Sulu enzimatik ekstraksiyon yöntemi ile ayçiçek yağı ve proteini eldesi
Sunflower oil and protein obtained by aqueous enzymatic extraction
Yazar: RUMEYSA BAYRAK
Danışman: DOÇ. DR. DERYA KAHVECİ KARINCAOĞLU
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Gıda Mühendisliği Ana Bilim Dalı / Gıda Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Gıda Mühendisliği = Food Engineering

Özet:
SULU ENZİMATİK EKSTRAKSİYON YÖNTEMİ İLE AYÇİÇEK YAĞI VE PROTEİNİ ELDESİ
ÖZET
Çevre kirliliğinin artması ile birlikte gıda kaynaklarının korunması ve sürdürülebilirliği önemli bir konu haline gelmektedir. Bu amaçla, günümüzde birçok alanda sürdürülebilir ve çevre dostu alternatif yöntemlere ihtiyaç duyulmaktadır. Solvent ekstraksiyonu, yağ endüstrisinde en yaygın kullanılan geleneksel yöntemlerden biridir ve bu yöntemle elde edilen yağ verimi oldukça yüksektir. Solvent ekstraksiyonunda hekzan ve/veya n-hekzan gibi organik çözücüler kullanılmaktadır. Ancak kullanılan bu organik çözücüler toksik ve yanıcı olması gibi sebeplerden dolayı bazı kısıtlamalara sahiptir. Aynı zamanda çok fazla çözücü kullanılması da çevre sorunlarını beraberinde getirmektedir. Sulu enzimatik ekstraksiyon yöntemi çözücü olarak su kullanılması sebebi ile çevre dostu bir yöntemdir ve bu yöntemle yüksek kalitede ürünler ekstrakte edilebilmektedir. Bununla birlikte herhangi bir bozulma olmadan yüksek besin içeriğine sahip yan ürünlerin de elde edilmesine olanak sağlamaktadır. Ayçiçeği, yağ, küspe ve biyodizel gibi kullanım alanları açısından önemli bir yağlı tohum bitkisidir. Günümüzde üretilen ayçiçeği tohumunun büyük bir kısmı yağ üretimi için kullanılmaktadır. 
Bu çalışmada, ayçiçeği tohumlarından yağ eldesinde, geleneksel solvent ekstraksiyonu yöntemi yerine sulu enzimatik ekstraksiyon yöntemi kullanılarak yağ elde edilmesi ve aynı zamanda yağ ekstraksiyonu sonrasında ayçiçeği proteinlerinin de eş zamanlı olarak elde edilmesi amaçlanmıştır. Sulu enzimatik ekstraksiyon sonrasında elde edilen yağda verim hesaplanarak Soxhelet ekstraksiyonu ile elde edilen yağ verimleri ile karşılaştırılmıştır. Aynı zamanda, sulu enzimatik ekstraksiyon sonrası sulu fazda alkali ekstraksiyon-izoelektrik çöktürme ile protein izolatı elde edilmiştir ve protein izolatlarında bulunan klorojenik asitin uzaklaştırılması için yıkama yapılmıştır. Sulu enzimatik ekstraksiyon için Yüzey Tepki Metodolojisi (RSM) kullanılarak 31 adet örnek deney tasarımı oluşturulmuştur. Optimum sulu enzimatik ekstraksiyon koşullarını belirlemek için 1:4, 1:7, 1:10 katı sıvı oranı ve 1,3,5 ml/100 g enzim oranları ve ekstraksiyon süresi olarak 30, 60, 90 dk (Celluclast® ve Alcalase® için ayrı ayrı) kullanılmıştır. Yapılan denemeler sonucunda, optimum sulu enzimatik ekstraksiyon parametreleri 4g/g katı sıvı oranı, 5mL/100g enzim konsantrasyonu, Celluclast® süre 1,5 ve Alcalase® süre 1,5 saat olarak belirlenmiştir. Bu koşullarda gerçekleştirilen SEE sonrası elde edilen yağ verimi %33,44 ve protein değeri %3,82 olarak bulunmuştur. Elde edilen yağın serbest yağ asidi değeri %0,74±0,05, peroksit değeri 1,55±0,175 meqiv/kg bulunmuştur. Sulu enzimatik ekstraksiyon ile elde edilen yağ verimi, solvent ekstraksiyonu ile elde edilen yağ verimi ile kıyaslandığında daha düşük bir yağ verimi elde edilmiştir.
Alkali ekstraksiyon-izoelektrik çöktürme ile elde edilen protein izolatı miktarı 1,60±0,07g ve protein içeriği %54,99±1,12 olarak bulunurken klorojenik asit uzaklaştırma işleminden sonra elde edilen protein izolatı miktarı 0,81±0,13g ve protein içeriği %58,27±0,15 olarak elde edilmiştir. Belirlenen optimum koşullarda HPLC kullanılarak izolatlardaki klorojenik asit miktarları tespit edilmiştir. Sulu enzimatik ekstraksiyon sonucu elde edilen protein izolatlarındaki klorojenik asit miktarı 2,43±0,56mg/g olarak tespit edilirken klorojenik asit yıkama sonrasındaki protein izolatlarındaki klorojenik asit miktarının 3,66±0,84mg/g olduğu gözlemlenmiştir ve klorojenik asit uzaklaştırma için denenen yöntemin etkili olmadığı gözlemlenmiştir.

Abstract:
SUNFLOWER OIL AND PROTEIN OBTAINED BY AQUEOUS ENZYMATIC EXTRACTION
SUMMARY
Sunflower seeds are one of the most important oil crops in the world and in Turkey. Global production of sunflower seeds in the world ranks third after soybeans and rapeseed. Sunflower seeds are produced in Europe and Turkey, especially in Ukraine and Russia. Nowadays, most of the sunflower seeds produced are used for oil production. Sunflower oil is generally considered a premium oil when compared to other vegetable oils due to its light colour, mild flavor and rich components.
As a result of oil extraction of sunflower seeds, a valuable by-product called oil cake is obtained. The oil cake obtained after extraction has a very rich content, especially in terms of protein (20-60%), and it can be evaluated as an alternative protein source. In addition, oil cakes are a source of bioactive compounds with beneficial properties for health. Sunflower seed meal appears to have a balanced amino acid profile when compared to other seed meals. However, the oil cake obtained as a result of oil extraction by traditional methods such as solvent extraction is used only as animal feed. Phenolic compounds, which are found in relatively high amounts in sunflower seeds, are also considered among the factors limiting the use of sunflower proteins. In particular, the presence of chlorogenic acid in sunflower seeds is an important problem. This is because phenolic compounds reduce both the digestibility and functionality of proteins as a result of their interaction with proteins. These reactions lead to the destruction of essential amino acids and the formation of toxic compounds. However, the presence of chlorogenic acid in sunflower seeds may cause undesirable color and flavor changes in sunflower protein isolates.Solvent extraction is one of the traditional methods of vegetable oil production and is widely used. Generally, solvents such as hexane and/or n-hexane are used in solvent extraction. However, such organic solvents have some limitations as they are toxic and flammable. At the same time, the use of excess solvent in the process also causes serious environmental problems.
With the increase in environmental pollution, the protection and sustainability of food resources becomes an important issue. Therefore, there is a need for sustainable and environmentally friendly alternative methods in many areas. Due to the use of water as a solvent in the aqueous enzymatic extraction method, it is an alternative to traditional methods, reliable and environmentally friendly, and it is possible to obtain high quality products with this method. In addition, by-products with high nutrient content can be obtained without degradation of the material to be extracted.
In this study, it was aimed to obtain oil from sunflower seeds by using aqueous enzymatic extraction method instead of traditional solvent extraction method. At the same time, it was tried to obtain sunflower proteins simultaneously after oil extraction. The yield of oil obtained after aqueous enzymatic extraction was calculated and compared with the oil yields obtained by Soxhelet extraction. After the aqueous enzymatic extraction, the protein isolate was obtained by alkaline extraction-isoelectric precipitation in the aqueous phase and washing was carried out to remove the chlorogenic acid present in the protein isolates.
The efficiency of Celluclast®, Alcalase®, Viscozyme® and Pectinex® enzymes individually and their combinations were evaluated in order to disrupt the cell wall structure of sunflower seeds and to release the bound oil. As a result of aqueous enzymatic extraction with Celluclast®, Viscozyme® and Pectinex® enzymes, no oil phase was formed. The highest oil yield was obtained by aqueous enzymatic extraction with Celluclast® -Alcalase®  enzyme combination. In order to decide on the extraction temperature beforehand, extraction trials were carried out at 50°C and 60°C. It was observed that there was no significant difference between the oil yields obtained after aqueous enzymatic extraction performed at 50°C and 60°C temperatures, but considering that high temperatures may affect the quality parameters of the oil, it was decided to perform the extraction at 50°C. Compared to traditional solvent extraction, the oil yield obtained by the aqueous enzymatic extraction method is relatively lower. For this reason, demulsification process is applied in the cream phase obtained at the end of the extraction in order to increase the oil yield. For this step, demulsification process was applied both with pH and by adding enzyme, and the efficiency of the two methods was evaluated. The oil yield obtained after the demulsification process using the enzyme was found to be relatively higher. However, due to the length of the process, it was decided to perform the demulsification process by adjusting the pH.
In order to determine the optimum extraction parameters for aqueous enzymatic extraction, 31 sample experimental designs were created by using the Surface Response Methodology (RSM). In order to determine the optimum aqueous enzymatic extraction conditions, 1:4, 1:7, 1:10 solid-liquid ratio and 1,3,5 mL/100 g enzyme ratios and extraction time were determined as 30, 60, 90 min for Celluclast®  and Alcalase®. As a result of the experiments, the optimum aqueous enzymatic extraction parameters were determined as 4g/g solid-liquid ratio, 5mL/100g enzyme concentration, Celluclast® time 1.5 and Alcalase® time 1.5 hours. The oil yield after SEE performed under these conditions was 33.44% and the protein value was 3.82%.
The free fatty acid value of the obtained oil was 0.74±0.05%, and the peroxide value was 1.55±0.175 meqiv/kg. It was determined that the oil yield was lower when the oil yield obtained by aqueous enzymatic extraction was compared with the oil yield obtained by solvent extraction.
Protein isolate was obtained by alkaline extraction-isoelectric precipitation from the aqueous phase after aqueous enzymatic extraction performed under optimum conditions. For this purpose, the aqueous phase obtained after the aqueous enzymatic extraction was collected and the pH was adjusted to 9 in order to extract the proteins in alkaline medium and mixed for 1 h. It was then centrifuged and the aqueous supernatant was collected and the same procedure was repeated. This time, it was aimed to precipitate the proteins at the isoelectric point by adjusting the pH to 4.5. The resulting precipitate was freeze-dried. In order to prevent the formation of green pigment as a result of the interaction of chlorogenic acid with proteins after oxidation in alkaline conditions, the aqueous phase obtained after aqueous enzymatic extraction was subjected to acidic washing before obtaining the protein isolate. After the aqueous phase obtained after the aqueous enzymatic extraction was collected, the pH of the medium was adjusted to 5 and subjected to a 30-minute mixing process. Then it was centrifuged and the same process was repeated by removing the precipitate from the mixture. After the precipitate remaining after centrifugation was dispersed in water at a ratio of 1:10 (w/v), protein isolate was obtained by alkaline extraction-isoelectric precipitation method. While the amount of protein isolate was 1.60±0.07g and the protein content was 54.99±1.12%, the amount of protein isolate obtained after chlorogenic acid removal was 0.81±0.13g and the protein content was 58.27±0.15%. The amount of chlorogenic acid in the isolates was determined using HPLC. While the amount of chlorogenic acid in the protein isolates obtained as a result of aqueous enzymatic extraction was determined as 2.43±0.56mg/g, the amount of chlorogenic acid in the protein isolates after chlorogenic acid washing was observed to be 3.66±0.84mg/g.