Resumo

ABUGOCH, Lilian et al. Study of the reineta protein modifications (Brama australis), put under freezing and storage to - 18º C and - 30º C.. ALAN [online]. 2006, vol.56, n.4, pp.350-355. ISSN 0004-0622.

The objective of the present work was to study functional and thermal properties of reineta ( Brama australis) frozen meat, analysed by water retention capacity (WRC), gel forming capacity ( GFC), texture, emulsifying capacity and differential scanning calorimetry ( DSC). For this study, reineta fillets were obtained and extracted by the same conditions, and cutted, packaged, frozen and stored at -18ºC and - 30ºC for 7 months. The results obtained, showed that there were no signifficant differences in the responses to thermal treatment for all the specimens. For samples frozen at -18ºC and -30ºC, the protein contents were 23.5 + 0.0 and 25.4 + 1.0%, respectively. The WRC values were 0.45 + 0.1 and 1.59 + 0.0 g water/ g protein, respectively. The gel forming capacity was only present in the fresh samples, whereas the frozen stored ones only form protein aggregates. The emulsifying capacity was between 960 and 1400 g oil / g protein, and the storage time increased this value. The miosin denaturation temperature (Td) and denaturation enthalpy ( ?H), obtained by DSC, fluctuated between 39.2 + 0.5 to 44.8 + 0.8 ºC and 1.12 + 0.3 to 0.52 + 0.2 J/g, respectively. The actina values were between 71.0 + 0.6 to 75.3 + 0.5 ºC and between 0.5 + 0.1 to 0.7 + 0.1 J/g. Cooperativity decreased as the storage time increased. This is showing a certain degree of protein displacement. The values found by thermal analyses showed a direct relationship with the functional properties, both decreasing with storage time.

Palavras-chave : Reineta; freezing; functional properties; thermal properties.