Antioxidative activity molecular mass

Fogliano et al.72 have prepared melanoidin [molecular mass (MM) >12 kDa] from glucose-glycine, lactose-lysine, and lactose-iV-acetyllysine lactose-lysine proved to be the odd one out, exhibiting less than one-tenth the absorbance of the other two at 460 and 520 nm. Their CAVs (colour activity value,73 defined as the ratio of a colorant s concentration to its visual detection threshold, both in pg kg-1) were 8000, 200, and 4000, respectively. Examination by MALDI-TOF gave results only for the lactose-A-acetyllysine melanoidin, with peaks around 6,12, and 24 kDa (the spectrum reproduced by Borrelli et al.74 shows peaks around 6, 7.5, and 12 kDa). The antioxidant effects of the melanoidins were also examined (see p. 129). 

Blue-Mi is the name given to a pigment isolated from D-xylose-glycine.75 It was identified as the pyrrolopyrrolium compound 30 and assumed to be a dimer of the yellow pyrrolopyrrole-2-carboxaldehyde.186 It is capable of polymerising further to melanoidins and, similar to melanoidins, it has strong antioxidant activity. There is evidence of another pigment, Blue-M2, with molecular mass (MM) = 0.942 kDa. 

Volatility and Migration Rate. A study of the half-lives (T ) of the antioxidants in the polymer (see Table 1) at the same temperature suggests a reason for the lack of correlation between the two sets of results. In an oxygen absorption test, volatilization cannot occur, and the result is a true measure of the intrinsic activity of the antioxidant molecule. In an air oven test, on the other hand, physical loss of the antioxidant by migration and volatilization from the surface must dominantly influence the test results. Billingham and his coworkers ( 2) have shown that these two physical parameters determine the rate of loss of antioxidants from polymers. Increase in molecular mass generally decreases molecular mobility as well as volatility, and which factor dominates depends on the thickness of the sample ( 2). 

Both molecular mass and sulfate content of fucoidan played very important roles in the effects on the azo radicals 2-2 -azobis (2-amidino-propane)dihydrochloride-induced LDL oxidation (Li et al., 2006). The correlation between the sulfate content and scavenging superoxide radical ability was positive, the ratio of sulfate content/fucose was an effective indicator to antioxidant activity of the samples (Wang et al., 2008). 

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