Brief Summary of Minutes of Annual Meeting

California The objective of this work was to characterize the flow patterns and quantitatively assess the degree of mixing in a SMX mixer (a type of inline static mixer) for miscible liquids of different viscosities using magnetic resonance imaging (MRI). Manuscript preparation is underway. The mechanical disintegration of food during gastric digestion is central to nutrient bioavailability. Little is currently known regarding the role of material properties on the breakdown behavior of food during digestion. This study investigated the effect of gastric juice on the material properties and subsequent disintegration of a particulate food system when exposed to different bulk loading conditions. Results illustrate the role material property changes during digestion play on the breakdown behavior of solid foods and provide the data needed to further investigate and model this relationship. University of Illinois (Takhar) and California-Davis/McCarthy completed collaborative research to address modeling and characterizing fried food. 2: Develop pedagogical methodologies for improved learning of food engineering principles. 3: Develop outreach programs to disseminate best practices for enhancing food safety and quality to stakeholders. Hawaii • Combination of microwave and ohmic heating techniques is expected to enable even temperature distributions in solid-liquid food mixtures by applying simultaneous electric current and electromagnetic waves. In this study, novel dual cylindrical microwave and ohmic heating chambers were designed and fabricated to maximize the electric field strength from microwave and ohmic power sources. Designing of the combination heating chamber was optimized and validated using the numerical simulation for electric field and potential distributions. A continuous flow combination heater has the potential to thermally process multiphase foods with improved uniformity, eventually benefitting the energy efficiency and food quality. Collaborations Dr. Sudhir Sastry, Ohio State University • A numerical model using COMSOL codes was developed to validate uniform heating of particulate foods in a continuous flow microwave and ohmic heating chamber. It was integrated with microwave heating, ohmic heating, incompressible laminar flow, forced-coupling method (FCM), heat transfer and arbitrary Langrangian-Eulerian (ALE) moving mesh technique. The solid particles were simulated to experience hydrodynamic viscous drag and pressure forces resulting from motion relative to the fluid. The stress tensors of forces exerted on the surfaces of the particles were successfully formulated by the use of FCM code. The electric fields and trajectories of particles inside the feeding tube, and heating patterns and velocity distribution of particulate foods were observed transiently. Idaho 1. Primary accomplishments for 2013-2014 include characterization of cottage cheese cream dressing using rheometry. There is little information available in the literature on cottage cheese cream dressing, and current cream dressing formulations often display instability during storage. This instability results in dressing separation and formation of a serum layer, which is unappealing to consumers. The effect of different hydrocolloids on stability of cottage cheese cream dressing was studied. Dressing stability and viscosity was affected by pH; temperature had little effect on dressing viscosity. Stability was also dependent on the hydrocolloids used in the dressing formulation. Use of a blend of hydrocolloids showed increased stability over time as compared to use of a single hydrocolloid, implying that there was a synergistic effect among the hydrocolloids when used in combination. This information can be used by dairy manufacturers to improve the stability of their cream dressing to yield a more appealing product. 2:-A case study project was developed to determine the effectiveness of clickers and cold calling on student participation and learning. Questions covered a range of engineering topics and cognitive levels. Students indicated on course evaluations that the questions promoted learning and aided in understanding concepts. -A project to develop learning modules to promote quantitative skills in undergraduates is in the initial stages. Undergraduates often do not have the skills needed to manipulate equations, apply mathematical concepts to an abstract problem, or translate the information given into a format that is needed for application of equations. A plan to develop and implement these learning modules was discussed. Currently, participants in this project are looking for funding sources. Illinois Hao Feng: Response surface modeling was used for achieving 5-log reduction of E. coli O157:H7 on alfalfa seeds by sonication and mild heat without compromising germination rates. Dr. Youngsoo Lee at University of Illinois, Urbana-Champaign and Dr. Mario Ferruzzi at Purdue University have been collaborating for a project, microencapsulation of resveratrol in protein matrices. Pawan Takhar: Frying of foods was studied in collaboration with UC-Davis, and expansion of biopolymers was studied in collaboration with University of Nebraska (UNL). Using Hybrid Mixture Theory, unsaturated fluid transport theory was developed for food biopolymers, which can be used for a large number of food and bioprocessing applications. Graciela Padua: Writing a book chapter on bi-continuos delivery systems as nano- and micro-scale vehicles for effective delivery of bioactive ingredients in functional foods Collaborations: Louisiana State University (Cristina Sabliov), USDA National Institute of Food and Agriculture (Hongda Chen). Indiana 1b. High voltage atmospheric cold plasma (HVACP) is a technology developed by Dr. Kevin Keener at Purdue University which allows one to generate atmospheric plasmas inside sealed containers with higher electron energy densities using less energy than current plasma jets or dielectric barriers. Within the past year, Dr. Keener and collaborators have demonstrated the ability of the HVACP to extend the shelf-life of tomatoes and strawberries, eliminate Salmonella enteritidis from shell eggs inside a package and manipulate the composition of packaging films. 1b. Develop new and improved processing technologies (Dr. Kevin Keener, Purdue University; Dr. Bruce Applegate, Purdue University; Dr. Paula Bourke, Dublin Institute of Technology, Ireland; and Dr. P.J. Cullen, University New South Wales, Australia) Iowa Instrumental texture and sensory analysis of model high-protein nutrition bars formulated at 30 % protein with extrusion-processed milk protein concentrate (80%, MPC80) was carried out during accelerated storage at three temperatures. Physical modification of milk protein concentrates using extrusion creates functional ingredient causing less hardening in high-protein bars. Dairy ingredient industry will benefit by use of a domestically produced functional ingredient in supplementing and or replacing more expensive casein-based ingredients in bar applications. The measurement of several important characteristics (health benefits and sensory quality) during Aronia berry maturation has permitted the estimation of the optimal harvest date. To determine this date, °Brix, Titratable Acidity, °Brix/acid ratio, antioxidant levels, total polyphenol and anthoacyanin levels were determined. Aronia berries have high antioxidant, polyphenol and anthocyanin contents. Preliminary correlations between Aronia berry characteristics and weather conditions were found. Accumulated GDD and VSM were correlated with °Brix, anthocyanin and polyphenol contents. The results from the Aronia research will aid farmers to harvest their crop at the optimum time for maximum levels of antioxidants, pigments (color), and other sensory properties. The work on food auditor training has resulted in a successful Webinar, which is available online. Minnesota We focused on development and evaluation of non-destructive and non-invasive analytical tools. Magnetic resonance imaging (MRI) is a very useful non-destructive and non-invasive technique for the study of food structure, distribution of water, fat, and temperature in foods, and heat and mass transfer in foods. During this reporting period, we further improved fast imaging techniques for small MRI instruments for low moisture foods and biological materials. This research is in collaboration with Harry Xie of Bruker Optics and researchers in Nanchang University, China. We focused on minimal processes that preserve and improve the nutritional values, health benefits, and safety of food products. During this reporting period, we continued to develop and study (1) processes to enhance bioavailability of bioactive compounds in whole grains, (2) low temperature pasteurization of liquid foods, and (3) study of shelf life of almonds during storage. 1. We explore the feasibility of using high pressure homogenization to inactivate microbes. 2. We continued to pursue research programs to investigate the effects of processed wheat bran on cholesterol. 3. A new research program to study the accumulation of EPA lipids in microalgae was initiated. Microalgae cultivated on media containing hydrolysates from acid hydrolysis of four different oil crop biomass residues were found to contain over 3 % of omega-3 fatty acid (EPA). 4. We are pursuing a research program on application of concentrated high intensity electric field (CHIEF) process to inactivation of thermophilic and thermoduric organisms present in milk. 5. We continued to study the physical, chemical (lipid oxidation), textural, aromatic, sensory quality of raw and roasted almond products during storage. New Jersey • The purpose of this project is to determine if a pressure profile would develop inside a heterogeneous food system, such as a soft food with hard inclusions, during high pressure processing (HPP) that could lead to non-uniformity in the microbial inactivation. • Our experiments were done in two model systems: (a) 20% gelatin and 2% agar gel, with a single wood inclusion or dispersed glass wool (2.5% v/v); (b) 3% agar gel, with plaster particles, up to 27%. We also carried out numerical simulations of stress distribution in a model system composed of gel and a wood inclusion, using a neo-Hookean model. The simulation results showed that pressure stress decreased from the surface toward the inclusion, and that shear stress developed near the gel-inclusion boundary and decreased toward the surface. When the Poisson’s ratio of the gel was close to 0.5 the pressure and shear stress gradients were insignificant, but they increased at lower values. No difference in the bacterial inactivation was detected between different positions in the gel with one inclusion. Higher amounts of plaster are expected to produce more regions of high shear and low pressure. • We have shown non-uniformity in the microbial inactivation in a heterogeneous system during high pressure processing. • Cold Atmospheric Pressure Plasma (CAPP) is considered a potentially useful non-thermal surface decontamination technique. Sandpapers of various roughness values were selected as the model system. The surface roughness was quantified using Confocal Laser Scanning Microscopy (CLSM). Microbial analysis was done using Enterobacter aerogenes. CLSM was done on various fruits to determine fruits that have similar roughness as the selected sandpapers. Golden Delicious Apples, Sunkist Oranges and Cantaloupes were selected as fruits possessing similar roughness to the sandpapers. We have shown that surface roughness affects the microbial inactivation due to CAPP treatment. New York (Ithaca) 1: Advancing the fundamental science and application of technologies to ensure food safety and improve quality of food products 1a. Utilize innovative methods to characterize food materials 1b. Develop new and improved processing technologies Structural Changes of Milk Protein Concentrates Induced by High Hydrostatic Pressure was studied. These changes suggest that HHP treatment of milk protein concentrates may represent the basis for the development of new types of protein rich foods of unique structure and texture. Safety of non-thermally processed apple juice was enhanced by combining microfiltration with UV treatment. The developed non-thermal hurdle treatment has the potential to significantly reduce pathogenic bacteria and protozoa in apple cider and thus improve its safety and quality. 1c. Develop mathematical models to enhance understanding of, and optimize food processes A three dimensional, multiscale model for growth, dispersion, spreading/shoving, and nutrient consumption of bacteria on a leaf surface is developed for a mechanistic understanding of the behavior of Escherichia coli O157:H7, Salmonella spp. and Pseudomonas fluorescens in a thin liquid film on a spinach surface acquired from CT. 2: Develop pedagogical methodologies for improved learning of food engineering principles. We have started building, testing, and evaluating preliminary versions of the simulation-based food safety education modules. We are currently working with faculty members from ~10 universities (includes Cornell Food Science) in implementing the learning modules. 3: Develop outreach programs to disseminate best practices for enhancing food safety and quality to stakeholders. Developed teaching, outreach and extension activities to educate cider producers on the use of the MF + UV combination treatments for enhancing safety of apple juice. Kentucky Fred Payne Online Fluorescence Sensor Development The development of an online fluorescence sensor for measuring and characterizing food properties was continued during the last year. The amino acid tryptophan, which is highly fluorescent was selected as the target (Excitation 280 nm/Emission 350 nm). Tryptophan fluorescence measurements are very temperature sensitive and can be affected by pH and other food product characteristics. In addition, the technology selected was front face fluorescence and it is most sensitive at low concentrations. Two online process control applications were selected for monitoring: milk coagulation and protein content in cheese whey permeate. The fluorescence signal was discovered to decrease significantly during the gel firming stage of milk coagulation. This may provide an excellent signal for coagulation endpoint selection. Fluorescence detection of protein content in whey permeate was found to be affected by solids concentration and especially by the annatto content. Thus the use of tryptophan fluorescence to monitor whey permeate for protein content may present some challenges. A processor based prototype was developed and tested in the laboratory. Plant based testing is the goal for the next year. Akinbode Adedeji started as an Assistant Professor of Food Process Engineering in the department of Biosystems and Agricultural Engineering at University of Kentucky in July 2014. He presently teaches a Food Engineering course to Food Science students. Co-submitted 2 Letter of intent for funding to two organizations, Bill and Melinda Gate’s Foundation Program for Emerging Agricultural Leaders and Kentucky Science and Engineering Foundation Program. Louisiana Acid tolerance of Lactococcus lactis ssp lactis and Lactococcus lactis ssp cremoris. can be improved using electric field strength of 2kV/cm, pulse period of 0.3 sec, pulse width of 5 µs, mild PEF treatment temperature of 45 C and flow rate of 60 mL / min. Reducing particle size of sodium chloride to submicron sizes (500 nm to 1900 nm) had a positive influence on some microbiological and sensory characteristics of surface salted cheese crackers. The sodium chloride micro and submicro particles maintained low counts in yeasts, no counts in molds and did not adversely influence quality attributes. The aim of this study was to formulate and characterize ?-tocopherol (?-T) and tocotrienol-rich fraction (TRF) entrapped in poly (lactide-co-glycolide) (PLGA) and chitosan covered PLGA (PLGA-Chi) based nanoparticles. In vitro uptake studies in Caco2 cells showed that PLGA and PLGA-Chi nanoparticles displayed a greater enhancement in the cellular uptake of ?-T and TRF when compared with the control without causing toxicity to the cells (p<0.0001). In summary, PLGA and PLGA-Chi nanoparticles may be considered as an attractive and promising approach to enhance the bioavailability and activity of poorly water soluble compounds such as ?-tocopherol and ?-tocotrienol. Collaborations (stations/members): Cristina Sabliov, Charles Boeneke, National Institute of Health. (NIH R01). Ravussin E. (PI), Greenway F (Co-PI), Martin C (Co-PI), Peterson C (Co-PI), Martin R (Co-PI), Keenan M (Co-PI), Aryana, K.J. (Co-PI), Marco M (Co-PI). “Role of slowly digestible starch in diabetes risk factors in pre-diabetic people.” 2012-2016 Granted $2,500,000. Maine (1) Sixty oysters-in-shell were measured for their shell dimensions and weight. The average length and width of the shell was 83.5 mm and 21.7 mm, respectively, while the gross wright was 55 gram. The shelled oysters were heat treated in the range of 40 – 90 °C in a water bath. Interestingly, the come-up-time in the shelled oysters was in the range of 41 – 50 min. This information helped understanding the changes in oyster quality parameters during come-up-time. (2) Quality attributes such as color, texture and pH of oysters at various times and temperatures combination was investigated and compared with commercially available oyster products. Color attributes of the raw and heat-treated oysters were analyzed using CIELAB color space i.e. brightness (L), redness/greenness (a) and blue/yellowness (b). As anticipated, brightness (L = 60) and yellowness/blueness (b = 13) of the raw was higher compared to heat-treated oysters. It was observed that the color attributes of heat-treated oysters changed faster due to Maillard browning reaction in the product. Measuring color attributes of the heat treated oysters using one point reading by hunter colorimeter may not provide accurate data as the color changes rapidly. Rapid change in color also provided higher variation in the color attribute data. Michigan 1: The impact of dynamic water activity on the efficacy of low-energy x-ray pasteurization and radio-frequency (RF) pasteurization of low-moisture foods is being tested at the pilot scale. Collaborations: The RF work is being conducted primarily at Washington State University, under the leadership of Dr. Juming Tang, as part of two USDA competitive grants (NIFSI and AFRI), with Dr. Marks as PI. 1c. Microbial inactivation models were developed (and are still being developed) as part of the following specific projects: a. Novel inactivation models for Salmonella in/on low-moisture foods are being developed and have been presented (as part of USDA-NIFSI and USDA-AFRI grants). b. The effects of process humidity and product water activity have been demonstrated, and the effects of product composition and structure are being tested, all aimed at developing improve methods for applying inactivation models to validation of pasteurization processes. c. The impact of rapid change of product (wheat flour) moisture content on the subsequent thermal resistance of Salmonella was quantified and reported (completed thesis and accepted journal article). d. The impact of inoculation methods on the resulting inactivation parameters for Salmonella in low-moisture foods was quantified and reported (MSU, WSU). e. The impact of data management strategies for low- and zero-count microbial survivor curves were demonstrated to significantly impact the resulting inactivation parameters estimated from those data. Bacterial transfer models are being developed for multiple processes, as part of the following specific projects: i. Collaborations: Jeyam Subbiah (Nebraska), Vasilis Valdramidis (U. Malta), Yoshiki Muramatsu (Tokyo University of Agriculture). Juming Tang (WSU) and Nathan Anderson (FDA) for low-moisture pasteurization work. 2. The microbial safety of low-moisture food products will be enhanced by improved methods for validating pasteurization processes. 3. Fresh-cut fruits and vegetables safety and quality will be enhanced. We expect number of outbreaks will be reduced. Missouri Tekwan is a traditional food from Palembang, Indonesia. Dried tekwan needs to be soaked in water for at least 6-9 h before cooking. This process is not only time consuming but also has safety and nutritional issues such as microbial growth and nutritional loss. This study used extrusion cooking and drying to prepare ready-to-cook tekwan. Tekwan was made using a 50 mm twin screw extruder with a circular die with 20 mm in diameter. The raw material used was prepared by mixing ground tilapia and tapioca at 1:1 ratio, and salt (2.8%) prior to extrusion. The experiment was a 3×3×2×2 factorial design consisting of three extrusion moistures (45, 50 and 55%), three extrusion screw speeds (50, 100 and 150 rpm), two types of post-extrusion process (with and without freezing) and two levels of final product thickness (1 and 1.5 cm). Screw speed had a significant effect on % degree of gelatinization, lightness, redness and hardness of extrudates, while extrusion moisture had a significant effect on moisture, redness, hardness and chewiness of extrudates. Freezing had a significant effect on moisture and density of dried tekwan. Thickness had significant effect on moisture, density, and rehydration assessment. Result showed that extrusion cooking improved water absorption of dried tekwan. Incorporating freezing as a pre-treatment of drying in tekwan production was beneficial to tekwan prepared from the conventional method, but not for that prepared from extrusion cooking. Recooked tekwan produced from a combination of 55% extrusion moisture, 100 and 150 rpm screw speed with a thickness of 10 mm had a texture profile closer to the fresh sample (extrudates) and fresh tekwan samples from the conventional method. Nebraska • Developed and validated a three-dimensional finite element model coupling electromagnetic, heat, and mass transport for describing multiphysics during microwave cooking of frozen microwaveable foods. • Working on radiofrequency processing, a novel thermal food processing technology, for improving microbiological safety of low-moisture foods such as egg white powder. • Collecting energy and water data in a beef packing plant to evaluate sustainability in beef industry. • Collaborations: Karen Schmidt, Kansas State University, Randy Phebus, Kansas State University, David Jones, University of Nebraska-Lincoln, Harshavardhan Thippareddi, University of Nebraska-Lincoln • The desorption isotherm profile of cooked pasta was measured using an automated vapor sorption analyzer at five temperatures from 20 to 60 °C, and over a water activity range of 0.1 to 0.9. • Working on radiofrequency processing, a novel thermal food processing technology, for improving microbiological safety of low-moisture foods such as egg white powder and peanut butter. Evaluated radiofrequency processing for pasteurization of shell eggs. • Developed and validated a three-dimensional finite element model coupling electromagnetic, heat, and mass transport for describing multiphysics during microwave cooking of frozen microwaveable foods. • Currently implementing blended learning techniques in the course, Engineering Properties of Biological Materials. • We have deployed our heat transfer and microbial models on the website, foodsafety.unl.edu so that food processors, students, and anyone could access and utilize these models. New Mexico Creation of scientific visualizations and industry outreach tools for several research projects, including “Pathogen Inactivation in Fresh Produce by Incorporation of Sanitizers into Existing Operations within the Produce-Chain.” ii.Collaborations (stations/members) Sudhir Sastry, The Ohio State University Gönül Kaletunç,The Ohio State University Ahmed Yousef, The Ohio State University Lester Wilson, Iowa State University Ohio • Kinetics of pectin methylesterase (PME) inactivation in tomato puree were investigated under conventional and moderate electric field (MEF) treatments using the Linearly Increasing Temperature Method (LITM). • Diffusion coefficients in porcine Longissiumus dorsi were determined in a diffusion cell at three frequencies (10, 50, and 100 Hz) and three electric field strengths (68, 136, and 189 V/m). • The prediction of thermo-physical properties (thermal conductivity, density, specific heat, and thermal diffusivity) of food based on composition is an important input for process design. • The quality of a frozen food is directly impacted by the air temperatures during storage and distribution. • Rinse effectiveness during CIP was correlated with Reynolds Number, and rinsing effectiveness increased with Reynolds Number. • The influence of the freezing process on food quality depends on temperature distribution within the product during the freezing process. • Combinations of gas and liquid sanitizers were investigated for inactivation of E. coli O157:H7 in baby spinach. Best combinations included the application and holding of liquid sanitizer for a half-hour, followed by vacuum cooling and application of ozone. • Hot break, cold break and commercially canned tomato juice was concentrated by vacuum concentration and solid-liquid separation (SLS). Most volatile levels in vacuum concentration greatly decreased initially then remained constant during further concentration. • Shelled raw peanuts were roasted using an oven at 163 to 204 °C, microwave, or oven and microwave combinations. The lethal effect of these treatments was investigated on peanuts inoculated with the Salmonella surrogate, Enterococcus faecium and stored at room temperature for 1 h, 24 h, or 7 d before roasting. • Powder separation causes uneven flavor and color on coated food products. Understanding the basis behind separation is needed to decrease separation. NaCl, starch, protein, sugar and mixtures of pairs of those powders were coated nonelectrostatically and electrostatically. Electrostatic coating generally decreased separation in the mixtures without NaCl. • Electrostatic atomization is one way to achieve even coverage of oil soluble flavor, color or nutrients; however, it is sensitive to changes in lecithin content, temperature and voltage. Soybean oil was sprayed on oil sensitive paper with 0–15% lecithin, at 4, 22 and 47C, 0–40 kV, to determine droplet distribution. Lecithin decreased electrical resistivity, increased viscosity, first increased then decreased surface tension and decreased droplet size. • Pressure ohmic thermal sterilization (POTS) involves ohmic heating of foods by applying an electric field under elevated pressure. This study demonstrates the potential to produce high quality shelf stable low-acid vegetable products using POTS. • A study was conducted to develop an integrated process lethality model for • pressure-assisted thermal processing (PATP) taking into consideration the lethal • contribution of both pressure and heat on spore inactivation. Oregon • Various food materials (berry fruit, surimi, tuna fish, and red meat) and food processing byproducts (fish bones, squid pens, fruit and wine grape pomace) were characterized in respect to their chemical compositions, bioactive compounds and functional properties. • Value-added products (surimi) and utilization of the food processing byproducts (?-chitosan extracted from squid pens and food items fortified with pomace) were developed and evaluated. • Different thermal and non-thermal processed technologies were evaluated for their capabilities to ensure food safety and quality. This included high hydrostatic pressure processing for ensuring food safety of red meat, thermal processing of tuna fish, and edible coatings for retaining natural food pigment and antioxidants during thermal and non-thermal processing. • Outreach programs were implemented to disseminate the research findings and help the stakeholders for ensuring their product safety and quality. This includes HACCP workshop, surimi school, better food processing control school, food quality analysis short course, etc. In additional, websites were developed for delivering the latest information to the stakeholders. Pennsylvania • Swamy Anantheswaran: Cocoa is a widely and highly consumed food commodity throughout the world. It is also a rich source of polyphenols, found to exceed that of green tea and red wine. Cocoa polyphenols are primarily flavan-3-ol monomers and proanthocyanidins (PaCs) with degree of polymerization (DP) previously identified up to ten. Ongoing research suggests that these PaCs may account for the potential health beneficial effects of cocoa. • Studies were conducted to investigate the effect polymer concentration (0.5% and 1.0%), chitosan molecular weight (low and high) and ratio of chitosan to alginate (expressed as 33%, 50% and 66% alginate fraction) on the release of nisin from chitosan-alginate films using a two-temperature disc agar diffusion bioassay. Additionally, an interaction study was conducted to determine the ratio at which the polymers showed maximum interaction, by measuring the specific viscosity of dilute chitosan-alginate solutions after centrifugal separation of bound polymers. The polymer concentration and alginate fraction had a significant effect (p<0.05) on nisin release. • Turbidity measurements confirmed high level of complexation between chitosan and alginate at alginate fractions between 66% to 75%, resulting in higher levels of unbound nisin in the films. • Ali Demirci: For cleaning-in-place (CIP) milking systems, the cleaning mechanisms of milk system by electrolyzed oxidizing (EO) water was continued by using a lab-scale milking system simulator. Building of mathematical model is still in progress. Also, the one-step cleaning approach by using neutralized (blended) EO water was evaluated as opposed to two-step approach with alkali and acid washes. Results demonstrated that blended EO water was able to do successful CIP cleaning of the pilot milking system. Tennessee We continued to study various delivery systems of antimicrobials, nutraceuticals and pigments and characterized physical, chemical, biological, and microbiological properties of these systems, as well as technologies improving heat stability of whey proteins and dispersion stability of corn zein nanoparticles. Dr. Zhong has the following projects under objective 1: (1) Delivery systems to improve effectiveness of lipophilic antimicrobials. In the USDA NIFA, OREI, and Center for Produce Safety projects, we continued to study various delivery systems of lipophilic antimicrobials to improve microbial food safety and quality of food products during shelf-life storage. (2) Technologies for improving heat stability of whey proteins. We continued to characterize physicochemical properties of whey proteins after glycation with various reducing sugars for high protein beverage applications. (3) Delivery systems for incorporation and protection of lipophilic nutraceuticals in beverages. Various colloidal systems are studied to improve the stability and bioactivity of nutraceuticals for functional foods applications. (4) Natural pigments: interactions with food biopolymers, delivery in beverages, and removal from cheese whey. (5) Structure-function correlations of food biopolymers and functionality improvement. Physical properties of food biopolymers, focusing on nanoscale structures, are studied to elucidate and improve macroscopic properties such as dispersibility, turbidity, and rheology. Collaboration: Dr. MaryAnne Drake at NC State and Dr. Salam Ibrahim at North Carolina A&T. Washington • Study influence of oxygen transmission rates of packaging polymers on chemical quality and shelf-life of thermally sterilized and pasteurized food products. The findings may guide food processing industry for design of polymeric packaging for food products. • Investigated UV-C inactivation of pathogenic microorganisms on plant surfaces of varied morphology. The study provided insight into interactions between plant surfaces and pathogens. • A US Army Natick Soldier Center team led by Dr. Tom Yang has completed a 10 week storage (at 7 and 10 C) sensory tests on three products processed using a pilot scale 915 MHz microwave assisted pasteurization (MAPS) system developed by Tang’s group as a part of USDA NIFA project. The process was designed to achieve 6-log reduction of C. Botulinum E spores (90C for 10 min). The product held quality well over the tested period. Microbial safety of the products was verified by independent tests in a commercial microbial laboratory and in a University of Tennessee (UT) laboratory (Dr. Michael Davidson). Two major US food companies are in discussion with Tang’s laboratory to explore the use of MAPS for chilled meals for retail markets. • Tang’s laboratory has evaluated quality of food processed by MAPS. The process was designed for control of HAV (75C 10 min, data from UT). Those processes are suited for chilled products with shelf-life of 10 days at 8C and applicable to small food companies catering urban population. Wisconsin Gunasekaran: A “green” synthesized nanomaterial-based thermal history indicator (nTHI) for monitoring low-temperature storage is proposed. The nTHI was synthesized and optimized in an environmental-friendly way by using gelatin, an edible protein, as a reducing reagent as well as stabilizer to control the growth of gold nanoparticles. The size and shape of the gelatin-functionalized AuNPs were characterized by UV-vis spectrophotometery and transmission electron microscopy (TEM). The nTHIs subjected to a low-temperature storage test revealed that those experiencing higher temperature treatments exhibited more intense color change. The observed color changes in nTHI can provide information regarding thermal history that it had experienced. Hartel: Based on previous work, we know that commercial ice creams exhibit a wide range of melting properties. Although ice cream melting is influenced by numerous factors, we hypothesize that the nature of fat globule clusters (due to fat destabilization during freezing) plays an important role, all else being equal. We have designed experiments to create ice creams with a wide range of fat globule cluster numbers and size to further evaluate their effects on melt-down properties. These studies are underway with results expected within the year. We also have begun a more fundamental investigation on arrested (or partial) coalescence of fat globules (USDA funded) to better understand how these clusters form during processing. We are investigating which parameters influence arrested coalescence in order to better control the process.

Publications are attached as a PDF file.