Yüksek amilozlu mısır nişastasından enzim ve mikrodalga modifikasyonları ile enzime dirençli nişasta üretimi ve karakterizasyonu

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada, yüksek amilozlu mısır nişastasından (Hylon VII, %70 amiloz) enzim hidrolizi ve mikrodalga ısıtma uygulamaları ile enzime dirençli nişasta üretimi gerçekleştirilmiştir. Doğal haldeki Hylon VII nişastasına pişirme ve otoklavlama işlemlerinin ardından, Design Expert 7.0 programında Yanıt Yüzey Yöntemi ile belirlenen koşullarda (%20-100 mikrodalga gücü ve 2-4 dakika süre) mikrodalga ısıtma uygulanmıştır. Mikrodalga uygulaması sonrasında örnekler 95ºC'de 24 saat bekletilmiştir. Her uygulama 1 döngü (MD1) ve 3 döngü (MD3) olmak üzere aynı koşullarda tekrarlanmıştır. Bekletme süresi sonunda örnekler etüvde 50ºC'de ya da liyofilizatörde kurutulmuştur. Enzim-mikrodalga modifikasyonu yönteminde ise örnekler pullulanaz enzimi ile (400 PUN/mL; 1500 U/kg nişasta) 60ºC'de 48 saat inkübe edilmiş ve ardından aynı koşullarda mikrodalga-bekletme döngülerine tabi tutulmuştur. Elde edilen örneklerde enzime dirençli nişasta (EDN) miktarı, RVA viskozite değerleri, çözünürlük, su bağlama kapasitesi ve renk değişimi belirlenmiştir. Üretilen örneklerde EDN miktarı mikrodalga döngü sayısı arttıkça artmış, 50ºC'de kurutulan örneklerin liyofilizatörde kurutulanlara göre daha yüksek EDN içerdiği belirlenmiştir. Liyofilize edilerek kurutulan örneklerin RVA ısıtma öncesi viskozite değerleri 50ºC'de kurutulanlardan yüksek bulunmuştur. İşlem görmüş tüm nişasta örneklerinin su bağlama ve çözünürlük değerleri doğal haldeki Hylon VII'ye göre yüksektir. Mikrodalga döngü sayısı ile uygulanan güç ve süre arttıkça örneklerin renk değerlerinde önemli değişimler gözlenmiştir. Enzim hidrolizi uygulanmış örneklerin EDN miktarları enzim ile hidroliz edilmemiş olanlara göre yüksek çıkmıştır. Viskozite değerlerinde enzim hidrolizi ile düşüş meydana gelmiştir. Örneklerin EDN miktarındaki değişmeler Design Expert Programı ile analiz edilmiş ve uygun olanlar için doğrusal ve ikinci dereceden modeller oluşturulmuştur. Modellerden elde edilen denklemlerden 0,6183 ile 0,8250 arasında değişen değerlerde R2'ler hesaplanmıştır. Anahtar Kelimeler: Enzime Dirençli Nişasta, Mikrodalga Enerjisi, Pullulanaz HidroliziIn this study, enzyme resistant starch from high amylose corn starch (Hylon VII, 70% amylose) was produced by enzyme hydrolysis and microwave heating processes. After cooking and autoclaving of native Hylon VII starch, the paste was treated by microwave heating at the conditions (20-100% microwave power and 2-4 minutes) determined by Response Surface Methodology by Desing Expert 7.0 programme. After microwave treatment, the samples were stored at 95ºC for 24 hours. Each treatment was repeated 1 cycle (MW1) and 3 cycles (MW3) at the same conditions. At the end of the storage period the samples were dried in the oven at 50ºC or freze-dryer. In enzyme-microwave modification method, samples were incubated at 60°C for 48 hours with pullulanase enzyme (400 PUN/mL; 1500 U/kg starch) and then treated with microwave-storage cycles at same conditions. Enzyme resistant starch (RS) content, RVA viscosity values, solubility, water binding capacity and colour changes of the produced samples were determined. Resistant starch contents of the samples were increased with increasing microwave cycle and were higher for oven dried samples than freeze-dried ones. RVA cold viscosity values of freze-dried samples were higher than those of oven-dried ones. All processed starch samples had higher water binding and solubility values than native Hylon VII starch. Changes in colour values became more significant with the increase in microwave cycles, power and time. Enzyme treatment with Pullulanase and microwave treatment together effected RS content increase much more than just microwave treatment. Viscosity values of combined treated samples reduced. Changes in RS contents of samples were analyzed by Design Expert Programme and lineer and quadratic models of fitted samples were determined. The R2 values were evaluated between 0,6183 and 0,8250 according to model equations. Keywords: Enzyme Resistant Starch, Microwave Energy, Pullulanase Debranchin

Optimization of resistant starch formation from high amylose corn starch by microwave irradiation treatments and characterization of starch preparations

The effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-400%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2 min. The F, p (<0.05) and R-2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones. (C) 2016 Elsevier B.V. All rights reserved

Enrichment of cookies with glutathione by inactive yeast cells (Saccharomyces cerevisiae): Physicochemical and functional properties

Cookie is one of the favorite cereal products which could be formulated by using various ingredients for enrichment. The aim of this study was to determine the effects of the inactivate yeast cells addition to cookie formulation in terms of glutathione (GSH) content, antioxidant activities, physicochemical and sensorial properties. Also, the cookies were produced with GSH (pure, 98%) addition to compare the effects of inactive yeast GSH with pure GSH on revealed properties. According to results, The GSH contents and the antioxidant activities increased in dough and cookie samples with inactive yeast addition compared to control and pure GSH added dough and cookie samples. The increases in GSH contents and antioxidant activities were observed after baking in all samples. The pure GSH addition increased the moisture content, spread ratio and L* value while decreased the hardness and b* values of the cookies. The contrary results were obtained by inactive yeast addition in terms of the physicochemical properties where the protein content of the cookies increased with inactive yeast addition by approximately 25%. The loss of GSH content decreased while the antioxidant activities and nutritional value increased in cookies by inactivate yeast addition. (C) 2017 Elsevier Ltd. All rights reserved