FREEZE-DRIED RASPBERRY POMACE: A RICH RESERVOIR OF POLYPHENOLS WITH ANTIOXIDANT AND PROTECTIVE EFFECTS AS A PROMISING FUNCTIONAL FOOD ADDITIVE

Abstract

Background. Raspberries (Rubus idaeus L.) hold significant importance in the food industry. Rasp berry pomace, commonly regarded as a waste product during fruit processing, is a rich source of biologi cally active components. This study aimed to assess the detailed profile of polyphenols in fresh and freeze dried raspberry pomace. Furthermore, we examined its potential to protect normal human gastric epithelial cells against oxidative stress in an H2O2-induced stress model. A qualitative and quantitative analysis of phenolic compounds was performed using the high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) method. Cell viability was assessed based on the integrity of lysosomal membranes (neutral red NR assay) and mitochondrial dehydrogenase activity (MTT). Additionally, the reducing potential (FRAP), the ability to scavenge free radicals in the DPPH• test and studies on ABC HP021X cells based on the H2DCFDA test were evaluated. Results and conclusion. It was found that the extract from freeze-dried raspberry pomace is a rich source of various polyphenolic compounds, including ellagitannins, epicatechin and anthocyanins. The extract was characterized by high antioxidant potential and exhibited a protective effect on human gastric epithelial cells against H2O2-induced cytotoxicity. Cell incubation with the extracts prior to oxidative stress induction attenuated H2O2-induced cytotoxicity in a concentration-dependent manner, and at a con centration of 250 µg/cm3 , it abolished the detrimental effects of H2O2. Additionally, the extract at this concentration restored the redox status in cells with induced oxidative stress and reduced ROS levels to values similar to the control. Thus, raspberry pomace extracts may be considered a valuable food supplement.