Food Engineering / Gıda Mühendisliği

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Adsorption Equilibrium and Dynamics of Lactase/Cm-sephadex System
(Kluwer Academic Publishers, 1995-08) Harsa, Hayriye Şebnem; Harsa, Hayriye Şebnem; Göksungur, Yekta; Güvenç, Ulgar; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Partitioning behaviour and adsorption isotherms of lactase/CM-Sephadex system at equilibrium were investigated together with the adsorption kinetics in this study. Maximum adsorption was obtained at the pH values between 5.5–6.0. Adsorption isotherm was a close fit to the Langmuir model.
Airborne fungi in a Turkish olive processing plant
(VTT Technical Research Center of Finland, 2009) Baysal, Ayşe Handan; Baysal, Ayşe Handan; Baysal, Taner; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Studies employing gravity settling culture plates (GSC) were conducted in order to analyse the airborne fungi of an olive processing (ripe pitted, natural calamata pitted and whole olive) plant in Izmir, Turkey, in May 2008. Sampling procedure for airborne fungi was performed 8 times during the processing. Numbers and types of airborne fungi in the air of olive processing areas were investigated by exposing a Petri dish of malt extract and potato dextrose agar medium for 15 min and then counting the number of colonies which develop after incubation at 25°C for 7 d.. Moulds were identified according to Pitt and Hocking (1997) and Samson et al. (1996).
Antimicrobial Effect of Natural Antimicrobial Agents Against Foodborne Pathogens
(Technical Research Center of Finland, 2008) Eroğlu, Erdal; Özen, Fatma Banu; Türe, Hasan; Soyer, Ferda; Soyer, Ferda; Özen, Banu; 04.03. Department of Molecular Biology and Genetics; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
Besides that foodborne infections and intoxications cause great danger for human health they have also adverse impact on the economics. Alternative food preservation techniques to produce safer foods e.g. systems containing natural antimicrobial agents have recently gained popularity. The consumers prefer foods with no chemical additives without shortened shelf-life. In this sense, natural antimicrobials have become promising alternatives for hurdle technology. However, most of the natural antimicrobials have limited spectrum of activity.
Antimicrobial Effects in Food and Prevention of Contamination in Food Industry
(VTT Technical Research Center of Finland, 2007) Hütt, Pirje; Korel, Figen; Songisepp, Epp; Güldaş, Metin; Tamme, Terje; Ormancı, Fatma Seda; Ayaz, Naim Deniz; Korel, Figen; Aarnisalo, Kaarina; Hradecka, Helena; Mikelsaar, Marika; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The most commonly recognized food-borne infections are caused by Campylobacter jejuni and Salmonella spp. In the past 25 years, Listeria monocytogenes has become increasingly important as a food-associated pathogen. Though, an annual incidence of human listeriosis is between two and ten reported cases per million in EU countries. Because of its high case fatality rate, listeriosis ranks among the most frequent causes of death due to food-borne illness. L. monocytogenes and C. jejuni has been shown to adapt to different environmental stress factors, including disinfectants. Salmonella enteritidis, C. jejuni and L. monocytogenes may also form a biolfim which helps to survive in the environment. For that reason, the food industrial hygiene has become important to avoid contamination of raw food and food products with these pathogens.
Aspergillus sojae tarafından poligalakturonaz (PG) enzimin üretimi ve pürifikasyonu: Morfoloji ve sıvı reolojisinin toplam sistem verimliliği üzerine olan etkilerinin endüstriyel uygulamalara yakın ölçeklerde deneysel ve teorik yaklaşımla incelenmesi
(2011) Tarı, Canan; Ünlütürk, Sevcan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
[No Abstract Available]
Aspergillus Sojae Tarafından Üretilen Poligalakturonazın Kısmi Saflaştırılması için Kromatografik Bir Yaklaşım
(Sidas Medya Ajans Tanıtım Danışmanlık Ltd. Şti., 2017) Şen, İlknur; Şen, İlknur; Mata-Gomez, Marco A.; Tarı, Canan; Palomares, Marco Rito; Tarı, Canan; Dinç, Melike; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Bu çalışmanın amacı, A. sojae mutantından poligalakturonaz üretilmesi ve ham ekstraktın kromatografik yöntemlerle kısmi saflaştırılmasıdır. Peptitlerin konfirmasyonu için ilk basamak olarak, jel içinde sindirilmiş sodyum-dodesil-sülfatpoliakrilamid-jel-elektroforezi (SDS-PAGE) jellerinde matriks-yardımlı lazer desorpsiyon/iyonlaştırmalı-uçuş zamanlıkütle spektrometresi (Maldi-TOF MS) analizi yapılmıştır. Poligalakturonaz üretimi için, katı-faz ve derin fermentasyonlarda üç farklı karbon kaynağı kullanılmıştır. Ham ekstrakt ilk olarak iyon değişim kromatografisi (IEXC) ile saflaştırılmıştır ve ardından bunu boyut eleme kromatografisi izlemiştir. Derin [acı portakal kabuğu, şeker pancarı melası ve (NH4)2SO4] ve katı-faz (buğday kepeği, şeker pancarı ve HCl) fermentasyonlarından elde edilen ham ekstraktlar yüksek seviyede poligalakturonaz enzim aktivitesi (sırasıyla 95.22 and 50.27 U/mL) göstermiştir. IEXC toplanmış fraksiyonunun (180, 200 ve 220 mM tuz fraksiyonları) boyut elemesi, en yüksek verimi (%36) ve saflaştırma katını (2.00) göstermiştir. SDS-PAGE'den elde edilen olası poligalakturonaz bantları jel içinde sindirilmiş ve peptit konfirmasyonu için Maldi-TOF-MS ile analiz edilmiştir.
Citation - Scopus: 3
Bacteria: Arcobacter
(Elsevier, 2014) Atabay, Halil İbrahim; Ceylan, Çağatay; Corry, Janet E.L.; Atabay, Halil İbrahim; Ceylan, Çağatay; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The genus Arcobacter currently comprises many phenotypically different species isolated from diverse niches. Although some Arcobacter spp. (particularly, Arcobacter butzleri, Arcobacter skirrowii, and Arcobacter cryaerophilus) are associated with various diseases in humans and animals, their exact epidemiological and pathological role is not completely understood, and few cases of human infection are reported. The primary mode of Arcobacter transmission is thought to occur via contaminated water and food and contact with pets. As some species are difficult to cultivate and all are difficult to identify using conventional biochemical tests, nucleic acid-based techniques such as polymerase chain reaction (PCR) and real-time PCR are increasingly used for their simultaneous detection, identification, and quantification. Their tendency to be resistant to antibiotics, and their ability to colonize food processing environments indicate that they could cause serious disease in the human population, particularly in susceptible individuals with impaired immune response. © 2014 Elsevier Inc. All rights reserved.
Bacterial Foodborne Pathogens of Concern
(VTT Technical Research Center of Finland, 2007) Roasto, Mati; Baysal, Ayşe Handan; Reinmüller, Berit; Vokk, Raivo; Baysal, Ayşe Handan; Polanc, Julijana; Veskus, Tiina; Juhkam, Kadrin; Terentjeva, Margarita; Mackiw, Elzbieta; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A high level of protection of public health is one of the fundamental objectives of food law as laid down in regulations (EC) No 178/2002 and 852/2004. Throughout the European Union (EU) consumers are requiring the food industry to provide them with an increasing range of safe, nutritious and healthy foods of high sensory quality and increased shelf life. To meet the demand for healthier food of high sensory quality, the use of additives and preservatives is being reduced or eliminated and minimal processing techniques introduced. To increase food safety and quality considerable amount of time, effort and money has been spent to food safety control and management (ISO 22000:2005) systems including better packaging methods and improved new pathogen detection methods.
Bakır mineralinin anemi durumundaki dengeleyici ve düzeltici etkisinin moleküler ve genetik düzeyde insan enterosit hücre modelinde araştırılması
(2017) Güleç, Şükrü; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Demir eksikliğine bağlı anemi, dünyadaki besin eksikliğinin neden olduğu hastalıklar arasında ilk sırada yeralan bir problemdir. Bu yüzden anemik durumu dengeleyici veya düzeltici faktörlerin bilinmesi demir metabolizmasının anlaşılması için önemlidir. Demir eksikliği anemisinde bağırsak enterosit hücrelerinde bakır seviyesinin arttığı gösterilmiştir ve bu da bakırın demir eksikliği anemisindeki durumu düzeltici etkisi olabileceğini düşündürmektedir. Bu bağlamda projede bakır mineralinin demir eksikliğine bağlı oluşturulan anemik durumdaki düzeltici etkisi moleküler ve genetik düzeyinde insan enterosit hücre modellinde (Caco-2) incelendi. Projenin ilk kısmında Caco-2 hücreleri 12 bölmeli steril hücre kaplarında 21 gün süre ile büyütüldü. İkinci kısımda, besinden gelen ve kandaki bakırın etkisinin in vitro olarak test edilebilmesi için insan bağırsak sistemi modellendi. Bunun için Caco-2 hücreleri özel membranlarda büyütülerek polarize olmaları sağlandı. Daha sonra hücrelere deferoksamin (DFO) verilerek demir eksikliğine bağlı anemi oluşturuldu. Hücreler bakır ve demir ile muamele edildi. Örneklerden RNA izolasyonu yapılıp, cDNA dönüşümü gerçekleştirildi. Bunu takiben RT–qPCR metodu ile gruplar arasındaki belirli genlerin mRNA ekspresyon seviyelerine bakıldı. Dmt1 ve Ftn genlerine ait mRNA regülasyonlarının hücre kültürü kabında ve membran sisteminde büyüyen hücreler arasında farklı olduğu gözlemlendi. Membran sistemindeki sonuçlara göre, bakırın demir eksikliği anemisinde artan Fpn ve Dmt1 genlerinin mRNA seviyelerini düşürdüğü saptandı. Daha da önemlisi bu anlamlı azalma, bakırın polarize olmuş hücrelerin yalnızca bazolateral kısmına verilmesiyle gözlemlenmiştir. Bu da kandaki bakırın demir eksikliği anemisinde bağırsak demir hemostazının hücre içi moleküler mekanizmasını etkilediğini göstermektedir. Buna ilaveten, kontrol grubuyla kıyaslandığında bakırın anemik koşullar altında regüle olan Ankrd37 ve Egln genlerinin mRNA ekspresyonlarını etkilemeği bulunmuştur. Projede anemi durumunda demir mineralinin bakır metabolizmasındaki genlere etkisi de incelenmiştir. Anemi durumunda bazolateral kısma verilen demir bakır ile regüle olan genler içinde yalnızca Atp7a mRNA ekspresyonunu etkilemektedir. Elde edilen bulgular, kandaki bakırın diyetten gelen bakıra göre enterosit hücrelerinde demir eksikliği anemisini azaltmada daha etkili olabileceğini göstermektedir. Bakır, anemi durumunda demir mineraline bağlı regüle olan Fpn ve Dmt1 genlerinin mRNA ekspresyonlarını enterosit hücrelerinin basolateral kısımları üzerinden etkilemektedir. Anemide Fpn ve Dmt1 genlerini regüle etmek için kandaki bakır tarafından etkilenebilen moleküler mekanizmaların neler olduğunu ortaya çıkaran fonksiyonel çalışmalara ihtiyaç vardır.
Citation - WoS: 3
Citation - Scopus: 5
Basic Strategies and Testing Methods To Develop Effective Edible Antimicrobial and Antioxidant Coating
(Elsevier, 2018) Yemenicioğlu, Ahmet; Yemenicioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Due 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)
Biyoaktif maddelerin kontrollu salımı için kompozit veya karışımlardan oluşan aktif yenilebilir gıda ambalaj malzemeleri geliştirilmesi
(2011) Yemenicioğlu, Ahmet; Atabay, Halil İbrahim; Uysal, İlke; Aydemir, Levent Yurdaer; Arcan, İskender; Korel, Figen; Boyacı, Derya; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Bu projede biyoaktif maddelerin kontrollü salımını gerçekleştirebilecek yenilebilir film ve kaplamalar geliştirmek amacıyla zein ve peyniraltı suyu proteinleri (PSP) temelli karışım ve kompozit yapılardan faydalanılmıştır. Zeinden elde edilen karışım filmler zeinin oleik, laurik ve linoleik asit gibi yağ asitleri ile karıştırılmasıyla, kompozit filmler ise karnauba, kandelilla ve balmumu gibi mumlar, mercimek veya soya globülin proteinleri veya mikrokristal selülozla karıştırılmasıyla elde edilmiştir. PSP‘den elde edilen karışımlar bu proteinlerin oleik asitle, kompozitler ise balmumu ve kandelilla mumuyla karıştırılmasıyla elde edilmiştir. Zein temelli filmlere ilave edilen biyoaktif maddeler kısmi saf ve saf lisozim, kateşin, gallik asit, phidroksibenzoik asit, ferulik asit, kuversetin ve flavon, PSP temelli filmlere ilave edilen biyoaktif maddeler ise saf ve kısmi saf lisozim ve kateşindir. Gösterdikleri kontrollu salım etkileri, antimikrobiyel ve antioksidant performanslar ve mekaniki özellikler dikkate alındığında en uygulanabilir filmlerin lisozimin kateşin ve/veya gallik asitle birlikte kullanıldığı zein-oleik asit karışımları ve zein-karnauba mumu kompozitleri olduğu belirlenmiştir. Ayrıntılı salım deneyleri zein karışım ve kompozitlerinde lisozim, kateşin ve kateşin-gallik asit karışımlarının salım hızının çoğunlukla filmlerin çapraz bağlanma düzeyini artıran fenolik bileşik konsantrasyonuyla ters ilişkili olduğunu göstermiştir. Karışım ve kompozitleri oluşturan mum, yağ asiti ve fenolik madde tipi de filmlerin morfolojisini, hidrofobisitesini ve dolambaçlı difüzyon yolu (tortuosity) gibi özelliklerini değiştirerek salım özelliklerini etkileyebilmektedir. Zein‘den elde edilmiş fenolik bileşikler veya lisozim ve fenolik bileşikleri birarada içeren karışım ve kompozit filmlerin antimikrobiyel testleri bu filmlerin gıdalardaki en kritik patojen bakterilerden olan Escherchia coli O157:H7, Listeria monocytogenes ve Campylobacter jejuni‘ye karşı laboratuvar ortamlarında ve/veya seçilmiş et ve süt ürünlerinde antimikrobiyel ve antioksidant etki gösterdiğini doğrulamıştır.
Correlation of Low Field Nuclear Magnetic Resonance Relaxation With Composition and Glass Transition of Hard Candies
(Frontiers Media S.A., 2024) Ozel, B.; Berk, Berkay; Berk, Berkay; Uguz, S.S.; Grunin, L.; Oztop, M.H.; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Hard 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 (Formula presented.) 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 (Formula presented.) 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. Copyright © 2024 Ozel, Berk, Uguz, Grunin and Oztop.
Covıd 19 Pandemi Döneminde Potansiyel Besin Önerileri
(Izmir Institute of Technology, 2020) Ağırbaşlı, Zeynep; Kamber, Aslıhan; Kamber, Aslıhan; Harsa, Hayriye Şebnem; Kılıç, Merve; Addıyaman, S. Cem; Harsa, Hayriye Şebnem; 01. Izmir Institute of Technology; 03.08. Department of Food Engineering; 03. Faculty of Engineering
İçinde bulunduğumuz COVID-19 pandemi sürecinde gıdaların rolü, önemi ve etkinliği hakkında Gıda Mühendisliği Bölümümüz öğretim üyesi, Prof. Dr. H. Şebnem HARSA önderliğinde ve Dr. S. Cem ADIYAMAN’ın desteğiyle, Zeynep AĞIRBAŞLI, Aslıhan KAMBER ve Merve KILIÇ’tan oluşan bir ekip tarafından hazırlanan “COVID19 Pandemi Döneminde Potansiyel Besin Önerileri” başlıklı bir çalışma yayınlandı. Bu süreçte önem arz eden çalışmanın amacı; bir bireyin beslenme durumunun SARS-CoV-II enfeksiyon riskini, klinik seyrini ve COVID-19’un sonuçlarını etkileyebileceği düşüncesinden yola çıkarak belirtilmiş olan biyoaktiflerin tavsiye edilen dozlarda tüketiminin, sağlığa yararlı etkileri ile bağışıklık sistemini destekleyebileceği yönünde.
Citation - WoS: 8
Citation - Scopus: 11
Development of a Functional Chocolate Using Gamma-Amino Butyric Acid Producer Lacticaseibacillus Rhamnosus Nrrl B-442
(Elsevier, 2022-06) Özer, Merve; Harsa, Hayriye Şebnem; Öztürk, Burcu; Hayaloğlu, Ali Adnan; Tellioğlu Harsa, Şebnem; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The human microbiota is influenced by the immune and nervous systems of the host. Gamma-aminobutyric acid (GABA) is known as bioactive compound and it has important physiological functions, such as anti-hypertensive and antidepressant activities. Lactic acid bacteria (LAB), especially Lactobacillus species are known as the most important GABA producers because of the food-grade nature. The purpose of this study is to develop a functional chocolate using microencapsulated GABA producer Lacticaseibacillus rhamnosus NRRL B-442 strain for patients having an anxiety disorder. Water-in-oil emulsion technique was conducted for microencapsulation using whey-pullulan complex. Microencapsulated and free L. rhamnosus cell counts were 6.75 and 7.20 log CFU/g in chocolates, respectively, at the end of 60 days. During simulated in vitro digestion analysis, survival rate of microencapsulated bacteria in chocolate samples was found at higher percentage (87%) than free bacteria (75%). Furthermore, microencapsulated L. rhamnosus did not affect the physical, chemical, and sensory properties of chocolate. Consequently, L. rhamnosus with the highest GABA producing capability may provide insight for an anxiety disorder patient, since this strain has been thought as having a therapeutic effect. A new functional food model was developed for “GutBrain Axis” phenomena since the chocolate could be accepted as a good carrier for GABA producer bacteria.
Discovery, Characterization, and Databases of Enzymes From Sourdough
(CRC Press, 2023) Ağırbaşlı, Zeynep; Harsa, Hayriye Şebnem; Harsa, Şebnem; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Sourdough enzymes have not been investigated in wide scale yet. Therefore, this chapter summarizes the main strategies and techniques used for the identification of sourdough enzymes together with the compilation of this information in databases for a wide variety of applications. The chapter describes a panel of methods based on different approaches, such as biochemical and molecular techniques for the identification of several key microbial enzymes emerged from sourdough or a combination thereof. Review includes information on the enzymes in carbohydrate metabolism, protein metabolism, phenolic metabolism, and stress metabolism together with enzymatic formation of bioactive compounds in sourdough. © 2024 selection and editorial matter, Marco Garcia-Vaquero and João Miguel F. Rocha.
Diyetten Alınan ve Kandaki Demir Mineralinin İnsan İnce Bağırsak Hücre Modelinde Demir Eksikliği Anemisine Etkisi
(Türkiye Diyetisyenler Derneği, 2018) Güleç, Şükrü; Güleç, Şükrü; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Amaç: Demir eksikliğine bağlı anemi (IDA), dünyada özellikle yeni doğanlarda, çocuklarda ve kadınlarda en sık görülen besinsel eksikliktir. Düşük demir içeriği olan besinlerin tüketilmesi ve ince bağırsaktan yeterli demirin emilememesi demir eksikliğine bağlı anemiye neden olmaktadır. Memelilerde fizyolojik olarak aktif demirin vücuttan atılımı için bir sistemin olmamasından dolayı bağırsak enterosit hücreleri, vücuttaki demir metabolizmasının dengeli bir şekilde devamlılığında hayati bir role sahiptirler. Yeterli bağırsak demir emilimi anemi riskini azaltmak için gereklidir. Diyetten alınan ve kanda bulunan demir insan vücudu için bulunan iki demir kaynağıdır. Bu çalışmada demir eksikliğine bağlı anemi durumunda bağırsak demir metabolizmasının moleküler ve genetik düzenlenmesinde diyetten gelen ve kanda bulunan demir mineralinin etkisinin incelenmesi amaçlanmıştır. Gereç ve Yöntem: İnsan kolon epitelyal hücreleri (CaCo-2) insan ince bağırsak sistemini modellemek için özel hücre kültürü membran sistemlerinde büyütülmüştür. Kolon hücrelerin apikal ve bazolateral polarizasyonu trans epitelyal rezistans (TEER) ölçümüyle test edilmiştir. Demir eksikliğine bağlı anemi Deferoxamine (DFO) ile indüklenmiş olup, demirin IDA üzerindeki etkisi RT-qPCR tekniği ile gen düzeyinde araştırılmıştır. Bulgular: Marker gen (TFR, DMT1) mRNA ekspresyon düzeyleri analiz edildiğinde, hücrelerin bazolateral kısmına demir verildiğinde apikal kısma verilene oranla IDA fenotipinin kaybolduğu gösterilmiştir. Sonuç: Sonuçlar kan demirinin bağırsak demir metabolizmasının düzenlenmesi için gerekli olduğunu göstermiştir. Kan demir düzeyi diyetten gelen demirle regüle edilir. Böylece, günlük demir alımı kan demiri düzeylerini düzenlemek için önemlidir. Bağırsak enterosit hücrelerinin bazolateral kısım boyunca demir mineralini algılama kabiliyetine sahip olabileceğini desteklemektedir.
Citation - WoS: 12
Citation - Scopus: 15
Drying of Olive Leaves in a Geothermal Dryer and Determination of Quality Parameters of Dried Product
(Elsevier, 2019) Helvacı, Hüseyin Utku; Helvacı, Hüseyin Utku; Menon, Abhay; Gökçen Akkurt, Gülden; Aydemir, Levent Yurdaer; Korel, Figen; Korel, Figen; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.08. Department of Food Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
In 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.
Citation - Scopus: 14
Edible Food Packaging With Natural Hydrocolloids and Active Agents
(CRC Press, 2022) Yemenicioğlu, Ahmet; Yemenicioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The aim of this book is to show the potential of natural hydrocolloids and active agents to develop sustainable edible packaging materials for food preservation. For this, the current and future sources of natural hydrocolloids have been reviewed along with their extraction methods, impact on health and ability to form different packaging such as film, casing, coating, mat, pad, etc. Similarly, natural active compounds were evaluated carefully considering their sources, extraction methods, regulatory status, and compatibility with edible packaging. The book emphasizes the recent developments in methods, strategies and technologies employed to enhance the performance of antimicrobial, antioxidant and bioactive packaging. The basic testing methods used to evaluate antimicrobial and antioxidant activity of edible packaging in model media and food were discussed, and carefully selected example active edible packaging applications for different food categories were provided with critical details such as the thin balance between effectiveness of packaging and sensory properties of food. As such, it helps in understanding necessary parameters in designing an effective active edible packaging that is applicable to the target food category. Moreover, readers are primed for the first time on how to develop a fully natural antimicrobial, antioxidant or bioactive edible food packaging. This book is different from most of the similar books' avail as it provides neither methodologies about classical active packaging based on chemicals and fossil polymeric films nor is it a thorough collection of different food packaging applications. It is also not a book that concentrates on physicochemical characterization methods and engineering aspects of packaging. Instead, this is a book that provides systematic knowledge about key methods of evaluating natural resources, agro-industrial wastes and by-products for development of edible packaging, and concentrates on concepts, strategies, technologies, and applications of active edible packaging based solely on natural components. It is designed to share both positive and negative experiences in an emerging field that is expected to play a central role in improving food safety and quality, human health and environmentally friendly practices.
Effect of Partial Replacement of Sucrose With Stevia and Sucralose on the Physicochemical and Structural-Mechanical Properties of Apple Marmalade
(2024) Berk, Berkay; Ünlütürk, Sevcan; Şirin, Pınar; Berk, Berkay; Ünlütürk, Sevcan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, low-sugar apple marmalade formulations were developed by partial replacement of sucrose with stevia and sucralose. Their rheological, textural, physicochemical properties and microstructures were evaluated. The concentration of sweeteners was found to have a significant effect on the physicochemical and rheological properties of the formulations. The hardness of marmalades decreased with addition of sweeteners. Herschel–Bulkley model was found to be the best model describing rheological behavior. The consistency index decreased with increasing sweeteners substitution, whereas the flow behavior index showed an increasing trend with the increase of the sweeteners content. Additionally, the microstructure of marmalades with sweetener substitution exhibited a porous structure in the gel network. The increase in sucralose concentration resulted in more surface deformation resulting in weaker gel formation than stevia. Marmalade prepared with 50% stevia substitution was found the best combination and resulted in good sensory properties like marmalade samples containing 500 g sugar.
Citation - WoS: 7
Citation - Scopus: 7
Effect of Process Parameters and Microparticle Addition on Polygalacturonase Activity and Fungal Morphology of Aspergillus Sojae
(Springer, 2022) Germeç, Mustafa; Tarı, Canan; Karahalil, Ercan; Yatmaz, Ercan; Tarı, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, the effects of process parameters (initial glucose concentrations, inoculation rates, and nitrogen sources including yeast extract, beef extract, and ammonium nitrate instead of peptone) on polygalacturonase production by Aspergillus sojae in the shaking incubator were examined. Subsequently, the effect of talcum microparticles on activity and morphology was investigated. Based on the results, the highest activity and lowest pellet diameter were 41.91 U/mL and 1411.9 µm when initial glucose concentration and inoculation size were 20 g/L and 12% (v/v), respectively. Besides, as inoculation rate increased, maximum specific growth rate and saturation constant decreased from 0.39 to 0.27 day−1 and 21.26 to 3.50 g/L, respectively. It was determined that highest activity and lowest pellet diameter were found as 18.53 U/mL and 2953.0 µm when medium was supplemented with 2.5 g/L yeast extract. It was also found that as yeast extract and beef extract concentrations increased, pellet diameter decreased. Additionally, medium was supplemented with talcum as a microparticle (0–25 g/L), and maximum activity was 26.59 U/mL (pellet diameter was 2756.3 µm) when talcum concentration was 5 g/L. In addition, as talcum concentration increases from 0.1 to 5 g/L, the biomass concentration increased relatively, but the enzyme activity increased significantly. However, although talcum concentration in the medium is increased until 20 g/L, while the biomass concentration increased, the activity decreased. Compared to control fermentation (without talcum), the activity increased ninefold. Polygalacturonase was also partially purified via ultrafiltration with the purification fold of 1.84. Consequently, fungal morphology in submerged fermentation can be controlled by microparticle addition fermentation, and thus the enzyme activity can be increased.

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