Development of Functional Biopolymers for Enhancing Food Safety and Quality

NON-TECHNICAL SUMMARY: The objective of this project is to develop new functional biomaterials with controlled release properties useful for enhancing food safety and quality. A conceptual framework will be used as a research roadmap to systematically and progressively guide the research activities to generate data which are useful for providing a deeper and more useful understanding of composition-processing-structure-property relationships and for developing new and useful concepts to advance the project. The project is aimed at leveraging the research progress obtained from our laboratory to capture the new research opportunities in functional biopolymers and synthetic-biopolymers with controlled release properties. The research will be strengthened by the collaboration of several knowledgeable researchers with well equipped laboratories. <P>APPROACH: The concept framework organizes the variables important to CRP into four groups: process variables, structure variables, property variables, and food variables. Manipulating Process Variables: The process variables include the following factors that can be manipulated directly to fit certain specific purposes or experimental designs. Active Compounds: We will incorporate natural antioxidants and antimicrobials, either alone or in combination, in biopolymer films. Specifically, we will use mixed tocopherols and sesamol since they are highly effective antioxidants. Tocopherols are nonvolatile compounds suitable for situations with direct contact between the food and the biopolymer film, while sesamol is a volatile compound suitable for situations with no direct contact. We will use nisin since it is a natural antimicrobial agent with activity against a wide variety of pathogenic food borne bacteria. These compounds are chosen also because we have much experience working with them. Polymer Composition: To provide a wide range of properties, we will use not only single biopolymers but also combinations of two or more biopolymers. For polymer blends, the types of biopolymers and their ratio are important variables. Processing Methods: Several processing methods will be attempted to produce packaging films from these biopolymers. For sensitive active compounds, the solution casting process will be used since it does not require high heat and shear conditions. For stable active compounds, the conventional extrusion process and the smart blending process will be used. Microcopy Analysis: Elucidating the molecular organization in different polymer films will be critical for understanding how active compounds are bound and released, and indeed is the key to eventually gaining control of release. Correlations of film structure and active compound localization with release behaviors will provide essential feedback to guide modifications of film composition and processing to obtain desired release rates. Release Kinetics of Active Compounds from Films: The release of tocopherols and nisin using the single-sided diffusion cell developed in our earlier studies. Release of active compound will be measured as a function of time and temperature. We will determine partition coefficients of active compound between food simulants and polymer films and calculate "overall diffusion coefficients" of active compound in the film using the Fickian model and also non-Fickian models. Determining System Relationships: We will determine structure/property relationships and develop mathematical models to quantify the relationship between the parameters characterizing microstructure (such as size distribution and open space) and transport properties (such as diffusion coefficient and partition coefficient). <P>

PROGRESS: 2007/01 TO 2007/12<BR>
ACTIVITIES: (1) developed an innovative smart blending process based on the principles of chaotic advection to incorporate active compounds such as antioxidants and antimicrobials into polymer films, (2) produced LDPE/PP polymer blended packaging films containing mixed tocopherols using the smart blending process and the traditional blown film and cast film processes to retard oxidation in foods, (3) developed methodologies to study the release of tocopherols from the films, (4) developed methodologies to study the effectiveness of the films to retard oxidation in food simulants, (5) developed methodologies to study the possible degradation of active compounds during processing, and (6) used scanning electron microscopy to study the morphologies of films. PRODUCTS: (1) assisted Pliant Corporation to develop a smart blending prototype line at Chippewa Fall, Wisconsin to produce functional polymer blended packaging films to enhance the quality and safety of foods, (2) fostered collaborations with Clemson University, Natick Soldier Center, Pliant Corporation, and Cargill Health & Food Technologies, and (3) trained two graduate students and two post-doctorial fellows. DISSEMINATION: (1) actively working with companies including Pliant Corporation, Quaker Oats, and Cargill Health & Food Technologies, (2) presented two papers at the 2007 IFT Annual Meeting in Chicago, (3) participated in the NASA Packaging Workshop in Houston, Texas on September 25-27, 2007; the research in the project is of great interest to NASA; and (4) will publish results in high impact peer-reviewed journals.
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IMPACT: 2007/01 TO 2007/12<BR>
CHANGES IN KNOWLEDGE: (1) Developed a conceptual framework to guide the systematic development of controlled release packaging to enhance food quality and safety; this framework is the distillation of our learning in a form which we believe will greatly help researchers in this area, (2) demonstrated that different release rates of active compounds may be achieved using polymer blends of various ratios; this knowledge will enable the development of polymer films with release rates suitable for a wide range of foods, (3) provided a better quantitative understanding of the relationships between composition, processing, structure, and properties useful for designing controlled release packaging, (4) developed processing and analytical methodologies necessary to develop and study controlled release packaging, and (5) developed a new concept called "target release rate" which is an important missing link necessary for applying this technology to the real world.
<BR> <BR> PROGRESS: 2006/01/01 TO 2006/12/31<BR>
The long-term goal of this project is to develop a new generation of packaging materials, called controlled release packaging (CRP), which can release active compounds at differentiable rates suitable for a wide range of food applications including reduction of lipid oxidation and inhibition of microorganisms, especially for extending the shelf life of foods. The motivation for developing CRP is to prolong stable shelf life without overloading foods with additives. Traditionally, active compounds such as antioxidants, antimicrobials, and anti-browning agents are incorporated into initial food formulations. However, once these additives are consumed in reaction, protection ceases and food quality degradation increases rapidly. CRP can overcome this limitation by continuously replenishing active compounds via controlled release from packaging, which is necessary for achieving long term stability of foods. In most cases, we envision that CRP will be used as the food-contact layer in a multilayer film or container consisting of one or more other supporting layers such as a gas barrier layer. A major hurdle limiting the development of CRP is the inability to deliberately control the release of active compounds and to provide rates suitable for a wide range of food systems and specific degradation reactions. This hurdle is due to a lack of fundamental understanding of the factors governing the release of active compounds from packaging materials. During the past year, we have developed a conceptual framework to systematically study the factors and relationships important to the development of CRP. Using tocopherols as a model active compound, we have made the following experimental observations about the pathways in the conceptual framework. (1) Tocopherol release is greatly affected by the polymer type and polymer ratio. (2) Tocopherol release is affected by the methods of processing. The smart blending process offers the greatest flexibility in manipulating film morphologies and release rates. While the range of release rates are more limited for cast film and blown film processes, it may be adequate for some food applications. (3) Tocopherol release is affected by the film morphology. The observations suggest that that the polymer composition and processing method may be manipulated to achieve predetermined film morphologies, thereby producing polymer blend films with a wide range of release kinetics for various foods. However, more experiments are will be conducted to confirm these observations.
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IMPACT: 2006/01/01 TO 2006/12/31<BR>
This project will provide science-based knowledge and a research roadmap for the development of controlled release packaging, which will provide consumers with foods of enhanced quality and safety.
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PROGRESS: 2005/01/01 TO 2005/12/31<BR>
Controlled release films containing mixed tocopherols have been produced using the blown film process, the cast film process, and the smart blending process. The microstructures of these films are being analyzed using scanning electron microscopy, and the release of mixed tocopherols from the films are being measured using the HPLC method developed in our laboratory. Ongoing work is being conducted to examine composition/structure/property relationships for the purpose of developing controlled release films to extend the shelf lives of a wide variety of foods.
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IMPACT: 2005/01/01 TO 2005/12/31<BR>
This project will provide a fundamental understanding of the relationships between composition, processing, structure, and properties in polymer blends necessary for the development of controlled release packaging. It will also benefit other food research areas where polymer blends may be used, for example high barrier films for protecting foods from the deteriorative effects of oxygen and water vapor, packaging films with selective permeabilities to oxygen and carbon dioxide for accommodate the respiration and transpiration of fresh produce in modified atmosphere packaging, and selective permeable film for gas membrane separation. In addition, the new knowledge is also useful for developing polymeric transdermal patches that deliver a drug by diffusing it through the patch and the skin to reach the systemic circulation.

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PROGRESS: 2004/01/01 TO 2004/12/31<BR>
It is too early to report on this project.
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IMPACT: 2004/01/01 TO 2004/12/31<BR>
It is too early to report on this project.