Dissertation
FLEXIBLE AND SEMIRIGID PACKAGING FOR HIGH PRESSURE AND MICROWAVE-BASED PASTEURIZATION AND STERILIZATION PROCESSES
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/112206
Abstract
Pressure-and microwave-assisted thermal processes are in-package processes and require packaging that can sustain thermal and mechanical stresses. Food packaging for such advanced technologies is evolving. Both flexible and semirigid polymeric-based packaging are suitable for these processes. This study aimed to understand the influence of these processes on packaging materials and develop sustainable packages for these advanced food processing technologies.
The first study focused on the role of package headspace on package functionality after high-pressure processing (HPP) and pressure-assisted thermal sterilization (PATS). Working pressures were 400–600MPa and vessel temperatures were 30–90°C. Two films were studied A:(PA/EVOH/PP) and B:(PET‐AlOx‐OC/PA6/PP). Results showed that headspace and temperature had a significant effect compared to operating pressure on visual defects. Packages with 0% headspace did not show any physical damage. This work provides a basic guideline to select the right headspace for a given type of packaged food whenever heat and pressure are used simultaneously.
The second study aimed to investigate PATS influence on the safety, nutrients, quality, and packaging of different fruit and vegetable purees. The processing parameters included preheating of purees at 98°C for 5min and pressurizing at 600MPa in a vessel set at 90°C for 5min. The colorimetric temperature sensor suggested the purees’ temperature reached 122°C. Thus, at least 9-log10 reduction of B. amyloliquefaciens spores was achieved and excellent retention of vitamin C, pigments, and color. This study suggests that PATS can be used to produce safe and high-quality shelf-stable fruit and vegetable products.
Reduced wall thickness ethylene-vinyl alcohol (EVOH) and polypropylene (PP)-based trays were developed and tested for microwave-assisted thermal sterilization (MATS) and microwave-assisted pasteurization system (MAPS). Results indicated that O2 ingress into package headspace and food weight loss during storage time were insignificant for pasteurized/MAPS trays. The headspace O2 concentration in trays sterilized using conventional thermal process was higher than trays sterilized using MATS. Comparable or better performance of O2 ingress and weight loss observed with a 24% reduction in wall thickness. There is a potential to utilize EVOH//PP-based trays with reduced wall thickness for MATS and MAPS that will result in less carbon footprint and better economical alternatives.
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Details
- Title
- FLEXIBLE AND SEMIRIGID PACKAGING FOR HIGH PRESSURE AND MICROWAVE-BASED PASTEURIZATION AND STERILIZATION PROCESSES
- Creators
- Saleh Mansour Al-Ghamdi
- Contributors
- Shyam S Sablani (Advisor)Juming Tang (Committee Member)Barbara Rasco (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 185
- Identifiers
- 99900581612401842
- Language
- English
- Resource Type
- Dissertation