包装工艺学Chapter 2.ppt

Simulated studies extend beyond the one-package/one-condition study. A survey of potential new packaging materials can be accomplished without need to retest the product. Only the changes in material parameters need be entered to test performance. Computer modeling has been used successfully for foods, over-the-counter products, and pharmaceuticals. 1 Product Evaluation 2 Package Evaluation 3 Model Fundamentals Computer Models for Shelf Life 1 Product Evaluation (1) The mode of failure for the product must be known prior to using any simulated approach. (What are they? P1104) e.g. moisture-sensitive products --- the moisture isotherm test (1-4 weeks) (calculations, example 3) oxygen-sensitive products --- the testing consists of evaluating product changes with oxygen uptake and can be performed by inverse gas chromatography, respirometry, Warburg or a variety of tests for degree of oxidation carbonated beverages packaged in permeable bottles --- the test would be to measure carbonation loss (soda), or oxidation (beer) or both. (2) The product testing should be performed at various temperatures if temperature effects are to be modeled. 2 Package Evaluation (1)For computer modeling purposes, the chief packaging characteristics are barrier properties. WVTR OTR Other Permeantion Rate Be tested in flat sheet or full package? What will happen if a system is poorly sealed? (2) The package material characteristics of sealability, printability, compatability, cost, mechanical strength, etc remain the province of the packaging engineer and are not usually incorporated into computer models. Nonbarrier parameters are not included in this discussion of shelf life. Those parameters that do affect shelf life, but are not in the model (e.g., light transmission for oxygen-sensitive products), must be considered in evaluating any computer printouts. 3 Model Fundamentals The Components which enter the package fr