Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Book Part Citation - Scopus: 3Infrared Spectroscopy for the Detection of Adulteration in Foods(John Wiley and Sons Inc., 2012) Özen, Banu; Tokatlı, FigenIR spectroscopy in combination with chemometric techniques is an effective tool for the detection of adulteration of high economic value food products such as wine, dietary supplements and olive oil. It provides practical and quick alternative to other commonly used analytical methods.Article Citation - WoS: 16Citation - Scopus: 16Secular Trends in Opportunistic Infections, Cancers and Mortality in Patients With Aids During the Era of Modern Combination Antiretroviral Therapy(John Wiley and Sons Inc., 2018) Sezgin, Efe; Van Natta, Mark L.; Thorne, Jennifer E.; Puhan, M. A.; Jabs, D. A.Objectives: The aim of the study was to estimate the incidence of, determine risk factors for, and investigate the consequences of opportunistic infections (OIs) and malignancies among patients with the acquired immune deficiency syndrome (AIDS) in the era of modern combination antiretroviral therapy (cART). Methods: Three enrolment periods (1998–2002, 2003–2005 and 2006–2012), corresponding to changes in predominant cART regimens, were compared among 1889 participants enrolled in a prospective cohort study, the Longitudinal Study of Ocular Complications of AIDS (LSOCA). Incidences of AIDS-related OIs and cancers were estimated. Multivariate logistic and Cox regression models were used to determine the effect of demographic and clinical characteristics on OIs and mortality. Results: Between participants enrolled in the 1998–2002 and 2006–2012 enrolment periods, the incidence of OIs decreased from 27 per 1000 person-years (PY) to 11 per 1000 PY (P < 0.001), and mortality decreased from 41 per 1000 PY to 18 per 1000 PY (P < 0.0001), corresponding to improvements in cART regimens. Conclusions: Improvements in cART regimens led to a progressive decline in the incidence of OIs and mortality between 1999 and 2013 among patients with AIDS in the era of modern cART.Article Citation - WoS: 87Citation - Scopus: 94Factors Related To Recurrence of Idiopathic Granulomatous Mastitis: What Do We Learn From a Multicentre Study?(John Wiley and Sons Inc., 2018) Uysal, Erdal; Soran, Atilla; Sezgin, Efe; Granulomatous Mastitis Study GroupBackground: Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory disease of the breast with unknown aetiology. Its treatment is controversial and the recurrence rate is high. The objectives of this study were to examine the demographic, sociocultural and clinical characteristics observed among a large cohort of IGM patients from Turkey and to identify factors related to the recurrence of IGM. Methods: The study was designed as a multicentre retrospective study including 22 breast centres in Turkey. A total of 720 IGM patients are included in the study. Patient data were obtained from the patient's files and electronic records based on the study protocol. Patients’ demographic, clinical, radiological, treatment and recurrence of IGM related characteristics were recorded. Results: Our results revealed a statistically significant association between IGM recurrence and history of pregnancy, breastfeeding, breast infection and smoking (P < 0.05). Having a chronic systematic disease, oral contraceptive, analgesic and herbal medicine consumptions, treatment choice, education, place of birth and current residence were not found to be associated with IGM recurrence (P > 0.05). Conclusion: Our findings show that history of pregnancy, breastfeeding, breast infection and smoking were the risk factors for IGM recurrence. As current treatment methods did not affect IGM recurrence, recurrence-related factors, such as breast infection and smoking, should be considered to eliminate while focusing on less invasive local treatment research.Article Citation - WoS: 1Citation - Scopus: 2Partial Purification of a Polygalacturonase From a New Aspergillus Sojae Mutant and Its Application in Grape Mash Maceration(John Wiley and Sons Inc., 2017) Yıldız, Semanur; Mata-Gomez, Marco A.; Tarı, Canan; Rito-Palomares, MarcoThe use of polygalacturonase (PG) preparations in winemaking promotes the release of phenolic compounds. A PG from a new source, Aspergillus sojae mutant, was semi-purified and tested for grape mash maceration. Crude extract (CE), a commercial pectinase, and two high PG activity semi-purified preparations, FI and FII , were applied for maceration at PG activity of 3.5 U g−1 of grape for 46 h. Enzyme-assisted maceration significantly (P < 0.05) increased the total phenolic content from 255.8 to 916.3 ± 5.2, 5732.9 ± 9.9, 563.4 ± 6.7 and 620.6 ± 18.4 mg L−1 for CE, commercial pectinase, FI and FII, respectively. The content of individual phenolics such as gallic, protocatechuic, chlorogenic and p-coumaric acids was improved. Principal component and hierarchical clustering analyses suggested that CE has a better performance upon the release of phenols. Semi-purified preparations acted similar to commercial pectinase. These findings open an opportunity for the potential use of PG from the mutant strain as an alternative macerating enzyme.Article Citation - WoS: 18Citation - Scopus: 19Control of Agitation Rate and Aeration for Enhanced Polygalacturonase Production in Submerged Fermentation by Aspergillus Sojae Using Agro-Industrial Wastes(John Wiley and Sons Inc., 2017) Fratebianchi, Dante; Crespo, Juan Manuel; Tarı, Canan; Cavalitto, SebastianBACKGROUND: The koji mold Aspergillus sojae, an industrially important microorganism, can produce high levels of pectinases utilizing agro-industrial wastes. This study introduces apricot and peach pomace, two agro-industrial wastes barely considered as raw material for the generation of value-added products, and focuses on its utilization together with orange peel for polygalacturonase production in submerged cultures using A. sojae. RESULTS: A Doehlert response surface methodology design conducted in shake flasks and applied individually with these three by-products led to 60–80 U mL−1 polygalacturonase activity. In bioreactor studies performed with a mixture of apricot pomace and orange peel, by fixing stirrer speed to 600 rpm and cascading airflow to the dissolved oxygen tension up to 1.7 vvm, oxygen limitation problems were overcome and polygalacturonase activity values of 380 U mL−1 were achieved. CONCLUSION: A simple and efficient strategy to minimize oxygen limitation with the lowest possible shear stress is provided for stirred-tank bioreactors working with highly viscous broths, so as to ultimately enhance microbial enzyme production. The polygalacturonase activity yields obtained in our study are among the highest reported in the literature.Article Citation - WoS: 13Citation - Scopus: 18Effect of Physicochemical Parameters on the Polygalacturonase of an Aspergillus Sojae Mutant Using Wheat Bran, an Agro-Industrial Waste, Via Solid-State Fermentation(John Wiley and Sons Inc., 2016) Demir, Hande; Tarı, CananBACKGROUND: Polygalacturonases (PGs) are valuable enzymes of the food industry; therefore it is of great importance to discover new and GRAS PG-producing microbial strains. In this study, PG enzyme produced from a high PG activity producer mutant Aspergillus sojae using wheat bran at the flask scale under pre-optimized conditions of solid-state fermentation (SSF) was biochemically characterized. RESULTS: The crude PG enzyme showed optimum activity in the pH range 4.0–5.0 and was stable in the pH range 3.0–7.0. The optimum temperature for the PG was 40 °C and it retained 99% of its activity at 50 °C. The mutant A. sojae PG could preserve more than 50% of its stability between 25 and 50 °C, both for 30 and 60 min, and was found to be stable in the presence of most of the tested compounds and metal ions. The inactivation energy (Ed) was determined as 125.3 kJ mol−1. The enthalpy (ΔH*), free energy (ΔG*) and entropy (ΔS*) of inactivation were found to be stable with increasing temperature. CONCLUSION: The mutant A. sojae PG could be suitable for the clarification (depectinization) of orange and grape juices and wine. © 2015 Society of Chemical Industry.Article Citation - WoS: 2Citation - Scopus: 2Microbial Profile and Bacterial Characterisation of Naturally Debittered Hurma Olives Compared To Non-Debittered Erkence Variety During Ripening Period(John Wiley and Sons Inc., 2016) Sözbilen, Gözde Seval; Baysal, Ayşe HandanNaturally debittered Hurma olive is grown in a specific area in Karaburun peninsula in Turkey. It is characterised by its sweet taste and it differs from other varieties by losing its bitterness caused by phenolic compounds during its maturation period on the tree. Therefore, Hurma olive does not require any further debittering process to be served as table olive. This study was particularly interested in the comparison of the microbial profile of Hurma olive during its 8 weeks of maturation period in two subsequent harvest years and Erkence (not naturally debittered) olive. In addition, main bacterial profile of both Hurma and Erkence olives were isolated and identified. Aerobic mesophilic microorganism (AMM), lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonadaceae, Staphylococci, Micrococcaceae, yeasts and moulds (Y&Ms) were detected (counted and isolated) in the olive drupes during the maturation period. Isolated bacteria were identified as different spp. of Bacillaceae, Enterobacteriaceae, Micrococcoceae and Pseudomonadaceae.Article Citation - WoS: 59Citation - Scopus: 71Microbial Safety and Shelf Life of Uv-C Treated Freshly Squeezed White Grape Juice(John Wiley and Sons Inc., 2015) Ünlütürk, Sevcan; Atılgan, Mehmet ReşatThe effects of UV-C irradiation on the inactivation of Escherichia coli K-12 (ATCC 25253), a surrogate of E. coli O157:H7, and on the shelf life of freshly squeezed turbid white grape juice (FSWGJ) were investigated. FSWGJ samples were processed at 0.90 mL/s for 32 min by circulating 8 times in an annular flow UV system. The UV exposure time was 244 s per cycle. The population of E. coli K-12 was reduced by 5.34 log cycles after exposure to a total UV dosage of 9.92 J/cm2 (1.24 J/cm2 per cycle) at 0.90 mL/s flow rate. The microbial shelf life of UV-C treated FSWGJ was extended up to 14 d at 4 °C. UV exposure was not found to alter pH, total soluble solid, and titratable acidity of juice. There was a significant effect (P < 0.05) on turbidity, absorbance coefficient, color, and ascorbic acid content. Furthermore, all physicochemical properties were altered during refrigerated storage. The microbial shelf life of FSWGJ was doubled after UV-C treatment, whereas the quality of juice was adversely affected similarly observed in the control samples. Practical Applications: UV-C irradiation is a non-thermal method used for processing of fruit juices with a minimal or no changes in flavor, essential nutrients, and vitamins. Fresh grape juice is a popular drink, usually consumed at summer time due to many beneficial health effects. Although thermal pasteurization is widely used for extending the shelf life of fruit juices, it causes a "cook taste" in grape juice. The applicability of UV-C irradiation as an alternative to thermal pasteurization was investigated. It is concluded that UV-C treatment can be used for extending the shelf life of fresh grape juice.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: 62Citation - Scopus: 73Antioxidant and Antimicrobial Activities of Thyme and Clove Essential Oils and Application in Minced Beef(John Wiley and Sons Inc., 2015) Zengin, Hatice; Baysal, Ayşe HandanIn this study, thyme and clove essential oils (EOs) were studied for their chemical composition, antioxidant, antiradical and antibacterial activity and application in ground beef. Carvacrol (75.27%) and eugenol (75.2%) were detected by gas chromatography-mass spectrometry analysis as the main components of thyme and clove EOs, respectively. Broth microdilution method showed all bacteria inhibited by the EOs, while Shewanella putrefaciens and Listeria innocua were the most resistant bacteria to thyme and clove EOs, respectively. EO treatment restricted the growth of artificially inoculated Salmonella typhimurium and native Coliforms in the ground beef. Antioxidant activity determined by ferric-reducing antioxidant power and 1,1 diphenyl-2-picrylhydrazyl methods demonstrated that clove EO had higher in vitro antioxidant activity than thyme EO. Similar results were obtained in ground beef application using 2-thiobarbituric acid value. EOs of clove (2MIC) exerted remarkable higher antioxidant activity in ground beef than EOs of thyme (4MIC), which represent valid alternative antioxidant in meat products. Practical Applications: Plant essential oils (EOs) serve as a "safe" alternative to chemical or synthetic antimicrobials and antioxidants to struggle with the foodborne pathogens or spoilage organisms, inhibiting lipid oxidation and thus extending shelf life. Antioxidant activity determined by ferric-reducing antioxidant power and 1,1 diphenyl-2-picrylhydrazyl methods showed that clove EO had higher in vitro antioxidant activity than thyme EO. Results obtained using 2-thiobarbituric acid value in ground beef application were found similar. EOs of clove (2MIC) exerted higher antioxidant activity in ground beef than EOs of thyme (4MIC). Therefore, EOs could be a valid alternative antioxidant in meat products.