Quantitative assessment of meat tissue structural damages promoted by mechanical action in tumbling

In meat brining-massaging salt homogenization, protein extraction and texture of cooked products partly depend on meat tissue structural modifications. Our aim was to quantify these damages by automated image analysis of many sirius red stained histological images from pork Semimembranosus muscles submitted to various massaging conditions (number and rate of deformations). Muscles were massaged in brine (5 or 13 %) using a new laboratory tumbling simulator that enable to control and characterize the mechanical treatment. In samples taken from massaged muscles, zones where fibres could not be automatically separated as in the reference samples were considered as damaged and the percentage of damaged area (Pda) in the images was calculated. The Pda was equal to about 40% in the middle of the muscle at the end of a mechanical treatment that was equivalent to usual massaging conditions in an large industrial tumbler. The cumulated deformation energy (Et) which was assessed from measured force versus strain curves during massaging was varied from 35 to 1500 J. Pda varied linearly with Log(Et) and stronger in muscle centre than on the periphery