Çiğitten yağ ekstraksiyonunun kinetiği
Küçük Resim Yok
Tarih
1994
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
ÖZET Çözgenle yağ ekstraksiyonu işlemine girecek yağlı tohumlar temizleme, kabuk kırma ve ayırma, pulcukl andırma ve kavurma ön işlemlerinden geçirilirler. Böylece; geçirgen olmayan hücre çeperlerinde ekstrakte edilmek istenen yağı bulunduran tohumlar mekanik ve ıs isal zorlamalara maruz kalırlar» Bunun sonucunda kırılan ve zedelenen yağlı tohum hücrelerinden bir miktar yağ serbest kalır, ön işlemler çözgen ekstraksiyonu işleminin verimi açısından oldukça önemlidir. Çözgen ekstraksiyonunda; Küspede bulunan yağ miktarı, ekstraksiyon süresine bağlı olarak değişim göstermektedir. Ancak; iki değişik çözgenle üç farklı nem ve sıcaklık değerleri ile, preslenmiş pamuk çiğitinde yapılan denemeler; ekstraksiyon hızının zamanla azaldığını göstermektedir. Bu durum; ekstraksiyon kinetiğinin birbirinden farklı iki mekanizmadan oluştuğunu göstermektedir. Yağın hızlı ekstrakte edildiği ilk mekanizma çözünme ekstraksiyonu evresi adını alırken; ekstraksiyon hızının azaldığı ikinci mekanizmaya difüzyon ekstraksiyonu denmektedir. çözünme ekstraksiyonu evresinde küspede kalan yağın ekstraksiyon süresi ile değişiminin doğrusal olduğu saptanmış t ir.Difüzyon ekstraksiyonu adını alan evrede ise s bu ilişki; en yüksek korelasyonu üssel modelde göstermektedir. Çözgen ekstraksiyonu işlemini ve yukarıda söz edilen mekanı zmaî B.rı, pulcuk kalınlığı ve çözgen /tohum oram.^nbit tutulmak knydıyla pulcuk nemi ve ekstraksiyon sıcaklığının etkileri hekzan ve propanol çözgenleri kullanılarak araştırılmıştır. Elde edilen sonuçlar aşağıda maddeler halinde ver i İmekt edi r. 1. Sabit sıcaklıkta uygulanan ekstraksiyonda, pulcuk nemi ekstraksiyon evresinde alınan yağ miktarı üzerinde önemli bir etki göstermektedir. Bu etki, propanolde daha yüksektir. 2. Sabit sıcaklıkta uygulanan ekstraksiyonda nemin difüzyon ekst raks iyonunun süresine etkisi; sıcaklığın etkisinden dahaönemli düzeyde olup; söz konusu etki propanol üzerinde daha da belirginleşmektedir. 3. Sabit pulcuk neminde uygulanan ekstraks iyonda, sıcaklık, çözünme evresinde alınabilen yag miktarını etkilemektedir. 4. Propanol, sıcaklık ve nem değişimlerinde hekzandan daha duyarlı bir çözgendir. 5. Ekstraksiyon süresinin; pulcuk nemi ve sıcaklıkla her iki çözgen için de ilişkisi ikinci dereceden polinomlarla açıklanmıştır
SUMMARY: Oil seed flakes are subjected to several stages ol preliminary operations, including cleaning, hull cracking anc seperation, flaking, condi t ioning(cooking) prior to extractior with solvents. By this way, mechanical and thermal stresses are presented to the cell walls which are non-permeable to both oil and solvent. A considerable part of the oil contained in the cells become easily extractable; since the cell walls are partially damaged through the preliminary operations. Therefore the extend, to which the preliminary operations are carried out effectively, is an important factor affecting the efficiency of solvent extraction. The amount of oil held by moisture free flakes is found to be dependent on the extraction time. As extraction proceeds; slower extraction rates are observed during the laboratory extraction of mechanically pressed cottonseed flakes of three different moisture levels, at three temperatures, and with two different solvents. The decrease in the extraction rate with time can be explained by two different mechanisms occured during solvent extraction. The first mechanism is named a? solution extraction, whereas the second is called as diffusion extract ion. The corelation between the oil held by moisture-free flakes with time is found to be linear during solution extraction, whereas it shows a power model during diffusion extraction. In this research, the effects of extraction temperature and moisture of flakes under constant flake thickness and solvent flow rate is discussed by performing extractions with commercial hoxane and propanol. The results are summarized as follows l 1. The moisture level of flakes have a crucial effect on the amount of easily extractable oil during solution extraction under constant operation temperature. This effect significantly increases with propanol as solvent. 2. Both moisture content and temperature, the former being more effective than the latter, increases the time elapsed during diffusion extraction. 3. The extraction temperature is not found to be effective on the amount of easily extractable oil obtained during solution extraction, but more effective than moisture on the time elapsed during this extraction. 4. Propanol is more sensitive to changes in moisture of flakes and the extraction temperature than hexane. 5. The extraction time is found to be dependent on the moisture of the flakes and the operation temperature by a polynomial corelation of second degree.
SUMMARY: Oil seed flakes are subjected to several stages ol preliminary operations, including cleaning, hull cracking anc seperation, flaking, condi t ioning(cooking) prior to extractior with solvents. By this way, mechanical and thermal stresses are presented to the cell walls which are non-permeable to both oil and solvent. A considerable part of the oil contained in the cells become easily extractable; since the cell walls are partially damaged through the preliminary operations. Therefore the extend, to which the preliminary operations are carried out effectively, is an important factor affecting the efficiency of solvent extraction. The amount of oil held by moisture free flakes is found to be dependent on the extraction time. As extraction proceeds; slower extraction rates are observed during the laboratory extraction of mechanically pressed cottonseed flakes of three different moisture levels, at three temperatures, and with two different solvents. The decrease in the extraction rate with time can be explained by two different mechanisms occured during solvent extraction. The first mechanism is named a? solution extraction, whereas the second is called as diffusion extract ion. The corelation between the oil held by moisture-free flakes with time is found to be linear during solution extraction, whereas it shows a power model during diffusion extraction. In this research, the effects of extraction temperature and moisture of flakes under constant flake thickness and solvent flow rate is discussed by performing extractions with commercial hoxane and propanol. The results are summarized as follows l 1. The moisture level of flakes have a crucial effect on the amount of easily extractable oil during solution extraction under constant operation temperature. This effect significantly increases with propanol as solvent. 2. Both moisture content and temperature, the former being more effective than the latter, increases the time elapsed during diffusion extraction. 3. The extraction temperature is not found to be effective on the amount of easily extractable oil obtained during solution extraction, but more effective than moisture on the time elapsed during this extraction. 4. Propanol is more sensitive to changes in moisture of flakes and the extraction temperature than hexane. 5. The extraction time is found to be dependent on the moisture of the flakes and the operation temperature by a polynomial corelation of second degree.
Açıklama
Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır. Yayınlanma izni olmayan tezlerin basılı kopyalarına Üniversite kütüphaneniz aracılığıyla (TÜBESS üzerinden) erişebilirsiniz.
Anahtar Kelimeler
Gıda Mühendisliği, Food Engineering, Tohumlar, Seeds, Özütleme, Extraction
