Gracilaria gracilis fortification as a sustainable strategy for improving nutritional quality and storage stability of Parizer: a laboratory-scale study

Processed meat products are widely consumed but are often associated with high fat content, oxidative instability, and pro-inflammatory effects. Incorporation of red macroalgae may improve their nutritional profile. This study investigated the effect of 5% Gracilaria gracilis incorporation on Parizer quality by evaluating compositional, cytocompatibility, structural, and oxidative stability parameters during refrigerated storage. Based on sensory evaluation, the control and the 5% G. gracilis formulation (Gracilaria-Parizer) were selected for further analysis. The fortified product showed improved nutritional characteristics, including reduced fat content (32.65% to 29.86%) and increased dietary fiber (0.82% to 2.17%), while maintaining protein levels. Cytotoxicity assays demonstrated good biocompatibility, with cell viability remaining above 98% in both THP-1 macrophages and Caco-2 intestinal epithelial cells. Microstructural analysis revealed a more cohesive protein network and improved fat distribution in the fortified product. In addition, G. gracilis incorporation enhanced oxidative stability during storage, as evidenced by lower peroxide and p-anisidine values and a slower decline in iodine values compared with the control. Protein secondary structure analysis indicated reduced storage-induced denaturation, while principal component analysis confirmed the overall improved stability of the fortified product. These findings suggest that G. gracilis is a promising functional ingredient for improving the nutritional quality and storage stability of Parizer.