[Study of the reineta protein modifications (Brama australis), put under freezing and storage to -18 degrees C and -30 degrees C].
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 -18 degrees C and -30 degrees C 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 -18 degrees C and -30 degrees C, 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 degrees C 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 degrees C 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.
Abugoch
Lilian
L
Universidad de Chile Facultad de Ciencias Químicas y Farmacéuticas, Depto. Ciencia de los Alimentos y Tecnología Química, Santiago, Chile.
Quitral
Vilma
V
Larraín
M Angélica
MA
Vinagre
Julia
J
Kriukov
Andrei
A
Chávez
Gloria
G
D000818:Animals; D004044:Dietary Proteins / Q000032:analysis; D029941:Fish Proteins / Q000737:chemistry*; D005399:Fishes; D005511:Food Handling / Q000379:methods* / Q000592:standards; D005615:Freezing; D005628:Frozen Foods / Q000032:analysis* / Q000592:standards; D013997:Time Factors
D004044:Dietary Proteins; D029941:Fish Proteins