Agnese Stunda-Zujeva

Growing and Drying Spirulina/Arthrospira for Producing Food and Nutraceuticals: A Review

Microalgae-cianobacteria Arthrospira (trade name Spirulina) are cultivated worldwide due to its nutritional and therapeutic qualities. The aim of this review is to summary production parameters affecting quality of Arthrospira. The biochemical composition of microalgae foodstuff is mostly determined by growing conditions, e.g. growth media, light intensity, temperature as well as drying method and conditions. This review showed that prospective directions for optimization of costs to cultivate Arthrospira indoors are: effective use of light, e.g., using effective artificial light sources like light emitting diodes (LED) in color with regards to necessary component in Arthrospira; mixotropic growth using growth media from food processing by-product/waste; and selection of Arthrospira strain according to available temperature. Common methods of algae drying for food and nutraceuticals are solar drying, convective drying, spray drying, lyophilization. The drying method and regime can greatly affect the amount of biologically active compounds and organoleptic quality.

Glass Formation and Crystallization in P2O5-Nb2O5-CaO-Na2O System

Abstract There is a lack of studies on a wide composition range for calcium phosphate glasses containing transition elements, e.g. niobium. Addition of Nb2O5 increases mechanical and chemical strength of calcium phosphate glasses and glass ceramics. Glass is formed in a wide range of compositions. CaO promotes batch melting. The oxidation state of niobium has important role in glass forming. Solid state reactions between P2O5 and Nb2O5 during batch melt change the oxidation state of niobium. Nb5+ in this system acts as an intermediate or conditional glass former (glass is yellow) while Nb4+ is a glass modifier (glass is blue). It is possible to obtain glass with Nb2O5 (Nb5+) content up to 70 mol%. The glass ceramics obtained by reheating powdered glass contained niobium in crystalline phases. The composition of crystalline phases depends on the phosphate amount.