BSG's composition varies greatly depending on various parameters such as barley variety and type (grilled, roasted, according to beer type), kilning temperature (KT, drying of the green malt after germination), malting process, mashing conditions, to name but a few. [25] As an example, the kilning temperature has a significative impact on the total phenolic content (TPC) of the malt with higher values (4 fold) recorded for paler malts with lower KT. [28] The mashing conditions allow to reduce carbohydrate content from 65 to 49 % by extracting most of the fermentable sugars leaving cellulose and hemicellulose behind. However, the remaining composition with high moisture content (75-80 %) is particularly vulnerable to bacteria, yeast and mould development. LCB compositions such as BSG are usually determined through fractionation and include: cellulose, hemicellulose, lignin, protein, lipids and ashes , with a C:N ratio of 13.9 for BSG. A meta-analysis of articles and reviews from the literature was conducted, gathering up to 38 references and the middles values alongside minimal and maximal percentage values are reported in It can be observed that for each fraction of BSG's lignocellulosic matrix, the percentage can go from simple to double, which confirms the high variability of its composition. However, it can be an advantage as the selection of a certain malt type and extraction condition can yield to a tailored composition richer in one or several fractions of interest, improving the potential valorisation for a specific fraction. The third fraction of BSG is proteins (15-25 %DM), mainly composed of hordein, gluten, globulin and albumin , with a composition of amino acids that greatly varies between pale and dark malt. Extracted proteins form BSG (104.2 mg/gBSG) were degraded in enzymatic conditions (Aspergillus niger) yielding 17 amino acids with the most prominent being valine, alanine, phenylalanine, tryptophan and proline.