Yazar "Eştürk, Okan" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim
    Öğe
    Comparative study on degradation, aggregation and rheological properties of actomyosin from cold, temperate and warm water fish species
    (2014) Eştürk, Okan; Park, Jae Won
    Bu çalışmada, Alaska pollock (Theragra chalcogramma), Pacific whiting (Merluccius productus), bigeye snapper (Priacanthus spp.), lizardfish (Saurida spp.) ve threadfin bream (Nemipterus spp.) surimilerinden hazırlanan aktomyozinin proteolitik parçalanma ve ısıl topaklanma eğilimi ve reolojik özellikleri karşılaştırmalı olarak incelenmiştir. Arıtılmamış aktomyozin örneklerinde belirgin bir endojen proteolitik aktivite görülürken, Pacific whiting ve lizardfish en yüksek proteolitik aktiviteyi göstermişlerdir. SDS-PAGE analizi, Pacific whiting, bigeye snapper, lizardfish ve threadfin bream miyozin ağır zincir bantlarının yoğunluğunun inkübasyon süresi uzadıkça azaldığını, orta ve düşük molekül ağırlıklı proteinlerin oluştuğunu göstermiştir. Test edilen bütün balık türleri için 0,5°C dk–1 ısıtma hızı daha yüksek bulanıklık değerlerine neden olurken, bunu 1,0°C dk–1 ve daha sonra 2,0°C dk–1 ısıtma hızları izlemiştir. Bulanıklığın artmaya başladığı sıcaklık değeri balık türünden belirgin bir şekilde etkilenmiştir. Aktomyozinin sıcaklık tarama testlerinden elde edilen dinamik depolama modülü pik sıcaklıklarının diferansiyel taramalı kolorimetre geçiş sıcaklık değerlerine yakın olduğu görülmüştür. Bu, dinamik testlerden elde edilen piklerin protein denatürasyon sıcaklıkları ile ilgili olduğuna işaret etmektedir. Düşük ısıtma hızları, ısıl geçiş sıcaklığının daha düşük bir değere kaydırmıştır. Bu sonuçlar, protein jeli oluşum özellikleri ve proteolitik parçalanma açısından balık türlerinin ısıl hassasiyetinin daha iyi anlaşılmasını sağlayacaktır.
  • Küçük Resim
    Öğe
    Drying properties and quality parameters of dill dried with intermittent and continuous microwave-convective air treatments
    (2010) Eştürk, Okan; Soysal, Yurtsever
    In this study, influence of various microwave-convective air drying applications on drying kinetics, color and sensory quality of dill leaves (Anethum graveolens L.) were investigated. In general, increasing the drying air temperature decreased the drying time, and increased the drying rate. Increasing microwave pulse ratio increased the drying time. Page, Logarithmic, Midilli et al, Wang & Singh and Logistic models were fitted to drying data and the Page model was found to satisfactorily describe the microwave-convective air drying curves of dill leaves. Comparing to the fresh dill, lightness (L*), greenness (-a*) and yellowness (+b*) decreased for all drying applications. The deviation from fresh product color (∆E*) increased as pulse ratio increased and drying air temperature decreased. Considering the product quality, continuous microwave-convective air drying combinations gave better results than intermittent microwave-convective air drying in terms of color and sensory evaluation results.
  • Küçük Resim
    Öğe
    Effect of modified atmosphere packaging on the quality and shelf life of minimally processed carrots
    (2008) Ayhan, Zehra; Eştürk, Okan; Taş, Emel
    The objective of this study was to investigate the effect of modified atmosphere packaging on the quality and shelf life of minimally processed carrots during cold storage. Ready-to-eat carrots (Nantes) prepared by manual peeling and automatic slicing were packed with passive (in air) and active modified atmospheres at low (5% O2, 10% CO2, 85% N2) and high oxygen concentrations (80% O2, 10% CO2, 10% N2). Minimally processed carrots were packed in polypropylene (PP) trays sealed with PP based film. Microbial, chemical, physical, and sensory analyses were conducted in carrots for 21 days at 4 °C. There was no yeast or mold growth during the 21 days of storage; however, the growth of mesophilic aerobic bacteria was observed at all treatments. The carrots packed with high oxygen and passive MAP retained quality properties better compared to low oxygen. The whiteness index did not significantly change during the 21 days of storage in all applications, indicating the good retention of orange color. The texture values declined for both passive and active MAP applications after 14 days of storage indicating a significant softening (P ≤ 0.05). According to oxygen level in the headspace and sensory results, shelf life of minimally processed carrots is suggested as 7 days for high oxygen and passive MAP application; however, it is limited to only 2 days for modified atmosphere with low oxygen.