Comment on Degradation of Ascorbic Acid in Ethanolic Solutions

Synthesis of Urchin-Shaped Gold Nanoparticles Utilizing Green Reducing and Capping Agents at Different Preparation Conditions: An In Vitro Study

“…It seems the role of ethanol is different in the two cases; in the case of using ascorbic acid, the used ethanol may reduce the particle size growth, but in the case of using gelatin, the used ethanol reduced the role of gelatin as a capping agent and enhanced the particle aggregation. The degradation effect of the ethanolic solution on the ascorbic acid was previously proven [64] in which the higher ethanol concentration (>50%) promotes lowering the water activity environment that supports the degradation of ascorbic acid into a transitional compound; L-xylosone, and then to other carbon compounds [65]. Therefore, adding the ethanol solution will lead to stopping the reducing reaction and result in a reduction in the particle size of the produced nanogold.…”

“…It is considered common knowledge that gold nanoparticles smaller than 2 nm do not demonstrate SPR [57,64]. Such small gold nanoparticles can be determined by using a particle size analyzer as shown in Figure 6.…”

“…The effect of ethanol is strongly illustrated by a reduction in the particle size of the formed gold nanoparticles produced using only the reducing agent (ascorbic acid) at 95 ± 3 • C from 257-421 nm to a much narrower 6-13 nm size, whereas the addition of ethanol to the solution of gold precursor and gelatin at BT resulted in shifting the particle size range from 45-74 nm to 95-200 nm. It is considered common knowledge that gold nanoparticles smaller than 2 n not demonstrate SPR [57,64]. Such small gold nanoparticles can be determined by u size analyzer; < 3 nm).…”

On the Reverse Stability Kinetics of Meat Pigment Oxidation in Aqueous Extract from Fresh Beef

“…In this letter we show our analysis of the data of Frelka et al. () to explain the reverse stability of oxymyoglobin in terms of thermodynamics using transition‐state theory, which has been used in the thermo‐kinetic analysis of chemical reactions in agricultural and food chemicals (Brock, Rosa, & Kang, ; Farhoosh, ; Fisher, Purnell, & Kang, ; Mock & Kang, ; Nayak, Berrios, Powers, & Tang, ; Tang & Skibsted, ). We also discuss an inconsistency found in the original paper and suggest a follow‐up experiment that will allow us to develop a deeper understanding of the oxidation process.…”