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The aim of the study was to assess the effect of the introduction of curing brine, massaging and pasteurisation on the dynamics of changes in collagen content and its thermohydrolysis rate in two bovine muscles with different topographic positions in the carcass: the semimembranosus muscle (m. semimembranosus) and the lumbar part of the longissimus dorsi muscle (m. longissimus lumborum). Brine contained, among other things, NaCl, phosphates and collagen protein. In the study the pH value of muscles, contents of crude protein and dry matter were determined together with the amount of collagen and its susceptibility to thermohydrolysis; moreover, shear force value was determined using the WBSF test. On the basis of the conducted tests it was found that the semimembranosus muscle contained more collagen than the lumbar part of the longissimus dorsi muscle. The introduction of brine, massaging and pasteurisation resulted in changes not only in its amount, but also in its susceptibility to thermohydrolysis. Curing resulted in a decreased rate of collagen thermohydrolysis in both analysed muscles in comparison to raw muscles: from several times in m. semimembranosus to around fifteen times in m. longissimus lumborum in terms of crude protein and over twenty times in relation to the total collagen content. The rate of collagen thermohydrolysis in both muscles varied: it was higher in m. semimembranosus than in m. longissimus lumborum. The most profound effect on changes in tenderness (test WBSF) was found for massaging, which in the semimembranosus muscle resulted in its decrease, while in the lumbar part of the longissimus dorsi muscle it caused an increase in comparison to the value obtained after the introduction of brine. It was found that after pasteurisation the dorsal muscle was more tender in comparison to the semimembranosus muscle in spite of the fact that it was characterised by a higher share of collagen in the total amount of protein.
The objective of the presented study was to assess the dynamics of changes of the histological parameters of the following two pork muscles: the semimembranosus muscle (musculus semimembranosus) and the quadriceps muscle of the thigh (musculus quadriceps femoris) under the influence of curing, massaging and pasteurisation processes with the assistance of the computer image analysis. The analysis of the muscle structure was conducted on the basis of: the surface and circumference of muscle fibres, Feret’s H and V diameter, percentage proportion of muscle fibres and their quantity in the analyzed field of view. The fibre shape was determined on the basis of the H/V ratio. It was found that the quadriceps muscle of the thigh exhibited greater dynamics of changes of the structure elements in comparison with the semimembranosus muscle under the influence of injection and plasticizing processes. The injection of ham muscles resulted in the loosening of muscle fibres, rounding of their contours as well as in the increase of their cross section area. The pasteurisation process failed to cause changes in the structure of the quadriceps muscle of the thigh, whereas in the semimembranosus muscle, pasteurisation increased the cross section area and circumference of muscle fibres and their percentage proportion in the examined field of view in comparison with the massaged muscle. The applied pasteurisation process was found to even out cell dimensions and to decrease inter-cellular spaces in both of the examined muscles.
Streszczenie. W pracy oceniono jakość mikrobiologiczną wędlin pakowanych próżniowo. Do oceny wybrano wędliny typu mielonka i salami parzone, dostępne w sprzedaży detalicznej. Wędliny pakowano w opakowania próżniowe i próżniowe termokurczliwe i składowano w temperaturze 4°C, przez 4-5 tygodni. Stan mikrobiologiczny oceniano po każdym kolejnym tygodniu przechowywania. Stwierdzono znaczne zanieczyszczenie wędlin bakteriami z grupy coli. Żadna z ocenianych prób nie spełniała wymagań normy po 3 tygodniach przechowywania (okres trwałości deklarowany przez producenta). Nie stwierdzono wpływu rodzaju opakowania na stan mikrobiologiczny ocenianych wędlin.
The influence of elevated fat content and brining process on muscle tissue from old cattle on the thermostability of collagen was the object of the study.
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