Antiradical efficiency,

Sanchez-Moreno and others (1998 1999a,b) proposed a new methodology for the evaluation of the antiradical efficiency toward DPPH. Their procedure takes into account not only the concentration of the antioxidant but also the reaction time to reach the plateau of the scavenging reaction, a modification that could be an advantage... 

Sanchez-Moreno C, Larrauri, JA and Saura-Calixto, F. 1998. A procedure to measure the antiradical efficiency of polyphenols. J Sci Food Agric 76(2) 270-276. 

Sanchez-Moreno C, Larrauri JA, Saura-Calixto F. A Procedure to Measure the Antiradical Efficiency of Polyphenols. Journal of the Science of Food and Agriculture. 1998 76 270-276. 

Antiradical efficiency (AE) can be determined using /V,V-dimethyl-/ -phenylene-diamine dihydrochloride (DMPD). If the amount of melanoidin (mg mL-1) required to reduce the concentration of DMPD cation radicals by 50% is EC50 and the theoretical time (min) required for EC50 to reach the steady state is TEC50, then... 

Morales, F.J. and Babbel, M.B. Antiradical efficiency of Maillard reaction mixtures in a hydrophilic... 

The other parameter to express antioxidant capacity is antiradical efficiency (AE), which is calculated by AE = (1/ICjq) x TICjq (Sanchez-Moreno et al., 1998 Perez-Jimenez and Saura-Calixto, 2005). The TIC50 is the time needed to reach the steady state with IC50. The larger the AE, the better the antioxidant capacity of the sample. In these results. 

Time required to decrease the concentration of test free radical by 50% (T cso) can also be calculated [31]. Based on the values, the kinetic behavior of AOXs can be classified as follows < 5 min (rapid) 5-30 min (intermediate) > 30 min (slow). Antiradical efficiency (AE) [23] has also been proposed as a parameter to characterize AOXs where... 

The HALS compounds are largely used for polyolefin photostabiUsation due to their competitive costs and high performances, which permit the utilization of lower amounts than UV absorbers such as benzophenone and benzotriazole compounds. The mixtures of HALS compounds with benzophenones present some synergic photostabUization effects [11], being reported also an antirad efficiency of them [44,45]. 

The inhibition of lipid peroxidation by metalloporphyrins apparently depends on metal ions because only compounds with transition metals were efficient inhibitors. Therefore, the most probable mechanism of inhibitory effects of metalloporphyrins should be their disuniting activity. Manganese metalloporphyrins seem to be more effective inhibitors than Trolox (/5o = 204 pmol I 1) and rutin (/50 112 pmol I 1), and practically equal to SOD (/50= 15 pmol I 1). The mechanism of inhibitory activity of manganese and zinc metalloporphyrins might be compared with that of copper- and iron-flavonoid complexes [167,168], which exhibited enhanced antiradical properties due to additional superoxide-dismuting activity. 

For flavonoids, there is no clear linear relationship between their antioxidant activity and the electrochemical signal. Thus, glycosylation of the 3-hydroyxl group decreases the antioxidant or antiradical activity in flavonols, but not their electrochemical behavior. This decrease can be attributed to the esteric hindrance posed by the glucose group in C3 or to a reduced solubility of the glycoside in the alkane solvent used in these experiments. Nevertheless, for most analytes the antioxidant efficiency could be related to the value of the first maximum, which corresponds to the lowest energy required to donate an electron. 

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