Dissertation
GAS BARRIER PROPERTIES OF POLYMER PACKAGING: INFLUENCE ON FOOD SHELF LIFE FOLLOWING MICROWAVE-ASSISTED THERMAL STERILIZATION
Doctor of Philosophy (PhD), Washington State University
01/2016
Handle:
https://hdl.handle.net/2376/112010
Abstract
The gas barrier properties are critical parameters controlling the mass transfer through a polymeric packaging system. Oxygen and water vapor transmission are most important factors that affect the food quality during storage and determine the food shelf life. Microwave assisted thermal sterilization (MATS) developed at Washington State University that utilized unique 915 MHz single-mode cavity has been approved by FDA and USDA recent years to produce low-acid shelf stable foods. Food products pre-packaged by high barrier polymeric pouches or trays and processed by MATS provide superior quality and sensory attributes comparing with retorted foods at the same lethality. Shelf life of MATS processed foods, however, still need to be investigated with the considerations on the influence of polymer packages, principally their barrier properties.
In this study, our objective is to exam the influence of oxygen transmission rates (OTRs) and water vapor transmission rates (WVTRs) on MATS processed foods principally oxidation, color change and water loss under different storage conditions as well as the alterations of barrier properties induced by the external factors. An accelerated shelf life testing was conducted using a mashed potato based model food packaged with three types of pouches stored at 23 °C, 37 °C and 50 °C for up to 12 months. After storage, food packaged in higher barrier pouches showed general less color change, oxidation (TBA value, Hexanal) and water loss than those in lower barrier pouches. Shelf life prediction determined as color difference ΔE reached to 12 resulted Q10 values from 2.85 to 3.15 similar to other thermally processed foods, and prediction as function of OTR at 23 °C showed a good linear correlation. The OTR and WVTR of two pouch films following MATS changed during storage probably resulted from the changing crystallinity and moisture content in polymer matrix or the changing coating morphology as affected by environment temperature, relative humidity or food components.
The findings of this work can be used for selecting or designing proper polymeric packaging for MATS processed foods. It also provides preliminary shelf life information to conduct necessary prediction for commercial products of the similar category.
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Details
- Title
- GAS BARRIER PROPERTIES OF POLYMER PACKAGING: INFLUENCE ON FOOD SHELF LIFE FOLLOWING MICROWAVE-ASSISTED THERMAL STERILIZATION
- Creators
- Hongchao Zhang
- Contributors
- Shyam S Sablani (Advisor)Juming Tang (Committee Member)Barbara Rasco (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Biological Systems Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 176
- Identifiers
- 99900581830701842
- Language
- English
- Resource Type
- Dissertation