Browsing by Author "Sahin, Oya Irmak"
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Item ENZYME CATALYZED BIOREMEDIATION IN FOOD INDUSTRY(Livre De Lyon, 2021-09) Sahin, Oya IrmakItem Microalgal biomass—a bio-based additive: evaluation of green smoothies during storage(International Food Research Journal, 2021-04) Sahin, Oya IrmakMicroalgae biomass addition to food has been studied for its nutritional fortification. The present work investigates the impact of microalgae (Chlorella vulgaris and Dunaliella salina) addition, in terms of quality characteristics, during a 28-day storage at 5°C. As much as 2.5% (w/v) of C. vulgaris and D. salina were separately added to fresh green smoothies (spinach, green apple, and cucumber) as food additive. Without any thermal application during storage at 5°C, the changes in pH, total soluble, solid contents, titratable acidity, microbial loads, phenolic contents, antioxidant activity, and sensory characteristics were determined. The addition of microalgae biomass, either Chlorella or Dunaliella, was found statistically significant, but this addition did not make a significant difference during the 28-day storage. Compared to control samples (at day 0; 163.16 mg GAE/100 g and 2.56 mmol GAE/100 g), Dunaliella biomass affected green smoothie more positively on total phenolic (at day 0; 395.79 mg GAE/100 g) and antioxidant activity (at day 0; 5.54 mmol GAE/100 g), than Chlorella biomass (at day 0; 384.21 mg GAE/100 g and 4.22 mmol GAE/100 g). Also, a shelf-life study on 28-day storage at 5°C found that Dunaliella-added smoothies were more preferred by the panellists, while Chlorella-added samples exhibited off-odour and off-flavour through storage. Smoothie supplementation with 2.5% microalgae biomass caused a decrease in the initial microbial load. Due to this reduction, it can be said that microalgae supplementation as an additive was effective, and microalgae-added samples were shown below the "microbiologically consumable level" throughout the 28-day shelf-life studyItem Production of Spirulina platensis Biomass Under Different Temperature and Nitrogen Regimes(Journal of Raw Materials to Processed Foods, 2021-12) Sahin, Oya Irmak; Akpınar Bayizit, ArzuSpirulina is of the worldwide cultivated and consumed microalgae. It is generally used directly or as an additive in the food industry due to its high protein content. Besides the high protein content Spirulina biomass contain important fatty acids, (e.g., GLA), vitamins, minerals, and some bioactive compounds, that are affected by the parameters of biomass cultivation. In the presented study, the limitation of nitrogen (25%, 50%, 75% and 100% N concentration) and temperature fluctuations (25°C and 30°C) on Spirulina platensis growth parameters, biomass, protein, total phenolic, total carotenoids and antioxidant capacity were investigated and the production of Spirulina platensis was optimized in terms of biomass and metabolites.While the amount of biomass increased in general with the increase in temperature, dry weight decreased. The highest level of the protein accumulation was determined at 30°C and Spirulina medium with 100% N concentration. Protein, total phenolic substance, and total carotenoid amounts were found at the higher level with the temperature increase to 30°C in all samples.Item Removal of Azo Dyes - Tartrazine, Carmoisine, and Allura Red - from Wastewater using Spirulina Biomass-Immobilized Alginate Beads: Equilibrium, Kinetics, Thermodynamics, Desorption, and Reusability(Desalination and Water Treatment, 2021-04) Sahin, Oya IrmakIn the present study, Spirulina microalgae-immobilized alginate beads (Alg-SP) were used as novel adsorbents for the adsorption of tartrazine, carmoisine, and Allura Red azo-dyes from wastewater. Synthesized Alg-SP beads were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry analyses. Maximum azo-dye removal percentages were achieved using 100 mg of Alg-SP beads with a ratio of 3.0%(w/v) within 2 h, and tartrazine, carmoisine, and Allura Red removal performances were determined to be 98%, 93%, and 82%, respectively. The adsorption data for azo-dyes onto Alg-SP beads were evaluated by several isotherm equations such as Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Halsey, and Harkins–Jura isotherm models, but were best described by the Langmuir and Harkins–Jura models as they gave the highest correlation. Pseudo-first-order, pseudo-second-order, Elovich, Weber–Morris, and Bangham models were investigated and dye adsorption onto Alg-SP beads was represented by pseudo-second-order and Elovich kinetic models. After the adsorption process, the beads can easily be regenerated by NaOH and effectively reused over three cycles. Consequently, Spirulina microalgae-immobilized alginate beads have considerable potential for the adsorption of dyes from wastewater.Item Seaweed Polysaccharides: Structure, Extraction and Applications(John Wiley & Sons, Inc., 2021-05) Sahin, Oya IrmakFor the last decades, there has been a profound interest in metabolites from marine sources. In marine habitat, seaweed is a precious source of biologically active compounds. Polysaccharide‐rich seaweeds contain these metabolites, such as agar, carrageenan, fucoidan, alginate and ulvan, in their cell walls and intracellular structures. These sulfate‐structured polysaccharides have drawn attention in recent years in the food, pharmaceutical, cosmetics and clinical fields. This chapter presents a general information about chemical structure, extraction procedures, properties and a brief report for the potential applications of these polymers.