Antioxidants evaluation

Figure 10. Antioxidant evaluation by oxidative polyamide fluorescence from soy lecithin liposomes. Key O, blank , lecithin plus hematin A, lecithin-hematin...

The antioxidants butylated hydroxyanisole (BHA), butylated hydroxytolu-ene (BHT), tm-butylhydroquinone (TBHQ), propyl gallate, ascorbyl palmitate and citric acid were evaluated for potential to reduce NOx emissions from a single cylinder, direct-injection, air-cooled, naturally aspirated Yanmar engine (Hess et al, 2005). BHA and BHT reduced NOx emissions by 4.4 and 2.9%, respectively, but the other antioxidants evaluated did not exhibit any beneficial effects (see Table 1.2). Antioxidants may impede NOx formation by inhibiting the formation of combustion-derived radicals. 

Figure 2. Structures of tocopherol-type antioxidants evaluated In oxidizing fish oils.

Antioxidant evaluation of heterocycHc compounds by cytokinesis-block micronucleus assay 13MRM431. 

Kontogiorgis, C. A. Sawoglou, K. Hadjipavlou-Litina, D. J. Antiinflammatory and antioxidant evaluation of novel coumarin derivatives. J. Fnzyme Inhib. Med. Chem. 2006, 21, 21—29. 

The activity of natural antioxidants is greatly affected by complex interfacial phenomena in emulsions and multi-component foods. The methodology to evaluate natural antioxidants must be carefully interpreted depending on whether oxidation is carried out in bulk oils or in emulsions, and which analytical method is used to determine extent and end-point of oxidation (Chapter 10). To understand and better predict how natural antioxidants may protect foods against oxidation, the following complex questions need to be carefully considered for the judicious choice of antioxidant evaluation protocols a) What are the protective properties of antioxidants b) What substrates are oxidized and what products of oxidation are inhibited c) In a multiphase food system is the antioxidant located where oxidation takes place d) Are there any... 

Each antioxidant evaluation should thus be carried out under various conditions of oxidation, using several methods to measure different products of oxidation related to real food quality. There cannot be a short cut approach to determining the activity of antioxidants. Various testing protocols should consider the following parameters and recommendations ... 

Fraga CG, Mactino US, Ferraro GE et al (1987) Flavonoids as antioxidants evaluated by in vitro and in situ liver chemiluminescence. Biochem Syst Ecol 36 717-720... 

If all parameters in the equations (6.13) and (6.14) are known, it is possible to quantitatively evaluate antioxidative efficiency as a function of concentration of the introduced antioxidant [AH]. The in-vivo antioxidative evaluation is extremely difficult and is almost... 

Fraser MH (2006) Ethnobotanical investigation of plants used for the treatment of type 2 diabetes by two Cree communities in Quebec Quantitative comparismis and antioxidant evaluation. M. Sc. thesis, McGill University, Canada... 

TGA analysis of two secondary antioxidants evaluated in this study also indicated that loss of stabilizer would not be expected under typical curing conditions. The phosphite, PHOS-1, has a 5% weight loss at 189 C and a 90% weight loss at 266"C. The thioester, DTDTDP, has a 5% weight loss at 227°C and a 90% weight loss at 328°C. Some antioxidant structures are given in Appendix 1. 

A variety of structurally dissimilar phenolic antioxidants were evaluated for performance as scorch inhibitors. The results of screening work are shown in Figure 4. In general, all of the antioxidants evaluated provided... 

Lee, J.H., Lee, K.-T., Akoh, C.C., Chung, S.K., and Kim, M.R., Antioxidant evaluation and oxidative stability of structured lipids from extravirgin olive oil and conjngated linoleic acid, J. Agric. Food Chem., 54, 5416-5421, 2006. 

The present study describes antioxidant activity of the eight Okinawan herbs, their constituents and antioxidant evaluation measured by several methods. 

Padayatty SJ, Katz A, Wang Y et al. (2003) Vitamin C as an antioxidant evaluation of its role in disease prevention. Journal of the American College of Nutrition 22 18-35. 

Table 1 Hindered phenol antioxidants evaluated in the study.

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