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Electrospinning of Edible, Food-Based Polymers
Published in V Ravishankar Rai, Jamuna A. Bai, Nanotechnology Applications in the Food Industry, 2018
Serife Akkurt, Lin Shu Liu, Peggy Tomasula
TFA (Trifluoroacetic acid) (CF3CO2H) is an organofluorine compound that is a stronger acid than acetic acid. It weakens the oxygen–hydrogen bond and stabilizes the anionic conjugate base due to its high electronegative fluorine atoms. This solvent has been used to dissolve food-grade proteins and polysaccharides to promote electrospinnability (Sangsanoh et al. 2010; Haider et al. 2015; Mendes et al. 2017) and has been used in electrospinning of collagen (Huang et al. 2015), silk (Elakkiya et al. 2014), or in a mixture with dichloromethane for electrospinning of chitosan (Sangsanoh et al. 2010).
An investigation on the morphology and microstructure of electrospun CMCH/PEO and CMCH/PVA nanofibers
Published in The Journal of The Textile Institute, 2022
Shabnam Kasraei, Hossein Tavanai, Mohammad Morshed, Amir Shahin Shamsabadi
Chitosan has a crystalline structure containing water molecules at ambient temperature. This leads to a large number of hydrogen bonds in the crystalline structure of chitosan which makes it almost insoluble. But unlike chitin, chitosan is soluble in highly concentrated acetic acid (90%) or some other organic solvents like trifluoroacetic acid, dichloromethane and hexafluoro-2-propanol, thanks to the protonation of amino side groups. The high price and toxicity of these solvents has limited the employment of chitosan and other chitin derivatives. But it has become known that chitosan derivatives like carboxymethyl chitosan (CMCH) is not only soluble in water (wide range of pH) but also shares the aforementioned merits of chitosan and chitin. CMCH has a high capability for absorbing metal ions as well. It is worth mentioning that in comparison to chitosan, CMCH has high chelating power, moisture absorption and moisture retention (Anh & Dumri, 2017; Ciechanska, 2004; Mourya et al., 2010; Rabea et al., 2009; Shalumon et al., 2009).
Optimization and application of HPLC for simultaneous separation of six well-known major anthocyanins in blueberry
Published in Preparative Biochemistry & Biotechnology, 2021
Yuanjing Zhou, Shangjun Long, Qing Xu, Changrui Yan, Jiang Yang, Yousong Zhou
First, the mobile phase was tested. Anthocyanins, as a group of water-soluble flavonoid, dissolve easily in water, methanol, ethanol, acetonitrile, and acetone. The proper use of elution solvents is crucial in the efficient release of anthocyanins from the stationary phase of HPLC. The most popular elution solvents used in HPLC include methanol and acetonitrile, as well as slightly acidified solvents, such as formic acid, acetic acid, trifluoroacetic acid, and phosphoric acid. Considering the need for maximized release of anthocyanins and safety requirements, water-methanol solvent and water-acetonitrile solvent were utilized to elute anthocyanins from the stationary phase of HPLC. As a result, the separation effect of acetonitrile-water solvent system was better than that of methanol-water solvent system, and the most suitable mobile phase was acetonitrile (solution A) and 0.3% phosphoric acid water (solution B). In this study, the methanol-water (contained 3% formic acid) system reported by wang et al.[36,37], who isolated three monomeric anthocyanins from lowbush wild blueberries by semi-preparative scale HPLC (LC-6AD, Shimadzu, Japan), was also tried, but the separation effect was not as good as that of cetonitrile-water (contained 0.3% phosphoric acid) system. It may be due to the different experimental materials, different types of anthocyanins, or different equipment used.
Assessment of Aflatoxin M1 and M2 exposure risk through Oaxaca cheese consumption in southeastern Mexico
Published in International Journal of Environmental Health Research, 2018
Estela Hernández Camarillo, Alejandra Ramirez-Martinez, Magda Carvajal-Moreno, Manuel Vargas-Ortíz, Nathalie Wesolek, Guadalupe Del Carmen Rodriguez Jimenes, Miguel Ángel Garcia Alvarado, Alain-Claude Roudot, Marco Antonio Salgado Cervantes, Victor J. Robles-Olvera
The aflatoxin content was extracted following the R-Biopharm user’s guide (2012) through the following protocol: 15 g of dry and ground Oaxaca cheese was mixed with 100 mL of MeOH: water (80:20 v/v) and 2 g NaCl (to clarify the extract). The mixture was centrifuged at 4500 rpm for 15 min, and 6.7 mL of the supernatant was added (equivalent to 1 g of sample) to 24 mL of phosphate buffer solution (PBS). Before samples were added, each immunoaffinity column (IAC) used to detect AFM1 was equilibrated with 20 mL of PBS at pH 7.4 at a flow rate of 5 mL/min. The sample was passed through the IAC and AFM1, and AFM2 were eluted using 1.5 mL of MeOH HPLC grade, followed by 1.5 mL of distilled water. The eluate was dried at 40 °C and then derivatized in 200 μL of acetonitrile and 800 μL of derivatizing solution. The derivatizing solution consists of 5 mL of trifluoroacetic acid (Sigma–Aldrich, St. Louis MO, USA), 2.5 mL of glacial acetic acid (Merck, Naucalpan, Estado de México, México) and 17.5 mL of deionized distilled water. This solution was stirred (Vortex G – 560, Bohemia NY, EE.UU.) for 30 s. The vials containing the dried eluates were heated in a steam bath at 65 °C for 10 min then cooled to room temperature. 60 μL of extract was injected to HPLC. All samples were analyzed in triplicate.