Sheyma Khemiri

Aligning with sustainable green practices, this study examines the partial replacement of chickpea protein isolate with commercially available autotrophic Chlorella vulgaris (Auto-Chlorella) and heterotrophic Parachlorella kessleri (Hetero-Chlorella) to assess impacts on food emulsions’ properties and potential functional value. Rheology and texture analysis show that Chlorella biocompounds enhance emulsions by creating a synergistic network with chickpea proteins. The type of Chlorella used significantly influences emulsion characteristics due to differences in culture and processing conditions. Hetero-Chlorella contributed to more structured emulsions, revealed by higher values of the viscoelastic functions (G′, G″, and G⁰_N), indicating a complex three-dimensional network (p < 0.05), while Auto-Chlorella excelled in augmenting dietary elements (p < 0.05), leading to emulsions rich in antioxidants and allowing for a ’rich in iron’ claim. Both types contribute to smaller oil droplet size, improved firmness, adhesiveness, and appealing coloration (p < 0.05). Preliminary findings on Vitamin B12 content suggest promising bioavailability potential. However, the nutritional density of Chlorella emphasizes the need for careful microbiological stability. Produced on a lab scale without preservatives, these emulsions highlight the need for preservation strategies in large-scale production. This research supports the potential for industrial microalgae-based mayonnaise, addressing consumer demand for innovation while prioritizing safety.

Summary: Enrichment of foods by algae or their derived nutrients is of a great interest to enhance nutritional properties leading to health promotion and disease prevention by a sustainable way. In this context, five Chlorella vulgaris and one micro‐macroalgae blend (Algaessence®) with different biochemical compositions were used (6%) in the formulation of couscous in an attempt to modulate glycemic response and enhance functional aspect. Phytochemicals, such as carotenoids and phenolics were retained to a higher extent in algae‐couscous being the highest (5.58 mg GAE/g and 1.05 mg/g, respectively) in the couscous formulated with autotrophic Chlorella (designated as Organic). Starch fractions and in vitro starch digestion of the products were determined. The highest starch content was found in control couscous (73.83%) which resulted in higher digestible starch (70.55%). The kinetic constant, designative of the hydrolysis rate in the early stage, was the lowest in algae‐couscous (0.022). The lowest hydrolysis index of 70.27% and 71.71% were observed in Organic and White couscous (heterotrophic), respectively; leading to lower glycemic index of 78.21% (Organic) and 79.00% (White). The obtained results evidence the potential use of algae in the formulation of value‐added food products designated for controlled diets.

The aim of this work was to develop functional couscous in a traditional Tunisian manner (hand rolling), enriched in algae biomass (6% w/w). Four Chlorella vulgaris (C. vulgaris) biomasses and one mixture of C. vulgaris and two macroalgae biomasses (Ulva rigida and Fucus vesiculosus) were used. The C. vulgaris strain was subjected to random mutagenesis and different culture conditions (Allmicroalgae), resulting in different pigmentations and biochemical compositions. Couscous samples were characterized in terms of nutritional properties, oscillatory rheology properties and digestibility. All biomasses provided a significant supplementation of nutrients and excellent acceptance. The enrichment resulted in lower firmness, higher viscoelastic functions (G′ and G″) and a significant improvement in the cooking quality. Major differences between couscous samples with different microalgae were observed in protein and mineral contents, fully meeting Regulation (EC) No. 1924/2006 requirements for health claims made on foodstuffs. The amount of digested proteins was also higher in algae-containing samples. The fatty acid profile of the enriched couscous varied in a biomass-specific way, with a marked increase in linolenic acid (18:3 ω3) and a decrease in the ω6/ω3 ratio. Sensory analysis revealed that microalgae-containing products could compete with conventional goods with an added advantage, that is, having an ameliorated nutritional value using algae as a “trendy” and sustainable ingredient.

Research background. Microalgae represent an emergent sustainable source of bioactive compounds such as antioxidants, vitamins, minerals and polyunsaturated fatty acids that can ameliorate the nutritional characteristics of foods. The biochemical composition of microalgae could be modulated by varying the culture conditions to enhance the accumulation of biomolecules of interest. The aim of this work is to optimise the nutri-functional properties of two microalgae that can be used in food production. Experimental approach. Nannochloropsis gaditana L2 and Chlorella sp. SM1 were screened for growth, biochemical composition and radical scavenging activity employing four different growth media (algal, BG-11, f/2 and Conway) with different nutrient composition. The feasibility of using Chlorella sp. SM1 cultivated in BG-11 medium, in an under-investigated Mediterranean dairy product ricotta cheese and its effect on the sensory attributes was investigated. Additionally, Arthrospira platensis was used as reference in sensory analysis. Results and conclusions. Nitrate- and phosphate-rich media (BG-11 and algal) enhanced the biomass productivity. However, the highest lipid production (23.10 and 11.86 mg/(L·day) by strains SM1 and L2 respectively) and carbohydrate content (34.79 and 44.84 % by SM1 and L2 respectively) were obtained with the nitrate-deficient f/2 medium. Regardless of the used medium, the lipid profile of Chlorella sp. SM1 and N. gaditana L2 remained adequate for different applications with >50 % C16-18 as the main fatty acids. Significant increase in oleic acid (C18:1) content was recorded in response to nitrogen deficiency, being the highest in SM1 in f/2 medium (34 %). Nitrogen deficiency was also found to enhance phenolic compound (expressed as gallic acid equivalents, 48.8 and 35.1 mg/g in SM1 and L2 respectively) and carotenoid contents (2.2 and 2.0 mg/g in SM1 and L2 respectively). Due to its interesting antioxidant potential, Chlorella sp. SM1 was used at different mass fractions (0.2, 1 and 1.5 %) to enrich the ricotta cheese. The sample with 0.2 % Chlorella sp. SM1 was found to give the most appreciated product. Novelty and scientific contribution. This study presents the production of an innovative ricotta cheese using Chlorella sp. as a functional ingredient, without altering the manufacturing procedure, while maintaining acceptable sensorial characteristics. The biochemical composition of the used strains varied depending on the culture medium composition, which enabled the accumulation of phytonutrients of interest.