title: State diagram of salmon (Salmo salar) gelatin films.
abstract: BACKGROUND
  A state diagram presents different physical states of a biomaterial as a function of solid content and temperature. Despite their technological interest, little information is available on protein systems such as gelatin/water mixtures. The objective of this work was to develop state diagrams of salmon gelatin (SG) and bovine gelatin (BG) in order to determine maximal freeze concentration parameters (T'(g) , T'(m) and X(s') ) and to relate possible differences to their biochemical characteristics.
  
  
  RESULTS
  Biochemical characterisation of SG showed lower molecular weight and iminoacid concentration compared with BG. Likewise, the glass transition temperature (T(g) ) was lower for SG at X(s) > 0.8, which was associated with its lower molecular weight. Unexpectedly, the depression of freezing temperature (T(f) ) was greater for SG at X(s) > 0.1, which was associated with its higher ash content. Isothermal annealing produced effective values of T'(g) ≈ - 52 °C, T'(m) ≈ - 46 °C and X'(s) ≈ 0.6 for both gelatins. Interestingly, the enthalpy change associated with T'(m) (ΔH T m) was significantly higher for SG than for BG after annealing, indicating a higher proportion of ice present at about - 50 °C.
  
  
  CONCLUSIONS
  Maximal freeze concentration parameters were similar between the two gelatins, though differences in biochemical properties were evident. The results show that there are likely different ways of interaction of SG and BG with water.
authors: Departamento de Ciencias y Tecnología de Alimentos, Universidad de Santiago de Chile, Av. Ecuador 3769, Estación Central, Santiago, Chile.
authors: Paulo
authors: P
authors: Díaz
authors: Daniel
authors: D
authors: López
authors: Silvia
authors: S
authors: Matiacevich
authors: Fernando
authors: F
authors: Osorio
authors: Javier
authors: J
authors: Enrione