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Utilization of Fisheries' By-Products for Functional Foods
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Muhamad Darmawan, Nurrahmi Dewi Fajarningsih, Sihono, Hari Eko Irianto
Strong evidence showed that many human diseases such as cancer, cardiovascular, stroke, diabetes, rheumatoid arthritis and dementia are associated with the accumulation of free radicals (Florence, 1995). Antioxidants are molecules that are able to donate an electron to a free radical and neutralize it, hence reducing the free radical damage capacity (Lobo et al., 2010). The potential of fish by-products’ protein hydrolysate as a natural antioxidant has also been highlighted and reported by many studies, such as Lassoued et al. (2015), who reported the high antioxidant activity of the pentapeptides Ala-Val-Gly-Ala-Thr purified from the Raja clavate (thornback ray) skin protease-hydrolyzed FPH. The antioxidant potential of fisheries’ by-product FPH was also reported by other studies, such as by Chi et al. (2015), who purified antioxidant peptides of Phe-Ile-Gly-Pro, Gly-Pro-Gly-Gly-Phe-Ile and Gly-Ser-Gly-Gly-Leu from protein hydrolysates of bluefin leatherjacket (Navodon septentrionalis) heads.
Environmental Performance of Bio-Based Polymer Additives: Thermal Stabilizers and Antioxidants
Published in Moayad N. Khalaf, Michael Olegovich Smirnov, Porteen Kannan, A. K. Haghi, Environmental Technology and Engineering Techniques, 2020
Hussein A. Shnawa, Moayad N. Khalaf
Antioxidant is any substance which when found into polymers at small amounts (less than 2 wt% per polymer weight), significantly leads to protection of the polymers and plastics (and other hydrocarbon materials) against thermal and/or photo-oxidative degradation processes. These materials at least, must delay the oxidation process that occur in thermal or photo conditions or during natural ageing. Some types of these additives come from natural resources such as vitamins and many naturally occurring plants products (phytochemicals), and other types produced chemically by industrial processes. Antioxidants are able to neutralize reactive molecules (free radicals) and reduce oxidative damage by different mechanisms. They attract intense scientific and economic interest in polymer and petrochemical industries, human health, and many food industries.16,17
Fire Hazards and Associated Terminology
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
Fuel, a flammable or combustible material, in combination with a sufficient quantity of an oxidizer such as oxygen gas or another oxygen-rich compound (though nonoxygen oxidizers exist), is exposed to a source of heat or ambient temperature above the flash point for the fuel–oxidizer mix. The fire tetrahedron or fire pyramid (Figure 1.2) adds a fourth component-chemical chain reaction–as a necessity in the prevention and control of fires. The free radicals formed during combustion are important intermediates in the initiation and propagation of the combustion reaction. Fire suppression materials that scavenge these free radicals are able to sustain a rate of rapid oxidation that produces a chain reaction. Fire cannot exist without all of these elements in place and in the right proportions. For example, a flammable liquid would start burning only if the fuel and oxygen are in the right proportions. Some fuel-oxygen mixes may require a catalyst, a substance that is not consumed when added, in any chemical reaction during combustion, but which enables the reactants to combust more readily.
Can Origanum be a hope for cancer treatment? A review on the potential of Origanum species in preventing and treating cancers
Published in International Journal of Environmental Health Research, 2023
Free radicals and reactive oxygen species (ROS) formed in the human body or taken from the outside (through nutrition, etc.) are among the factors that play an important role in cell damage. These free radicals, which adversely affect the immune system and damage human metabolism, are unstable, high-energy compounds with one or more unpaired electrons in their outer orbitals (Yabalak et al. 2020). Therefore, the increasing amount of free radicals in the human body damages or destroys many biological materials (DNA, protein, carbohydrates, etc.) in metabolism. It has been also reported that free radicals play an important role in the pathogenesis of many conditions such as atherosclerosis, aging, cancer, Alzheimer’s and ischemic heart diseases. The increase in free radicals in the human body and the deficiency of antioxidants, which play an active role in the body’s defence by eliminating the harmful effects of free radicals, cause the diseases mentioned above (Stadtman 1992; Guyton and Kensler 1993; Cerutti 1994; Feig et al. 1994). Thus, antioxidants prevent or minimize the harmful effects of the free radicals (Wettasinghe and Shahidi 1999; Koleva et al. 2002).
Cationic cellulose nanocrystals as sustainable green material for multi biological applications via ξ potential
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Sara Mohamed Mahmoud, Safwat Hassan Ali, Mohamed M. A. Omar
Antioxidant activity for four doses (10, 50, 100 and 500 μg/mL) of cellulose nanocrystals was performed by DPPH radical method (Figure 8). DPPH is a stable, lilac-colored free radical that is nitrogen-centered. It transforms into a stabilized molecule (DPPH-H) with a yellow color when it interacts with an antioxidant that can give the DPPH radical an electron. The results showed that CNCs has higher antioxidant activity > 50% inhibition at high dose 500 μg/mL, which presented a high positive correlation (p < 0.05) of DPPH and IC50 was 1467 ± 25.9 µg/mL, than both two doses 50 and 100 μg/mL give approximately the same value for antioxidant activity. While, low dose 10 μg/mL, inhibit less value for antioxidant activity < 50% inhibition, 435 ± 16.7 µg/mL, at this concern, the antioxidant activity increases ascend in order to concentration. Antioxidants protect cells from the harmful effects of reactive oxygen species by neutralizing free radicals before they have a chance to damage particular cells. So, cationic CNCs are anticipated to be powerful antioxidants at dose 500 μg/mL.
Developing of thermoregulating cotton fabric by incorporating of the poly(methyl methacrylate-co-methacrylamide)/fatty alcohol latent heat storing nanocapsules
Published in The Journal of The Textile Institute, 2022
Simge Özkayalar, Sennur Alay-Aksoy
To confirm the synthesizing of the P(MMA-co-MAA) and PMMA polymer shells and presence of the core content of the nanocapsules, FTIR spectroscopy analysis of the monomers, core materials and nanocapsules were carried out. In preparation process of the nanocapsules, the synthesis of shell polymer from the MMA and MAA monomers takes place around the emulsified oil core in the water phases by free-radical addition polymerisation. The possible mechanism for the free-radical polymerization of the PMMA and P(MMA-co-MAA) initiated by the chemical initiator (ammonium persulfate) was given in Figure 1. Besides, one of the possible cross-linking mechanisms of the polymers by cross-linker (EGDM) was illustrated in Figure 1. The MMA, MAA, and EGDM acrylic monomers are carbon–carbon double bonded vinyl monomers which can polymerize by adding of the monomeric radicals. In the free radical polymerisation, firstly, radicals are created from the initiating molecules and then, radicals are transferred from the initiator molecules to the monomer units present. The polymer is formed by addition of monomeric free-radical units (Ramelow & Pingili, 2010; Yu et al., 2014) (Table 3).