title: Microbial inactivation kinetics during high-pressure carbon dioxide treatment: nonlinear model for the combined effect of temperature and pressure in apple juice.
abstract: Isobaric and isothermal semi-logarithmic survival curves of natural microflora in apple juice treated with high-pressure carbon dioxide at 7, 13, and 16 MPa pressures and 35, 50, and 60 degrees C temperatures were fitted with a nonlinear equation to find the values of the coefficient b(P), b(T), n(P), and n(T). Profiles of the model parameters were obtained as a function of pressure and temperature. The model fitted with good agreement(R(2) > 0.945), the survival curves. An empirical equation was proposed to describe the combined effects of pressure and temperature. The equation, derived from a power law model, was written in the form: log(10) S(t) = -log(e) [C(0)+C(1) x exp (K(T) x (T-T(C))-C(2) x exp (K(P) x (P-P(C))) x t (C(3)xT(2)+C(4)xT+C(5)). The proposed model fitted the experimental data well. At 7 MPa and 50 and 60 degrees C, 13 MPa and 35 and 60 degrees C, 16 MPa and 35 degrees C, the model provided (log)10 reduction residual values (observed value-fitted value) lower than 0.284 showing a good agreement between the experimental and the predicted survival levels.
authors.affiliation: Dept. of Chemical and Food Engineering, Univ. of Salerno Via Ponte Don Melillo, 84084 Fisciano (SA), Italy. gferrentino@unisa.it
authors.forename: G
authors.initials: G
authors.lastname: Ferrentino
authors.forename: G
authors.initials: G
authors.lastname: Ferrari
authors.forename: M
authors.initials: M
authors.lastname: Poletto
authors.forename: M O
authors.initials: MO
authors.lastname: Balaban
mesh_terms: D001628:Beverages / Q000382:microbiology*; D002245:Carbon Dioxide / Q000008:administration & dosage*; D005511:Food Handling / Q000379:methods*; D005638:Fruit / Q000382:microbiology*; D007700:Kinetics; D027845:Malus; D017711:Nonlinear Dynamics; D011312:Pressure; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D002245:Carbon Dioxide