Green Processing of Black Raspberry Pomace: Application of Sonotrode-Based Extraction Technique and Particles from Gas-Saturated Solutions (PGSS) Technology

The aim of this study was to develop, for the first time, anthocyanin-enriched fractions from black raspberry pomace (BRP) using ultrasound-assisted extraction (UAE) via sonotrode and the Particles from Gas-Saturated Solutions (PGSS) process. UAEs with different amplitudes and sonication times were evaluated and showed relevant effects on the yields of target analytes. The raspberry pomace extracts were formulated in a powder form by PGSS using glyceryl monostearate as a carrier at different extract-to-carrier ratios of 1:11, 1:5, and 1:3. The effects of all variables were evaluated in terms of extraction yield, total phenolic content, and encapsulation yield. UAE was strongly affected by amplitude, and the highest amplitude (100%) provided the best results for extraction yield and total phenolics. HPLC of UAE extracts and powders was utilized for quantification of polyphenol compounds, showing cyanidin-3-rutinoside as a main compound, followed by cyanidin-3-glucoside, rutin, ellagic acid, and gallic acid. These results show that these time-efficient and high-performance techniques enable the production of natural fractions from industrial BRP with acceptable characteristics to be used for the development of nutraceuticals and different food formulations.