Hüsnü Yusuf Gökalp

Antagonistic effect on Listeria monocytogenes and L. innocua of a bacteriocin-like metabolite produced by lactic acid bacteria isolated from sucuk

Two Lactobacilli and four Pediococci strains producing bacteriocin-like metabolities isolated from sucuk were tested with agar spot tests and well diffusion assays for their inhibitory activity against 16 Listeria strains, also isolated from sucuk. The production of organic acids and hydrogen peroxide limited, L. sake Lb 706 (used as a bacteriocin producer strain) and the isolated lactic acid bacteria (LAB) showed inhibitory activity against all of the Listeria strains, while L. sake Lb 706-A (used as a bacteriocin non-producer mutant) had the same effects against only two Listeria monocytogenes strains (51, 52) in agar spot tests. In the well diffusion assays, while L sake Lb 706 and four Pediococci isolates (413, 416, 419, 446) exhibited inhibitory activity against all of the Listeria strains tested, L. sake Lb 706-A and two of the Lactobacilli isolates (77, 116) showed no effect on the Listeria strains tested.

Basic chemical characteristics of fresh, non-packed and vacuum-packed sheep-tail and tail-fat stored frozen for different periods

Fatty tails were obtained after the slaughter of Morkaraman sheep, which are a common breed of fatty-tailed sheep in Turkey. Fat obtained from sheep tails, (called tail-fat) is used either in fresh condition or after frozen storage. This fat is commonly used as a food source in many countries in which fat-tail sheep breeds are raised; but there has been no detailed research on fatty tails or the tail-fat. In this work some quality criteria such as water, fat and nitrogen content, 2-thiobarbituric acid and peroxide numbers, free fatty acids, melting point, iodine and saponification numbers were studied in sheep tails and sheep tail-fat, both in the fresh condition and after storage at -18 ± 1°C for up to 60 days. The effect of vacuum packaging versus storage in netting bags (no-protection, non-packed), was also determined. The fat content of the tails was around 94%. Thus, the tail is a concentrated fat source. Some quality criteria of the tail and the tail-fat were determined and are given in the text. Overall results indicated that both the tail and the tail-fat can be effectively used in various types of food and food processing, especially after performing some technological and refining processing. If the fatty tail has to be stored, it should be vacuum packed and stored frozen. At -18°C, vacuum-packed tail samples could be stored around 45 days, but in the netting bags, this storage period should not exceed 30 days.

Effects of shooting period, times within shooting periods and processing systems on the extract, caffeine and crude fiber contents of black tea

ZusammenfassungDie in den verschiedenen Sproßperioden und in unterschiedlichen Zeiten innerhalb der einzelnen Sproßperiode erhaltenen frischen Teeproben wurden mit den fünf verschiedenen kommerziellen Walzmethoden zu schwarzem Tee verarbeitet. Bei diesen Teeproben wurden der Extrakt-, Coffein- und Rohfasergehalt bestimmt. Der Extrakt- und der Rohfasergehalt von schwarzem Tee werden durch alle Faktoren und deren Wechselwirkungen signifikant (P<0.01) beeinflußt. Die Sproßperiode und die Zeit innerhalb der Sproßperioden wirkten auf den Coffeingehalt von schwarzem Tee ein. Es wurde festgestellt, daß die Verarbeitungsmethode keine signifikante Wirkung (P<0.05) auf den Coffeingehalt hatte. Der Extrakt- und der Coffeingehalt nahmen von der ersten Sproßperiode bis zur dritten, und auch vom Anfang der einzelnen Sproßperiode bis zum Ende ab. Der Rohfasergehalt von schwarzem Tee nahm dagegen insbesonders vom Anfang der einzelnen Sproßperiode bis zum Ende der Sproßperiode zu.AbstractThe extract, caffeine and crude fibre contents of black tea, from different shooting periods, different times within each shooting period and processed by five different commercial rolling methods, were examined. The extract and crude fibre contents of black tea were significantly (P<0.01) affected by all these factors and their interactions. The caffeine content of black tea was affected by the shooting period and times within the shooting period. It was determined that processing methods did not have a significant (P<0.05) effect on the caffeine content. The amount of extract and caffeine decreased from the first shooting period to the third, and also from the beginning of each shooting period to the end. However, the crude fibre content of the black tea increased, especially from the beginning of each shooting period to the end of each shooting period.