Ph 211

In this in vitro study enamel and dentin samples (n = 120 each) from caries-free extracted third molars were covered with modelling wax (Schuler-Dental GmbH und Co. KG, Ulm, Germany). To achieve a standardized evaluation of the lesions, a wax-free test area (≥2.5 mm length/1.2–1.5 mm width) was created in the middle of the outer enamel surfaces). For dentine lesions, the wax-free area was created in the coronal third of the root.
Enamel specimens were exposed to a demineralization solution (DS) for 14 days, and dentine specimens for 7 days. In both experimental arrangements (enamel and dentin) the DS was replaced daily. After 7 days, the DS was completely renewed.
During the experimental demineralization all specimens were stored at 37 °C (Incubator: BED 53, WTB Binder Labortechnik GmbH, Tuttlingen, Germany) in a solution composed of 0.1 molar sodium acetate buffer in 6% hydroxyethylcellulose (HEC) at pH 4.92 ± 0.02 (pH-meter: pH 211, HANNA-Instruments GmbH, Kehl am Rhein, Germany), supplemented with 0.9 mmol/L KH₂PO₄ and 150 mmol/L CaCl₂ [28 (link)].

Each HU compounded oral liquid was prepared in triplicate (n = 3). Formulations prepared using a mortar or a mixer were stored in amber plastic bottles (polyethylene terephthalate—PET, Richards Packaging, QC, Canada) with child-resistant caps, while the ones prepared using QuartetRx were stored in the patented amber QuartetRx plastic bottles (polypropylene, P&C Pharma, OH, USA). All bottles were stored at controlled room temperature (25 ± 2°C / 60 ± 5% RH–Thermo Scientific, Forma Environmental Chamber, OH, USA) for 90 days. Two 3.0-mL amber oral plastic syringes (NeoMed Inc, GA, USA) were filled with each formulation and stored in the same conditions for 14 days.
An aliquot (2.0 mL) was sampled on day 0, 7, 14, 30, 45, 60, 75 and 90 for samples stored in bottles, while sampling was stopped on day 14 for the ones stored in syringes. Bottles and syringes were shaken by hand prior to sampling.
On each time point, samples were evaluated for both chemical and physical stabilities. On the day of preparation and after 90 days of storage, pH measurements were performed to detect pH changes over time (pH 211, Hanna Instruments, QC, Canada).

The pH values of the smoothies, SYSC, PP-SYS1, PP-SYS2, PP-SYS3, and PP-SYS4, were calculated using a pH meter (pH 211, HANNA, Nusfalau, Romania). Standard method 942.15 was used to estimate the titratable acidity, which was recorded as a percentage of citric acid. A refractometer was used to calculate the TSS. AOAC [24 ] was also used to assess vitamin C concentration. The Gerber technique was used to determine fat content; an increase in fat percentage from 0.4 to 4% while keeping protein constant improved texture, stability, and perceived viscosity. The total sugars were estimated by El-Saadony et al. [38 (link)].

CD spectra were recorded on a Jasco J-720 spectropolarimeter (JASCO, Espoo, Finland) at room temperature in a 0.5 mm quartz cell under a constant stream of nitrogen (4 L/min). Buffer with ammonium acetate (15 mM) of pH 6.6 or pH 7.4 was used as the solvent. The Aβ_(1–16) peptide concentration was 256 µM. Spectra were the average of five scans between λ 180 and 260 nm. The results were expressed as molar ellipticity, after subtracting the buffer spectrum. A HANNA pH 211 microprocessor pH meter was used to measure the pH values.

The gelation time is defined as the time required for tannin/formaldehyde from a colloidal solution to become a solid or semi-solid jelly or gel. According to previous works [20 (link)], an aqueous solution of 45% of tannin was placed in a glass test tube. Then, 5% of paraformaldehyde (based the weight of tannin) was added and held in a water bath at temperature of 100 °C. The time taken to reach the gel point was recorded during constant stirring with the aid of a wire spring and a stopwatch. The test was duplicated three times. The pH of the mixture was measured using a microprocessor pH meter (Hanna pH 211).

Initially, a 10 g sample was combined with 50 mL of cold (4 °C) distilled water at pH 7 for 1 min. The pH was measured potentiometrically at room temperature with a microprocessor pH meter (pH 211 Hanna Instruments Inc. Nusfalau, Romania).