Delivering natural antioxidants via controlled release packaging

 

K.M. Schaich and K. Yam,

Dept. of Food Science

Rutgers University

New Brunswick, NJ, USA

Controlled release food packaging is a new generation of materials which, at least in concept, release active compounds at differentiable rates for extended stabilization of foods, e.g. weeks to months for inhibition of microorganisms in fresh foods food and several years for reduction of lipid oxidation in processed foods. The goal of controlled release packaging is to replenish active compounds as they are consumed in reaction in order to maintain concentrations sufficient to prevent microbial growth and onset of lipid oxidation. While this concept is receiving increase attention, practical applications of the technology have not yet been achieved because a) development has been largely trial and error and b) conventional polymer films are not adequate for the task. To advance this technology, increased understanding of major factors controlling release of active compounds from packaging materials is needed.

This paper will present results of recent systematic studies seeking to establish relationships between polymer composition, processing, film morphology, and release properties of polymer blend films containing mixed tocopherols (a nature antioxidant). Early studies showed that LLDPE produced by conventional cast-film extrusion released tocopherol within 24 hours while HDPE films did not release tocopherol at all. This difference seemed clearly related to polymer morphology in the films, so studies to systematically modify film morphology and determine effects on tocopherol release were initiated using two approaches: polymer blending of LLDPE, PP, and PS in varying proportions, and modification of processing that compared traditional cast film and blown film processes with an innovative smart blending process incorporating chaotic advection. Film morphologies were analyzed by scanning electronic microscopy and tocopherol release from films, bare and in model diffusion cells, into 95% ethanol and Miglyol oil as food simulants was measured by HPLC.

Results suggest that release of tocopherols is governed most strongly by morphology (polymer network structure and localization of tocopherols in major and/or minor phases) of packaging films, but polymer composition (types and proportions of polymers) exerts important more subtle influences. Smart blending appears to be particularly useful for manipulating film morphology without changing film composition and generates morphologies not attainable by conventional extrusion. Strong relationships between composition and structure, as well as between structure and release property, have now been documented. By selective combination of polymers and processing, a range of release rates has been obtained and tocopherol release time has been extended significantly. Work is underway to increase release time further and to match tocopherol delivery to lipid oxidation and tocopherol consumption in model systems.

These relationships provide encouraging evidence that it should indeed be possible to creatively and deliberately manipulate polymer composition and processing conditions to achieve desirable film morphologies, thereby enabling production of films with controlled release properties suitable for shelf life extension for a wide range of foods.

 

EDUCATION:

l965-67    Indiana University, Bloomington, Indiana;  Honors Pre-Med Program,   Valedictorian Scholarship

l967-69    Purdue University, W. Lafayette, Indiana;    B.S. with Honors. 

                          Food Research, Independent Study Option (Interdisciplinary Science focus as basis for research)

                          Undergraduate honors research: "Fish Protein Concentrate-Supplemented Bread as Affected by Various Dough Improvers", Mary K. Head, Adviser.

l969-70    University of Massachusetts, Amherst, Massachusetts;  Food Science,  University Fellowship

l970-74    Massachusetts Institute of Technology, Cambridge, Massachusetts; Sc.D., Food Science

                          NDEA Fellowship l970-73,  Research Assistantship l973-74

              Dissertation:  "Free Radical Formation in Proteins Exposed to Peroxidizing Lipids",

                          Marcus Karel, Adviser.

 

POSTDOCTORAL STUDIES:

l974-76  Research Associate with Donald C. Borg, M.D.

                        Medical Department, Brookhaven National Laboratory

                       Studies on involvement of membrane lipid oxidation in extrapulmonary ozone toxicity mechanisms in rats; model system studies of free radical interactions of oxidizing lipids and biologically important molecules; electron spin resonance studies of free radical signals in blood and other tissues.

 

EMPLOYMENT:

10/88 - present:  Dept. of Food Science, Cook College, Rutgers University

   4/94 - present Associate Professor of Lipid Chemistry (with tenure)

 10/88 - 4/94                  Asst. Professor                                        

   5/90 - Present Member Graduate Faculty, Toxicology Program, UMDNJ and Rutgers University

 10/95 - Present Faculty Fellow, Douglass College, Rutgers University

 10/86 - 9/95     Guest Scientist, Medical Department, Brookhaven National Laboratory

 1982 - 1986    Scientist “

 1979 - 1982       Associate Scientist “

 1976 - 1979       Assistant Scientist “

                     Electron spin resonance (ESR) and biochemical studies of free radicals and free radical reactions in biological systems (see Research Interests below); studies on biochemical mechanisms of cytotoxicity of oxidizing pollutants; studies on roles of metals in generating oxygen radical species and of lipid oxidation in mechanisms of cytotoxicity.

 1973 - 1974    Research Assistant, Food Chemistry, Massachusetts Institute of Technology

 1970               Dietician, Food Service Manager,

                          Methodist Camps and Conferences, Camp Aldersgate, N. Scituate, Rhode Island

 1968-69             Research Technician, Dr. Donald R. Brown, Psychology Department, Purdue University

 1966-67             Research Technician, Psychology Department, Off. Naval Research, Indiana University

 

HONORS:      Listed in:   American Men and Women in Science

                                       Two Thousand Notable American Women

                                       The World Who's Who of Women

                                       Who's Who in American Education

                                        Who’s Who in the East

                                       Who’s Who in America

 

                      2005 American Biographical Institute Woman of the Year Award

                      2005 American Biographical Institute Woman of Distinction Award

                      2005 Cook College Sustained Excellence in Teaching Award

                      2005 Rutgers University Graduate Teaching Award

                      2003 Women’s International Hall of Fame Inductee

                      2003 USDA Northeastern Region Award for Excellence in College and University Teaching

                      2003, 1987  AOCS Outstanding Paper Award

                      2000-2003  IFT Distinguished Lecturer: Diversity and Mentoring

                      2002 Rutgers University Warren I. Susman Award for Excellence in Teaching

                      2001 Eastern Food Science Conference XII Outstanding Professor Award

                      2001, 1999, 1996, 1993 Endel Karmas Award for Excellence in Food Science Teaching

                      2000  Fellow of the Institute of Food Technologists

                      1999  Institute of Food Technologists Wm. V. Cruess National Award for Excellence in Teaching

 

Professional Societies:           American Association for the Advancement of Science

                                             American Association of Cereal Chemists

                                             American Chemical Society

                                             American Oil Chemists Society

                                             International ESR Society

                                             Institute of Food Technologists

                                             International Society for Free Radical Research/ Oxygen Society (U.S.)

                                             New York Academy of Sciences

 

Scientific Honoraries:                Omicron Nu

                                             Phi Tau Sigma

                                             Sigma Xi

 

Other                            MENSA

 

AREAS OF RESEARCH INTEREST:

 

Multidisciplinary research in lipid oxidation and lipid chemistry:

           A)  Chemistry:  EPR (electron paramagnetic resonance) studies of free radical intermediates and their reactions, particularly of lipids; lipid oxidation  --  mechanisms of initiation, electrochemistry of protic versus aprotic lipids, metal and heme catalysis, phase effects (aqueous vs. lipid vs. mixed) on kinetics and mechanisms, analytical methods, metal-lipid and chelator-lipid interactions, co-oxidations of proteins and nucleic acids by oxidizing lipids; development of supercritical fluid extractions of lipids; free radical chemistry of natural antioxidants; stability of medium chain triglycerides and structured lipids.

           B)  Biochemistry:  lipid oxidation in living tissues; factors affecting oxidative stability of membranes, cells, and tissues; cellular repair of oxidative damage; lipids and signal transduction under oxidative stress

           C)  Food Science:  EPR studies of free radicals in foods; lipid free radical vs. lipid oxidation product interactions with proteins and carbohydrates in the oxidative deterioration of foods; relationships of phase, metal, and moisture to lipid oxidation in foods; free radical chemistry of natural phenolic antioxidants; natural photosensitizers; design of new phase-specific chelators and antioxidants for use in foods; development of methods for demetalling food oils; heme and metal catalysis of oxidations in muscle foods; free radical chemistry of proteins and starches in extruded products; development of new HPLC and chemiluminescence analyses of lipid oxidation; supercritical fluid extraction of lipids from low-lipid food products; fat substitutes; protein degradation during food processing.

           D)  Toxicology and Medicine:  lipid co-oxidation of proteins and nucleic acids in oxidative cytotoxicity, disease, and cancer;  heme and metal catalysis of lipid oxidation in vivo; detection and accurate measurement of  early stages of lipid oxidation in tissues and in vivo.

           E)  Nutrition:  effect of dietary lipid and pro- or anti- oxidants on oxidative stability of membranes; effect of diet on response to oxidative stress; toxicity of dietary oxidized lipids.

 

Electron paramagnetic resonance/ Free radicals in foods and biological tissues:

A)  Free radicals in lipid oxidation and lipid co-oxidations

B)  Free radicals formed during processing and storage of foods, e.g. extrusion, baking, heating of muscle foods; protein oxidation and NO· release during thermal processing

C)  Antioxidant identification and mechanisms: ease of free radical formation, radical lifetimes, and                   reactivity of free radicals

D)  Spin label studies of hydration and molecular mobility of macromolecules in foods with limited                          water activity

E)  Free radicals in tissues: involvement in physiological and pathological processes

F)  Oxygen free radical species in toxicology (spin traps and direct detection)

G)  Reactions of metals and metalloproteins, including heme proteins

 

RESEARCH IN PROGRESS:

 

           a)  Bioavailability and bioactivity of flavonoid and polyphenol compounds in cranberries and blueberries.  Large scale isolation of purified fractions for animal, tissue culture, and chemical reactivity studies as basis for genetic manipulation to generate cranberry and blueberry varieties with improved health effects.  Co-PI with N. Vorsa (Plant Science, Rutgers), collaborating with D.K. Sarkar (Animal Science), G. Knipp (Pharmacy, Rutgers), S. Hultgren (Washington University School of Medicine, Department of Molecular Microbiology), H. Koo (University of Rochester).

           b)  Development of active packaging, manipulating molecular morphology of polymer films by chaotic advection and use of various polymer blends to provide controlled release of natural antioxidants for long-term stabilization of foods.  Co-PI with K Yam, Food Science, Rutgers; collaboration with D. Zumbrunnen, Mechanical Eng., Clemson University; pursuing further collaboration with Nissim Garti, Israel.

           c)  Antioxidant activity of antioxidants from natural sources: development of EPR and spectrophotometric flow methods for studying very short-lived phenolic radicals; determination of free radical formation, reactivity, and lifetimes; determination of metal binding and redox potentials, phase partitioning and reaction specificity.

           d)  Chemiluminescence (CL) assays for lipid oxidation:  development of new chemiluminescence instrumentation with high sensitivity and spectral differentiation capabilities; validation and quantification of  CL by correlation of specific emissions with traditional chemical measures of lipid oxidation in oxidizing neat lipids, intact samples of food, and biological materials; patent application for new instrumentation design being prepared; negotiations with industry for development underway.

           e)  Fundamental studies on mechanisms of lipid oxidation and shifts in reaction pathways with reaction conditions.

materials and model systems, correlating free radicals with other chemical changes (e.g. protein oxidation, protein crosslinking, sulfhydryl/disulfide contents) and physical/textural properties; antibody detection and identification of proteins modified  during extrusion; molecular mechanisms and structures responsible for extrudate textures.  Developing molecular model for chemistry involved in texturization during extrusion.

           f)  Free radical chemistry in food products:  EPR research studying radical production by heat, shear forces, and lipid oxidation in extruded cereals and other food

           g) Free radical mechanisms in atherosclerosis.  Collaboration with Tamara Sanikidze, Medical School, University of Tbilisi, Republic of Georgia (part of former USSR)