Ultrasound and Enzyme-Assisted Development of Advanced Ingredients from Rowanberry (Sorbus aucuparia L.) Pomace and Its Application in Bread

Novel ingredients from rowanberry pomace were developed for French-type bread applications via supercritical CO2 extraction and the enzymatic and ultrasound treatment of the defatted residue (DFR), which contained 6.367% of proteins, 8.36% of soluble, and 43.04% insoluble fiber. Proteolytic enzymes from Bacillus licheniformis and Aspergillus oryzae, and cellulolytic enzyme mixtures Viscozyme L and Celuclast, were used to increase the soluble fraction. Treating DFR with enzymes generated significant amounts of soluble substances containing oligosaccharides, fructose, and glucose, with Viscozyme L being more effective than proteases. Tri-, and tetrapeptides, chlorogenic acids, and dihydroxy coumarins were also present in the soluble extracts of fermented DFR. The antioxidant characteristics of treated DFR were evaluated by the in vitro assays. Substitution of >5% of wheat flour with untreated DFR significantly reduced bread volume and crumb porosity; however, these adverse effects were mitigated by using fermented DFR. The highest bread volume (1845 cm3) and porosity (78.38%) were observed in bread containing 5% pomace that underwent enzymatic hydrolysis and ultrasound treatment. The substitution of flour with DFR significantly increased the antioxidant characteristics of bread samples and the substances generated during the in vitro digestion. It may be concluded that rowanberry pomace ingredients may improve bread nutritional quality and assist in the sustainable use of fruit processing by-products.