Assessment of TNF-α (-857 C/T) gene polymorphism in oral lichen planus disease: A case-control study.

Background and aims: Oral lichen planus (OLP) is an inflammatory mucocutaneous disorder with an immune-mediated pathogenesis. The tumor necrosis factor-α (TNF-α) level in the serum of OLP patients is significantly higher than in the control group. TNF-α-857 C/T polymorphism can be related to the increased TNF-α level in blood circulation. This study investigated the relationship between TNF-α (-857 C/T) polymorphism and OLP patients in an Iranian population. Methods: Saliva samples were taken from 200 people, including 100 patients with OLP and 100 healthy people who did not have significant differences in age and sex. Then, DNA was extracted from them and the TNF-α (-857 C/T) genotype was identified using the polymerase chain reaction with confronting two-pair primers method. Statistical Package for the Social Sciences version 16 software analyzed the results. Results: The frequency of C/C, C/T, and T/T genotypes of the TNF-α-857 C/T polymorphism in the patient group were 78%, 18%, and 4%, respectively, and in the control group were 72%, 23%, and 5%, respectively. The differences between the two groups regarding allele (χ 2 = 0.97, p = 0.32) and genotype (χ 2 = 0.96, p = 0.62) frequency among the studied population were insignificant. Conclusion: This study showed that the difference in the frequency of single nucleotide polymorphism TNF-α-857 C/T polymorphism in the patient and control group had no significant relationship with the increased OLP incidence. Also, no significant association was observed between allele and genotype frequency of TNF-α (-857 C/T) with OLP subtypes.

Effect of Combined Application of Hydrofluoric and Phosphoric Acids and Active Irrigation with a Microbrush on Shear Bond Strength of Lithium Disilicate Ceramics to Enamel.

Background: This study assessed the effect of combined application of hydrofluoric (HF) acid and phosphoric acid (PA) and active irrigation (AI) with a microbrush on shear bond strength (SBS) of lithium disilicate (LDS) ceramics to enamel. Materials and Methods: This in vitro study was conducted on 40 extracted teeth that received enamel preparation with a #12 cylindrical bur. Forty IPS e.max LT rods (3mm diameter, 6mm height) were fabricated and randomly assigned to four groups (n = 10) for surface treatment with 5% HF (group 1), 5% HF and AI with a microbrush for 20 seconds (group 2), 5% HF and 32% PA (group 3), and 5% HF and 32% PA plus AI with a microbrush for 20 seconds (group 4). Silane and Choice 2 cement were used for bonding rods to enamel. The SBS was measured by a universal testing machine. Data were analyzed by two-way analysis of variance (ANOVA), Bonferroni, and Chi-square tests (alpha = 0.05). Results: Group 4 had the highest SBS, and group 1 had the lowest SBS (P < 0.05). Group 2 had a significantly higher SBS than group 1, and group 4 had a significantly higher SBS than group 3. AI with a microbrush significantly increased the SBS (P < 0.05), but the application of PA caused no significant change in SBS (P > 0.05). The interaction effect of PA and AI on SBS was not significant (P > 0.05). Conclusion: The application of PA in addition to 5% HF acid caused no significant change in the SBS of LDS ceramic to enamel. However, AI with a microbrush significantly increased the SBS.

Evaluation of the association between TNF-α-1031 T/C polymorphism with oral lichen planus disease.

BACKGROUND: Oral lichen planus (OLP) is a T-cell-mediated autoimmune disease that affects the epithelial cells of the oral cavity. This study was performed to investigate any possible relationship between - 1031(T/C) polymorphism (rs1799964) of the tumor necrosis factor α (TNF-α) gene with the risk and severity of oral lichen planus (OLP) disease among an Iranian population. METHOD: Saliva samples were collected from 100 patients with OLP and a similar number of healthy controls (age and sex-matched). Then, DNA was extracted from the collected samples for genotyping TNF-α-1031 T/C polymorphism using the PCR-CTPP method. The results were assessed using SPSS software. RESULTS: The findings revealed a significantly higher prevalence of the C allele in OLP patients (53%) compared to healthy controls (36%), suggesting an association between TNF-alpha gene polymorphism and OLP. A multivariate logistic regression analysis supported this finding, as the presence of the C allele was significantly associated with an increased risk of OLP [χ2 = 4.17, p = 0.04, 95% CI = 1.01-2.65, OR = 1.64]. However, our data indicated no significant association between TNF-alpha-1031 T/C gene polymorphism and OLP severity. CONCLUSIONS: These findings provide the first evidence supporting a possible role of TNF-α-1031 T/C gene polymorphism in OLP susceptibility in the Iranian population. The findings of this study demonstrate a positive association between TNF-α-1031 C/T allele distribution and the risk of OLP disease in the Iranian population. Therefore, carrying the C allele may increase the susceptibility to OLP disease.

Applying artificial intelligence to detect and analyse oral and maxillofacial bone loss-A scoping review.

Radiographic evaluation of bone changes is one of the main tools in the diagnosis of many oral and maxillofacial diseases. However, this approach to assessment has limitations in accuracy, inconsistency and comparatively low diagnostic efficiency. Recently, artificial intelligence (AI)-based algorithms like deep learning networks have been introduced as a solution to overcome these challenges. Based on recent studies, AI can improve the detection accuracy of an expert clinician for periapical pathology, periodontal diseases and their prognostication, as well as peri-implant bone loss. Also, AI has been successfully used to detect and diagnose oral and maxillofacial lesions with a high predictive value. This study aims to review the current evidence on artificial intelligence applications in the detection and analysis of bone loss in the oral and maxillofacial regions.

The Role of Psychological Distress in the Relationship between Personality Dimensions and Pregnancy Outcome of Women Undergoing Assisted Reproductive Treatment (IVF/ICSI).

Objective: The aim of this study was to determine the role played by psychological distress in the relation between personality dimensions and pregnancy outcome of women undergoing in vitro fertilization/Intra-Cytoplasmic Injections (IVF/ICSI) treatment. Method : This prospective cohort study was conducted for 12 months on 154 infertile women who were receiving IVF/ICSI assisted reproductive treatment for the first time. Research instruments for measuring psychological distress included the Fertility Problem Inventory (FPI) and the Depression, Anxiety, and Stress Scale (DASS-21). One of these was completed prior to ovarian stimulation and the other during the embryo transfer stage. The temperament and Character Inventory-Revised (TCI-R 125) was employed once to assess personality dimensions prior to the ovarian stimulation stage. Independent t-test, Mann Whitney test, Repeated Measures and path analysis were performed for statistical analysis of data. Results: The results of this study showed no significant difference between the pregnant and non-pregnant groups in personality traits (Harm avoidance and self-directness) and psychological distress (FPI and DASS scores). Repeated measures showed a significant difference in stress, anxiety, and depression levels between the two stages of ovarian stimulation and embryo transfer (P < 0.01). Path analysis showed no significant direct and indirect effect for harm avoidance on the pregnancy outcome when psychological distress was mediated. Conclusion: The effect of psychological factors on IVF outcomes is more complicated than is generally assumed and more studies are mandatory to clarify the relationship between personality traits and infertility treatments.

Association of interleukin-8 polymorphism (+ 781 C/T) with the risk of oral Lichen Planus disease.

BACKGROUND: Oral Lichen Planus (OLP) is a chronic inflammatory mucosal disease. The pathogenesis of OLP is unknown. The Single Nucleotide Polymorphism (SNP) that occurs in the regulatory position + 781 could affect the expression of interleukin-8. This polymorphism is probably associated with increased serum levels of IL-8. The current study aimed to investigate the genotype and allele frequencies of IL-8( + 781 C/T) in OLP patients and whether it is associated with the severity of OLP disease in an Iranian population. METHODS: Three milliliters of saliva were taken from 100 patients with OLP and 100 healthy individuals who were matched in age and gender. After DNA extraction from saliva samples of patients and healthy individuals, the genotype of IL-8 at position + 781 is detected using the PCR-RFLP method. The results were analyzed using SPSS software. RESULTS: Frequency of C/C, T/C, and T/T genotypes at position IL-8 + 781 gene in the patient group were 47%, 41%, and 12%, respectively, and in the control group, were 37%, 42%, and 21%. The difference between the two groups regarding allele frequency distribution was statistically significant (χ2 = 3.86, p = 0.049, 95% CI = 0.44-1, OR = 0.66). Our results indicated the significantly higher frequency of the TT genotype in the erosive OLP compared to the nonerosive group (p = 0.03, OR = 0.89, 95% CI = 0.49-1.6). CONCLUSION: This study depicted the difference in the frequency of SNP IL-8 + 781 C/T allele in the patient and control groups had a significant association with the risk of OLP. In addition, our data revealed that IL-8 + 781 C/T polymorphisms might be associated with the severity of OLP in the Iranian population.

Analyzing the relationship between tissue color observed in VELscope examination and histopathological factors in OSCC patients.

OBJECTIVE: Early detection of OSCC is a crucial step towards improving OSCC prognosis. In recent years, novel diagnostic aids such as light-based detection systems have been introduced for early diagnosis. VELscope is one such light-based device which is used to examine tissue fluorescence. Based on different studies, VELscope has a sensitivity of 90% in the diagnosis of oral premalignant and malignant lesions. Tumor depth of invasion and invasive front have recently been proposed as influential factors in OSCC prognosis. Therefore, the aim of this study was to assess the relationship between tissue color seen through this device and tumor depth of invasion. METHODS & MATERIALS: 20 histopathologically approved OSCCs were included in this study. Conventional oral examination was carried out followed by an assessment of the lesion using VELscope. The H&E slides prepared following the final OSCC surgeries were then examined by an oral pathologist to assess tumor depth of invasion (interpreted as low-risk/high-risk), invasivefront (low-risk/high-risk) and perivascular and perineural invasions. Data was transferred to SPSS 16 software. The association between color changes and histopathological factors was analyzed using the fisher's exact and chi-square tests. RESULTS: The mean age of the patients was 51/5+/-16/74, 60% of which were men. Most lesions were exophytic and the most common color seen during VELscope examination was red. 55% and 50% of the OSCCs showed high-risk tumor depths and high-risk invasive fronts respectively. Perivascular and perineural invasion was seen in 55% and 35% of the samples respectively. Statistical analysis showed that 72/2% of the lesions with high tumor depths and 70% with high-risk invasive fronts were seen as red, although these associations were not significant (P>0/05). Tumor depth was significantly correlated with invasive front (P<0/05). CONCLUSION: There was no significant relationship between the type of color seen through VELscope and tumor depth of invasion, however most cases with high-risk depth of invasions were red.

The relationship between coping strategies and infertility self-efficacy with pregnancy outcomes of women undergoing in vitro fertilization: A prospective cohort study.

Background: Assisted reproductive technology treatments are stressful procedures, but there are individual differences in the emotional response to them. Differences in response to this stress may be related to the outcome of infertility treatment. Objective: This study aimed to investigate the relationship between coping strategies and infertility self-efficacy with pregnancy outcomes of women undergoing in vitro fertilization/intracytoplasmic sperm injection treatment. Materials and Methods: This was a prospective cohort study and the 154 infertile women were psychologically evaluated in 2 stages: once before ovarian stimulation and again during embryo transfer. The research measurements used were the Revised COPE, the Depression Anxiety Stress Scale (DASS-21) and the Infertility Self-Efficacy Scale. Results: There was no significant difference between the group of non-pregnant women and the positive pregnancy group in terms of coping strategies (mental rumination, self-blame, active confronting, goal replacement, avoidance) or self-efficacy in either of the 2 stages of ovarian stimulation and embryo transfer. The Mann-Whitney test did not show any statistical difference between the clinically pregnant women and the only laboratory positive pregnant group. Moreover, the self-blame and mental rumination strategies were positively related with anxiety and depression. Conversely, active confronting, goal replacement, avoidance and self-efficacy were associated with decreased depression, anxiety and stress levels. Conclusion: It can be concluded that there is no relationship between coping strategies and infertility self-efficacy with in vitro fertilization/intracytoplasmic sperm injection outcomes. Further research is needed to clarify the effects of other psychological factors on the pregnancy outcomes of assisted reproductive treatment.

A systematic review and meta-analysis on serum and salivary levels of total antioxidant capacity and C-reactive protein in oral lichen planus patients.

OBJECTIVE: Oral lichen planus (OLP) is an inflammatory disease that total antioxidant capacity (TAC) and C-reactive protein (CRP) play an important role in its pathogenesis. In this meta-analysis, we compared the salivary and serum levels of TAC and CRP between OLP patients and controls. DESIGN: A comprehensive search was performed in four databases (PubMed, Scopus, Web of Science, and Cochrane Library). Standardized mean difference (SMD) and 95% confidence intervals (CI) were computed by the RevMan 5.3. Sensitivity analysis, subgroup analysis, meta-regression, and publication bias were analyzed by the CMA 2.0. RESULTS: Nineteen articles were included in the meta-analysis. The pooled SMDs were -1.80 µmol/L (95%CI: -2.75, -0.85; p = 0.0002) and -2.56 µmol/L (95%CI: -4.40, -0.72; p = 0.006) for the salivary and serum levels of TAC, respectively. The SMDs for salivary and serum levels of CRP were 0.64 µg/L (95%CI: 0.35, 0.94; p < 0.0001) and 0.97 mg/L (95%CI: 0.56, 1.338; p < 0.00001), respectively. Geographical area based on the country was a significant factor in the subgroup analysis for salivary TAC level. There was adequate evidence supporting the occurrence of less salivary and serum TAC levels in OLP patients than controls, but the amount of information was inadequate to make valid conclusions for salivary CRP level. CONCLUSIONS: In OLP patients, salivary and serum levels of TAC is significantly lower while the salivary and serum levels of CRP is significantly higher than controls.

A Randomized Triple-Blind Clinical Trial of the Effect of Low-Level Laser Therapy on Infiltration Injection Pain in the Anterior Maxilla

Abstract Objective: To evaluate the level of pain experienced during infiltration anesthesia of the anterior maxilla following low-level laser therapy (LLLT) with 810-980 nm wavelengths. Material and Methods: In the current triple-blind clinical trial, 84 patients received a total of 168 infiltration anesthesia injections (1.8 mL of 2% lidocaine plus 1:100,000 epinephrine) in the anterior maxilla. Each patient received two injections into the buccal mucosa of the right and left central incisors with a two-week interval. One injection was performed after LLLT, while the other injection was administered conventionally without laser. The pain level was measured immediately after injection using a visual analog scale (VAS). Results: There was a significant difference in the pain level experienced with and without LLLT, such that the mean pain score following LLLT was significantly lower than that without LLLT (p<0.05). No significant difference was found in the pain level between laser and no laser groups in males, but the difference in this regard was significant in females (p<0.05) and female patients experienced a significantly lower level of pain following LLLT. Conclusion: The low-level laser therapy can be successfully used to decrease the level of pain experienced during infiltration anesthesia of the anterior maxilla (AU).

A PRISMA-compliant meta-analysis on association between X-ray repair cross complementing (XRCC1, XRCC2, and XRCC3) polymorphisms and oral cancer susceptibility.

BACKGROUND: Oral Cancer (OC) is one of the leading causes of death and the disease mainly occurs over 50 years of age. Herein, a meta-analysis aimed to assess the association between X-ray repair cross complementing (XRCC) polymorphisms and OC risk. METHODS: Four databases were searched extensively until June 5, 2020. Subgroup analysis, meta-regression, and funnel plots, as well as the quality assessment were estimated. RESULTS: Fifteen studies were entered to the analysis. With regards to allele, homozygote, heterozygote, recessive, and dominant models, the pooled ORs for XRCC1 rs1799782 polymorphism were 1.51 (P = 0.01), 1.45 (P = 0.11), 1.45 (P = 0.0003), 1.44 (P = 0.0002), and 1.29 (P = 0.26); for XRCC1 rs1799782 polymorphism were 1.65 (P = 0.11), 1.50 (P = 0.33), 1.06 (P = 0.83), 1.57 (P = 0.12), and 1.32 (P = 0.45); for XRCC1 rs25489 polymorphism were 0.01 (P = 0.19), 1.44 (P = 0.48), 1.21 (P = 0.72), 1.17 (P = 0.19), and 1.38 (P = 0.54); for XRCC2 rs2040639 polymorphism were 0.68 (P = 0.0002), 0.63 (P = 0.02), 0.95 (P = 0.92), 0.79 (P = 0.49), and 0.61 (P = 0.005); and for XRCC3 rs861539 polymorphism were 1.24 (P = 0.20), 1.28 (P = 0.48), 0.99 (P = 0.95), 1.15 (P = 0.46), and 1.52 (P = 0.15), respectively. CONCLUSIONS: The T allele and CT genotype of XRCC1 rs1799782 polymorphism had an elevated risk, whereas the G allele and GG genotype of XRCC2 rs2040639 polymorphism had a protective role in OC.

The Use of Antimicrobial Photodynamic Therapy to Maintain a Hopeless Tooth With a PeriodonticEndodontic Lesion: A Case Report.

Background: In spite of some advances in periodontal generative methods, it is impossible to stop progressive Loss of supporting alveolar bone in some end-stage periodontitis. The aim of this study is to report a kind of treatment modality which was seemed to be successes full in maintaining teeth. In this case-report, a hopeless tooth was saved by combined non-surgical periodontalendodontal treatment and antimicrobial photodynamic therapy (aPDT). Case Report: A 58-year-old male presented with a chief complaint of pain and mobility of tooth number 38. Clinical examinations revealed a periodontic-endodontic lesion with clinical attachment loss exceeding 10 mm and grade III mobility. To preserve the tooth, we operated nonsurgical periodontal treatment including scaling and root planning (SRP) plus root canal therapy (RCT) combined with intra-root canal non-aPDT laser decontamination. Then we applied laser pocket therapy with and without aPDT. Following 6 months of the aPDT treatment, the mobility and pocket depth of the tooth improved from grade III to I and from 10 to 3 millimeters respectively. Conclusion: aPDT is a novel adjunctive therapy that can be used for various conditions with microbial etiology. This case report demonstrated that aPDT might be effective in the treatment of periodontic-endodontic lesions in a hopeless tooth.

Recent innovations in functionalized layered double hydroxides: Fabrication, characterization, and industrial applications.

Layered Double Hydroxides (LDHs) are a group of hydrotalcite-like nano-sized materials with cationic layers and exchangeable interlayer anions. The wide range of divalent and trivalent cationic metals and anionic compounds are employed in the synthesis of LDH materials, which have improved their importance among the researchers. Because of their high anion exchange property, memory effect, tunable behavior, bio-friendly, simple preparation, and their affordability, these nano-materials are essentially interested today. Modification of LDHs improves their behaviours to make them appropriate in industrial fields, including biological, adsorbent, mechanical, optical, thermal, electrical fields, etc. This review has critically discussed the structural features, main properties, and also clarified the most important methods of modification and intercalation of LDH nano-materials. Moreover, some novel reported researches related to the successful modification of LDH materials have been characterized and briefly the advantages, disadvantages, and applications are presented in the industrial fields.

Fabrication and characterization of pH-sensitive bio-nanocomposite beads havening folic acid intercalated LDH and chitosan: Drug release and mechanism evaluation.

In this paper, folic acid (FA) as drug model was intercalated in the structure of layered double hydroxide (LDH) as drug carrier with two coprecipitation and anion exchange methods. The existence of FA drug between the LDH layers was confirmed with FT-IR and XRD analyses. Also, the results of UV-Vis confirmed that the FA loading in the structure of LDH was about 33.35% and 15.57% for coprecipitation and anion exchange methods, respectively. Then, FA intercalated LDH (LDH-FA) was composited with different weights of chitosan (Cs) as bio-polymer and the obtained nanocomposite beads was characterized. Subsequence, the release of FA drug from obtained hybrids was examined at simulated condition similar to the gastrointestinal tract with different pHs. The achieved bio-composite beads showed the pH-sensitive swelling property and also the release test showed the higher shield of acidic pH and the release rate of FA drug was decreased with addition of Cs concentration. Also, several well-known kinetic models were examined in order to study the FA release mechanism which suggested some release processes such as diffusion controlled of flat surface by heterogeneous sites, ion exchange process, LDH intra-particle diffusion and also concurrent leaching of the FA anions from LDH structure.

The diagnostic value of the native fluorescence visualization device for early detection of premalignant/malignant lesions of the oral cavity.

PURPOSE: The present study aimed to determine the diagnostic value of a native fluorescence visualization device in the identification of oral malignant/dysplastic lesions. METHODS: This study involved 45 patients who had oral lesions that were suspected to be malignant, potentially malignant, or benign. The patients visited the Oral Medicine Department of the Mashhad Dental School. The sensitivity, specificity, positive and negative predictive values, and likelihood ratio of this device were determined. RESULTS: The histopathological assessment of samples showed 9 cases of oral squamous cell carcinoma and 12 lesions with dysplasia. Ten samples of dysplastic lesions and all malignant lesions appeared dark or red/orange when examined with the native fluorescence visualization device. In 90% of the dysplastic/malignant lesions, the label-free fluorescence results were positive. The sensitivity, specificity, and positive and negative predictive values of this device were 90%, 15%, 40%, and 71%, respectively. CONCLUSIONS: The native fluorescence visualization device can be used in specialized centers as an adjunctive device to increase the sensitivity of a clinical examination, but is not capable of distinguishing benign lesions from malignant and dysplastic ones due to its low specificity.

Extranodal NK/T Cell Lymphoma with Destruction of the Uvulae: A Case Report.

INTRODUCTION: Extranodal Natural Killer (NK)/T-cell lymphoma (NKTCL) nasal type is a rare but well-known disease with poor prognosis. NKTCL is more prevalent in Asia and comprises about 7-10% of all non-Hodgkin lymphoma cases in this region. The characteristic clinical pattern of NKTCL is the destruction of the midline structures of the mid-face. CASE REPORT: The present study examines a case of NKTCL in a 23-year-old man with a destructive ulcer of the palate and uvulae. Based on immunohistochemical results, after three months of delay, the definitive diagnosis was revealed to be Extranodal NK/T cell lymphoma. Following the third cycle of chemotherapy, the patient died due to sepsis and infection. CONCLUSION: It is very common to misdiagnose NKTCL with other clinical conditions such as necrotizing stomatitis, deep fungal ulcers, Wegener's Granulomatosis disease, etc. Delay in diagnosis can worsen the course of the disease and its prognosis.

Herpes Zoster Induced Alveolar Bone Necrosis in Immunocompromised Patients; Two Case Reports.

INTRODUCTION: Herpes zoster Infection (HZI) is a viral disease with painful skin rashes and blisters in a limited area on one side of the body, often in a strip. Osteonecrosis with spontaneous exfoliation of teeth in association with HZI of the mandibular nerve is a rare phenomenon. In this report, such an unusual complication of HZI is presented. CASE REPORT: The clinical course of a 53-year-old woman and a 54-year-old man with HZI associated with alveolar bone necrosis and tooth exfoliation were reviewed in order to develop a patient profile for this rare combination of physical findings. CONCLUSION: In immunocompromised patients, the clinicians should consider HZI as a possible cause of tooth mobility, exfoliation, and alveolar osteonecrosis, which needs early intervention to prevent secondary complications.

Milk protein-gum tragacanth mixed gels: effect of heat-treatment sequence.

The aim of this study was to investigate the role of the heat-treatment sequence of biopolymer mixtures as a formulation parameter on the acid-induced gelation of tri-polymeric systems composed of sodium caseinate (Na-caseinate), whey protein concentrate (WPC), and gum tragacanth (GT). This was studied by applying four sequences of heat treatment: (A) co-heating all three biopolymers; (B) heating the milk-protein dispersion and the GT dispersion separately; (C) heating the dispersion containing Na-caseinate and GT together and heating whey protein alone; and (D) co-heating whey protein with GT and heating Na-caseinate alone. According to small-deformation rheological measurements, the strength of the mixed-gel network decreased in the order: C>B>D>A samples. SEM micrographs show that the network of sample C is much more homogenous, coarse and dense than sample A, while the networks of samples B and D are of intermediate density. The heat-treatment sequence of the biopolymer mixtures as a formulation parameter thus offers an opportunity to control the microstructure and rheological properties of mixed gels.

Effect of gum tragacanth exuded by three Iranian Astragalus on mixed milk protein system during acid gelation.

The effects of various concentrations of three species of gum tragacanth on the gelation process, microstructure and viscoelastic properties of milk protein mixed gels acidified at 37°C by glucono-δ-lactone (GDL) were investigated using dynamic rheometry and microscopy. According to rheological measurements, the addition of gum tragacanth in the range of 0.05-0.2% (w/w) into milk protein dispersions led to a weaker structure for the milk protein network, compared to the control sample. This weakening effect could be eliminated by adding 0.3% (w/w) gum tragacanth exudates from A. gossypinus; the compositional features of gum tragacanth may have been responsible for the improved protein-protein interactions, greater structural strength and reduced gelation time onset. It was determined by scanning electron microscopy that the addition of gum tragacanth at a low concentration caused the density of the matrix to increase, while an open structure was observed in the presence of a higher gum concentration.

Effect of co-solute and gelation temperature on milk protein and gum tragacanth interaction in acidified gels.

The aim of this study was to investigate the role of process conditions and system composition on the acid-induced gelation of a mixture of milk protein and gum tragacanth. This was studied by determining the effects of co-solute (lactose) addition (3, 5 and 7%) and gelation temperature (25, 37 and 45°C) on the mixture's rheological properties and microstructure using a combination of techniques including small-deformation rheology and scanning electron microscopy. The presence of lactose played an important role in the microstructure formation of gels but did not change most rheological properties. The microstructure of gels formed in the presence of lactose was coarser and more particulate, but less interconnected; this can be explained by lactose's role in improving protein aggregation. Gels prepared at a lower temperature had a high structure strength, as indicated by their high storage modulus, τ(f) and G(f) values. Low gelation temperature also caused a more branched and homogenous microstructure.