05/09/2023
By Danielle Fretwell

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a doctoral dissertation defense by Md. Akiful Haque on “Degradation Behavior of Multilayer Packaging Films in Presence of a Highly Acidic Sauce”.

Candidate Name: Md. Akiful Haque
Degree: Doctoral
Defense Date: May 18, 2023
Time: 9 to 11 am
Location: Perry 415

Those interested in attending should contact the student MdAkiful_Haque@student.uml.edu and committee advisor, gracewanting_chen@uml.edu at least 24 hours prior to the defense to request access to the meeting.

Committee:

  • Advisor Wan Ting (Grace) Chen, Assistant Professor, Department of Plastics Engineering, UMass Lowell
  • Amy M. Peterson, Associate Professor, Department of Plastics Engineering, UMass Lowell
  • Margaret J. Sobkowicz, Professor, Department of Plastics Engineering, UMass Lowell
  • Akshay Kokil, Assistant Teaching Professor, Department of Plastics Engineering, UMass Lowell)
  • Jo Ann Ratto, Research Engineer, U.S. Army DEVCOM Soldier Center

Brief Abstract:
Highly acidic accompaniments, including hot sauce, have a propensity to deteriorate Meal, Ready-to-Eat (MRE) packaging films, subsequently diminishing the shelf life of preserved food products. This current doctoral research investigates the degradation behavior of several multilayer packaging films when subjected to acidic hot sauce.

Until now, only a multilayer polymeric film (polyethylene terephthalate /ink /polyethylene /foil /polyethylene /SiOx coated polyethylene terephthalate /adhesives /Barex®) using a patented resin, Barex®, as a constituent polymeric layer has demonstrated the ability to effectively preserve hot sauce for military rations. Nonetheless, it is important to note that the manufacturing of Barex® was discontinued in 2016. In an effort to identify potential replacements for Barex®, an immersion study was undertaken, examining several commercially available multilayer films (polyethylene terephthalate/ ink/ adhesive/ polyamide/ adhesive/ polypropylene and polyethylene terephthalate/waste low-density polyethylene/aluminum foil/adhesive/polyester/low-density polyethylene) alongside a monolayer Barex® (acrylonitrile methyl acrylate copolymer) film. These films were immersed in hot sauce, acetic acid, and sodium chloride solutions at 50°C for 12 weeks. Every three weeks, the mass, thickness, morphology, and chemical compositions of each film were assessed. This study presents two key findings: 1) most likely, acidic constituents in hot sauce caused degradation of multilayer packaging films by transforming aluminum foil into a soluble salt and inducing polyethylene oxidation, and 2) the considerable influence of surface erosion in promoting polyethylene oxidation.

Following the accelerated immersion test, four selected multilayer structures were made into pouches to assess their ability to store hot sauce in compliance with shelf-life requirements. These pouches were subjected to an accelerated storage test at 80°F and 100°F, containing hot sauce (both liquid and powder forms) and water as a control. The mass, thickness, morphology, chemical composition of the sealant layer, barrier performance, and seal strength of each pouch were examined at one, six, and 12-month intervals. Sensory tests were conducted to assess the food quality of the hot sauce. Liquid hot sauce resulted in the delamination of Pouch 1 and 2 after one month of storage at both temperatures. At the 12-month mark, liquid and powder hot sauce caused delamination in Pouch 3 at 80°F, reducing its seal strength by 62% and 24%, respectively. This investigation identified a single pouch structure (Pouch 4) that displayed no significant degradation after 12 months at 80°F and 100°, which is promising to preserve hot sauce quality and is thus recommended to the U.S. Army for a 3-year shelf-life study.

Preliminary observation from the pouch-level study suggests that the permeability of water vapor in the packaging material may have something to do with its deterioration upon exposure to hot sauce. A hypothesis was thus formed—acidic compounds present in hot sauce permeate through MRE ration packaging films with water, causing delamination of the multilayer films and/or degradation of the innermost layer that has direct interactions with hot sauce. To test this hypothesis, water vapor transmission rate of five selected multilayer films were measured. Meanwhile, a rapid immersion test was conducted for six weeks, at 50 °C, in an effort to simulate extended storage conditions. The objective of this study was to examine the relationship between the water vapor barrier properties of polymeric films and their level of deterioration, shifts in color, and changes in surface morphology in the context of packaging films for liquid hot sauce in MRE products. The study involved conducting evaluations at regular intervals of three weeks until the six-week period was completed. The characterization outcomes were then analyzed to establish the relationship between the degradation level and the water vapor transmission rate (WVTR) of the multilayer packaging systems.

This study is the first to comprehensively examine the degradation behavior of multilayer packaging films used to store highly acidic food in MRE military rations. New knowledge generated from this research offers insights into the degradation mechanism of how hot sauce deteriorates multilayer MRE packaging, which could be used to guide future designs of MRE ration packaging for preserving highly acidic food. Beyond food packaging applications, other packaging applications such as acidic chemical packaging could also benefit from the findings learned from this PhD dissertation.

All interested students and faculty members are invited to attend the online defense via remote access.