Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 1Citation - Scopus: 1Correlation of Low Field Nuclear Magnetic Resonance Relaxation With Composition and Glass Transition of Hard Candies(Frontiers Media S.A., 2024) Ozel, Baris; Berk, Berkay; Uguz, Sirvan Sultan; Grunin, Leonid; Oztop, Mecit HalilHard candies produced from sucrose and doctoring agents such as glucose syrup (GS) and high fructose corn syrup (FS) have been investigated in terms of their final composition, glass transition temperature (Tg), degree of crystallinity, total soluble solids (TSS) content and water activity (aw). Time domain (TD) 1H NMR longitudinal relaxation time (T1) and second moment (M2) measurements have been used to understand the glassy state and crystallization characteristics for different hard candy formulations. The investigated candies include sucrose as the main sugar component. Different levels of doctoring agents have been mixed with sucrose to obtain products with different characteristics. It has been shown that addition of any doctoring agent to sucrose formulations decreases the Tg of the system significantly (p <= 0.05). Furthermore, GS or FS addition also induce significant changes in TSS and aw. T1 and M2 results are almost parallel to each other, both reaching the highest values for the highest sucrose concentration (p <= 0.05). The results demonstrate that the glass transition and crystallization characteristics of hard candy formulations can be monitored and analyzed by TD NMR relaxometry, alternative to other frequently used conventional methods including differential scanning calorimetry (DSC) and X-ray diffraction.Article Citation - WoS: 17Citation - Scopus: 18Incorporation of Organic Acids Turns Classically Brittle Zein Films into Flexible Antimicrobial Packaging Materials(Wiley, 2022) Sozbilen, G.S.; Çavdaroğlu, E.; Yemenicioglu, A.This study aimed to turn classically brittle zein films into flexible antimicrobial ones by the use of lactic (LA), malic (MA) and tartaric acids (TA). The most effective plasticizer was LA (400% elongation at break [EB] at 4%), while MA (189% EB at 4.5%) and TA (68% EB at 5%) showed moderate and limited plasticizing effects, respectively. The LA- and MA-loaded films maintained their flexibility during 30-day storage at 4°C or 25°C. Fourier transform infrared (FTIR) analysis suggested that the plasticization of LA and MA could be related to secondary structural changes in zein such as increased α-helix and random coils (mainly by MA) and spaced/modified intermolecular (only by LA) and intramolecular (mainly by MA) β-sheets. Atomic force and scanning electron microscopy showed that LA and MA gave more homogenous and smoother films than TA. Films with LA showed the highest water vapour permeability followed by those of control, MA- and TA-loaded films. Films with 3%–4% LA or MA formed clear zones on Listeria innocua and Klebsiella pneumonia, but only films with LA formed clear zones on Escherichia coli. All OA-loaded films gave unclear zones on Staphylococcus aureus in disc-diffusion tests, but this bacterium was inactivated rapidly in antimicrobial tests based on surface inoculation tests. LA is the best OA to develop flexible antimicrobial films from zein, an industrial by-product that films could not have been utilized as a widespread packaging material due to their brittleness. © 2021 John Wiley & Sons, Ltd.Article Citation - WoS: 34Citation - Scopus: 32Lymphedema After Sentinel Lymph Node Biopsy: Who Is at Risk(Mary Ann Liebert, Inc., 2022) Isik, A.; Soran, A.; Grasi, A.; Barry, N.; Sezgin, E.Background: Sentinel lymph node biopsy (SLNB) is the accepted approach to stage the clinically negative axilla. The incidence of lymphedema (LE) after SLNB is about 5%. We hypothesize that patients undergoing axillary excision of >5 lymph nodes (LNs) are at increased risk of developing LE. Methods and Results: A single institution prospective breast cancer database was retrospectively reviewed from January 2013 to December 2017, to identify patients who underwent SLNB and were diagnosed with LE. Inclusion criteria was (1) de novo breast cancer, (2) SLNB in clinically node negative patients, and (3) no preoperative diagnosis LE of an extremity. Exclusion criteria was history of axillary lymph node dissection. Age, body mass index, tumor-node-metastasis status, surgery type, neoadjuvant or adjuvant chemotherapy, radiotherapy, and hormone therapy were analyzed. Of the 3325 patients identified, 2940 patients met the inclusion criteria and were included in the final analysis. Median follow-up time was 24 months. Forty-seven (2%) patients were diagnosed with LE, and nine patients (19%) had >5 LNs excised. LE was diagnosed in 3.7% of patients who had >5 LNs excised versus 1.4% of patients with ≤5 LNs excised. Incidence of LE was higher in patients with >5 LNs excision (p = 0.006). Conclusion: Our study showed that patients have a higher likelihood of developing LE when >5 LNs are excised. © Copyright 2022, Mary Ann Liebert, Inc., publishers 2022.Conference Object Potential Application of Natural Phenolic Antimicrobials and Edible Film Technology Against Bacterial Plant Pathogens(International Society for Horticultural Science, 2020) Alkan, Derya; Yemenicioğlu, AhmetIn this study, antimicrobial edible film technology used frequently for inhibition of human pathogens in processed food was employed as a postharvest bio-based preservation method to prevent bacterial spoilage of fresh fruits and vegetables. Antimicrobial edible zein films were developed by incorporation of pure phenolic acids (PAs) such as gallic acid (GA), cinnamic acid (CA), vanillic acid (VA); essential oils (EOs) such as carvacrol (CAR), thymol (THY), eugenol (EUG) and citral (CIT) and phenolic extract (PE) from clove. In order to test synergetic effect of PAs, different amounts of PAs were added into film solution to obtain films containing mixture of GA and CA, GA and VA, CA and VA at different concentrations. The antimicrobial performances of edible films were tested on selected plant pathogenic bacteria including Pseudomonas syringae, Erwinia amylovora, Xanthomonas vesicatoria and Erwinia carotovora. The overall results of antimicrobial tests showed that films containing PAs between 1 and 4 mg cm-2 inhibited all pathogens while EOs at concentrations between 2 and 4 mg cm-2 and clove extract between 4 and 8 mg cm-2 were found effective against pathogens except P. syringae. Morover, the incorporation of combination of different PA showed greater inhibitory activity on plant pathogens than incorporation of a single PA into films. The edible zein coatings have already been applied for coating of fresh fruits and vegetables at the postharvest stage to suppress their respiration rate and prolong their refrigerated storage. This work clearly showed the benefit of incorporating a single or mixture of antimicrobial phenolic compounds, EOs and PEs in edible zein films against bacterial plant pathogens. The developed films might be employed against plant pathogens by coating fresh fruits and vegetables, seeds, seedlings, tree stems, soil as well as agricultural tools and constructions without using toxic chemicals. © 2020 International Society for Horticultural Science. All rights reserved.Conference Object Citation - Scopus: 2Preparation and Characterization of Hydroxyapatite/Calcium Phosphate Powders(Trans Tech Publications, 2004) Şimşek, Deniz; Çiftçioğlu, Rukiye; Harsa, ŞebnemThe preparation of calcium phosphate based powders through chemical precipitation in order to determine the optimum conditions for the preparation of stoichiometric, thermally stable hydroxyapatite (HA) powders was investigated in this work. The effects of parameters like pH, aging time, and heat treatment temperature on the phase structure and morphology of the powders were investigated by SEM and XRD.HA was prepared at a Ca/P ratio of 1.67. The precipitation pH had a profound influence on the morphology and crystallite size of the powders in the 4-11 pH range. Relatively large 5 mum prismatic particles were obtained at low pH whereas the powders were formed from agglomerates of nano sized particles at high pH. Powders had a HA dominant phase structure above a pH of 8. Phase pure HA powders were obtained with close to theoretical yields at pH = 10 and 11. The crystallite sizes of the powders varied from about 30 nm at 90degreesC to 50-90 mn at 1250degreesC with the smallest crystallite sizes obtained for pH 10 and 11 powders at 1250degreesC. The crystallite size increased significantly with aging temperature.Book Part Strategies for Controlling Major Enzymatic Reactions in Fresh and Processed Vegetables(Taylor & Francis, 2016) Yemenicioğlu, Ahmet[No abstract available]Book Part Citation - WoS: 7Citation - Scopus: 8Impact of Irradiation on the Microbial Ecology of Foods(Wiley, 2016) Ünlütürk, Sevcan; Ünlütürk, SevcanBook Part Citation - WoS: 3Citation - Scopus: 5Basic Strategies and Testing Methods To Develop Effective Edible Antimicrobial and Antioxidant Coating(Elsevier, 2018) Yemenicioğlu, AhmetDue to the continuous increase in microbial outbreaks originated form minimally processed and ready-to-use food [1,2], the active food packaging has become one of the top research topics in food science. A properly designed active packaging might increase the microbial safety or delay the spoilage of food (antimicrobial packaging), it might delay oxidative changes in food (antioxidant packaging), or it might help increasing functional properties of food by delivery of nutrients or bioactive substances to food surface in bioavailable form (bioactive packaging)Conference Object Citation - WoS: 14Citation - Scopus: 16Drying of Olive Leaves in a Geothermal Dryer and Determination of Quality Parameters of Dried Product(Elsevier, 2019) Helvacı, Hüseyin Utku; Menon, Abhay; Aydemir, Levent Yurdaer; Korel, Figen; Gökçen Akkurt, GüldenIn this study, a cabinet type geothermal dryer was designed, operated and tested for drying olive leaves with minimum losses of phenolic content and antioxidant capacity by optimization of drying conditions. Two factors; face centered central composite design was applied and response surface methodology was used to optimize the drying conditions of olive leaves. The results indicate that phenolic content stability were mainly affected by air temperature, whereas antioxidant capacity is affected by both air temperature and velocity (p<0.05). The optimal drying conditions were found to be at 50°C of air temperature and 1 m/s of air velocity for the minimum losses of determined quality parameters, where 88.8% of phenolic content and 95.3% of antioxidant capacity were recovered.Book Part Citation - WoS: 12Citation - Scopus: 16Zein and Its Composites and Blends With Natural Active Compounds: Development of Antimicrobial Films for Food Packaging(Elsevier Ltd., 2016) Yemenicioğlu, AhmetIn this chapter the current developments in using biopolymer zein for active edible film-making are discussed with particular emphasis on antimicrobial packaging. Recent studies have showed the possibility of developing effective antimicrobial edible packaging materials through the incorporation of different natural antimicrobial compounds, including antimicrobial enzymes, peptides, and phenolic compounds, into zein films. The zein-based films that contain antimicrobial enzyme lysozyme and bacteriocin nisin have great potential as antilisterial edible packaging materials. Additionally, zein-based films that contain natural phenolic compounds might be suitable for antimicrobial, antioxidant, and/or bioactive packaging. The use of composites of zein with waxes and blends of zein with fatty acids enables researchers to obtain antimicrobial zein-based films with controlled release properties.