Two barley varieties, Gan4 and Hamelin, were malted to investigate the evolution of phenolic compounds and antioxidant activity during malting. The antioxidant activity was evaluated with DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, and metal chelating activity. Results showed that malting had significant influences on individual and total phenolic contents as well as antioxidant activities of two barley varieties. The contents of some phenolic compounds and the antioxidant activities decreased significantly during steeping and the early stages of germination and then increased remarkably during the later stages of germination and subsequent kilning. The most phenolic compounds identified in barley were (+)-catechin and ferulic acid, which both changed significantly during malting. Moreover, results from the Pearson correlation analysis showed that there were good correlations among DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, total phenolic content and sum of individual phenolic contents during malting.

When hydroxyl groups are derivatized to apply the CD exciton chirality method, the absorption maxima of introduced chromophores should not overlap with that of the substrate, except for cases in which the coupling between the existing and the introduced chromophores are deliberately sought for. Thus, the availability of red-shifted chromophores that do not overlap with the substrate absorption would greatly expand the applicability of this versatile CD method. Four such red-shifted chromophores, chrom-II, -III, -IV, and -V, have been developed to convert hydroxyl groups into esters that absorb strongly in the range 360-410 nm. Using the chromophoric triazole amide, they can readily derivatize hydroxyl groups of the substrates on a microscale. The bischromophoric esters of l(/?),2(/?)cyclohexanediol (14-18) exhibited intense exciton-split CD curves with the signs correctly representing the absolute sense of twist between the two hydroxyl groups. The 1,2-diol moieties of taxinine ( 2) and chromomycin A3 (3) derivatives, already having strong absorptions at 260-275 nm, were esterified with the new chromophores; this gave rise to strong couplets isolated from the CD Cotton effects of starting materials, the signs of which were in agreement with the absolute configurations of these two natural products. These O-acylating chromophores should be useful for determinations of absolute configurations and conformations of chiral substrates, including biopolymers; they could also be conveniently used in conjunction with the red-shifted chromophores developed recently for primary amino groups.

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