Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

Arthrospira platensis is a cyanobacterium that exhibits a large biotechnological interest for the food industry because of its high protein content, pigments, lipids and carbohydrates. The extracellular polymeric substances (EPS) are co-products of secondary metabolism that may present thickening or gelling property. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) to evaluate the biomass and EPS production by Arthrospira platensis. The best result for biomass production was obtained under condition 6 (2 g.L-1 NaNO3 and 600 µE.m-2s-1) leading a biomass concentration of 1.292 mg.L-1. Condition 1 (0.25 g.L-1NaNO3 and 200 µE.m-2s-1) produced the major EPS yield (111 mg.g-1) followed by condition 9 (2 g.L-1NaNO3 and 1000 µE.m-2s-1). The present of carboxylate and sulfate functional groups was identified in EPS samples. Rheological studies performed for some EPS products at 5 and 10 g.L-1 concentrations revealed a dilute solution behavior.

Phase selective organogel from an imine based gelator for use in oil spill recovery

The superior gelling property of anthracene anchored Schiff base is used as a phase-selective gelator promoting it for oil spill recovery from oil–water mixtures, even in the presence of salts, acids and bases.

Improvement of Gel Properties of Fish Gelatin Using Gellan

The impact of gellan (GL) at different levels (5–20 % of total solid) on the properties of fish gelatin (FG) gels was studied. Gel strength and hardness of FG/GL mixed gel increased, while springiness and cohesiveness decreased as the levels of GL were increased (p< 0.05). Gelling and melting temperatures also increased with increasing levels of GL incorporated (p< 0.05).L*- andb*-values of FG/GL mixed gel decreased, whereas∆E*-value increased with increasing GL levels (p< 0.05). Microstructure studies revealed that denser structure with very small voids in gel network was observed upon GL addition. The addition of GL at a low level (5 %) had no adverse effect on sensory property, and no effect on syneresis of FG/GL mixed gels. Therefore, the addition of 5 % GL can be used to improve gelling property of FG via increasing gelling points without affecting sensory property of the resulting gel.

Effect of Trypsin on Antioxidant Activity and Gel-Rheology of Flaxseed Protein

Enzymatic hydrolysis of flaxseed protein (FP) was carried out using trypsin in order to obtain flaxseed protein hydrolysates possessing better antioxidative property and modified rheological properties. The antioxidative properties of hydrolysates were much higher than the unhydrolyzed flaxseed protein. The hydrolysis also significantly reduced the hydrodynamic diameter of the magnitude of zeta potential of the dispersions. The gelling point of the hydrolysates occurred earlier than the unhydrolyzed sample while the duration of hydrolysis (30–120 min) did not affect gelling point of the hydrolysates. Considerable decrease in the gel strength and the frequency dependence of gel strength were observed in gels produced using hydrolyzed flaxseed protein. The above findings indicate that hydrolysates possessing high degree of antioxidative properties. The gels produces from these hydrolysates will have fast gelling property and will produce gels with reasonable strength. Thus, flaxseed protein hydrolysates obtained from trypsin hydrolysis can be used in applications that require proteins with higher antioxidative properties but softer texture.