Determination of the fruit content of strawberry yogurt by gravimetric quantification of hemicellulose

The applicability of a recently developed method for the determination of the fruit content of fruit preparations to strawberry yogurts was investigated. For this purpose, the protein matrix of the yogurts was enzymatically digested using commercial protease preparations. the alchol-insoluble residue (AIR) was isolated and subsequently differentiated in the pectin, hemicellulose, and cellulose fractions. The calculation of the fruit content of the strawberry yogurts eas based on the amount of hemicellulose, wich was quantified gravimetrically. A good agreement of initial and calculated fruit content was obtained for yogurt containing 30% strawberrys (31.5%), whereas larger deviations were observed with decreasing strawberry contents.