Cocoa shells and beet pulp also show an increase in soluble products while apple pomace seems to follow no clear trend (Figure ). When comparing the composition of all lignocellulosic feedstocks we noticed that wheat straw has the lowest amount of extractives with 14.3 % while the other substrates contain 39-47 %. Since wheat straw showed the highest amount of soluble products after mechanocatalysis the influence of the extractives towards the reaction is investigated under assumption that extractives may hinder a successful reaction to soluble products due to blocking some acid amount and because soluble non-structural glycans are favored to depolymerize. Therefore, pre-extractions based on the NREL regulations were carried out with beet pulp and apple pomace. Afterwards the processes were continued with 170 min milling duration and an acid content of 6 %. The results are shown in Figure . Combining the extractives with the soluble products leads in total to a higher soluble fraction than for the non-extracted substrates. Considering that the extractives make up 39 % and 47 % for apple pomace and beet pulp respectively, a huge increase up to 40 % of the desired soluble glycancontaining product fraction can be seen. Also a lower content of solid residue for beet pulp compared to apple pomace was observed which probably can be explained by the lower lignin content. As mentioned previously, the obtained molecular weight distribution of the soluble product fraction is of interest and is therefore shown in Figure for the soluble glycan-containing fraction of the non-extracted as well as the pre-extracted apple pomace. The non-extracted apple pomace shows a bimodal molecular weight distribution in two nonfavored regions below 1 kDa and above 10 kDa, that supports the hypothesis that soluble non-structural glycans are favored to depolymerize while the structural larger ones depolymerize afterwards. In contrast the pre-extracted apple pomace shows a broad molecular weight distribution in the favorable region. This circumstance can be attributed to the pre-extraction where low molecular weight compounds like sugars as well as already soluble glycans are extracted from the sample and therefore the partial depolymerization of the macromolecules is less hindered.