Total Sulfhydryl Groups Research Articles

Endocan and advanced oxidation protein products in adult population with hypertension.

Hypertension is closely related to oxidative stress and inflammation. Endocan is a new inflammation marker whose role is not completely elucidated in hypertension. The aim of this study was to explore the association between endocan and several oxidative stress markers [i.e., advanced oxidation protein products (AOPP), total protein sulfhydryl (SH-) groups and prooxidant-antioxidant balance (PAB)] in adult population with hypertension. A total of 90 patients with hypertension were compared with 44 controls. Blood pressure, anthropometric and biochemical parameters were measured. Associations of clinical data with hypertension were tested with univariable and multivariable logistic ordinal regression analysis. Endocan and AOPP were significantly higher in hypertensive patients than in the controls (p=0.006 and p=0.046, respectively). In the multivariable logistic regression analysis, AOPP and endocan kept their independent positive associations with hypertension. As AOPP rose by 1 μmol/L and endocan rose by 1 pg/mL, the probability for hypertension presence rose by 4.2% and 32.2%, respectively and 39.9% of variation in hypertension could be explained with the Model. The area under the Receiver Operating Characteristic curve [(AUC) for AOPP=0.638 (0.550-0.719), p=0.01 and for endocan=0.679 (0.593-0.757), p<0.001] demonstrated sufficient clinical accuracy towards hypertension. On the contrary, the Model showed very good clinical accuracy [AUC= 0.825 (0.749-0.900), p<0.001]. Endocan and AOPP are independently correlated with hypertension in adult population and these tested markers together could be reliable parameters to discriminate patients with hypertension from normotensive ones.

Factors associated with oxidative stress status in pediatric patients with type 1 diabetes mellitus

Background Oxidative stress is implicated in both, the onset and the progression of type 1 diabetes mellitus (T1DM). There is accumulated evidence of increased biomarkers of oxidative stress in newly diagnosed, T1DM patients without complications, and in those with advanced disease. In this cross-sectional study, we investigated factors affecting oxidative stress status in pediatric patients with T1DM. Methods Advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), total sulfhydryl (SH) groups, and superoxide dismutase (SOD) activity were determined in 170 children and adolescents with T1DM. Principal component analysis was used to investigate clustering of clinical and laboratory variables associated with elevated oxidative stress and reduced antioxidative defense biomarkers. Results Factor analysis extracted five factors, interpreted as (1) "weight status factor" including age, BMI, waist and hip circumferences; (2) "proatherogenic factor" that included LDL-cholesterol, non-HDL-cholesterol, and triglycerides; (3) "metabolic control factor" including glucose and HbA1c; (4) "renal marker factor" with positive loading of urinary albumin excretion rate and negative loading of GFR; and (5) "antiatherogenic factor" that included HDL-cholesterol. High AOPP levels were independently predicted by "proatherogenic" (OR: 2.32; 95% CI: 1.44-3.71; p < 0.001), "metabolic control" (OR: 2.24; 95% CI: 1.35-3.73; p < 0.01), and "renal marker" (OR: 1.65; 95% CI: 1.03-2.65; p < 0.05) factors. "Renal marker factor" was a significant predictor of PAB (OR: 0.52; 95% CI: 0.34-0.81; p < 0.01). Regarding antioxidative defense markers, reduced SH groups were predicted by "proatherogenic factor" (OR: 0.56; 95% CI: 0.34-0.94; p < 0.05), while "weight status factor" predicted lower SOD activity (OR: 1.66; 95% CI: 1.03-2.67; p < 0.05). Conclusions Cardiometabolic risk factors and renal function are associated with oxidative stress in pediatric T1DM patients.

Açaí (Euterpe oleracea Martius) Promotes Jejunal Tissue Regeneration by Enhancing Antioxidant Response in 5-Fluorouracil-Induced Mucositis

Intestinal mucositis (IM) caused by antineoplastic chemotherapy is characterized by an important inflammatory process, which may compromise ongoing treatment. Our study aimed to investigate the effect of Açaí (Euterpe oleracea Martius) on the antioxidant response in BALB/c mice pretreated with Açaí pulp (200 g/kg) for 14 day. A group of animals receiving a single intraperitoneal injection of 5-FU (200 mg/kg) were euthanized on day three (D3) or seven (D7) after administration, the distal jejunum was isolated for the analyses of histology, superoxide dismutase (SOD) and catalase (CAT) enzyme activities, and concentration of total sulfhydryl groups (GSH). Seven days after induction, the intake of Açaí by the IM group almost completely regenerated tissue histology. Notably, SOD activity decreased in the MUC + Açaí group (D3). CAT activity reduced on D3 and D7 in the IM groups and Açaí treatment groups, respectively. No change was observed in the total GSH concentration at the tissue level. Our results demonstrated the protective effect of Açaí pulp components on intestinal damage induced by 5-FU, as well as the ability to control the response to oxidative stress, in order to mobilize defense pathways and promote tissue repair.

Effect of Atmospheric Pressure Cold Plasma on Biophysical Properties and Aggregation of Natural Actomyosin from Threadfin Bream (Nemipterus bleekeri)

Biophysical properties and aggregation of natural actomyosin (NAM) from threadfin bream (Nemipterus bleekeri) subjected to atmospheric pressure cold plasma (APCP) treatment with different contact times were determined. Protein solubility, turbidity, Ca2+-ATPase activity, total sulfhydryl (SH) group content, protein carbonyl content, and SDS-PAGE were monitored. With increasing APCP contact times (from 0 to 30 min), total SH group content (5.74–3.77 mol/105 g protein), Ca2+-ATPase activity (0.32–0.23 μmol Pi/mg protein/min), and solubility (100–92%) of NAM decreased, while protein carbonyl content (1.43–36.47 μmol/g protein) increased to a higher extent. During APCP treatment, cross-linking via disulfide bond as visualized by SDS-PAGE along with increased turbidity of NAM was observed. Therefore, APCP treatment markedly induced biophysical changes and aggregation of NAM which can be used as a possible approach to strengthen the gel formation of threadfin bream surimi.

Comparative analysis of quality uniformity of ohmic and water bath heating treated pork batter with different fat content

The effects associated with fat content (0% to 40%) of pork batter and the positions (center and surface) on both ohmic heating (OH) and water bath heating (WB) treated samples, were investigated. The OH achieved a more uniform temperature distribution in pork batter as compared to WB- and OH-treated samples showed lower cooking loss values for all samples tested. Besides, the thiobarbituric acid reactive substances values showed a tendency to increase as fat content increased for both treatments. The lipid oxidation showed a positive correlation with the carbonyl content and a negative correlation with the total sulfhydryl groups. The differences of lipids and protein oxidation between the center and surface of OH-treated samples were less than WB-treated ones. The higher fat content showed a favorable protective effect on Escherichia coli O157:H7 by both OH and WB treatments, however, the protective role of fat was more noticeable for OH treatment. Practical applications The ohmic heating (OH) principle is based on electric current passing through the food, the resistance of the food will generate heat in food. The efficiency of OH depends on the electrical conductivity of food. Fat, one of the primary constituents of meat, the presence of fat into the meat has a noticeable effect on the electrical conductivity, cooking loss, lipid and protein oxidation, and inactivation of microorganism. Therefore, the effects of fat content on the electrical, nutritional, and microbiological parameters of OH-treated pork batter at the central and surface position were investigated. The results of this study suggested that OH is suitable for meat processing.

Intervention on activity and structure of cathepsin L during surimi gel degradation under microwave irradiation

This study was aimed to investigate the effect of microwave heating (MWH) on the activity and conformation of cathepsin L (Cat L) compared to traditional conduction heating during surimi gel degradation stage. The gel properties and SDS-PAGE analysis showed that hydrolysis of myosin heavy chain was prevented by microwave. The activity of Cat L was affected by microwave power and heating time, which inhibited by MWH mainly due to the changes of conductivity caused by the vibration of polar groups under MWH. In addition, the reduction of total sulfhydryl group of Cat L during microwave irradiation led to conformation changes of Cat L. Significant decrease (P < 0.05) in α-helix of Cat L was found using circular dichroism, revealing that MWH altered the secondary structure of Cat L. The molecular chain configuration of Cat L under microwave irradiation was characterized by Laser light scattering. The Rg/Rh of Cat L molecule increased first and then decreased, illustrating that the molecular structure of Cat L was curled up and active center was buried, which lead to the inhibition of Cat L.

ОКИСНА МОДИФІКАЦІЯ БІЛКІВ У СИРОВАТЦІ КРОВІ ЩУРІВ ЗА УМОВ ЕКСПЕРИМЕНТАЛЬНОГО ОСТЕОАРТРИТУ ТА СУМІСНОГО ВВЕДЕННЯ ХОНДРОПРОТЕКТОРА ТА МУЛЬТИПРОБІОТИКА

One of the actual problems of modern medicine is joint disease. Among them, osteoarthritis occupies an important place. The formation of osteoarthritis is accompanied by the development of inflammation, which leads to damage to all structures of the joint. An important role in inflammatory processes is played by the intensification of free radical processes. As the disease develops, the joints lose their mobility, which leads to a decrease in the quality of life of patients and the development of disability. In this regard, it is important to search for drugs that have regenerative, anti-inflammatory and antiradical properties. The aim of our study was to investigate the combined effect of chondroitin sulfate and multiprobiotic on the content of oxidative protein modification products and the level of sulfhydryl groups in rat blood serum under conditions of monoiodoacetate-induced osteoarthritis. The study included participation of white male non-linear rats (weighing 180–240 g) adherence to the general ethical principles of animal experiments. An experimental osteoarthritis model was created by introducing 1 mg of sodium monoiodoacetate into the knee ligament. Chondroitin sulfate and multiprobiotic were used as therapeutic agents. The content of products of oxidative modification of proteins was determined by the level of carbonyl derivatives, which are manifested in the reaction with 2,4-dinitrophenylhydrazine. The level of total, protein-bound and non-protein sulfhydryl groups was measured by the Elman method. It was found that under conditions of monoiodoacetate-induced osteoarthritis in the blood serum of rats, the content of products of oxidative modification of proteins increases. The level of neutral aldehyde products (E max = 356 nm) is increased by 2.5 times and neutral ketone products (E max = 370 nm), respectively, by 2,1 times compared to the control. Under the same experimental conditions in the blood serum, the amount of basic aldehyde products (E max = 430 nm) increases by 1.9 times, while the content of the main ketone products (E max = 530 nm) increases by 1,7 times compared to the control groups. In experimental osteoarthritis in the blood serum, the content of sulfhydryl groups decreases: non-protein SH-groups – 1,5 times, protein and general SH-groups – 1,7 times relative to the control. This indicates disturbance of the oxidative-antioxidant balance and the development of oxidative stress in the organism during experimental osteoarthritis. It was shown that the combined administration of chondroitin sulfate and multiprobiotics in animals with experimental osteoarthritis partially restored the above parameters.

A first record of the antioxidant defense and selected trace elements in Salamandra salamandra larvae on Mt. Avala and Mt. Vrsacki Breg (Serbia)

We investigated the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the phase II biotransformation enzyme glutathione S-transferase (GST) in the whole body of fire salamander larvae (Salamandra salamandra) from two localities on Mt. Avala (AVS and ABP) and one locality on Mt. Vrsacki Breg (VSB), Serbia. We also determined the total glutathione (GSH) and sulfhydryl group (SH) contents, as well as the concentrations of manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), arsenic (As), cadmium (Cd), lead (Pb) and uranium (U). The obtained results show that animals from VSB had significantly lower weights and lengths than animals from AVS and ABP. The activities of all investigated enzymes were significantly higher, while the SH content was significantly lower in animals from VSB compared to those from AVS and ABP. No correlations between trace-element concentrations in water and animal tissue were observed. We concluded that the obtained results were more likely a consequence of the combination of developmental differences and the effects of different habitat conditions, environmental and anthropogenic influences than of concentrations of trace elements in the water alone.

Optimization of Enzymatic Hydrolysis Process of Antarctic Krill and Cryoprotective Effect of Enzymatic Hydrolysates on Oyster Meat

In order to develop a safe and efficient non-phosphorus antifreeze agent,enzymatic hydrolysates of Antarctic krill were prepared to evaluate their cryoprotective effects,providing basic data for the development of new antifreeze agents.The alkaline protease was screened from the four proteases as experimental enzymes,and the enzymatic hydrolysis process was optimized by single factor experiment and orthogonal experiment. The freezing protection of oyster meat by enzymatic hydrolysates of Antarctic krill was studied with the indexes of the water loss rate,salt-soluble protein content,total sulfhydryl group content and Ca2+-ATPase activity.The results showed that the optimum conditions for enzymatic hydrolysis of Antarctic krill by alkaline protease were as follows:Temperature 55℃,pH8.5,enzyme dosage 2.6%,enzymatic hydrolysis time 5 h. Under these conditions,the relative molecular weight of enzymatic hydrolysates of Antarctic krill mainly distributed in the range of 100~5500 Da,accounting for 79.69% of the total enzymatic hydrolysates. The enzymatic hydrolysate of Antarctic krill could inhibit the loss of water after freezing storage,retard the decrease of salt-soluble protein content,Ca2+-ATPase activity and total sulfhydryl content,and its effect was better than that of phosphorus-containing antifreeze agent.Therefore,the enzymatic hydrolysate of Antarctic krill had freezing protection activity,which could be further separated and identified.

In vitro ispitivanje antioksidativne aktivnosti preparata ruzmarinske kiseline i meda

Disrupted balance between free radicals and antioxidants leads to a pathophysiological state of oxidative stress, which is the underlying cause of many diseases. Since some synthetic antioxidants show some potentially adverse effects, many studies aim to find natural antioxidants. Secondary plant metabolites, such as polyphenols, phenolic acids, which include rosmarinic acid, terpenes and terpenoids have antioxidative properties and can be found in different hydrosols and honey. The aim of this study is to evaluate the in vitro antioxidative activity of the supplement based on hydrosol mixture, rosmarinic acid and honey. A series of diluted (100%, 50%, and 25%) supplements were added to the serum pool, collected from healthy donors. A second series of samples was prepared with the same amounts of supplement and addition of tert-Butyl hydroperoxide (TBH) as a prooxidant. Alongside these samples, sera samples with Trolox (hydrophilic vitamin E analog) and Trolox with TBH were prepared. All these samples were tested for the following oxidative stress parameters: total antioxidative status (TAS), paraoxonase-1 (PON-1), total sulfhydryl groups content (SHG), total oxidative status (TOS), prooxidative-antioxidative balance (PAB) and advanced oxidation protein products (AOPP). TAS/TOS ratio was calculated as a quantitative measurement of antioxidative and oxidative substances ratio in the serum. Antioxidative parameters TAS, SHG, TAS/TOS ratio and prooxidant/antioxidant balance parameter PAB, were not significantly different for the supplemened samples with and without the addition of TBH, which indicates that the supplement keeps its antioxidative properties, despite the addition of TBH. The supplement showed significant antioxidative properties as a result of the synergistic effect of rosmarinic acid, terpenes, and terpenoids from hydrosols and polyphenols and other antioxidant substances from honey.

Textural, rheological and chemical properties of surimi nutritionally-enhanced with lecithin

Surimi-based products enhanced with lipid nutrients have been getting more and more attention. To develop a lecithin-rich surimi product, the effects of lecithin addition at different levels (0–2.0 g/100 g) on chemical, rheological and quality properties of surimi were investigated. Although addition of lecithin decreased the breaking force and deformation of surimi, no significant effects were found for 0.4 g/100 g and 0.8 g/100 g groups (P > 0.05), and also, the water holding capacity (WHC) of surimi was the highest when 0.4 g/100 g lecithin was added. The addition of lecithin reduced heat-induced protein gelation to a certain degree as demonstrated by decreased storage modulus (G′) and loss modulus (G″) by dynamic rheology analysis. Lecithin resulted in increase of the surface hydrophobicity (S0) and decrease of hydrophobic interactions and disulfide bonds of the protein, while showed no significant effect on total sulfhydryl groups (P > 0.05). And no significant influence on the gel network structure of surimi was found when 0.4–1.2 g/100 g lecithin was incorporated. It can be demonstrated that a lecithin concentration of 0.4–0.8 g/100 g is recommended for lecithin-rich surimi product production.

Thiram-induced cytotoxicity and oxidative stress in human erythrocytes: an in vitro study

Tetramethylthiuram disulfide, commonly known as thiram, is an organosulfur compound which is used as a bactericide, fungicide and ectoparasiticide to prevent disease in seeds and crops. Being a fungicide there is a high probability of human occupational exposure to thiram and also via consumption of contaminated food. In this work, the cytotoxicity of thiram was studied under in vitro conditions using human erythrocytes as the cellular model. Erythrocytes were incubated with different concentrations of thiram (25–500 μM) for 4 h at 37 °C. Control cells (thiram untreated) were similarly incubated at 37 °C. Whole cells and hemolysates were analyzed for various biochemical parameters. Treatment of erythrocytes with thiram increased protein and lipid oxidation and hydrogen peroxide level in hemolysates but decreased glutathione and total sulfhydryl group content. This was accompanied by hemoglobin oxidation, heme degradation and release of free iron. Activities of all major antioxidant enzymes were inhibited. The antioxidant power of thiram treated erythrocytes was lowered resulting in decreased metal reducing and free radical quenching ability. These results suggest that thiram enhances the generation of reactive species that cause oxidative modification of cell components. This was confirmed by experiments that showed enhanced generation of reactive oxygen and nitrogen species in thiram treated erythrocytes. Activities of marker enzymes of glucose metabolism and erythrocyte membrane were also inhibited. All effects were seen in a thiram concentration-dependent manner. Electron microscopy further supported the damaging effect of thiram on erythrocytes. Thus thiram induces oxidative stress condition in human erythrocytes and causes oxidative modification of cell components.

Nigella sativa oil and thymoquinone reduce oxidative stress in the brain tissue of rats exposed to total head irradiation

Purpose: To evaluate the antioxidant and radio-protective effects of Nigella sativa oil (NSO) and thymoquinone (TQ) on radiation-induced oxidative stress in brain tissue.Materials and methods: Fifty-four Sprague-Dawley rats were divided into six groups to test the radio-protective effectiveness of Nigella sativa oil and thymoquine administered by either orogastric tube or intraperitoneal injection. Appropriate control groups were also studied.Results: Brain antioxidant capacity, as measured by the levels of total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), superoxide dismutase, paraoxonase (PON) activities, total antioxidant status and total sulfhydryl (-SH) group, were lower in the irradiation (IR) only group while xanthine oxidase (XO) activity, total oxidant status (TOS), oxidative stress index (OSI) and lipid hydroperoxide (LOOH) levels were higher in the group compared with all other groups. Brain glutathione-S-transferase (GST) activity significantly decreased in the IR only group when compared with the control groups. Glutathione peroxidase (GSH-Px) activity was lower in the IR only, NSO plus IR, TQ plus IR groups when compared with the control group of TQ. Arylesterase (ARYL) activity was not statistically significant in the IR only group compared with all other groups.Conclusions: The results suggest that Nigella sativa oil (NSO) and its active component, TQ, clearly protect brain tissue from radiation-induced oxidative stress.

Some indices of the cats’ protein metabolism under the obesity

Obesity is one of the most widely-distributed metabolic disturbances in cats, herewith the animals’ number with a given pathology is constantly increasing. The excess mass and obesity lead to the extreme metabolic disturbances including all the chains of metabolism. The cats belong to wild animals and are characterized by a high level of protein metabolism, herewith they are incapable to keep up with the level of the particular amino acids under their constant introduction into the feeds. The intensity of glucogenesis for which the amino acids are viscous material and are involved into the process of dissemination under the obesity is constantly increasing. It results in increasing the amount of final product of nitrogen metabolism. The paper researches the total protein content as well as that of albumin, ammonia, urine, creatinine and creatine kinase activity of the cats’ blood which had the excess mass or obesity. In addition, it has become necessary to determine the content of amino acids cysteine sulfhydryl groups, which essentially contributes to the process of cats’ metabolism. To perform the research two groups of cats (female and male) aged 3–7 were formed, the control group consists of 7 clinically healthy animals that corresponds to the BCS 4–5 index according to the nine grading scale, the experimental group consists of 5 animals of the same age and they have BCS – 7–9 index, that testifies to the excess mass and obesity processes. The concentration of the total protein, albumin, ammonia, urine, creatinine as well as of creatine kinase activity of the total and free(nonprotein) sulfhydryl groups was found in the cats’ blood. The significant decreasing of the albumin part has been revealed in cats with the excess mass and obesity that causes the liver function disturbances and results in increasing of its protein decomposition. The increasing quality of the ammonia content by 31% and urine by 21% has been revealed in cats of the experimental group, however the individual ranges of given indexes within both control and experimental groups were considerable ones. The creatinine concentration and creatine kinase activity in cats with the obesity increases, that testifies to the destructive processes intensification in the muscular tissues. Sulfhydryl groups of the cysteine are of great importance for the metabolic processes in particular in the processes of detoxication, disease-resistance as well as of antioxidant processes. The total concentration of SH-blood groups made no essential difference in cats of the control and experimental groups, while the concentration of free SH-blood groups of experimental animals was by 31% less than in its control analogues. Thus, the obesity has an essential effects on the protein metabolism that causes the amino acids decomposition processes as well as the accumulation of the metabolic final products and free sulfhydryl groups reducing.

Effects of low frequency magnetic field on myoglobin oxidation stability

The effects of low frequency magnetic field on myoglobin (Mb) oxidation stability were evaluated by treatments at 0, 3, 6, 9, 12 mT and storage for 10 h. The results showed that Mb oxidation was inhibited under all magnetic field treatments, due to the increase of total sulfhydryl and free amino groups (9 or 12 mT) from unfolding of Mb clusters (3, 9, 12 mT) as well as β-turn and β-sheet structures (9 or 12 mT). The unfolding also induced (i) the destruction or burial of iron porphyrin and tyrosine residues; (ii) the exposure of tryptophan; (iii) more uniform Mb particle size distribution (3, 9, 12 mT) and increased zeta potential (3, 6, 12 mT). Overall, magnetic field promoted exposed active groups as the preferred oxidation target, thus decreasing the oxidation rate of central iron atoms. It also promoted Mb stability by redistributing particle size and increasing zeta potential.

Duck egg albumen hydrolysate-epigallocatechin gallate conjugates: Antioxidant, emulsifying properties and their use in fish oil emulsion

Duck albumen hydrolysates (DAH) conjugated with epigallocatechin gallate (EGCG) at various levels (2–5%, w/w) were prepared and characterized. FTIR analysis showed that the conjugation between DAH and EGCG induced the change of secondary structure and modified functional groups of DAH. Furthermore, surface hydrophobicity of DAH was increased, while total sulfhydryl group and total carbonyl contents were decreased when EGCG was conjugated, especially when EGCG at higher levels was used (P < 0.05). Antioxidant activities and emulsifying properties of DAH-EGCG conjugates were enhanced, particularly when DAH conjugated with 4% EGCG (P < 0.05). Storage stability of fish oil emulsion (FOE) stabilized by DAH or DAH-EGCG conjugate was also investigated up to 15 days at 26–28 °C. Emulsion stabilized by DAH-EGCG conjugate had higher magnitude of ζ-potential (negative charge), smaller oil droplets size (d43), as well as lower flocculation and coalescence of oil droplets as compared to those of emulsion prepared using DAH throughout the storage. Moreover, oxidative stability of FOE was improved when DAH-EGCG conjugate was incorporated as evidenced by lowered thiobarbituric acid-reactive substances and peroxide value. Thus, the conjugate between DAH and 4% EGCG could serve as an antioxidant emulsifier for enhancement of physical and oxidative stability of FOE.

Effect of Topical Prostaglandin F2α Analogs on Selected Oxidative Stress Parameters in the Tear Film.

Background and Objectives: Topically administered antiglaucoma medications, especially those containing benzalkonium chloride (BAC), may cause local adverse effects and compromise ocular surface. The aim of the study was to assess the effect of topical prostaglandin F2α analogs (PGAs): preservative-free latanoprost, BAC-preserved latanoprost, preservative-free tafluprost, and BAC-preserved bimatoprost, on selected oxidative stress parameters in the tear film. Materials and Methods: The patients were divided into five groups: group C (n = 25) control group—subjects who did not use topical antiglaucoma medications, group L (n = 22)—patients using topical preservative-free latanoprost, group L+BAC (n = 25)—patients using topical BAC-preserved latanoprost, group T (n = 19)—patients using topical preservative-free tafluprost, and group B+BAC (n = 17)—patients using topical BAC-preserved bimatoprost. The oxidative stress markers in the tear film samples were evaluated: total protein (TP) concentration, advanced oxidation protein products (AOPP) content, total sulfhydryl (-SH) groups content, the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as Total Oxidant Status (TOS), Total Antioxidant Response (TAR), and Oxidative Stress Index (OSI). Results: The TP concentrations in the groups L, L+BAC, and B+BAC were statistically significantly higher in comparison with group C. The SOD and CAT activities in the groups L+BAC and B+BAC were statistically significantly higher when compared to group C. As compared to group C, AOPP and TOS were statistically significantly higher in all the study groups. OSI was found to be statistically significantly higher in the groups L+BAC, T, and B+BAC in comparison with group C. Conclusion: Use of topical PGAs by the patients with ocular hypertension or primary open-angle glaucoma is associated with increased oxidative stress in the tear film which is additionally exacerbated by the presence of BAC in the formulation.

Preparation and characterization of hen egg proteins-soybean protein isolate composite gels

The physicochemical properties, rheology, texture, water state and microstructure of gels formed from different ratio of egg proteins and soybean protein isolate were investigated. Results showed that composite solution that contained 75% egg proteins had the highest protein surface hydrophobicity while the biggest solubility was found when the proportion of egg proteins was 25%. Solid content and total sulfhydryl groups content before centrifugation increased as the proportion of egg proteins raised while total sulfhydryl groups content after centrifugation had less fluctuations because of the changes of protein solubility. Egg proteins-soybean protein isolate composite solutions had various growth ratio of G’ during different stages of solution-gel transition process, suggesting the composition of the solutions affected the molecular interactions and then changed the gelling properties. Besides, composite gels that contained the whole egg had higher hardness and lower springiness than those gels that contained egg yolk. The gel hardness after 50% addition of the whole egg and egg yolk was about 561% and 329% of the original gel strength while the gel springiness was 0.91 and 0.94, respectively. From results of microstructure, egg yolk-soybean protein isolate composite gels possessed denser gel network, which may be related with higher solid content of egg yolk. Conversely, the whole egg-soybean protein isolate composite gels showed rigid fiber network with holes, leading to better water mobility, higher hardness and lower springiness.

Membrane filtration and isoelectric precipitation technological approaches for the preparation of novel, functional and sustainable protein isolate from lentils

Isoelectric precipitation and ultrafiltration were investigated for their potential to produce protein products from lentils. Higher protein concentrations were obtained when ultrafiltration was used (> 90%), whereas isoelectric precipitation resulted in higher contents of dietary fibre and some minerals (i.e., sodium and phosphorus). Differences in the functional properties between the two ingredients were found as the isoelectric precipitated ingredient showed lower protein solubilities over the investigated pH range (from 3 to 9) which can be linked to the slightly higher hydrophobicity values (2688.7) and total sulfhydryl groups (23.9 µM/g) found in this sample. In contrast, the protein ingredient obtained by ultrafiltration was superior with regard to its solubility (48.3%; pH 7), fat-binding capacity (2.24 g/g), water holding capacity (3.96 g/g), gelling properties (11%; w/w), and foam-forming capacity (69.6%). The assessment of the environmental performance showed that both LPIs exhibited promising properties and low carbon footprints in comparison to traditional dairy proteins.

Hydrolysates from rainbow trout (Oncorhynchus mykiss) processing by-products: Properties when added to fish mince with different freeze-thaw cycles

Rainbow trout (Oncorhynchus mykiss) mixed processing by-product homogenates were subjected to 8 mM CaCl2-5 mM citric acid (1:5 w/v) pretreatments followed by hydrolysis with Alcalase (W-CaCi-RTBH). These hydrolysates decreased the loss of total sulfhydryl groups, protein solubility and protein carbonyl formation in a fish mince after 6 freeze-thaw cycles (P ≤ 0.05). The thermal properties of myosin heavy chains and actin were maintained as shown using differential scanning calorimetry (DSC) (P ≤ 0.05). Based on low field NMR T2 relaxation, the fastest relaxation component (T21) showed no changes with addition of W-CaCi-RTBH into a fish mince after 6 freeze-thaw cycles, indicating no changes for the major pool of water molecules within the myofibrillar protein structure (P ≥ 0.05). After 6 freeze-thaw cycles, W-CaCi-RTBH had better antifreeze activity when combined with sucrose – sorbitol (4%) (P ≤ 0.05). Therefore, W-CaCi-RTBH could potentially be an additive in frozen fish mince.