Oleraceins are a class of indoline amide glycosides found in Portulaca oleracea L. (Portulacaceae), or purslane. These compounds are characterized with 5,6-dihydroxyindoline-2-carboxylic acid N-acylated with cinnamic acid derivatives, and many are glucosylated. Herein, hydromethanolic extracts of the aerial parts of purslane were subjected to UHPLC-Orbitrap-HRMS analysis, conducted in negative ionization mode. Diagnostic ion filtering (DIF), followed by diagnostic difference filtering (DDF), were utilized to automatically filter out MS data and select plausible oleracein structures. After an in-depth MS2 analysis, a total of 51 oleracein compounds were tentatively identified. Of them, 26 had structure matching one of already known oleraceins and the other 25 are new, undescribed in the literature structures, belonging to the oleracein class. Moreover, diagnostic fragment ions were selected, based on which clustering algorithms and visualizations were employed. As we demonstrate, clustering methods can provide valuable insights into the mass fragmentation elucidation of natural compounds in complex mixtures.

In this study, Portulaca oleracea (purslane) was investigated as a potential antioxidant supplement in cooked sausages, with a focus on its effects on lipid oxidation, fatty acid composition, and antioxidant activity. The fatty acid profile of the sausages enriched with 1.2% of purslane powder, revealed a 1.3-fold increase in alpha-linolenic acid (ALA), an essential omega-3 fatty acid. Improved oxidative stability during refrigerated storage was observed, with peroxide values of 10.9 meq/kg in the sausages with purslane by day 10, compared to 12.5 meq/kg in the control sausages. Thiobarbituric acid (TBA) values, reflecting lipid peroxidation, were also significantly lower in the sausages with purslane. The antioxidant capacity was significantly enhanced in the sausages containing purslane, which demonstrated a Ferric Reducing Antioxidant Power (FRAP) of 13.5 mg GAE/g, whereas the control sausages showed undetectable FRAP levels. Additionally, the DPPH radical scavenging activity in the sausages with purslane was 21.70%, compared to 13.73% in the control. These findings suggest that purslane not only improves the nutritional profile of meat products by increasing beneficial fatty acids but also provides substantial protection against oxidative spoilage. Portulaca oleracea offers a promising natural alternative to synthetic antioxidants, enhancing both the shelf life and quality of processed meats.