Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 9Citation - Scopus: 8White Bean and Hazelnuts Flours: Application in Gluten-Free Bread(Academic Press, 2023) Tuna, Ayça; Cappa, Carola; Tokatlı, Figen; Alamprese, CristinaThis study investigated the effects of white bean and hazelnut flour addition (15–30% alone or in combination) to a rice flour-corn starch mixture in gluten-free (GF) breads formulated according to a mixture design. The chemical composition of flours and pasting properties of their mixtures were investigated, as well as the spectroscopic characteristics and leavening performance of doughs. Physical properties of fresh and stored (up to 48 h) bread samples were analyzed. Bean and hazelnut flours had higher protein and fiber contents, and lower carbohydrates content than rice flour and corn starch. Although the reference bread made of rice flour-corn starch mixture (STD) resulted in the highest specific volume (7.0 mL/g) and the lowest hardness (0.43 N), the sample enriched with 15% hazelnut flour (H15) approached these characteristics the most (3.8 mL/g and 1.59 N, respectively). After 48 h of storage, H15 also showed lower hardness than STD. This study paves the way for new applications of white bean and hazelnut flours and showed as a simple reformulation can help to develop healthier bread: the European legal constraint for “fiber source” claim was achieved for breads with 15 or 30% hazelnut flour, and 30% bean-hazelnut mixture, with a fiber content of 3.34, 4.48, and 3.27 g/100g, respectively. © 2023 The AuthorsArticle Citation - WoS: 61Citation - Scopus: 70Use of Ftir and Uv-Visible Spectroscopy in Determination of Chemical Characteristics of Olive Oils(Elsevier, 2019) Uncu, Oğuz; Özen, Banu; Tokatlı, FigenIt was aimed to predict fatty acid ethyl ester (FAEE), wax, diacylglycerol (DAG) and color pigment contents of olive oils by using rapid and non-destructive spectroscopic techniques (FTIR and UV-vis) individually and in combination. Prediction models were constructed by using partial least squares (PLS) regression with cross and external validation. FAEEs were estimated best with FTIR + UV-Vis spectroscopy (R-cv.(2) = 0.84, R-pred(2) = 0.90, and RPD = 3.0). PLS model with R-cv.(2) = 0.79, R-pred(2) = 0.71, and RPD = 1.9 was obtained for the estimation of 1,2 DAG using FTIR spectral data. Major pigments, lutein, pheophytin a and their derivatives and total xanthophylls were quantified successfully by FTIR + UV-Vis with a range of R-cv.(2) of 0.71-0.85, R-pred(2) of 0.70-0.84, and RPD = 1.5-2.5 values but the prediction of the rest of the pigments were poor (R-cv(2) = 0.60-0.76, R-pred(2) = 0.42-0.62, and RPD = 1.2-1.5). Combination of two spectral data resulted in average prediction of wax content of oils (R-cal(2) = 0.95, R-pred(2) = 0.75, and RPD = 1.9). FTIR and UV-vis spectroscopic techniques in combination with PLS regression provided promising results for the prediction of several chemical parameters of olive oils; therefore, they could be alternatives to traditional analysis methods.Editorial Citation - Scopus: 1Novel Methodologies for Food Quality and Provenance Fingerprints Assessment(Hindawi Publishing Corporation, 2019) Ceto, Xavier; Diaz-Cruz, Jose M.; Tokatlı, Figen; Lucci, Paolo; Moret, SabrinaThe development of novel reliable methodologies that allow the control, assessment, and prediction of the characteristics of food products is a field under expansion nowadays, especially those that allow their characterization, classification, and authentication. On the one side, the highly competitive global environment in food industry requires continuous innovation and a better sustainable usage of our natural resources in order to improve the high standards of food producers, leading to high value-added products. The linkage of new research ideas with food production provides a competitive advantage to food makers to fulfil the competitive market challenges.Article Citation - WoS: 27Citation - Scopus: 29Differentiation of Wines With the Use of Combined Data of Uv-Visible Spectra and Color Characteristics(Academic Press Inc., 2016) Şen, İlknur; Tokatlı, FigenUV-visible spectra and color parameters of monovarietal wines with orthogonal partial least square-discriminant analysis (OPLS-DA) were shown to be practical and rapid methods for classification purposes. Red and white wines from the 2006-2009 vintages were characterized in terms of color, anthocyanin content and UV-visible spectra. Syrah and Cabernet Sauvignon wines had high color density and intensity. Kalecik Karasi wines had the highest CIELab parameters and the lowest color density. Boğazkere and Öküzgözü wines showed similarities with respect to their high red color parameters and were distinct from other wines. Merlot, Syrah and Öküzgözü wines had the highest total anthocyanin content (61.9-55. mg/L as median values). White wines made from Chardonnay, Muscat and Emir grapes were found to have different color characteristics. The vintage-based discrimination of red wines was mostly apparent in total anthocyanin contents. Different UV wavelength regions were found to be effective in classification with respect to variety and vintage. Correct classification rates in the validation set were 100% and 75%, for varietal and vintage classifications, respectively. This study demonstrated the potential of combination of UV-visible spectra and color characteristics to be used in the authentication of wines.Article Citation - WoS: 42Citation - Scopus: 47Effects of Malaxation Temperature and Harvest Time on the Chemical Characteristics of Olive Oils(Elsevier Ltd., 2016) Jolayemi, Olusola Samuel; Tokatlı, Figen; Özen, BanuThe aim of the study was to determine the effects of harvest time and malaxation temperature on chemical composition of olive oils produced from economically important olive varieties with a full factorial experimental design. The oils of Ayvalik and Memecik olives were extracted in an industrial two-phase continuous system. The quality parameters, phenolic and fatty acid profiles were determined. Harvest time, olive variety and their interaction were the most significant factors. Malaxation temperature was significant for hydroxytyrosol, tyrosol, p-coumaric acid, pinoresinol and peroxide value. Early and mid-harvest oils had high hydroxytyrosol and tyrosol (maximum 20.7 mg/kg) and pigment concentrations (maximum chlorophyll and carotenoids as 4.6 mg/kg and 2.86 mg/kg, respectively). Late harvest oils were characterized with high peroxide values (9.2-25 meq O2/kg), stearic (2.4-3.1%) and linoleic acids (9.3-10.4%). Multivariate regression analysis showed that oxidative stability was affected positively by hydroxytyrosol, tyrosol and oleic acid and negatively by polyunsaturated fatty acids.Article Citation - WoS: 27Citation - Scopus: 30Combination of Visible and Mid-Infrared Spectra for the Prediction of Chemical Parameters of Wines(Elsevier Ltd., 2016) Şen, İlknur; Öztürk, Burcu; Tokatlı, Figen; Özen, BanuRapid and environmentally friendly methods for the prediction of chemical compositions have been an interest in the wine industry. The objective of the study was to show the potentials of combined use of visible and mid-infrared (MIR) spectroscopies to improve the prediction of various chemical compounds of wine as opposed to using mid-infrared range only. Wine samples of twelve grape varieties from two harvest years were analyzed. The chemical composition of wine samples was related to MIR and visible spectra using orthogonal partial least square (OPLS) regression technique. The prediction abilities were tested with crossvalidation and independent validation sets. The coefficient of determination of validation (R2 val) for anthocyanin compounds of red wines were between 0.76 and 0.90, and that for total phenol content was 0.90. Range of R2 val for glycerol, glycerol/ethanol ratio, malic acid, o-coumaric acid and °Brix were between 0.77 and 0.96. The spectral ranges that played significant roles in the predictions were also determined. The validations with independent data sets showed that the combination of visible and MIR ranges with multivariate methods improved the prediction of anthocyanin compounds and total phenols; produced comparable results for the rest of the parameters as MIR. This is the first study in the literature that shows the practical use of visible spectra along MIR. The combined use of these spectral ranges with multivariate models can be applied for the rapid, on-line determination of quality parameters and chemical profiles of wines.Article Citation - WoS: 39Citation - Scopus: 39Authenticity of Wines Made With Economically Important Grape Varieties Grown in Anatolia by Their Phenolic Profiles(Elsevier Ltd., 2014) Şen, İlknur; Tokatlı, FigenThe aim of this study was to characterize and compare the wines of main native and nonnative grape varieties grown in Turkey. The polyphenol compositions of red and white monovarietal wines of 11 grape varieties have been evaluated for four vintages (2006-2009). Discrimination of wines with respect to variety and vintage was studied by partial least square-discriminant analysis. Boǧazkere red wines were the highest and Kalecik Karasi{dotless} red wines were the lowest in total phenol content. Syrah wines were the highest in anthocyanin compounds. (+)-catechin and (-)-epicatechin contents of Cabernet Sauvignon, Merlot and Syrah wines were the highest, whereas those compounds were detected in lower amounts in native wines. For the case of white wines, the discrimination among Emir, Muscat and Sultaniye wines was based on hydroxycinnamic acids, flavan-3-ols and total phenol content. The vintage based discrimination of red wines was affected at most from malvidin compounds. White wines could also be discriminated according to their vintage based on the presence of quercetin-3- O-galactoside, vanillic acid and o-coumaric acid. The phenolic descriptors of wines can be used in the authentication of wines with respect to variety and harvest year. © 2014 Elsevier Ltd.Article Citation - WoS: 15Citation - Scopus: 16Comparison of Some Chemical Parameters of a Naturally Debittered Olive (olea Europaea L.) Type With Regular Olive Varieties(Elsevier Ltd., 2014) Aktaş, Ayşe Burcu; Özen, Banu; Tokatlı, Figen; Şen, İlknurSome olives grown in Karaburun peninsula in the west part of Turkey and mostly coming from Erkence variety lose their bitterness while still on the tree and are called Hurma among locals. This olive type does not require further processing to remove the bitter compounds. In this study, sugar, organic acid and fatty acid profiles of Hurma, Erkence (not naturally debittered) and Gemlik (commonly consumed as table olive) olives were determined throughout 8 weeks of maturation period for two consecutive harvest seasons, and the results were analysed by principal component analysis (PCA). PCA of sugar and organic acid data revealed a differentiation in terms of harvest year but not on variety. Hurma olive is separated from others due to its fatty acid profile, and it has higher linoleic acid content compared to others. This might be an indication of increased desaturase enzyme activity for Hurma olives during natural debittering phase.Article Citation - WoS: 94Citation - Scopus: 106Distribution of Simple Phenols, Phenolic Acids and Flavonoids in Turkish Monovarietal Extra Virgin Olive Oils for Two Harvest Years(Elsevier Ltd., 2009) Ocakoğlu, Derya; Tokatlı, Figen; Özen, Fatma Banu; Korel, FigenMonovarietal extra virgin olive oils extracted from six dominant and economically important Turkish olive cultivars (memecik, erkence, domat, nizip-yaglik, gemlik, ayvalik) were examined for their simple phenolics, phenolic acids and flavonoid compounds over 2005 and 2006 harvest years. Total phenol contents, oxidative stabilities and chromatic ordinates as colour parameters were also measured. The most typical phenolic compounds that were identified in both years are hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, cinnamic acid, luteolin, and apigenin. Multivariate data were analysed by principal component and partial least square-discriminant analyses. It was observed that phenolic profiles of olive oils depended highly on harvest season. In addition, oils of different olive cultivars have different distribution of phenols. No significant correlation was observed between oxidative stability and phenolic compounds. Increase in peroxide value over an accelerated oxidation period of 11 days showed weak correlations with total phenol content, vanillin, syringic acid and colour parameter a*, as 0.56, 0.55, -0.42, and 0.51, respectively, in terms of correlation coefficient r.Article Citation - WoS: 35Citation - Scopus: 39Optimisation of the Effect of Colemanite as a New Synergistic Agent in an Intumescent System(Elsevier Ltd., 2006) Atikler, Ulaş; Demir, Hasan; Tokatlı, Figen; Tıhmınlıoğlu, Funda; Balköse, Devrim; Ülkü, SemraAn intumescent system including ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonific agent and colemanite as a synergistic agent is used to enhance flame retardancy of polypropylene (FR-PP). In order to investigate the synergism between colemanite and the flame retardant materials (APP and PER), D-optimal mixture design was employed. The limiting oxygen index (LOI) and amount of residue (AoR) were accepted as response 1 and response 2, respectively. Applying D-optimal strategy, 18 experiments were performed. Filler content was fixed at 30 wt% of total amounts of flame retardant PP composites. Constraints were determined according to the ratio of APP/PER ranging between 1 and 3. Statistical analysis of the cubic model revealed that lack of fit (LoF) was not significant for the cubic and linear model for both responses. The model suggested an optimum composite formulation with concentration levels 65% of APP, 28% of PER and 7% of colemanite that gives an LOI of 40.3. The experimental LOI and AoR of optimum formulation were achieved as 39.3 and 21.4 with 2.5% and 2.2% errors, respectively.