Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2022Effect of Brewing Conditions on Sensorial and Antioxidant Properties of Sage Tea
Ilyasoglu, Huri; Zemzemoglu, Tuba Eda Arpa
In this study, the effects of infusion time and temperature on the sensorial properties and antioxidant capacity of sage tea were evaluated by using the response surface methodology. The obtained quadratic models explained more than 90% variability in the responses. The infusion temperature showed significant negative effect on the sensorial properties whereas it had significant positive effect on the total phenolic content and antioxidant capacity (p<0.05). Moreover, the infusion time showed significant negative effects (p<0.05) on the responses. The best combination of brewing conditions was determined as 75-80 degrees C and 2-4 min.
- MakaleYalnız künye2022EFFECT OF REPLACEMENT OF WHEAT FLOUR WITH BLACK LENTIL FLOUR ON BREAD QUALITY
Çelik, Meryem; Ilyasoglu, Huri
The aim of this study was to investigate the effect of black lentil flour (BLF) on the quality of wheat bread. The control bread with wheat flour and BLF-supplemented breads (2, 6 and 10 %, respectively) were prepared and analyzed in terms of proximate composition, physicochemical and sensorial properties, total phenolic content (TPC), and antioxidant activity. The BLF-supplemented breads provided significantly higher protein compared to the control bread (p < 0.05). Moreover, it improved significantly TPC and antioxidant capacity (p < 0.05). However, the addition of BLF reduced significantly the specific volume of the bread, L* and b* values of both crumb and crust (p < 0.05). The BLF had no influence overall acceptability. Our findings revealed that the BLF may a have potential use to enhance the quality of wheat bread.
- MakaleYalnız künye2020Development of a healthy corn-based snack with sage (Salvia officinalis L.) seed
Yuksel, Ferhat; Ilyasoglu, Huri; Baltaci, Cemalettin
A healthy corn-based snack was developed from the corn flour and sage (Salvia officinialis L.) seed flour. The effects of the process variables (sage seed flour: 0–15%, frying temperature: 170–190 °C, and frying time: 40–60 s) on the nutritional properties, fatty acid composition and oxidative stability of the snack chips were evaluated via Response Surface Methodology (RSM). The response models explaining 72–96% variability in the responses were obtained. Only sage seed flour presented significant effects on the nutritional properties (p < 0.05). The interaction term of sage seed flour and frying temperature showed significant effects on the fatty acid composition (p < 0.05). The sage seed flour could decrease total starch and in vitro glycemic index and increase total dietary fiber. The snack chips contained unsaturated fatty acids more than 60%, and their oils had acceptable peroxide value. The fortification of corn-based snack with sage seed enhanced the nutritional value.
- MakaleYalnız künye2019Caffeic acid grafted chitosan as a novel dual-functional stabilizer for food-grade emulsions and additive antioxidant property
Ilyasoglu, Huri; Nadzieja, Marcin; Guo, Zheng
The aim of this study was to develop a novel dual-functional stabilizer for food-grade Pickering emulsions by grafting caffeic acid onto chitosan via a free radical mediated method. The grafting of caffeic acid onto chitosan was confirmed by UV-vis absorption spectra, FTIR spectra and H-1 NMR spectra and DSC thermogram. The antioxidant properties of the caffeic acid grafted chitosan (CA-g-Ch) were measured by three in vitro assays. Caffeic acid-grafted chitosan displayed much better Fe2+ chelating property than both chitosan and caffeic acid, and retained comparable DPPH radical scavenging activity as caffeic acid. Moreover, the formation of the CA-g-Ch based emulsion was monitored by the turbidity, zeta potential, and particle size measurements. The CA-g-Ch polymers were found to be pH-responsive. The oil (linoleic acid) in water emulsions with the CA-g-Ch (as emulsifier/Pickering stabilizer) was prepared to examine its potential to stabilize Pickering emulsions, as well as its additive antioxidant properties. The results (zeta potential, mean droplet size, creaming index and TBARS values etc) demonstrated that the CA-g-Ch could act as a dual-functional stabilizer for Pickering emulsions. The emulsions made with the CA-g-Ch were found to be stable at a broad pH range of 3-6. Our findings proved that CA-g-Ch as novel dual-functional polymeric surfactant, may have great potential to find applications in food and pharmaceutical industries.
- MakaleAçık Erişim2016Investigation of Hydroxymethylfurfural Formation in Herle
Baltacı, Cemalettin; Ilyasoglu, Huri; Gundogdu, Ali; Ucuncu, Osman
Mulberry pestil and köme are Turkish traditional foods made from herle. Browning leads to quality losses in the herle, and its products. In this study, the effect of thermal treatment on the hydroxymethylfurfural formation and color values in the herle was evaluated. The herle samples were kept at different temperatures (60–110°C) and times (2–6 h). The hydroxymethylfurfural formation was found to increase with increasing time and temperature. The legal limit for hydroxymethylfurfural in the pestil (50 mg/kg) was exceeded at temperatures above 90°C. The lightness (L* value) of the sample decreased with the thermal treatment, indicating browning.
- MakaleAçık Erişim2015Changes in sterol composition of hazelnut during fruit development
Ilyasoglu, Huri
Hazelnut is a valuable source of fat-soluble bioactive components. Among the fat-soluble bioactive components, phytosterols have gained much interest due to their cholesterol reducing properties. This study presents the evaluation of changes in the sterol composition of Turkish hazelnut cultivars (Tombul, Palaz, and Sivri) during fruit development. Three major sterols (β-sitosterol, campesterol, and Δ5-avenasterol), and five minor sterols (clerosterol, brassicasterol, stigmasterol, Δ7-stigmastenol, and Δ7-avenasterol) were detected in all hazelnut cultivars during all stages. The total sterol contents of Turkish hazelnut cultivars reached the maximum values at the early stage and a significant reduction in the total sterol content occurred at the harvest stage.
- MakaleYalnız künye2013Production of human fat milk analogue containing α-linolenic acid by solvent-free enzymatic interesterification
Ilyasoglu, Huri
Human milk fat (HMF) analogue was synthesized by lipase-catalysed interesterification of tripalmitin with extra virgin olive oil, and flaxseed oil in a solvent-free media. Lipozyme® TL IM, immobilized sn-1,3 specific lipase, was used as biocatalysts. Substrate molar ratio, reaction temperature and reaction time were used to model and to optimize the reaction conditions via response surface methodology. Good quadratic models were obtained for the incorporation of palmitic acid and α-linolenic acid. At the optimal conditions generated from the model, the palmitic acid and α-linolenic acid contents of the product were found to be 25.2g/100g and 15.9g/100g, respectively. The chemical properties (free fatty acid, iodine value, and saponification value), sn-2 positional fatty acid composition, and sterol composition of the final structured lipid (SL) were determined. Furthermore, the oxidative stability of the SL and the SLs with antioxidants (BHT, gallic acid, and rosemary extract) was evaluated. The peroxide and thiobarbituric acid reactive substances (TBARS) values of the SLs showed they had antioxidant activity on the SL. The HMF analogue synthesized in this study may have potential use in infant formulas to provide omega-3 fatty acids (α-linolenic acid).
- MakaleYalnız künye2011Cultivar characterization of Aegean olive oils with respect to their volatile compounds
Ilyasoglu, Huri; Ozcelik, Beraat; Hoed, Vera Van; Verhe, Roland
Cultivar characterization of Aegean olive oils (cv. Ayvalik and Memecik) based on their volatile compounds was carried out. The main volatile compounds detected in the Aegean olive oils were the C6 compounds derived from polyunsaturated fatty acids through the lipoxygenase pathway. The C6 aldehydes and C6 alcohols contributing to the green and fruity sensory notes of olive oil were determined in the Aegean olive oils as the major volatile compounds. Significant differences in the levels of hexanal, (E)-2-hexenal, 3-ethyl-1,5-octadiene and total compounds from linolenic acid were observed between Ayvalik and Memecik oils (p < 0.01). Principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to process the experimental data. The results of the chemometric analysis revealed that the two cultivars were clearly discriminated on the PC1-PC3 planes and LDA produced a 100% correct group classification.
- MakaleAçık Erişim2011Production of human milk fat substitute with medium-chain fatty acids by lipase-catalyzed acidolysis: Optimization by response surface methodology
Ilyasoglu, Huri; Gultekin-Ozguven, Mine; Ozcelik, Beraat
The aim of this study was to synthesize human milk fat substitute (HMFS) enriched with medium-chain fatty acids (MCFAs) by Lipozyme® RM IM-catalyzed acidolysis. The reaction substrates (tripalmitin, hazelnut oil fatty acids and Neobee® fatty acids) were specially chosen to mimic human milk fats and to enrich HMFS with MCFAs. Substrate molar ratio, reaction temperature and enzyme content were used to model and to optimize the reaction conditions via response surface methodology. The experiment was carried out at the optimal condition generated from the model yielded structured lipids with caprylic acid (12.8 g/100 g), capric acid (10.6 g/100 g) and palmitic acid (30 g/100 g). These values were found similar to the values predicted by the model (15.9 g/100 g, 14.1 g/100 g and 33.3 g/100 g). It can be concluded that the potential use of the structured lipids (SLs) produced in infant formulas provide energy source delivering a reduced calorie value for newborn, term and preterm infants.
- MakaleYalnız künye2011Determination of seasonal changes in olive oil by using differential scanning calorimetry heating thermograms
Ilyasoglu, Huri; Ozcelik, Beraat
Thermal properties (upon heating) of extra virgin olive oils (EVOOs) from Aegean cultivars were determined to evaluate the possibility of using differential scanning calorimetry (DSC) as a tool for monitoring seasonal changes in chemical composition. Chemical properties of the samples were analyzed to assess the relationship between the thermal properties and chemical properties as well. The thermal properties of Aegean cultivars were found to be influenced by major components (palmitic acid, oleic acid, linoleic acid, triolein and palmitodiolein). The melting offset temperature, the temperature range of melting and the melting enthalpy of Aegean cultivars presented significant differences with respect to crop season (p < 0.05). DSC may be utilized to evaluate compositional changes with respect to crop season.