Abstract: A method of treating plant biomass material involves treating the material with sesquioxide mineral forming constituents to form protective coatings on surfaces of the material and to alter the bulk physical and chemical properties of the treated material. The material is treated with an aqueous solution of soluble iron and/or aluminum thus improving microbial stability and quality of the materials.

Abstract: A protein stabilizer additive comprises two or more of a tris compound of the formula (1): (HOCH.sub.2).sub.3 --C--R, wherein R is: C.sub.1 -C.sub.4 alkyl, substituted C.sub.1 -C.sub.4 alkyl, NH.sub.2 ; NR.sup.1 R.sup.2 wherein R.sup.1 and R.sup.2 may be independently: H, C.sub.1 -C.sub.4 alkyl sulphonate, C.sub.1 -C.sub.4 hydroxyalkyl sulphonate; C.sub.1 -C.sub.4 alkyl NHC(CH.sub.2 OH).sub.3, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 hydroxyalkyl; C.sub.1 -C.sub.4 alkyl carboxylate; a polyelectrolyte; a buffer; and one or more additional components for example divalent metal salts.