Yasemen Yanar

Antimicrobial Activity of the Chitosan Extracted from Metapenaeus stebbingi Shell Wastes

In the study, chitosan chemically extracted from Metapenaeus stebbingi shells obtained from shrimp processing factories and commercial chitosan were used as antimicrobial materials. Antimicrobial activities of the chitosans dissolved in acetic, lactic, formic and hydrochloric acid at different concentrations (1.00, 0.50, 0.25, 0.10 and 0.05%) were tested in vitro by using the disk diffusion method with standard microorganisms (Pseudomonas putida, Pseudomonas fluorescens, Vibrio parahaemolyticus, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli 1, Escherichia coli 2, Listeria monocytogenes, Enterecoccus faecalis, Aeromonas caviae). On the other hand, gentamicin was used as positive control. Antimicrobial test results indicated that chitosan demonstrated different effects depending on the chitosan concentration, solvent material and bacteria type. In the present study, both the extracted and commercial chitosans were observed to have antimicrobial effects on nearly all types of the bacteria.

Effects of cooking methods on electrophoretic patterns of rainbow trout

The aim of this study was to determine the effects of different cooking methods on the electrophoretic patterns of rainbow trout (Oncorhynchus mykiss) fillets using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Raw rainbow trout were deep-fried, microwaved, grilled, and baked and then monitored for changes in the electrophoretic pattern. All cooking methods resulted in significant moisture loss when compared to the raw sample (P<0.05). Water losses, occurring during cooking resulted in a higher protein content in all of the cooked fish, with regard to raw fish. Deep fried fish had higher lipid content than raw or other cooked fish. The electrophoretic pattern of samples showed a considerable number of protein bands. The bands did not disappear completely, but changed remarkably after cooking. Considering myosin and actin bands, the highest rate of bands disappearance was observed with microwaved sample, while the lowest rate occurred with deep-fried sample.

Fatty Acids Profile, Atherogenic, Thrombogenic, and Polyene Lipid Indices in Golden Grey Mullet (Liza aurata) and Gold Band Goatfish (Upeneus moluccensis) from Mediterranean Sea

ABSTRACT The aim of this work was to study the seasonal variations of the proximate compositions, fatty acids contents, and related lipid indices (atherogenic index [AI], thrombogenic index [TI], and polyene index [PI]) of golden grey mullet (Liza aurata) and gold band goatfish (Upeneus moluccensis) caught from the northeastern Mediterranean Sea. Proximate compositions and fatty acid contents of both fish species showed statistically significant seasonal variations (p < 0.05). The lipid contents were highest in autumn and lowest in winter in golden grey mullet and gold band goatfish. The main saturated and unsaturated fatty acids were palmitic acid (C16:0), stearic acid (C18:0), palmiteoleic acid (C16:1n-7), oleic acid (18:1n-9c), arachidonic acid (C20:4n-6), eicosapentaenoic acid (EPA, C20:5n-3), and docosahexaenoic acid (DHA, C22:6n-3). The total polyunsaturated fatty acids in gold band goatfish did not show any differences among the seasons, whereas that in golden grey mullet was highest in winter. Levels of EPA, DHA, and n-3/n-6 ratios, as well as AI, TI, and PI, were significantly changed among seasons. The results show that golden grey mullet and gold band goatfish, which are among the important fish in Turkey and of commercial value, are a good source for human consumption in terms of their nutritional quality.

Effects of Hot and Sweet Red Peppers (Capsicum annuum) as Feed Supplements on Pigmentation, Sensory Properties and Weight Gain of Rainbow Trout (Onchorhynchus mykiss)

Abstract This study was conducted to evaluate the effects of diets, including 0.5, 2 and 4.4% dried hot or sweet red pepper and a control diet without added red pepper, on pigmentation, sensory properties and weight gain of rainbow trout, with average initial weight of 60 g, for a rearing period of 80 days. Both red pepper types had similar effects on the carotenoid accumulation, weight gain and sensorial properties of the fish (P>0.05). Total carotenoid accumulation in the fish muscle increased significantly with increasing inclusion of red peppers. However, only the diet consisting of 4.4% hot or sweet red pepper provided adequate carotenoid accumulation in the fillet of the fish, that is, the desired colouration in the fish. Fish fed diets containing red peppers exhibited higher appearance and colour scores compared to control group (P<0.05). Irrespective of being hot or sweet, red pepper can be successfully used as an alternative natural carotenoid source in rainbow trout diets.

Su ürünleri enzimleri ve enzimlerin işleme endüstrisinde kullanım olanakları

Enzymes which have very important metabolic functions are structurally proteins that catalyse biochemical reactions and they become a part of daily and economical life. The aquatic environment contains a wide variety of genetic material and, hence represents an enormous potential for different sources of enzymes. This review summarizes information related to digestive and muscular enzymes in fish and aquatic invertebrates. In addition, potential applications of enzymes in seafood processing endustry is discussed.Biyokimyasal reaksiyonlari kataliz ederek, cok onemli metabolik fonksiyonlara sahip olan protein yapisindaki enzimler, gunluk ve ekonomik hayatin bir parcasi olmaya baslamistir. Cok genis genetik materyale sahip olan sucul cevre, farkli enzim kaynaklarindan dolayi bu alanda onemli bir potansiyel sunmaktadir. Bu derlemede balik ve diger sucul organizmalarin sindirim ve kas dokuda bulunan enzimleri hakkinda bilgi verilmektedir. Ayrica enzimlerin su urunleri isleme endustrisindeki potansiyel uygulamalari anlatilmistir.

Antioxidant effects of chitosan in European eel (Anguilla anguilla L.) fillets during refrigerated storage

In this study, the effects of chitosan extracted from Metapenaeus stebbingi shells and commercial chitosan on lipid oxidation of European eel (Anguilla anguilla L.) during refrigerated storage (+4°C) were examined. The control and treated fillet samples were analyzed periodically for pH value, free fatty acid (FFA), thiobarbituric acid (TBA) number, and peroxide value (PV). The results indicated that both chitosans significantly reduced FFA content, TBA number, and PV (P < 0.05). It was concluded that 10 g/L of extracted chitosan solution was the optimal concentration for extending the shelf life of eel fillets.