Sodium dihydrogen phosphate anhydrous 1.936g effervescent tablets

The ever-increasing generation of waste glass, poses a major environmental challenges due to its large volume and limited recycling options. This research explores a novel sustainable approach to repurposing this waste by transforming it into silicate based bioactive glass-ceramics (SBGCs). The glass waste was recycled into powder form and homogeneously mixed with sodium dihydrogen orthophosphate (NaH 2 PO 4 ) in the step of 2, 4, 6, 8 and 10 wt % respectively with addition of organic binder and sintered by microwave irradiation approach. The obtained SBGCs were then characterized for its phase constituents, microstructure, physical, mechanical, and in-vitro bioactivity behaviour. The results showed that the samples exhibited considerable density and porosity while both the micro-hardness and compressive strength decreased with increased phosphate content. Sample SLP2% showed optimum hardness and compressive strength of 7.3 GPa and 87 MPa respectively. Combeite was obtained as the major phase while wollastonite and quartz were also detected. The developed SBGCs also showed increased hydroxyapatite (HA) formation after immersion in simulated body fluid (SBF) and displayed good antibacterial capacity when reacted with four bacteria strains. The results obtained indicate that the developed SBGCs might be considered a potential candidate for biomedical applications. However, sample SLP8% is the best sample to serve as bioactive glass-ceramics considering the combination of its high HA and good CHA formation, besides its considerable density and mechanical properties.

Abstract licence: CC BY

Sodium tripolyphosphate (STPP), sodium dihydrogen phosphate (SHP), disodium hydrogen phosphate (DSP), sodium hexametaphosphate (SHMP), and tetrasodium pyrophosphate (SPP) were employed for the moist-heat phosphorylation of whey protein isolate (WPI90) under varying temperatures and pH conditions. Phosphorylated proteins with stronger heat resistance were selected to determine their solubility, free sulfhydryl content, surface hydrophobicity, secondary structure, sodium, phosphorus, and calcium contents. Furthermore, they underwent ultra-high temperature (UHT, 135 ℃) processing followed by evaluation of their thermal stability indicators, including centrifugal precipitation rate, viscosity, and particle size as well as their solubility and structure. Commercial heat-stable whey protein was used as control. The results revealed that phosphorylation at 75 ℃ led to an increase in the content of free sulfhydryl groups and a decrease in surface hydrophobicity. The incorporation of phosphates increased the sodium and phosphorus contents while reducing both soluble and total calcium contents, with SPP and SHP resulting in the lowest soluble calcium levels (< 3 mg/g). Fourier transform infrared spectroscopy (FTIR) indicated alterations in protein secondary structure, characterized by a general decrease in β-sheet content and an increase in β-turn content. Phosphorylation at 85 ℃ increased the random coil content. All phosphates except DSP enhanced the thermal stability of whey protein at pH 7.0 and different temperatures (75, 80, and 85 ℃), preventing flocculation of whey protein after UHT treatment. The SHMP-modified protein demonstrated the lowest centrifugal precipitation rate and apparent viscosity after UHT treatment, with an overall particle size below 15 µm. Moreover, phosphorylation with SPP, STPP, and SHP at 75 ℃ improved the solubility of WPI90 to different extents, while phosphorylation with SHMP did not. For both 75 and 80 ℃, SPP phosphorylation resulted in the highest solubility of WPI90. In conclusion, this study demonstrates that moist-heat phosphorylation effectively modifies the structure and functionality of whey protein while influencing the salt ion contents in the protein system. Specifically, the addition of SHMP under neutral pH conditions significantly enhances the thermal stability of whey protein, being of guiding significance for the UHT processing of whey protein concentrate.

Abstract licence: CC BY-SA