Effects of Growth Medium Variation on the Nutri-Functional Properties of Microalgae Used for the Enrichment of Ricotta

• Published in: Food technology and biotechnology 2022-01, Vol.60 (1), p.29-40
• Main Authors: Khemiri, Sheyma, Bouchech, Ines, Berrejeb, Nadia, Mejri, Mondher, Smaali, Issam, Khelifi, Nadia
• Format: Article
• Language: English
• Subjects: Accumulation; Algae; Analysis; antioxidant ability; Antioxidants; Aquatic microorganisms; Arthrospira platensis; Bioactive compounds; Biochemical composition; Biochemistry; Biomolecules; Carbohydrates; Cheese; Chlorella; Chlorella sp; Composition; Culture media; Dairy products; Fatty acids; Food composition; Food production; Gallic acid; Growth; Growth media; Lipids; Microalgae; Minerals; Nannochloropsis gaditana; Nitrogen; Nutrients; Nutrition; nutritional profile; Oleic acid; Original Scientific Papers; Pharmaceutical industry; Phenolic compounds; Phenols; Polyunsaturated fatty acids; ricotta cheese; Scavenging; Sensory evaluation; Sensory properties; Unsaturated fatty acids; Vitamins
• ISSN: 1330-9862; 1334-2606
• DOI: 10.17113/ftb.60.01.22.7105

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. L2 and 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 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, was used as reference in sensory analysis. 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 sp. SM1 and 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, sp. SM1 was used at different mass fractions (0.2, 1 and 1.5%) to enrich the ricotta cheese. The sample with 0.2% sp. SM1 was found to give the most appreciated product. This study presents the production of an innovative ricotta cheese using 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.