ABSTRACT
The present study was carried out to study the physico-chemical changes that take place in both product and oil during the deep fat frying of a traditional savoury snack 'kodubale', at 120-160 °C for 120-600 s using coconut oil (CO) and nutra-coconut oil (NCO). Further, kinetic studies on moisture loss, oil uptake, color and degradation of ß-carotene, total polyphenol content and antioxidant activity for kodubale was carried out during frying as a function of temperature and time. The study showed that the kinetic coefficients for above parameters increased with temperature and time and the data obtained were well fitted with first order kinetic model. The results also revealed that NCO fried product retained major phenolic acids due to the presence of antioxidants in the NCO which was enriched with flaxseed oil concentrate. The fatty acids profile of oil extracted from products obtained by frying using NCO was characterized with higher ω-3 and ω-6 fatty acids content as compared to same obtained using CO. However, the breaking strength and sensory characteristics of CO and NCO fried kodubale was found to have no significant difference (p < 0.05).
ABSTRACT
The freshwater green algae, Scenedesmus obtusus, was cultivated in a 3.4 L airlift photobioreactor. The hydrodynamic parameters were estimated at different inlet gas flow rates (1, 2, 3, and 4 LPM) and their subsequent impact on the growth and biochemical characteristics of microalgae was studied. The biomass concentration and productivity increased with an increase in flow rates from 1 to 4 LPM. A maximum of 0.07 g L-1 day-1 productivity of biomass was attained at 3 LPM. An increase of total carbohydrate content from 19.6 to 26.4% was noticed with increment in the inlet flow rate of gas from 1 to 4 LPM. Major variations in total fatty acid content were not observed. The impact of light irradiance on growth and biochemical characteristics of S. obtusus was also evaluated. A maximum biomass productivity of 0.103 g L-1 day-1 was attained at an illumination of 150 µmol m-2 s-1 under continuous light. The major fatty acids reported were palmitic acid (C16:0), α-linolenic acid (C18:3), linoleic acid (C18:2), and oleic acid (C18:1). Biodiesel properties of the microalgae were estimated under various culture conditions. The light profile inside the airlift reactor was experimentally measured and the predictive modelling of light profile was also attempted.
Subject(s)
Scenedesmus , Biomass , Fresh Water , Hydrodynamics , Light , Microalgae , Photobioreactors , PhotoperiodABSTRACT
Scenedesmus obtusus, a freshwater microalga, was evaluated for its growth and biochemical characteristics under various culture conditions. S. obtusus was tolerant at all tested CO2 concentrations up to 20%. Among the different nitrogen sources, urea showed enhanced biomass productivities up to 2-fold compared to control, where the nitrogen source was sodium nitrate. Light intensity and photoperiod had a significant effect on growth rate and biomass productivity. The growth rate was observed maximum under continuous light exposure at the light intensities, 30µmolm(-2)sec(-1) and 60µmolm(-2)sec(-1) The species was able to tolerate the salinity levels up to 25mM NaCl, where, the increase in the concentration of NaCl suppressed the growth. Ammonium acetate and glycine showed better growth rate and biomass productivity indicating mixotrophic ability of S. obtusus. Supplementation of acetate and bicarbonate significantly enhanced the biomass productivity. Biodiesel properties of S. obtusus cultivated at various culture conditions were estimated.
