Gıda ambalaj malzemesi hedefli berberin katkılı kitosan filmlerin hazırlanması ve karakterizasyonu
Preparation and characterization of food packaging material targeted films with the addition of berberine to chitosan films
Yazar: SERAY ÖZTÜRK
Danışman: PROF. DR. FATMA BEDİA BERKER ; ÖĞR. GÖR. ZEYNEP KALAYCIOĞLU
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Kimya Ana Bilim Dalı / Kimya Bilim Dalı
Derece: Yüksek Lisans, 2022
Konu: Kimya = Chemistry
Dizin: Berberin = Berberine ; Gıda ambalajı = Food packaging ; Kitin = Chitin ; Kitosan = Chitosan

Özet:
Gıda ambalajları gıdanın raf ömrünün uzamasında ve gıdayı dış etkenlerden korumada birincil rol oynar. Gıda endüstrisinin sahip olduğu geniş yelpaze, doğru orantılı olarak ambalaj endüstrisinin büyümesine yol açar. Ambalaj malzemelerinin kaynak olarak petrokimyasal bazlı ürünlerden elde edilmesi, atık ambalajların bir çevresel soruna dönüşmesine neden olur. Çevresel kirliliği önlemek için gelişen hassasiyetlerle birlikte doğa dostu ambalaj malzemeleri oluşturulmaya başlanmıştır. Doğa dostu olarak ifade edilen ambalaj malzemeleri, biyobozunur ve biyouyumlu özellikler taşırlar. Bu çalışmada, bir biyopolimer olan kitosana berberin klorür standardı eklenerek alternatif bir gıda ambalaj malzemesi oluşturmak hedeflenmiştir.
Kitosan, birçok canlının yapı polisakkariti olan kitinin deasetilasyonu sonucu elde edilen bir biyopolimerdir. Seyreltik asit ile hazırlanan kitosan çözeltisi, çözelti dökme tekniği ile film haline getirilir. Böylece kitosan, ambalaj malzemesi olarak kullanılabilecek bir yapıya dönüştürülür. Ayrıca kitosan, biyobozunurluk, biyouyumluluk, biyoyararlılık ve toksik olmama gibi önemli özelliklere de sahiptir.  Kitosanı çeşitli biyoaktif ürünlerle katkılandırmak mümkündür. Bu sayede sentetik gıda koruyucuları kullanmadan doğal kaynaklar yoluyla gıdaların bozulmasını önleyebilecek gıda ambalaj malzemeleri geliştirilebilir. 
Bu yüksek lisans tez çalışması kapsamında kitosan filmin katkılandırılması berberin klorür standardı ile sağlanmıştır. Berberin, çeşitli bitkilerin yapısında bulunan bir alkaloid bileşiğidir. Berberin katkısı ile kitosan filme antioksidan ve antimikrobiyal aktivite kazandırılarak, berberin içerikli kitosan filmin aktif paketleme ürünü olması hedeflenmiştir. Berberin klorür standardının suda çözünmesi 2-hidroksipropil-β-siklodekstrin kullanılarak gerçekleştirilmiştir. Saf kitosan film, berberin ilaveli film ve berberin hariç tüm bileşenleri içeren kontrol filmin özellikleri karşılaştırmalı olarak incelenmiştir. Elde edilen filmler sodyum tripolifosfat çözeltisi ile fiziksel olarak çapraz bağlanmıştır. Hazırlanan 3 farklı filmin şişme, çözünürlük, su buharı geçirgenliği ve çekme kuvvetine yönelik deneyler yapılmıştır. Ayrıca filmlerin, antioksidan ve antibakteriyel aktiviteleri de incelenmiştir. Yapılan deneyler sonucunda, berberin klorür standardı içeren kitosan filmin, kontrol film ve saf kitosan filme göre fiziksel özelliklerinin iyileştiği gözlenmiştir. Berberin katkısının kitosan filmlerin antioksidan ve antibakteriyel aktivitesini artırdığı da görülmüştür.
Yapılan çalışmalar ve elde edilen sonuçlar ışığında berberin klorür standardı içeren kitosan filmin alternatif bir gıda ambalaj malzemesi olabileceği sonucuna başarı ile ulaşılmıştır.

Abstract:
Food packaging takes an active role in both extending the shelf life of the food and protecting the food from external factors. The wide range of the food industry leads to growth directly proportional to the packaging industry. As a result of increased food consumption, packaging materials are produced exceedingly. Obtaining packaging materials from petrochemical-based substances as a source causes becoming an environmental problem of waste packaging. Although plastic and its derivatives, which are traditional packaging materials, are effective in protecting foods, they create serious environmental problems that present the food industry as a source of pollution and social concern.  Increasing sensitivity to environmental pollution has enabled the production of eco-friendly packaging materials. Packaging materials, which are expressed as eco-friendly, have biodegradable and biocompatible properties. In this master's degree thesis, it was targeted to generate an alternative food packaging material by adding berberine chloride standard to chitosan as a biopolymer. 
Chitosan is a deacetylation product of chitin which is the structural polysaccharide of many living beings. Some insects, sea creatures, and fungies carry chitin structurally. Chitosan is obtained from chitin by some processes. Prepared with a diluted acid solution, chitosan is turned into a film by a solution casting process. Firstly, chitosan is dissolved with a diluted acid then this solution is poured into a petri dish. Poured film solution is dried at room temperature or a specific temperature in an oven. Lastly, the dried film is peeled from the petri dish.  By using this method, chitosan is converted to a form that can be used as a packaging material. In addition to this, chitosan has biodegradability, biocompatibility, bioavailability, and non-toxicity properties. These properties make the chitosan film eco-friendly material. Though the traditional plastic packagings have some advantages such as plenty of availability, mechanical properties and cost efficiency, this type of packaging causes environmental pollution and accumulation of some greenhouse gases such as carbon dioxide and methane. Furthermore, to reduce the effect of plastic packaging pollution, recycling have to be used but the recycling process requires energy and cost-efficiency. At this point, chitosan film can be a good candidate for its biodegradability property.  It is possible to add various products to the chitosan. In this way, it is gained to chitosan such properties antioxidant and antibacterial activities which are responsible for preventing the spoilage of foodstuffs. Antioxidants are compounds that prevent radical oxidation reactions. 
These types of substances are added to the foodstuffs to prevent them from spoilage. Generally, some synthetic antioxidants such as butylated hydroxy anisol (BHA) and butylated hydroxytoluene (BHT) are added to the foods but some research is shown that these substances have negative impacts on the human body. 
When considered from this point, chitosan has advantages because it can be incorporated with some natural antioxidant sources. Using this application active food packaging materials can be developed that can prevent foodstuffs from spoilage through natural antioxidants without using synthetic antioxidants. It was understood from the 'active' expression that the packaging material supplemented with natural sources plays an active role in food packaging. Traditional packaging materials cover the foodstuffs and protect them from external factors. In the contrary, active packaging materials play a role not only in coverage but also in preventing spoilage of the foodstuffs.  
It is usually utilized from vegetable oils, fruit, and vegetable extracts as additive substances. In this thesis study, berberine which is a compound that can be found in many plants is used as a standard form. This form is berberine chloride standard. The chitosan film which was including the berberine chloride standard showed antioxidant activity by comparison with the control film. The antioxidant activity was measured with the DPPH method. This method is based upon the reduction reaction. Antioxidant substance reacts with the DPPH and the reaction has resulted in the reduction of DPPH. More reducing means more antioxidant capability. Furthermore, the reaction is followed and calculation is done by absorbance change. This easy application makes the DPPH analysis popular. It is applied easily and got results in a short time. 
Within the scope of this master thesis, berberine which is an alkaloid compound found in the structure of various plants, has been used to increase the efficiency of chitosan film. Using berberine provides antioxidant activity to chitosan film. Chitosan has a mild antibacterial property against some microorganisms which is one of the essential properties to protect the foods. In this study, berberine incorporation increased the antibacterial activity of chitosan film against Bacillus cereus and Salmonella Typhimurium. The physical properties of the film with increased antioxidant and antimicrobial properties as an active food coating material were also determined.
It has benefited from cyclodextrin to dissolve the berberine chloride standard. Cyclodextrins are substances like a truncated cone shape. These substances have a hydrophobic cavity and hydrophilic outer surface. This type of structure makes cyclodextrins popular for water-insoluble substances. The dissolving of the berberine chloride standard is provided with the hydrophobic cavity of the cyclodextrin.  In this master study, 2-hydroxypropyl- β- cyclodextrin has been used to dissolve the berberine chloride standard.  After dissolving of the berberine chloride standard, it is incorporated with chitosan solution.  The incorporated solution is the film solution containing a berberine additive. This film solution is poured into a petri dish and then dried in the oven.
The properties of pure chitosan film, berberine added film and control film containing all components except berberine were examined comparatively. All the films have been crosslinked with sodium tripolyphosphate solution. The crosslinking process has been done after the films have been dried. After all, the steps are completed, the film samples have been kept in a humidity cabinet that has 25 ⁰C temperature and 50 % relative humidity. 
Characterization experiments were carried out on all the films. These are swelling, solubility, water vapor permeability, tensile strength, and antioxidant and antibacterial activity tests.   Physical tests, antioxidant and antibacterial activity results of chitosan film containing berberine chloride were more successful than control film and pure chitosan film in terms of properties of a food packaging material. The addition of berberine chloride made the chitosan film more durable. The fact that the addition of berberine chloride increases the antioxidant and antibacterial activity of the film is an indication that the obtained films can prevent the deterioration of foodstuffs. In the light of the studies and the results obtained, it has been successfully concluded that chitosan film containing berberine chloride can be an alternative food packaging material. Finally, it is advisable to apply the combination of chitosan with some natural substances. Applications of biopolymeric materials cover a very wide area.  Increasing environmental pollution, problems, and concerns are prompting us to do something about saving nature for generations to come. Scientific research is opening a new door and view in many areas like this master thesis. Not only this study but also many other academic studies aim to give a point of view on this subject. This study aimed to develop a product that will solve environmental concerns and shed light on this issue in the future. Moreover, increasing sensitivity to environmental issues can create a new sustainable world. Governments, organizations, and public attention are necessary at this point.  Like many other problem solving, environmental problems require working together.