of these process parameters on soil properties of hydrochars like water holding capacity (WHC) and cation exchange capacity (CEC) are missing.In this study, a rush-rich biomass was carbonized within defined HTC process conditions under variation of reaction time and process temperature to produce hydrochars. Analysis of WHC, CEC, the elemental composition and Fourier-transform infrared spectroscopy (FT-IR) were performed to evaluate the influence of HTC process conditions on the pedological hydrochar properties. The results indicated that at increasing reaction severity (reaction time and process temperature) WHC and CEC decreased as well as the elemental O/C ratio. The decrease of WHC and CEC is based on the decrease of the hydrochar surface polarity. However, even the lowest WHC and CEC of investigated hydrochars still exceeded those of pure quartz sand by factors of 5–10. An application of hydrochars produced at severe HTC conditions could improve WHC and CEC of sandy soils. This has to be investigated in further studies.

Influence of sugarcane dietary fiber on water states and microstructure of myofibrillar protein gels

The effects of different size particles and contents of sugarcane dietary fiber(SDF) on water state, water holding capacity(WHC), gel strength and microstructure of myofibrillar protein gels was studied. It was found that gel strengths were improved with the increase in SDF particle size and content, and the value of water holding capacity (WHC) reached a maximum with the addition of 80-mesh SDF at 2%. Discrete exponential fitting analysis and multi-exponential function analysis of the T2 relaxation time revealed that three categories of water, each having different mobility states in the gels, had different effects on the blended gel systems. Also, the intrinsic T21 relaxation time of immobile water in gels containing SDF was shorter than that in pure gels. Pronounced differences in myofibrillar gel network structures were observed during heating at 80 °C for 20 min. The fractal dimension which was determined by the box count method and the pore density (diameter < 0.1 μm or < 1 μm) further demonstrated that the homogeneity and compactness of gels increased with higher SDF content. However, the formation of numerous SDF cavities, whose particle size and number was enormously affected by the particle size and ratio of SDF added, is likely to have been responsible for the decrease in WHC and the extension of the intrinsic T21 relaxation times of immobilized water.

PHYSICOCHEMICAL CHARACTERIZATION OF FRUIT AND VEGETABLE FIBER SUSPENSIONS. II: EFFECT OF VARIATIONS IN HEAT TREATMENT

ABSTRACTThe pectin content in the soluble and insoluble fractions of fiber suspensions from carrot, potato pulp and apple heat treated in four different ways was determined together with the particle size distribution, water‐holding capacity (WHC), morphology and rheological properties of the fiber suspensions. In the carrot and apple suspensions, where β‐elimination was favored, the soluble pectin increased, whereas a significant but small decrease of the mean particle size of the insoluble material was obtained together with a significant decrease in WHC. For the potato pulp suspensions, however, only minor pectin solubilization was observed by heat treatment. Instead remaining starch in the cell matrix swelled on prolonged heating, leading to a different particle size distribution and a significant increase in WHC However, only minor effects on heating were seen on the elastic modulus for all fiber sources studied. But the source of fiber seems to be more important for the elastic modulus of the suspension, where the order of firmness in heated tissues (not the suspensions) seems to be the determining factor, being in the order of apple &gt; potato &gt; carrot.PRACTICAL APPLICATIONSHeat treatment of dietary fiber before use as an additive in food products, or during the production of innovative products, can change its physicochemical properties. These changes must be understood in order to predict the changes in the final product containing dietary fiber. The findings in the present study show that heat treatment that increased β‐elimination (high temperatures for a long time) caused reduced water‐holding capacity by decreasing the content of network‐forming insoluble material. It was also found that the physicochemical properties of the potato pulp fiber suspensions are mainly affected by the gelatinization of the starch remaining within the fiber structure.

Effects of oxidative modification on thermal aggregation and gel properties of soy protein by peroxyl radicals

SummaryEffects of protein oxidation on thermal aggregation and gel properties of soy protein by 2,2′‐azobis (2‐amidinopropane) dihydrochloride (AAPH)‐derived peroxyl radicals were investigated in this article. Incubation of soy protein to increase concentration of AAPH resulted in a decrease in particle size and content of thermal aggregates during thermal‐induced denaturation. Protein oxidation resulted in a decrease in water‐holding capacity (WHC), gel hardness and gel strength of soy protein gel. An increase in coarseness and interstice of the gel network was accompanied by uneven distribution of interstice as extent of oxidation of soy protein increased. A decrease in disulphide content and formation of oxidation aggregates in the process of oxidative modification were contributed to the decline of particle size and content of thermal aggregates during thermal‐induced denaturation, leading to a decrease in WHC, gel hardness and gel strength of soy protein gel.