Ozan N. Ciftci

Conversion of olive pomace oil to cocoa butter-like fat in a packed-bed enzyme reactor

Refined olive pomace oil (ROPO) was utilized as a source oil for production of cocoa butter-like fat. Immobilized sn-1,3 specific lipase catalyzed acidolysis of ROPO with palmitic (PA) and stearic (SA) acids was performed in a laboratory scale packed-bed reactor. Effect of reactor conditions on product formation was studied at various substrate mole ratios (ROPO:PA:SA; 1:1:1, 1:1:3, 1:3:3, 1:2:6), enzyme loads (10%, 20%, 40%), substrate flow rates (1.5, 4.5, 7.5, 15 ml/min) and solvent amounts (150, 400 ml). The highest yield (10.9% POP, 19.7% POS and 11.2% SOS) was obtained at 40% enzyme load, 1:2:6 substrate mole ratio, 45 degrees C, 7.5 ml/min substrate flow rate, 150 ml solvent and 3h reaction time. The melting profile and SFC of the product were comparable to those of CB. Polarized light microscope (PLM) images showed no drastic changes in polymorphic behavior between CB and product.

Genetic programming approach to predict a model acidolysis system

This paper models acidolysis of triolein and palmitic acid under the catalysis of immobilized sn-1,3 specific lipase. A gene-expression programming (GEP), which is an extension to genetic programming (GP)-based model was developed for the prediction of the concentration of major reaction products of this reaction (1-palmitoyl-2,3-oleoyl-glycerol (POO), 1,3-dipalmitoyl-2-oleoyl-glycerol (POP) and triolein (OOO). Substrate ratio (SR), reaction temperature (T) and reaction time (t) were used as input parameters. The predicted models were able to predict the progress of the reactions with a mean standard error (MSE) of less than 1.0 and R of 0.978. Explicit formulation of proposed GEP models was also presented. Considerable good performance was achieved in modelling acidolysis reaction by using GEP. The predictions of proposed GEP models were compared to those of neural network (NN) modelling, and strictly good agreement was observed between the two predictions. Statistics and scatter plots indicate that the new GEP formulations can be an alternative to experimental models.

Formation of nanoporous aerogels from wheat starch

Biodegradable nanoporous aerogels were obtained from wheat starch using a simple and green method based on supercritical carbon dioxide (SC-CO2) drying. Effects of processing parameters (temperature, wheat starch concentration and mixing rate during gelatinization; temperature, pressure, and flow rate of CO2, during SC-CO2 drying) on the aerogel formation were investigated, and optimized for the highest surface area and smallest pore size of the aerogels. At the optimized conditions, wheat starch aerogels had surface areas between 52.6-59.7m(2)/g and densities ranging between 0.05-0.29g/cm(3). The average pore size of the starch aerogels was 20nm. Starch aerogels were stable up to 280°C. Due to high surface area and nanoporous structure, wheat starch aerogels are promising carrier systems for bioactives and drugs in food and pharmaceutical industries.

Reduction of Free Fatty Acid Content of Olive-Pomace Oil by Enzymatic Glycerolysis

The enzymatic glycerolysis of free fatty acids in olive-pomace oil was carried out by immobilised Candida antarctica lipase. The effects of time, molecular sieve, enzyme concentration and reaction temperature on free fatty acids content were investigated. The initial acidity of the olive-pomace oil (32%) was reduced to 2.36% in the presence of 750 mg of molecular sieve in the reaction mixture. The effectiveness of glycerolysis was directly related to the amount of molecular sieve present. As the amount of molecular sieve increased, the conversion of free fatty acids also increased at a defined time. In the absence of molecular sieve, the esterification reaction forced to reverse reaction that is the hydrolysis. The greater conversion of free fatty acids into glycerides was observed at an enzyme concentration of 27.2 mg/mL within 60 min. ANOVA showed that the effects of temperature on fatty acid content was significant (p < 0.05). Results obtained from non-linear regression analysis indicated that reaction order was 1.3 for fatty acid reduction in the olive-pomace oil. Calculated activation energy for fatty acid reduction was 32.89 kJ/mol.

Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry

Camelina seed is a new alternative omega-3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega-3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol-modified supercritical carbon dioxide (SC-CO2 ) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC-CO2 was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC-CO2 methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 °C/min). Increasing ethanol level in the ethanol-modified SC-CO2 increased the oxidative stability. Based on oxidation onset temperatures (Ton ), SC-CO2 containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants.

Lipid composition and emulsifying properties of Camelina sativa seed lecithin

There is no information on the chemical composition of camelina seed lecithin; therefore, the objective of this study was to investigate the chemical composition and emulsifying properties of lecithin recovered from camelina seed oil by water (WDCL) and enzymatic degumming (EDCL) using phospholipase A1 (PLA1). The lecithin obtained by both WDLC and EDLC was rich in phosphatidylinositol (PI), and contents were 37.8 and 25.2wt%, respectively. Lecithin recovered by enzymatic degumming contained more lysophospholipids compared to water degumming. The saturated fatty acid content of the EDCL was significantly higher than that of the WDCL. Emulsions stabilized using EDCL resulted in the highest stability when deionized water was used as the aqueous phase (original pH); however, at pH=7.5, emulsions stabilized using EDCL and WDCL were less stable compared to the emulsion stabilized with soy lecithin. Results showed that camelina seed lecithin is a promising alternative PI-rich emulsifier for various food applications.

Potential Applications of Green Technologies in Olive Oil Industry

Supercritical Fluid Technology (SFT) has received growing interest as a green technology, with extraction being the main application in the food industry. Fluids become supercritical by increasing pressure and temperature above the critical point. Supercritical fluids have liquid-like solvent power and gas-like diffusivity. These physical properties make them ideal clean solvents for extraction of lipids.

In Vitro Digestibility of Nanoporous Wheat Starch Aerogels

This study reports the in vitro digestibility of starch aerogels for the first time. The relative crystallinities of the wheat starch aerogels (WSAs) produced at gelatinization temperatures of 120 °C (WSA-120C), 130 °C (WSA-130C), and 120 °C with the addition of sodium metaphosphate (STMP) (WSA-STMP) and xerogel were similar. However, WSA-120C showed the highest amylose-lipid complex content. The addition of STMP created some cross-linked starch with a phosphorus content of 0.023%. Resistant starch (RS) contents of WSA-STMP (33.5%) and xerogel (26.9%) were higher than the other samples when they were uncooked prior to digestion. Nevertheless, the RS contents of WSA-STMP and xerogel decreased drastically with cooking. RS contents of WSA-120C and WSA-130C were stable with cooking and provided 4.5- and 3.0-fold increases in the RS content, respectively. WSA is a promising functional food ingredient with a high RS content, even after cooking.

Development of omega-3-rich Camelina sativa seed oilemulsions

Abstract Camelina sativa seed is an underutilized oil source rich in omega‐3 fatty acids; however, camelina oil is not fully explored for food applications. Its high omega‐3 content makes it susceptible to oxidation, which may limit food applications. Therefore, the main objective of this study was to investigate the potential of camelina seed oil to form physically and oxidatively stable emulsions as a potential delivery system for omega‐3 fatty acids. Effects of homogenization conditions, namely, pressure (15 MPa‐30 MPa), number of passes (1,3,5, and 7), and type of homogenizers (high pressure and high shear) on the structural properties and stability of camelina seed oil emulsions stabilized with whey protein isolate were studied. High homogenization pressure (30 MPa) and number of passes (>3) reduced the particle size (278 nm) and formed more physically and oxidatively stable emulsions compared to high shear homogenization; high shear homogenization generated bigger oil particles (~2,517 nm). Apparent viscosity and consistency index (k) decreased with increasing pressure, number of passes, and shear rate. Emulsions prepared with high pressure homogenization at both 15 and 30 MPa with 3 and more passes did not exhibit any peroxide formation over 28 days. Results indicated that camelina seed oil is a promising alternative oil source to form stable omega‐3‐rich emulsions for food applications.

Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology

Malaria is a high priority life‐threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin‐based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC‐CO2) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9–30 MPa), temperature (33–67°C), and co‐solvent (ethanol, 0–12.6 wt.%). Optimum SC‐CO2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC‐CO2 and Soxhlet extractions. Results indicated that SC‐CO2 and SC‐CO2+ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.