Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Review Citation - WoS: 25Citation - Scopus: 27Bacillus Cereus: a Review of “fried Rice Syndrome” Causative Agents(Academic Press, 2023) Leong, Sui Sien; King, Jie Hung; Korel, Figen“Fried rice syndrome” originated from the first exposure to a fried rice dish contaminated with Bacillus cereus. This review compiles available data on the prevalence of B. cereus outbreak cases that occurred between 1984 and 2019. The outcome of B. cereus illness varies dramatically depending on the pathogenic strain encounter and the host's immune system. B. cereus causes a self-limiting, diarrheal illness caused by heat-resistant enterotoxin proteins, and an emetic illness caused by the deadly toxin named cereulide. The toxins together with their extrinsic factors are discussed. The possibility of more contamination of B. cereus in protein-rich food has also been shown. Therefore, the aim of this review is to summarize the available data, focusing mainly on B. cereus physiology as the causative agent for “fried rice syndrome.” This review emphasizes the prevalence of B. cereus in starchy food contamination and outbreak cases reported, the virulence of both enterotoxins and emetic toxins produced, and the possibility of contaminated in protein-rich food. The impact of emetic or enterotoxin-producing B. cereus on public health cannot be neglected. Thus, it is essential to constantly monitor for B. cereus contamination during food handling and hygiene practices for food product preparation. © 2023 Elsevier LtdArticle Citation - WoS: 12Citation - Scopus: 16Control of Lactic Acid Bacteria in Fermented Beverages Using Lysozyme and Nisin: Test of Traditional Beverage Boza as a Model Food System(Wiley, 2018) Sözbilen, Gözde Seval; Korel, Figen; Yemenicioğlu, AhmetThe objective of this study was to increase quality and limited shelf-life of boza (3–15 days), a traditional Balkan origin fermented beverage using lysozyme (LYS) and/or nisin (NIS). For this purpose, the effectiveness of NIS, LYS and LYS:NIS combinations was first tested in a broth medium at 4 °C for 3 weeks on Lactobacillus plantarum, one of the frequently isolated lactic acid bacteria in boza. Stability of LYS and NIS in boza, their effects on LAB counts, and chemical and sensory properties of boza were then evaluated during cold storage at 4 °C. Results of LAB counts as well as pH, d- and l-lactic acid, and titratable acidity measurements showed that LAB in boza containing NIS (250 μg g−1) or LYS:NIS (500:250 μg g−1) could be controlled without reducing LAB counts below 6 log CFU mL−1 during 2 weeks shelf-life. In contrast, LYS (500 μg g−1) alone could not control LAB in boza to delay its acidic spoilage. Positive effects of NIS and LYS:NIS application on quality of boza were also proved with sensory analysis by panelists and e-nose measurements. This work showed that use of natural GRAS agents in preservation of fermented beverages containing probiotic LAB is possible without affecting their characteristic aroma and flavour.Article Citation - WoS: 4Citation - Scopus: 4The Volatile Compounds, Free Fatty Acid Composition and Microbiological Properties of Sepet Cheese Packaged With Different Modified Atmosphere Conditions(Kafkas Üniversitesi, 2017) Akpınar, Aslı; Yerlikaya, Oktay; Kınık, Özer; Kahraman, Cihan; Korel, Figen; Uysal, Harun RaşitThe objective of this present study was to investigate traditional sepet cheese samples which were packaged with different modified atmosphere conditions (MAP). The volatile compounds, free fatty acid composition and microbiological properties of Sepet cheeses were analyzed on 1., 45., 90. and 180. day of the storage period at +4°C. In packaking of cheese, three different modified atmosphere packaging conditions were tried. These cheeses were packaged into polystyrene packages that include 100% N2 (N), 80% N2 + 20% CO2 (NC), 100% CO2 (C). In accordance with volatile compounds of sepet cheese samples, it was shown that control cheese sample was different from MAP samples in terms of aroma fractions. MAP samples showed variability in preservation of aroma fractions. When fatty acid composition during the storage period was researched, it was found that there was a significant difference in all samples. When microbiological properties were investigated statistically, it was determined that there was not a significant difference in samples during storage. In general, it could be said that sepet cheeses that were packaged in different modified conditions protected their specialities better.Article Citation - WoS: 5Citation - Scopus: 6Chemometric Studies on Znose™ and Machine Vision Technologies for Discrimination of Commercial Extra Virgin Olive Oils(John Wiley and Sons Inc., 2015) Kadiroğlu, Pınar; Korel, FigenThe aim of this study was to classify Turkish commercial extra virgin olive oil (EVOO) samples according to geographical origins by using surface acoustic wave sensing electronic nose (zNose™) and machine vision system (MVS) analyses in combination with chemometric approaches. EVOO samples obtained from north and south Aegean region were used in the study. The data analyses were performed with principal component analysis class models, partial least squares-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). Based on the zNose™ analysis, it was found that EVOO aroma profiles could be discriminated successfully according to geographical origin of the samples with the aid of the PLS-DA method. Color analysis was conducted as an additional sensory quality parameter that is preferred by the consumers. The results of HCA and PLS-DA methods demonstrated that color measurement alone was not an effective discriminative factor for classification of EVOO. However, PLS-DA and HCA methods provided clear differentiation among the EVOO samples in terms of electronic nose and color measurements. This study is significant from the point of evaluating the potential of zNose™ in combination with MVS as a rapid method for the classification of geographically different EVOO produced in industry.Article Citation - WoS: 16Citation - Scopus: 15Characterization of Silk Fibroin Based Films Loaded With Rutin-Ss Inclusion Complexes(Kluwer Academic Publishers, 2014) Şamlı, Merve; Bayraktar, Oğuz; Korel, FigenIn this study, cyclodextrin inclusion complexes with rutin were prepared via co-precipitation method. Stability constant and solubility energy of beta-cyclodextrin complex were calculated as 262 M-1 and 1,737 kJ mol-1, respectively. Aqueous solubility of rutin was increased with inclusion complex of beta-cyclodextrin. The effect of temperature on both aqueous solubility of free rutin, and its inclusion complex was also studied. Characterization of cyclodextrin complexes were conducted with UV-Vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry, thermal gravimetric analysis, nuclear magnetic resonance spectroscopy and scanning electron microscopy techniques. Characterization results supported formation of inclusion complexes. Dissolution profiles of rutin, physical mixture and inclusion complex of rutin were observed at 37 °C. Dissolution results proved the effect of cyclodextrin addition on solubility rate of rutin. After loading rutin and its complexes into silk fibroin based films, release tests were performed at 37 °C in neutral pH conditions for 24 h. Most of the rutin were released from silk fibroin films within the first 5 h and the rest of it was released slowly (sustained release). Electron microscope analyses showed that films had homogenous and dense morphologies. These results revealed that silk fibroin is useful for preparing bioactive films loaded with natural compounds and for modifying their release behaviour at physiological conditions.Article Citation - WoS: 14Citation - Scopus: 16Classification of Turkish Extra Virgin Olive Oils by a Saw Detector Electronic Nose(John Wiley and Sons Inc., 2011) Kadiroğlu, Pınar; Korel, Figen; Tokatlı, FigenAn electronic nose (e-nose), in combination with chemometrics, has been used to classify the cultivar, harvest year, and geographical origin of economically important Turkish extra virgin olive oils. The aroma fingerprints of the eight different olive oil samples [Memecik (M), Erkence (E), Gemlik (G), Ayvalik (A), Domat (D), Nizip (N), Gemlik-Edremit (GE), Ayvalik-Edremit (AE)] were obtained using an e-nose consisting a surface acoustic wave detector. Data were analyzed by principal component analysis (PCA) and discriminant function analysis (DFA). Classification of cultivars using PCA revealed that A class model was correctly discriminated from N in two harvest years. The DFA classified 100 and 97% of the samples correctly according to the cultivar in the 1st and 2nd harvest years, respectively. Successful separation among the harvest years and geographical origins were obtained. Sensory analyses were performed for determining the differences in the geographical origin of the olive oils and the preferences of the panelists. The panelists could not detect the differences among olive oils from two different regions. The cultivar, harvest year, and geographical origin of extra virgin olive oils could be discriminated successfully by the e-nose.Article Citation - WoS: 48Citation - Scopus: 64Active Packaging of Ground Beef Patties by Edible Zein Films Incorporated With Partially Purified Lysozyme and Na 2edta(John Wiley and Sons Inc., 2011) Uysal Ünalan, İlke; Korel, Figen; Yemencioğlu, AhmetIn this study, antimicrobial activity of zein films incorporated with partially purified lysozyme and disodium ethylenediaminetetraacetic acid (Na 2EDTA) has been tested on selected pathogenic bacteria and refrigerated ground beef patties. The developed films containing 700μgcm -2 lysozyme and 300μgcm -2 Na 2EDTA showed antimicrobial activity on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium. The application of lysozyme and Na 2EDTA incorporated zein films on beef patties significantly decreased total viable counts (TVC) and total coliform counts after 5days of storage compared to those of control patties (P<0.05). Zein films incorporated with lysozyme and Na 2EDTA or Na 2EDTA alone significantly slowed down the oxidative changes in patties during storage (P<0.05). Redness indices of patties coated with zein films were significantly lower than those of uncoated control patties during storage (P<0.05). This study demonstrated the potential usage of zein films containing lysozyme and Na 2EDTA for active packaging of refrigerated meat products. © 2011 The Authors. International Journal of Food Science and Technology.Article Citation - WoS: 35Citation - Scopus: 40Flavour of Natural and Roasted Turkish Hazelnut Varieties (corylus Avellana L.) by Descriptive Sensory Analysis, Electronic Nose and Chemometrics(John Wiley and Sons Inc., 2012) Alasalvar, Cesarettin; Pelvan, Ebru; Bahar, Banu; Korel, Figen; Ölmez, HülyaA total of eighteen natural and roasted hazelnut varieties (amongst which only Tombul variety is classified as prime quality), grown in the Giresun province of Turkey, were compared for their differences in descriptive sensory analysis (DSA), electronic nose (e-nose) data and chemometrics. Differences in some descriptive of DSA between natural and roasted hazelnuts as well as within the varieties were observed. Although Tombul hazelnut was selected as one of the best varieties in terms of flavour attributes and received the highest intensities in general, no significant differences (P>0.05) existed among hazelnut varieties except in certain flavour attributes ('after taste' and 'nutty'). DSA and e-nose data of natural and roasted hazelnuts were also evaluated for discrimination using principal component analysis (PCA) and cluster analysis. Results of PCA using e-nose data showed that extracted principal components explained 99.7% and 99.8% of the total variance of the data for natural and roasted hazelnut varieties, respectively. Both DSA and e-nose can be used for discrimination of natural and roasted hazelnuts. © 2011 The Authors. International Journal of Food Science and Technology © 2011 Institute of Food Science and Technology.Article Citation - WoS: 36Citation - Scopus: 38Antimicrobial Activity of Lactoperoxidase System Incorporated Into Cross-Linked Alginate Films(John Wiley and Sons Inc., 2009) Yener, Fatih Yalçın Güneş; Korel, Figen; Yemenicioğlu, AhmetIn this study, the antimicrobial effect of lactoperoxidase (LPS) incorporated alginate films was investigated on Escherichia coli (NRRL B-3008), Listeria innocua (NRRL B-33314), and Pseudomonas fluorescens (NRRL B-253) in presence of different concentrations of H2O2 (0.2, 0.4, and 0.8 mM) and KSCN (1, 2, and 4 mM). The incorporation of 70 nmol ABTS/min/cm2 LPS into alginate films gave 0.66 to 0.85 nmol ABTS/min/cm2 enzyme activity at 0.2 to 0.8 mM H2O 2 concentration range. The antimicrobial activity of LPS system on target bacteria changed according to the concentrations of KSCN and H 2O2. The growth of all tested bacteria was prevented for a 6-h period by applying LPS system in presence of 0.4 or 0.8 mM H 2O2 and 4 mM KSCN. At 0.8 mM H2O2 and 4 mM KSCN, the LPS system also inhibited growth of L. innocua and P. fluorescens for a 24-h incubation period, whereas E. coli growth could not be inhibited for 24 h under these conditions. At 0.2 mM H2O2 and 1 to 4 mM KSCN, a considerable inhibitory effect was obtained only on P. fluorescens. The decreasing order of the resistance of studied bacteria to LPS system is as follows: E. coli, L. innocua, and P. fluorescens. The developed antimicrobial system has a good potential for use in meat, poultry, and seafood since alginate coatings are already used in these products. Further studies are needed to test the LPS incorporated edible films in real food systems.Article Citation - WoS: 8Citation - Scopus: 12Odor Evaluation of Shrimp Treated With Different Chemicals Using an Electronic Nose and a Sensory Panel(Taylor and Francis Ltd., 2007) Luzuriaga, Diego A.; Korel, Figen; Balaban, Murat ÖmerAn electronic nose with 12 conducting polymer sensors was used to measure odors of raw shrimp treated with different chemicals. Headless shell-on pink shrimp (Pandalus jordani) were treated with bleach (0, 25, 50, 100 and 200 ppm), phosphates (0, 2, 4 and 6% w/v) and sulfites (0, 0.75, 1.25 and 2% w/v) and stored at 2°C for 48 hours. Odors were evaluated by sensory panels and an electronic nose. Aerobic plate counts were performed. Discriminant function analysis was used as the pattern recognition technique to differentiate samples based on odors. Results showed that the electronic nose could discriminate differences in odor due to chemicals present in shrimp. The correct classification rates for bleach, phosphate and sulfite treated shrimp were 92.7, 95.8, and 99.2%, respectively.