Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Now showing 1 - 6 of 6
  • Master Thesis
    Development of Probiotic Bar With Microencapsulated Probiotics
    (01. Izmir Institute of Technology, 2024) İriçağıl, Zelihan; Harsa, Hayriye Şebnem; Baysal, Ayşe Handan
    Bu çalışma, Saccharomyces boulardii CNCM-I745 ve Alkalihalobacillus clausii (N/R, O/C, SIN, T) gibi probiyotikleri mikroenkapsüle ederek, bu yararlı mikroorganizmaların stabilitesini ve canlılığını artırmayı amaçlayan bir probiyotik barın geliştirilmesini incelemektedir. Mikroenkapsülasyon, probiyotikleri koruyucu bir matris sağlayan lupin protein izolatı-ksantan gam-trehaloz kompleksi kullanılarak gerçekleştirilmiştir. Mikroenkapsüle edilmiş probiyotikler, glutensiz yulaf, hurma, fıstık ezmesi, kuru incir, ceviz, keten tohumu, tarçın ve tuz içeren bir bar formülasyonuna eklenmiştir. Nem içeriği, su aktivitesi, doku ve renk ölçümleri gibi fizikokimyasal analizler, barların kalitesini değerlendirmek için yapılmıştır. Ayrıca, probiyotiklerin canlılığını izlemek amacıyla 4°C'de 90 günlük bir depolama çalışması yürütülmüştür. Sonuçlar, mikroenkapsülasyonun probiyotiklerin stabilitesini ve hayatta kalma oranını önemli ölçüde artırdığını, canlı sayılarının depolama süresi boyunca 106 CFU/g üzerinde kaldığını ve Türk Gıda Kodeksi standartlarını karşıladığını göstermiştir. Özellikle, mikroenkapsüle edilmiş probiyotikler 90 günlük depolama süresince 1 log CFU/g'den az bir azalma gösterirken, serbest probiyotikler 3 log CFU/g'den fazla bir azalma göstermiştir. Çalışma ayrıca, probiyotiklerin in vitro gastrointestinal hayatta kalma oranlarını incelemiş ve mikroenkapsüle edilmiş probiyotiklerin simüle edilmiş mide ve bağırsak koşullarına karşı üstün direnç gösterdiğini ortaya koymuştur. Mikroenkapsülasyon süreci, depolama ve sindirim sırasında karşılaşılan zorlu çevresel faktörlerden koruyarak probiyotiklerin canlılığının korunmasını iyileştirmiştir. Bu araştırma, mikroenkapsülasyon tekniklerinin fonksiyonel gıdaların geliştirilmesindeki potansiyelini vurgulamakta ve yenilikçi, süt içermeyen probiyotik ürünler yaratma konusunda gıda endüstrisine değerli bilgiler sağlamaktadır.
  • Master Thesis
    Development of Aronia Based Vegan Nutritional Supplementation
    (01. Izmir Institute of Technology, 2024) Oruç, Yaren Tuğba; Harsa, Hayriye Şebnem
    Fonksiyonel gıdalar, özellikle Kovid-19 salgını sonrasında değişen yaşam standartlarıyla birlikte küresel tüketici kitlesi ve gıda sektörü için büyük önem kazanmıştır. Aronia melanocarpa, biyoaktif madde içeriği yüksek, antioksidan içeriği ve zengin besin değeri olan, tüm dünyada yaygınlaşan ve bununla birlikte Türkiye'de de giderek yaygınlaşma hızını artıran bir meyvedir. Gerçekleştirilen çalışmada Aronia melanocarpa'nın süper meyve olarak seçilmesi nedenlerinden olan bu zengin ve faydalı içerik ile insanlığın uğraşmak zorunda kaldığı büyük ve ciddi sorunlara etkili olabilecek bir fonksiyonel gıda ürünü tasarlamak amaçlanmıştır. Hazırlanan ürünlerin fiziksel, kimyasal, mikrobiyolojik, raf ömrü ve duyusal özellikleri analiz edilmiş ve bunun yanında Aronya smoothie ürünü in vitro sindirim ve ADE engelleyici aktivite açılarından da incelenmiştir. Bu fonksiyonel ürünün kırmızı mercimekten ekstrakte edilen protein tozu ile protein seviyesi artırılmış ve Aronya toz karışım ürünü için %23,7, Aronya smoothie ürünü için ise %3,74 protein içeriği elde edilmiştir. Aronya smoothie ürününe uygulanan in vitro sindirim sonrası ürünün fenolik ve antioksidan özelliklerinde artış gözlenmiştir. Aronya smoothie ürününün dünya genelinde uğraşılan ciddi kronik sağlık sorunlarından olan hipertansiyon ve kalp hastalıkları üzerinde olumlu etkisi bulunan mekanizma ADE engelleyici aktivitesi %22 olarak tespit edilmiştir. Duyusal analiz sonucunda Aronya smoothie ürününün genel kabul edilebilirlik puanı 3,65 elde edilmiştir.
  • Master Thesis
    Functionalization of a Vegan Snack With Antimicrobial Edible Coating
    (01. Izmir Institute of Technology, 2022) Atik, Hande; Harsa, Hayriye Şebnem
    Pomegranate peel is usually considered as a waste of fruit by many people, but it has quite high content of antioxidant, phenolic and antimicrobial compounds. The objective of this thesis is to observe the effect of edible film in vegan snack bar containing of dried fruits, nut and to functionalize the snack bar with enrichment of protein and antimicrobial content. The edible film was composed of 8% w/v of lentil protein extract, 15% w/w of pomegranate peel depends on protein content, 2% of pectin as a stabilizer and 0.5% of glycerol as a plasticizer. Application of coating was carried out by dipping method. Then, the coated vegan snack bar was dried at 40oC for 16 hours. The coated and uncoated bars were investigated in different conditions as 30% RH at 25 oC and 75% RH at 35 oC for 90 days. Optical properties, texture, total phenolic content, sensory, microbial and water activity analysis were determined to evaluate the impact of edible coating incorporation onto surface of the bar. The results showed that the coated bars have been preserved better than uncoated ones in terms of prevention of color change, microbial and textural properties, phenolic content and moisture loss in both conditions.
  • Master Thesis
    Organosolv Treatment for Prebiotic Oligosaccharide Production From Agro-Food Waste
    (01. Izmir Institute of Technology, 2020) Temelli, Nuran; Büyükkileci, Ali Oğuz
    Xylooligosaccharides (XOS), which are among the prebiotic carbohydrates, are produced by hydrolysis of xylan in the lignocellulosic agricultural and food wastes. Production processes, such as autohydrolysis and enzymatic hydrolysis following alkali extraction, have some limitations. In this study, it was aimed to develop a process that could overcome those limitations. Corn cob was used as the model biomass and it was pretreated with organosolv. The organosolv pretreatment conditions (solvent concentration, time, temperature, catalyst addition) were adjusted to maximize the lignin removal from the biomass while recovering xylan in the biomass. Delignification could be achieved with 40%-50% lignin removal, and around 85% of the xylan was retained in the biomass. The effect of the organosolv conditions on XOS formation was investigated by the hydrolysis of the pretreated biomass using three commercial xylanases. The organosolv and the enzymatic hydrolysis conditions influenced the XOS formation. The maximum XOS production was observed with the biomass pretreated at 150°C for 1 h with 70% ethanol and 0.1 M MgO. That biomass was enzymatically hydrolyzed at 70°C with 0.6 U/ml xylanase and 70% of the xylan was converted to XOS yielding a hydrolysate containing 9.5 g/l XOS. With the process developed in this study, the need for the application of concentrated alkaline and acidic solutions can be eliminated since the xylan extraction step is not needed. In addition to that, the formation of carbohydrate degradation products can be avoided due to the lower treatment temperatures compared to autohydrolysis. These can simplify the downstream processing following the production of XOS and minimize the environmentally harmful chemical wastes. In this process, a liquid stream rich in lignin and a solid stream rich in cellulose were released. Following a biorefinery concept, these streams can potentially be valorized together with the xylan, so that lignocellulosic wastes can have an added value. This study will be followed by related projects on XOS purification and determination of the prebiotic potential of XOS. In addition to that, the process developed will be tested on other lignocellulosic wastes.
  • Master Thesis
    Testing of Antidiabetic Features of Formulated Food Products in Enterocyte Cell Culture Model
    (Izmir Institute of Technology, 2017) Pilatin, Gözde; Güleç, Şükrü
    In recent years, there has been an increasing interest in designing low calorie functional foods that might have health benefit against development of obesity and T2D. However, researches on developing low calorie foods in Turkey are quite insufficient. Even if the products are developed, in vitro and in vivo approaches to design low calorie foods are not carried out properly. Thus, we aimed to test diabetic features of newly formulated low calorie and no-added sugar containing cake, almond paste and pudding in intestinal cell culture system. Cake, almond paste and pudding were developed by “Egepak Gıda ve Ambalaj San.” and same type foods were chosen from market to use as reference. We modeled human carbohydrates digestive systems in test tube and relative glucose efflux were measured from rat enterocyte cells that were grown on bicameral cell culture system. Bioaccessibility of glucose was found at least 61%, 89% and 64% lower in cake, almond paste and pudding respectively relative to references. The levels of cellular glucose efflux were significantly lower from 30min (for cake 1.9 fold; for almond paste 4.3; for pudding 3.3 fold) to 120 min (for cake 2.2 fold; for almond paste 3.7 fold) to 180 min (for pudding 2.0 fold) in products than their references. To the best of our knowledge, this is the first exemplary study in Turkey to develop newly formulated foods by analyzing their diabetic features in in vitro model of human intestine system.
  • Master Thesis
    Development of Novel Functional Foods From Turkish Kabuli Type Chickpeas
    (Izmir Institute of Technology, 2015) Şahin, Damla Öykü; Yemenicioğlu, Ahmet; Yemenicioğlu, Ahmet
    The aim of this thesis is to obtain novel functional chickpea and chickpea products by incorporating bioactive green and black tea phenolics into Turkish Kabuli type chickpeas during controlled rehydration. The rehydration of chickpeas in green or black tea infusions and green tea extracts increased the total phenolic content and bioactive properties of chickpeas. Chickpeas rehydrated in green tea extract or green tea infusions for 2 hours showed almost 2.2 2.5 fold higher total phenolic content, flavonoid content and free radical scavenging based antioxidant capacity, and rehydrated in green tea extract, green tea or black tea infusions almost 2.2-2.6 fold higher antidiabetic activity than control chickpeas rehydrated in water. The increase of rehydration period from 2h to 10h could increase the total phenolic content and antioxidant activity of chickpeas, but the increased incubation period did not have any considerable positive effects on antidiabetic activity of chickpeas. No significant reductions were o served in total phenolic content, flavonoid content and antio idant activity of phenolic enriched chickpeas kept frozen at 18°C while some limited reductions were observed in phenolic content and antioxidant activity of phenolic enriched chickpeas dried and stored at +4°C for 3 months. The extraction and then characterization of the phenolic content, and antioxidant and antidiabetic activity of protein from phenolic enriched chickpeas clearly showed the binding of the incorporated phenolic compounds onto chickpea protein. Thus, it appeared that the protein extracted from phenolic enriched chickpeas could also be used as a functional food ingredient. This work clearly showed the possibility of obtaining functional chickpeas and chickpea protein by use of controlled rehydration in presence solutions containing green and black tea phenolics.