Unveiling the critical pH values triggering the unfolding of soy 7S and 11S globulins and enhancing their encapsulation efficiency

The pH-shifting process is an effective encapsulation method, and it is typically performed at extreme alkaline pH, which severely limits the application. In this study, we found that there were critical pH for the unfolding proteins during pH-shifting from 7 to 12, and upon the critical pH, physiochemical characteristics of protein greatly changed, leading to a sharp increase of encapsulation of hydrophobic actives. Firstly, the critical pH for β-conglycinin (7S) or Glycinin (11S) unfolding was determined by multispectral technology. The critical pH for 7S and 11S were 10.5 and 10.3, respectively. The encapsulation efficiency (EE) obtained by β-conglycinin-curcumin nanocomposite (7S-Cur) (88.80 %) and Glycinin-curcumin nanocomposite (11S-Cur) (88.38 %) at critical pH was significantly higher than that obtained by pH 7 (7S-Cur = 16.66 % and 11S-Cur = 15.78 %), and both values were close to EE obtained by at 12 (7S-Cur = 95.16 % and 11S-Cur = 94.63 %). The large-scale application of hydrophobic functional compounds will be enhanced by the experimental results.

Determination of the critical pH for unfolding water-soluble cod protein and its effect on encapsulation capacities

Hydrophobic polyphenols, with a variety of physiological activities, are often practically limited due to their low water solubility and chemical instability, among which curcumin (Cur) is a representative hydrophobic polyphenol. To improve Cur, the cod protein (CP)-Cur composite particles (CP-Cur) were successfully prepared using the pH-shift method, but this pH-shift method (7-12-7) required a higher pH, which limited application and increased cost. The critical pH of CP structure unfolding during pH-shift and its encapsulation effect on Cur were investigated in this paper. During the pH-shift process, the critical pH of the structural unfolding of CP was pH 10, and the degree of protein structure unfolding was higher, which was attributed to the increasing electrostatic repulsion, and the weakened hydrogen bond and hydrophobic interaction. The encapsulation efficiency of CP-Cur formed after pH 10-shift was higher than that formed after pH 9.8-shift, which increased by 22.17 %. At pH 9.8, the binding sites in CP reached saturation at the molar ratio of 10, while at pH 10 and 10.2, the binding sites in CP both reached saturation at the molar ratio of 14, also indicating that the protein treated with critical pH could bind more Cur. The binding between Cur and CP was mostly hydrophobic interaction, accompanied by hydrogen bonding and electrostatic interactions. The above results verified the necessity of critical pH in the experiment, indicating that critical pH could indeed improve the encapsulation effect and obtain a higher encapsulation efficiency. This work will help improve the large-scale application of hydrophobic functional substances in production.

Phase coherent quasi-particle formation in biological systems

The problem of the origin of canonical and aberrant DNA mutations and the contribution of protons to genetic stability is an essential topic in molecular biology. Based on the empirical results, we reconsidered canonical and tautomeric mutations under the two-fluid model of quantum physics. We assumed that the pressure exerted by protons (H+) in the DNA environment, through changes in pH, could alter the concentration ratio of canonical and tautomeric base pairs, which were found to be different at and beyond the criticality level, respectively. We anticipate that the deviation of the cellular system from a specific (critical) temperature at which dynamic entropy reaches a minimum and a critical pH occurs could result in tautomerization and point mutations.

Can acid produced from probiotic bacteria alter the surface roughness, microhardness, and elemental composition of enamel? An in vitro study

Probiotics are live microorganisms that upon administration in adequate amounts provide various health benefits to the host. Probiotics are "lactic acid-producing bacteria" as they release large amounts of organic acids, particularly lactic acids, in their surrounding environment. Although the acids produced by probiotics are beneficial for gastrointestinal and vaginal health, the acidogenic nature of probiotics has raised concerns among dental professionals, especially concerning their effect on the enamel and dentin. Previous studies have found that probiotics can lower the pH of the saliva and cause essential elements like Calcium and Phosphorus to leach from the enamel. This can alter the surface topography of enamel and increase the risk of enamel defects. Studies have also noted that probiotic bacteria can replace cariogenic bacteria and lower the risk of tooth decay. However, the effect of acid produced by probiotics on the enamel surface remains unclear. Hence, the present study aims to evaluate the effect of probiotics on the surface roughness, microhardness, and elemental composition of enamel compared to 0.1 M Lactic acid (demineralizing agent). Twenty enamel sections were randomly divided into groups and subjected to a pH cycling model using a probiotic suspension and 0.1 M lactic acid. The changes in the surface roughness, microhardness, surface morphology, and elemental composition of the enamel with regard to Carbon, Oxygen, Sodium, Hydrogen, Magnesium, Phosphorus, Fluoride, Chlorine, and Calcium of the enamel were evaluated before and after the emersion in both the groups. The results showed a significant increase in the mean surface roughness in the probiotic group before and after the exposure. The microhardness of the enamel decreased along with altered arrangement of the enamel prisms, increased striations, scratch marks, and pitting after exposure to the probiotic group. A decrease in the atomic/weight% for Calcium, Phosphorous, Fluoride, Aluminium, and Oxygen and an increase in the weight/atomic% for Carbon, Nitrogen, and Sodium were noted compared to the baseline in the probiotic solution. The results in the probiotic group were comparable to the 0.1 M lactic acids. The pH changed from 5.78 to 3.06 at the end of 24 h in the probiotic group. Based on these findings, we conclude that exposure to probiotics can affect microhardness and surface roughness and cause leaching of essential elements like Calcium and Phosphorous from the enamel.

Comparative evaluation of qualitative and quantitative remineralization potential of four different remineralizing agents in enamel using energy-dispersive X-ray: An in vitro study

Background:

The principles of minimally invasive dentistry clearly tells us the need for clinically effective measures to remineralize the early enamel caries lesions.

Aims and Objectives:

The aim of this study was to evaluate the remineralisation potential of four different remineralisation agents used quantitatively by surface microhardness and qualitatively by energy dispersive X ray analysis.

Materials and Methods:

Artificial enamel lesions were created on the buccal surfaces of 60 extracted mandibular second premolar. Specimens were randomly assigned to four groups (n=15) according to the remineralisation agents used: Group 1-Nano Hydroxyapatite, Group 2-Fluoride, Group 3-CPP ACP, Group 4-Chitosan 5mg. All products were applied according to the manufacturer's instructions and specimens were stored in daily renewed artificial saliva. Surface microhardness was assessed using Rockwell hardness test and change in mineral content was evaluated using Energy Dispersive X ray analysis.

Statistical Analysis:

One way analysis of Variance test and post-hoc Tukey test were conducted for multiple group comparison.

Results:

There was remarkable remineralisation in Hydroxyapatite treated comparatively to the other three groups.

Conclusion:

All remineralising agents showed improved surface remineralisation. However complete remineralisation did not occur within 7 days. Nanohydroxyapatite showed the highest potential for remineralisation followed by CPP-ACP, Chitosan and Fluoride.

Interpolymer complexes of carbopol® 971 and poly(2-ethyl-2-oxazoline): Physicochemical studies of complexation and formulations for oral drug delivery

Carbopol® 971 and poly(2-ethyl-2-oxazoline) form hydrogen-bonded interpolymer complexes in aqueous solutions and their complexation is strongly dependent on solution pH. This work investigated the complexation between these polymers in aqueous solutions. The compositions of interpolymer complexes as well as the critical pH values of complexation were determined. The structure of these complexes was studied in solutions using transmission electron microscopy and in solid state using elemental analysis, FTIR spectroscopy and differential scanning calorimetry. Solid compacts were prepared based on interpolymer complexes and physical blends of these polymers and their swelling behaviour was studied in aqueous solutions mimicking the fluids present in the gastrointestinal tract. These materials were used to prepare oral formulations of mesalazine and its release from solid matrices was studied in vitro. It was demonstrated that the complexation between Carbopol® 971 and poly(2-ethyl-2-oxazoline) has a profound effect on the drug release from matrix tablets.

Analyses of the Erosive Potential of Various Soft Drinks and Packaged Fruit Juices on Teeth

AIM

This study aimed to evaluate the erosive potential of twenty beverages (8 carbonated drinks and 12 packaged fruit juices).

MATERIALS AND METHODS

Twenty-one sound permanent freshly extracted teeth were segmented into small enamel slices and stored in normal saline. The titratable acidity of each experimental drink was measured as the amount of 0.1 N sodium hydroxide (NaOH) required to raise pH to 5.5 and 7. The enamel specimens were incubated in freshly collected human saliva for 3 hours. One enamel slice was immersed in each beverage and percentage weight loss in the enamel slice was calculated after 6 and 24 hours intervals.

RESULTS

The titratable acidity values of the experimental drinks ranged from 0.2 to 5.6. The mean titratable acidity values of the packaged fruit juices were higher than carbonated drinks. A significant difference (p < 0.0 5) was found in the percentage weight loss of enamel specimens after 6 and 24 hours immersion in the carbonated drinks than packaged fruit juices. Apple juice followed by thumps up were found to be the most erosive drinks with the least effects of Miranda and Guava juice.

CONCLUSION

Most of the beverages tested in this study showed erosive potential. The carbonated drinks caused significant dental erosion.

CLINICAL SIGNIFICANCE

Individuals at risk for beverages-associated erosion, particularly those with high intakes or decreased salivary flow, should be provided preventive guidance regarding habits of beverages intake. Specific dietary recommendations for the prevention of dental erosion may now be developed based on the patient's history of beverage consumption.