Effects of addition of algae biomass on the structure, bioactivity and nutritional properties of Halloumi-like cheese

Abstract

The incorporation of microalgal biomass into milk products has gained as a way to create more sustainable and nutritionally enhanced fermented products. This study aimed to assess how adding algae (specifically Chlorella vulgaris and a blend of C. vulgaris, Fucus vesiculosus, and Ulva rigida) influences the rheological behavior (Small Amplitude Oscillatory Shear - SAOS), nutritional value, and bioactivity of Halloumi-like cheese. Since it is usually consumed grilled, frequency sweep tests at 20 °C and temperature sweeps from 20 °C to 90 °C were conducted. The results showed that the addition of microalgae at levels ranging from 1 % to 5 % w/w noticeably affected the cheese's rheological properties. Texture analysis of the cheeses carried out using a puncture test evidenced a decrease in hardness as algae content increased. Nutritional composition (namely moisture, protein, and ash) was significantly (p < 0.05) influenced by the inclusion of different concentrations of algal biomass. A 5 % Chlorella-enriched cheese showed a 40.5 % rise in ash-in-dry-matter (with notable increases in sodium (Na), manganese (Mn) and iron (Fe)) and a 10.6 % rise in protein-in-dry-matter compared to the control sample. In terms of bioactivity, the results showed an increased antioxidant capacity (ferric ion reducing antioxidant power - FRAP assay) and higher levels of total phenolic compounds (Folin-Ciocalteu technique), especially in treatments supplemented with 3 % and 5 % C. vulgaris (p < 0.05). Sensory evaluation of Halloumi-like cheeses indicated that panelists preferred the control and 1 % Chlorella-enriched cheese, both scoring an overall acceptability of 4.2 on a 1–5 scale. Moreover, 53 % and 30 % of the panel members indicated they “would probably buy” the cheese fortified with 1 and 3 % C. vulgaris, respectively, suggesting potential customers appeal for these innovative cheeses combining both animal and plant-based ingredients.