Thermal Characteristics and State Diagram of Freeze-Dried Broccoli: Freezing Curve, Maximal-Freeze-Concentration Condition, Glass line and Solids-Melting
In this study, the state diagram of broccoli was developed considering freezing curve, glass line, maximal-freeze concentration conditions, solids-melting and BET-monolayer line. The freezing point, glass transition and solids-melting were measured and modeled by Chen’s model, Gordon-Taylor model, and Flory-Huggins model, respectively. The ultimate maximal-freeze-concentration conditions (Tm)u (i.e. end temperature of freezing) and (Tg)u [i.e. end glass transition at (Tm)u] were found as -30.0oC and -32.2oC, respectively, and solids content (i.e. Xs) at this point was 0.70 g/g sample. The solids-water interaction () during melting was estimated as 0.69 (dimensionless) from Flory-Huggins model, and BET-monolayer was observed as 0.089 g/g dry-solids at 20oC.