Tenderizing preparations which are applied intramuscularly or via the blood vessels spread throughout the endomysium and the perimysium and produce there their effects (especially on the collagenous portion of the connective tissue) during cooking in certain ranges of temperature. Sarcoplasmic proteins are also attacked, whereas myofibrillary proteins are not affected. Consequently, in contrast to natural meat ageing, only the collagen-induced background toughness is actually eliminated, and the actomyosin-induced toughness is influenced only in so far as the degradation of the connective tissue causes a general structural loosening of the meat.