Ultrasound-Assisted Extraction of Phenolic Compounds from Post-Fermentation Cherry Residues. Effects of Particle Size and Drying Methods

The utilization of various fruits such as cherries in liquor production is a well-established approach in the food industry. However, the production of these liquors results in the generation of substantial by-products, such as post-fermentation sour cherry residues (PFCR). These by-products remain rich in bioactive compounds and can be valorized through the recovery of these compounds. In this research, an ultrasound-assisted extraction method was employed to recover phenolic compounds from PFCR. The efficiency of the extraction process was evaluated by varying the particle size and the drying method of samples before extraction. Initially, the PFCR was subjected to drying using both oven-drying and freeze-drying methods. The dried samples were ground, and three different particle sizes were obtained using sieves. The findings indicated that smaller particle sizes resulted in higher extraction efficiency, presumably due to the increased surface area of the smaller particles. Moreover, freeze-drying of PFCR resulted in extracts with significantly superior total phenolic content and antioxidant activity compared to oven-drying (P<0.05). The extracts obtained from the samples with the smallest particle size were incorporated into sunflower and soybean oils to enhance their oxidative stability. The results from the Rancimat test demonstrated that both extracts significantly increased the antioxidant activity index (p<0.05). This study concluded that extracting phenolic compounds from freeze-dried PFCR with low particle size holds potential for various applications in the food industry.