Ultrasound- and Enzyme-Assisted Valorization of Defatted Viburnum opulus L. Berry Pomace for the Development of...

This research aims to develop functional ingredients from guelder-rose (Viburnum opulus L.) fruit pomace (VoP) using supercritical CO₂ extraction, enzyme and/or ultrasound treatments, and to test selected VoP ingredients in bread formulae. The defatted by supercritical CO₂ VoP contained 9.29% protein, 62.01% insoluble, 4.81% soluble dietary fiber, 2.33% minerals, and 39.11 mg/g gallic acid equivalents (GAEs) of phenolics. Its ABTS^•+-radical-scavenging capacity was 120.2, and the oxygen radical absorption capacity (ORAC) was 52.93 mg trolox equivalents (TEs)/g. The defatted VoP was further treated with Viscozyme L, Alcalase, and Flavourzyme. Viscozyme/ultrasound recovered the highest yield (35.13%) of soluble compounds; however, the extracts obtained with Flavourzyme/ultrasound demonstrated the highest antioxidant capacity: TPC of 108.3 mg GAE/g and ABTS^•+ scavenging, 195.3, and ORAC, 219.3 mg TE/g. Insoluble fiber was further fermented with Viscozyme L and Celluclast 1.5 L with or without ultrasound, resulting in the formation of 6.66%-17.82% of soluble substances. Carbohydrate composition was determined in the solubilized substances after first and second steps of fermentation. VoP was used in bread recipes as a substitute for 5%, 7.5%, and 10% of the wheat flour. Higher doses of untreated VoP adversely affected bread volume and porosity; however, these effects were mitigated by Viscozyme/ultrasound treatments, with bread containing 7.5% VoP exhibiting the best-quality properties. Antioxidant capacity was 2.7-3.6 times higher in bread with 10% VoP than in bread without additives. Antioxidant release from baked products with VoP was also remarkably higher than that from control bread, according to in vitro digestion research. PRACTICAL APPLICATIONS: Guelder-rose berry pomace, a by-product of juice pressing, can be successfully used as a partial replacement for wheat flour in bread. Enzymatic and ultrasound treatments mitigate the adverse effects of a higher replacement level and significantly increase the nutritional value of bread. The developed ingredients and technology are ready for industrial upscaling and practical application. The study may help improve the sustainability of small fruit processing and the healthiness of bread.