FORMULATION OF EFFERVESCENT GRANULES FROM RED GINGER (ZINGIBERIS OFFICINALE ROSCOE VAR. RUBRUM) EXTRACT AND ITS ANTIOXIDANT ACTIVITY

Objective: Ginger is one of the Indonesian plants that has been used as traditional medicine. The flavonoids and phenols compounds contained high antioxidant activity. This study aimed to formulate effervescent granules (EG) from red ginger (RG) extract and evaluate its antioxidant activity. Methods: The formulation of EG from RG extract was prepared by the wet granulation method using different concentrations of polyvinylpyrrolidone (PVP). Furthermore, the flowability of granules was evaluated, including flow rate, angle of repose, bulk density, tapped density, Carr's index, Hausner ratio, and effervescent time. The physical stability of granules such as organoleptic evaluation, effervescent time, and pH measurement was also evaluated after 28 d of storage, and the antioxidant activity of EG from RG extract was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Results: The result showed that the EG of RG extract was successfully prepared by wet granulation with a concentration of 15%. In addition, the flowability study showed that all formulas of EG from RG extract have good flow properties, and the granules showed excellent flow properties based on Carr′s index results. The effervescent time of granules remained within the acceptable range according to USP, and the physical stability did not change even after 28 d of storage. The IC50 of EG from RG extract was 283.28±3.6 ppm and has moderate in free radicals scavenging activity. Conclusion: EG from RG extract can be used as food supplements to protect the human body from free radicals and inhibit oxidases.

Application of Computational Fluid Dynamics (CFD) in the Deposition Process and Printability Assessment of 3D Printing Using Rice Paste

Computational fluid dynamics (CFD) was utilized to investigate the deposition process and printability of rice paste. The rheological and preliminary printing studies showed that paste formed from rice to water ratio (100:80) is suitable for 3D printing (3DP). Controlling the ambient temperature at C also contributed to improving the printed sample’s structural stability. The viscoelastic simulation indicated that the nozzle diameter influenced the flow properties of the printed material. As the nozzle diameter decreased (1.2 mm to 0.8 mm), the die swell ratio increased (13.7 to 15.15%). The rise in the swell ratio was a result of the increasing pressure gradient at the nozzle exit (5.48 × 106 Pa to 1.53 × 107 Pa). The additive simulation showed that the nozzle diameter affected both the residual stress and overall deformation of the sample. CFD analysis, therefore, demonstrates a significant advantage in optimizing the operating conditions for printing rice paste.

Effect of Chain Lengths at Constant Molecular Weights of Water Reducing Admixture on Properties of Cementitious Systems Containing Fly Ash

In this study, the effect of main chain and side chain length of polycarboxylate-ether based high range water reducing admixture (WRA) on the fresh properties, compressive strength and water absorption of cementitious systems containing 0, 15, 30 and 45 wt.% fly ash was investigated. For this purpose, 3 WRAs with same molecular weight but different chain lengths were produced. According to test results, flowability of paste and mortars was negatively affected when the length of the main chain and side chains of the admixture was longer or shorter than a certain value. This adverse effect is thought to be arisen from the weakening of the adsorption of admixture with increase of its chain lengths. However, when the main chain and side chain lengths of the admixture were shorter or longer than a certain value, the time-dependent flow properties of the mortar mixtures improved. The main chain and side chain lengths of the WRAs had not a significant effect on the compressive strength and water absorption capacity of the mortar mixtures. However, irrespective of the admixture characteristics, with the increase of fly ash substitution the flow and time-dependent flow properties of the mixtures were negatively affected but their water absorption decreased.