Modeling of modified-atmosphere packaging of nectarines

The main objective of this research was to investigate the O{dollar}sb2{dollar} consumption (RRO{dollar}sb2){dollar} and CO{dollar}sb2{dollar} production (RRCO{dollar}sb2){dollar} rates of nectarines (cv. 'Red Gold') under several O{dollar}sb2{dollar} concentrations (1-21%), CO{dollar}sb2{dollar} concentrations (0-21%) and temperatures (0{dollar}spcirc{lcub}-{rcub}25spcirc{dollar}C) to establish a comprehensive tool for prediction of the optimum films to extend quality shelf life and/or the O{dollar}sb2{dollar} and CO{dollar}sb2{dollar} concentrations developed inside the packages.; Empirical models for both RRO{dollar}sb2{dollar} and RRCO{dollar}sb2{dollar} were built and the film permeability dependency on temperature (5{dollar}spcirc{lcub}-{rcub}15spcirc{dollar}C) was evaluated under dry conditions for Saran{dollar}spcircler,{dollar} linear low density polyethylene (LLDPE) and PD941 (a multilayer polyolefin) packaging films.; The permeation-respiration model was applied to predict O{dollar}sb2{dollar} and CO{dollar}sb2{dollar} concentrations in modified atmosphere packaging (MAP) of nectarines at 0{dollar}spcirc{dollar} and 10{dollar}spcirc{dollar}C using the empirical models and the film permeability equations. Model predictions were validated with the above films at the predicting temperatures.; Results showed that RRO{dollar}sb2{dollar} was highly dependent on temperature, moderately dependent on O{dollar}sb2{dollar} concentration, but independent from CO{dollar}sb2{dollar} concentration. While RRCO{dollar}sb2{dollar} was highly dependent on temperature, but independent from O{dollar}sb2{dollar} and CO{dollar}sb2{dollar} concentrations.; Oxygen and carbon dioxide fraction comparisons between predictions and experimental data showed an overall fair agreement evaluated by the root mean square error term, which ranged between 0.01 and 0.09. At both 0{dollar}spcirc{dollar} and 10{dollar}spcirc{dollar}C, departures found between predictions and experimental data were mainly attributed to variations in RRO{dollar}sb2,{dollar} RRCO{dollar}sb2{dollar} and gas transmission rates.; An evaluation of the permeation-respiration model and the effect of input variables such as respiration and gas transmission rate showed that a {dollar}pm{dollar}20% fluctuation in either parameter had a substantial influence on the agreement between predictions and experimental data.; To illustrate the application of modeling of MAP of nectarines, the permeation-respiration model was used to make predictions of optimum O{dollar}sb2{dollar} and CO{dollar}sb2{dollar} transmission rates at 0{dollar}spcirc{dollar}C. Film PD941 (an option) was used to make predictions of O{dollar}sb2{dollar} and CO{dollar}sb2{dollar} concentrations developed in the transient and the steady state at 0{dollar}spcirc{dollar} and 10{dollar}spcirc{dollar}C.