Biomass and lipid productivities of Isochrysis galbana were optimized using nutrients of molasses (4, 8, 12 g l(-1)), glucose (4, 8, 12 g l(-1)), glycerol (4, 8, 12 g l(-1)) and yeast extract (2 g l(-1)). Combinations of carbon sources at different ratios were evaluated in which the alga was grown at three different light intensities (50, 100 and 150 μmol m(-2) s(-1)) under the influence of three different photoperiod cycles (12/12, 18/6 and 24/0 h light/dark). A maximum cell density of 8.35 g l(-1) with 32 % (w/w) lipid was achieved for mixotrophic growth at 100 μmol m(-2) s(-1) and 18/6 h light/dark with molasses/glucose (20:80 w/w). Mixotrophic cultivation using molasses, glucose and glycerol was thus effective for the cultivation of I. galbana.

The present study evaluates the oxidative stability in chikkis enriched with omega 3 fatty acids using natural antioxidant from Rosmarinus officinalis. The best condition for the extraction of phenolic compounds from Rosmarinus officinalis L. (rosemary) was established, and the antioxidant activity was demonstrated based on inhibition of DPPH free radical formation. Nannochloropsis oculata and Isochrysis galbana are rich sources of Eicosapentanoic acid (EPA) and Docosahexaenoic acid (DHA). Biomass of these microalgae were incorporated in chikkis as omega 3 fatty acid source. Effects of addition of natural and synthetic antioxidants (BHA) on oxidative stability of chikkis were analyzed for storage period of 2 months. Evaluation of peroxide value (PV) and fatty acid profile showed that the process of oxidation slowed down. Natural antioxidant was found to be more effective when compared to synthetic antioxidant (BHA). Omega-3 PUFA levels (EPA+DHA) of 75 and 240 mg/ 100 g chikkis were observed if enriched with 1 and 3 % Nannochloropsis oculata biomass respectively. Similarly, Omega-3 PUFA levels (EPA+DHA) of 102 and 320 mg/ 100 g chikkis were observed if enriched with 1 and 3 % Isochrysis galbana biomass respectively. The effects of microalgae and antioxidant incorporation on the chikkis showed that color values remained stable during storage period of 2 months with no significant change (P<0.05) in texture. Sensory evaluation revealed that up to 3 % microalgal biomass incorporation was positively classified and accepted.