CHEMICAL-COMPOSITION OF OLIVE BY-PRODUCT AND MODIFICATIONS THROUGH ENZYMATIC TREATMENTS

The purpose of the present work was to study the dietary fibre (DF) fr action of olive cake and modify the fibre structure through enzymatic treatments in order to improve the sensory quality of this by-product for its incorporation into a baked product. Two different commercial e nzyme preparations were used for enzymatic modifications: Viscozyme L, a hemecellulase/cellulase multienzyme complex, and Olivex which conta ins different pectolitic main activities as well as various side activ ities, hemicellulases and cellulases. DF consists of 800 g total dieta ry fibre per kg dry matter. More than 91% of the DF are insoluble and the monosaccharide composition of this fraction indicates the presence of mainly cellulose and xyloglucans or xylans. Approximately 75% of t he uronic acids found in olive cake are associated to the insoluble DF (IDF). Arabinans and uronic acids polysaccharides are the major fibre components in the soluble DF (SDF) fraction. Enzymatic treatments wit h commercial preparations caused changes in the DF content and in the IDF:SDF ratio depending on enzyme concentrations and incubation time. Baking experiments showed that a substitution of 10% of wheat flour by enzymatically modified olive cake led to an improved texture compared to products containing untreated cake.