RESUMO

Long-time low-temperature (LTLT) cooking of meat is known to produce a tender product. The current work tested the hypothesis that LTLT cooking for periods of up to 24 h at 60 °C reduces the contribution of intramuscular connective tissue to cooked meat toughness. Tensile tests on perimysium excised after cooking showed that its strength diminished with cooking time, although not as markedly as the Warner-Bratzler peak force measure of toughness. A gradually increasing susceptibility to trypsin digestion with increasing heating time demonstrated that there was a slow and gradual increase in the proportion of denatured collagen in the perimysium. Differential scanning calorimetry on perimysium excised after cooking showed an endothermic peak representing the denaturation of the collagen not already denatured on cooking. With increasing cooking time, the energy per milligram of collagen necessary to denature this remaining fraction increased. These results support the hypothesis that there is both an easily destabilized and more resistant fractions of the collagen in intramuscular connective tissue.

Assuntos

Tecido Conjuntivo/química , Músculo Esquelético/química , Carne Vermelha/análise , Animais , Bovinos , Colágeno/química , Culinária , Temperatura Alta

RESUMO

Gluten-free muffins with squash seed flour (SSF) were developed for contribute to reduce nutritional deficiencies and improving the health of the celiac population. Physicochemical and sensory properties of muffins were evaluated. SSF was incorporated at two levels (10 and 20% w/w) in commercial gluten-free premix (control). Incorporation of SSF increased total dietary fiber content, protein and unsaturated fatty acids. The addition of SSF at 10% resulted in a muffin that did not differ significantly from the control muffin; and also that formulations with SSF at 20% caused an increase in the browning index. Browning was favored by the increase of SSF with higher levels of fiber content. Incorporation of SSF at 20% had a significant effect on the textural parameters (firmness and chewiness) of the muffin. Also, both formulations containing SSF showed a higher overall acceptability, particularly muffins with 20% of SSF that rendered the highest scores for sponginess, texture, taste and colour.