Zmiany w mikrostrukturze i teksturze mięśni bydlęcych podczas dojrzewania poubojowego i ogrzewania

Krystyna Palka

Abstract

Changes occurring in the microstructure of meat during post mortem ageing and processing have a significant influence on its quality traits, especially texture, tenderness and water holding capacity. The aim of the study was to determine relationships between the structural changes taking place in meat during ageing and heating and its texture, tenderness, water holding capacity and the solubility of intramuscular collagen. The investigations were carried out on sernitetzdinosus muscles removed from the carcasses of 18-month-old bulls, class E, 24 hours after slaughter. After 5 days of ageing at a temperature of 4 °C, 20 mm slices of muscles were vacuum-packed and retorted at a rate of 6 °C/min to the following internal temperatures: 50, 60, 70, 80, 90, 100 and 120 uC, or packed into aluminium foil and roasted at a rate of 3 °C/min to the internal temperatures 50, 60, 70, 80 and 90 °C in an electric oven heated to 170 "C. Muscles aged for 12 days at 4 °C were roasted in the same conditions. This was followed by morphological and physico-chemical examinations. The microstructural changes in meat were investigated using a scanning electron microscope. The chemical composition of samples was established according to the relevant Polish standards, and the quantity and solubility of collagen — according to the method described by Palka 119991. Texture profile analysis (TPA) and shearing tests of samples were conducted using a texture analyser. Cooking losses were calculated as differences between the masses of the samples before and after heating. At the same degree of meat maturity the structural changes and cooking losses were lower, and the values of TPA parameters, hardness and chewiness, were higher in roasted samples then in retorted ones. Biochemical changes underwent by meat during ageing influenced the rate of thermal changes in its structural components. A sig-nificant decrease in fibre diameter and in sarcomere length occurred in 5-day-aged meat roasted to 60"C and in 12-day-aged meat roasted to 50 °C. In the longer aged raw meat the solubility of collagen was twice as high as in that aged for a shorter time, and the values of TPA parameters, tenderness and chewiness, were lower by about 50 %. The solubility of intramuscular collagen during the retorting of meat did not change up to 60 "C and increased two times at 70 ue. During the roasting of meat there was a similar tendency, but the twofold increase was observed at 80 °C. At higher temperatures the solubility of collagen decreased in meat aged for 5 days, or was at the same level in meat aged for 12 days. Shear force values of cooked meat were positively correlated with the total intramuscular collagen content. The cooking losses increased with temperature, most considerably in the range of 50 to 70 °C, and were negatively correlated with the length of sarkomeres.
Other language title versionsChanges in the microstructure and texture of bovine muscles during post mortem ageing and heating
Book typeMonograph
Other categories ROZPRAWA_HABILITACYJNA
Author Krystyna Palka (FoFT / DoAPT)
Krystyna Palka,,
- Department of Animal Product Technology
PublisherUniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW [80]
Publishing place (Publisher address)Kraków
Issue year2000
Book series /Journal (in case of Journal special issue)Zeszyty Naukowe Akademii Rolniczej im. H. Kołłątaja w Krakowie. Rozprawy, ISSN 1233-4189, (0 pkt)
No270
Pages68
Publication size in sheets4.5
Languagepl polski
Score (nominal)20
Citation count*2 (2016-05-19)
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