Abstract
The relationship between the moisture content of raw material and the distribution of volatile components in silage, and changes in composition of volatiles after opening silos were studied. Cocksfoot was ensiled in three states; high moisture silage, immediately ensiled; medium moisture silage, pre-wilted for about 24h; low moisture silage, pre-wilted for about 36h; and then preserved for 70 days under anaerobic conditions in the bags of polyethylen film. The pH values of both high and medium moisture silages were higher than that of low moisture silage, but the lactic acid contents of the former were lower than that of the latter at opening and during aerobic deterioration. A number of volatiles were found in the silage distillates, and the total yield of volatile components at opening silos was much higher, in high moisture silage than in both medium and low moisture silages. Among the volatiles ; iso-pentanol, cis-3-hexenal, β-phenylethanol, 4-ethylguaiacol, 4-ethylphenol in the high moisture silage ; iso-pentanol, β-phenylethanol, 4-ethylguaiacol, 4-ethylphenol, ethyl linolenate in the medium moisture silage ; and iso-petanol, , β-phenylethanol, ethyl linolenate in the low moisture silage were relatively large in peak area distribution at opening, respectively. The patterns of the peak area distribution of the volatile components in silages were altered by both the moisture contents of silages and the time intervals under aerobic condition.
