Marcelina Stach

Despite increasing interest in raspberry leaves (Rubus idaeus L.) as a source of bioactive compounds, comparative information linking their phenolic composition to multiple biological properties remains limited. This study compared the polyphenolic profiles and biological properties of leaves from seven raspberry cultivars representing Rubus idaeus L. and Rubus occidentalis L., grown under identical environmental conditions. Phenolic compounds were characterized by UPLC–Q/TOF-MS, while antioxidant capacity, α-amylase and α-glucosidase-inhibitory activities, inhibition of COX-1 and COX-2, and effects on colorectal cancer cell viability were evaluated. A total of 37 phenolic compounds were identified or tentatively characterized, with flavan-3-ols and procyanidins representing the quantitatively predominant phenolic group, followed by flavonols. Considerable variation in both phenolic composition and biological responses was observed among the cultivar-specific composite samples. Red-fruited samples generally showed higher antioxidant capacity, whereas α-amylase- and α-glucosidase-inhibitory activities varied among the samples. In contrast, the strongest COX-1 and COX-2 inhibition was observed for the yellow-fruited Poranna Rosa sample. Effects on colorectal cancer cell viability also varied among the samples, with the red-fruited samples generally producing greater reductions in LOVO, LOVO-DX, and SW48 cell viability. Exploratory Spearman correlation analysis using exact permutation-based p-values followed by FDR correction showed that flavan-3-ol and total polyphenol concentrations were positively associated with ABTS and FRAP antioxidant capacity and inversely associated with LOVO, LOVO-DX and SW48 cell viability at 600 μg/mL. No FDR-significant associations were observed for carbohydrate-hydrolyzing enzyme or COX inhibition. Overall, these results demonstrate substantial variation in the phenolic composition and biological properties among the analyzed raspberry leaf samples analyzed. Because the species, cultivar identity, and fruit color group cannot be separated within the present experimental design, the observed differences should not be independently attributed to genotype or fruit color. These findings support further investigation of raspberry leaves as sources of bioactive phenolic compounds for potential food and nutraceutical applications.

The purpose of this article is to present information about changes in physical properties (pH, TA, and color) and chemical components with bioactive activity in cold brew coffee beverages, during storage before and after HTST processing. Coffee samples were tested using industrial technology (12,000 bottles per batch). The antioxidant activity of the samples was analyzed using ABTS and FRAP methods, the concentration of polyphenols was determined using the UPLC-MS chromatography coupled with mass spectrometry method, and microbiological tests were performed according to PN-ISO/PN-EN ISO standards. The pH value decreased during coffee storage, and the color changed significantly in brightness. Polyphenol concentrations were calculated in the range of 1800 to almost 3400 mg/L, and the antioxidant capacity for ABTS and FRAP reached the ranges of the results successively: 123–195 µMol/100 mL and 158–212 µMol/100 mL. It was observed that HTST pasteurization has a beneficial effect on preserving the beverage in microbiological terms. Also, a positive effect of the process on the release of chemical components responsible for bioactive properties from the beverage was observed, followed by a reduction in antioxidant activity during the first 90 days of storage and between 180 and 270 days during storage.

The aim of the study was to evaluate the effect of the use of different polysaccharides and their mixtures on the structure of chokeberry hydrogel microcapsules and the stability of polyphenolic compounds and antioxidant capacity during one month of refrigerated storage. As a coating material, alginate and its mixtures with pectin, carrageenan, and chitosan were used, while chokeberry juice and preparation of polyphenolic compounds were used as a core. In non-stored capsules, the addition of carrageenan, pectin, and chitosan to alginate increased the content of total polyphenolic compounds and antioxidant capacity. When compared to non-encapsulated juice, the capsules had a greater decrease in antioxidant capacity during storage. The coating variant composed of alginate and carrageenan was found to be the most beneficial for the preservation of the capsules’ phenolic compounds. The findings revealed that proper polysaccharide coating selection is critical for the proper course of the microencapsulation process, the polyphenolic content of chokeberry capsules, and their antioxidant properties.