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Microstructural changes in m. rectus abdominis bovine muscle after heating
Thierry Astruc1, Philippe Gatellier, Roland Labas
1INRA de Clermont-Ferrand-Theix, UR370 QuaPA, F-63122 St Genès Champanelle, France. thierry.astruc@clermont.inra.fr
Abstract:
A histological and ultrastructural study was conducted to characterize changes in beef muscle structure after heating. Pieces of rectus abdominis muscle were heated at 100 degrees C over varying time frames from 15 min to 60 min and at 270 degrees C for 1 min; samples were then prepared for optical and transmission electron microscopy. After 15 min of heating, at 100 degrees C, a lateral shrinkage in fibre of 48% and an increase in gaps between the myofibrillar masses of 27% was noted. No more significant evolution was observed as heating duration escalated. The ultrastructure showed strong myofibril to sarcolemma detachments in which granular aggregates, coming in part from myofibrillar proteins, are stored. Neighbouring muscle fibres showed strong heterogeneity in morphological behaviour after thermal treatment, suggesting that differences in composition and structure of the cytoskeleton proteins in the different fibres can cause denaturation/shrinkage of the proteins at different times along the timescale of microstructural changes during heating. Short heating at high temperatures expanded the gaps between myofibrillar mass, but the overall changes in the ultrastructure were similar to those obtained when heating at 100 degrees C.
Insights
Heating beef muscle causes significant fiber shrinkage and gaps between myofibrils, with structural changes stabilizing quickly. Differences in muscle fiber composition influence denaturation rates during thermal processing.
Area of Science:
- Food Science
- Microscopy
- Muscle Biology
Background:
- Beef muscle undergoes microstructural changes during thermal processing.
- Understanding these changes is crucial for predicting texture and quality.
Purpose of the Study:
- To characterize histological and ultrastructural changes in beef muscle after heating.
- To investigate the effects of different heating times and temperatures on muscle fiber morphology.
Main Methods:
- Histological and transmission electron microscopy of beef rectus abdominis muscle.
- Samples were heated at 100°C (15-60 min) and 270°C (1 min).
Main Results:
- Heating at 100°C for 15 min caused 48% lateral fiber shrinkage and 27% increase in myofibrillar gaps.
- Further heating duration showed minimal additional changes.
- Myofibril-sarcolemma detachments and granular aggregates were observed.
- Heterogeneity in fiber response suggests cytoskeleton protein differences.
Conclusions:
- Beef muscle microstructural changes during heating stabilize rapidly.
- Cytoskeleton protein composition influences fiber denaturation and shrinkage rates.
- High-temperature, short-time heating yields similar ultrastructural changes to prolonged lower-temperature heating.
