Presentation on theme: "UNIVERSITY OF MINNESOTA"— Presentation transcript:
1 UNIVERSITY OF MINNESOTA Probe Structure-function Relationships in Foods Using Nuclear Magnetic ResonancePaul Chen, Ph.D., Senior Research AssociateDepartment of Bioproducts and Biosystems EngineeringProgram DirectorCenter for BiorefiningUNIVERSITY OF MINNESOTA
2 OutlineIntroductionProbe structure-function relationships in foods using NMR techniquesFuture research and teaching in cereal science and technology
3 Agric-product Processing Structure-functionFunctional and health-promoting ingredientsShelf life of foodsHeat and mass transferNon-thermal processesBiorefining process developmentModelingAreas of InterestAgric-product ProcessingPomologyFood ScienceBSMSPhD198319861990199419972002BotanyPhysiologyBiochemistryMicrobiologyGeneticsBreedingPathologyPostharvest handlingFood chemistryFood nutritionFood processingFood storageCoursesFacultyPost-docRes. Assoc.Sr. Res. Assoc.LMTEMCryo-SEMX-ray microanalysisViscometryTPAColor analysisMass transferMath modelingTechniquesResearchTeachingPapersReportsGrantsServicesResponsibilities
4 Snapshots of Some Projects Structure-function relationships of highly refined cellulose (HRC) – dietary fiberFunctional and health-promoting ingredients in red corn (anti-oxidant), buckwheat (fagopyritol), and lily (soluble polysaccharides)Hardening of dehydrated fruits in breakfast cerealsStickiness of tortilla wrapsWater migration between pizza crust and toppingsRheological and water properties of flour doughFoods/ingredientsFunctionalCereals/Flour-based Foods
5 Snapshots of Some Projects (cont’d) Staling of baked goods and cooked wild riceCaking of powered foodsFirming of high protein bars, caramel candiesOzone-aided corn steeping processOzone treatment for barley maltingFusarium scab and mycotoxin in wheatNon-destructive analysis of sweet corn maturityWater distribution in corn kernel and soybeans during soaking and dryingEffect of storage on dry bean soakingFood polymerScienceGrain Processing
6 - Dr. Allen Levine, Prof. and Head, FScN 2004 Annual Report Structure-Function“Our strength resides in two signature areas:The structure and function, including sensory and microbial properties, of healthy, safe, and high quality foods; andThe impact of nutrients and bioactive food components on chronic diseases and obesity across diverse populations.”- Dr. Allen Levine, Prof. and Head, FScN 2004 Annual Report
7 Structural Elements Chemical structure (molecular level) Small chemicals: water, salts, minerals, simple sugars (e.g., plasticizers in state transition)Macromolecules: proteins, complex carbohydrates (e.g., starch retrogradation vs staling)Physical structureMicroscopic level: cellular structure, food matrixMacroscopic level: dimensions, multi-components (e.g., particulate foods in soup, sandwich)
8 Functional Elements Physical Physiochemical Enzymatic and non-enzymatic reactionsDigestibility and bioactivitiesMicrobial deteriorationDisease preventionTextureViscosityCohesiveness, stickinessHydrationDehydrationHeating/coolingSolubilityDiffusionDeformationPorosityMolecular mobilityGeletinizationCrystallizationMeltingPhase/state transitionProperties of waterEmulsification and foamingBiological & HealthPhysicalRheologicalPhysiochemicalProcessing
9 NMR Relaxometry & MRI Major relaxation parameters: A function of: Signal intensity – proportional to proton densityRelaxation times: spin-lattice relaxation time (T1) and spin-spin-relaxation time (T2) – related to molecular mobilityA function of:Concentration of proton-containing compounds (e.g., water & lipids)Chemical and physical structuresTemperatureIn magnetic resonance imaging (MRI), spatial information is encoded into the signal intensity, T1 and T2
10 NMR and MRI Non-destructive Non-invasive Temperature control MARAN DRX, 21.4 MHz, Resonance Instruments, Oxon, UK
11 Large Bore MRIWhole food itemsSmall processing devicesSmall animals
12 Analysis of Structure-function in Foods Using NMR Techniques Dough rheologyFirming of baked and boiled starch-based foodsFirming of food barsCaking of dry powdersPhysiochemical properties of extrudates, breakfast cereals, wrapsPhysiology of sweet cornFreezing of doughHeat and mass transfer during soaking, drying, cooling, and heating
13 Examples Chemical structure changes Starch retrogradation Bread stalingWater-solid interactionsState transitionCaking of powdered ingredientsMulti-component systemProcess modelingHeating of particulates-in-liquid system
14 Chemical structure changes Starch retrogradation Bread staling
15 Starch Retrogradation and Bread Staling Native crystalline starchGelatinizationAmorphous starchRetrogradationCrystalline starchChange in Firmness of Crumb During Storage
16 NMR Relaxation Properties of Bread Crumb To Analyze change in the properties of water in bread-with-crust with normal packagingMobilityIntensityLow mobility waterMedium mobility waterHigh mobility water
17 Structure transformation and properties of water Change during StalingMobilityAmountCrust & SurroundingsGluten transformationreleasing waterPlasticizationWater incorporated into crystalline amylopectinFraction 3Hi mobilityFraction 2Me mobilityFraction 1Lo mobility
18 Water-solid interactions State transition Caking of powdered ingredients
19 State TransitionGlass-rubber transition and glass transition temperatureTexture, physiochemical changes, chemical and biological reactionsMeasurement: DSC, DMA, DMTA, ……Water - plasticizer and probeNMR based techniques
20 NMR State DiagramTemperature increasingRelationship between spin-spin relaxation time (T2) and temperature in PLASpin-spin relaxation time (T2) as a function of temperature (T) in maltodextrins (DE15). The legends indicate the grams of water in 1kg maltodextrins.
21 ImplicationsNMR-determined transition temperatures are generally lower than DSC-determined TgMobility is detected below DSC-determined TgThis may be an explanation for reported chemical and biological activities below DSC-determined TgIt is possible that NMR is more temperature sensitive.
22 NMR state diagrams for powdered ingredients Evaluating Caking Tendency of Dry Powered IngredientsNMR state diagrams for powdered ingredients
23 TTranABCDTemperature (°C)T2KPTKBTSchematic demonstration of four different temperature-T2 curve patterns for the dry soup powders.Caking was found to be a function of curve pattern characterized by transition temperature (TTran), slope before transition (KBT), and slope post transition (KPT). This technique is being used by a company for caking prediction and development of caking resistant formula.
24 MRI & Process Modeling Analysis of: Model verification Moisture, fat, and mobility distribution in foodsWater movement during storage, soaking, dryingTemperature mapping/heat transferModel verificationMathematical modeling – numerical simulationVerification by experiment data from MRI
25 2D MR ImagesKiwifruit: Conversion of starch and pectin to soluble compounds during maturity of the fruit has an effect on the structure and mobility of water in the tissue.RawMatureEgg: Cooking caused egg protein to denature, which reduced the mobility of water.RawCookedHardSoftBruisedStrawberry: Softening (high maturity) and physical damages increased the mobility of water in the tissue.
26 2D MR Images of DoughCalculation of volume and distribution of air bubblesLow resolutionHigh resolution
27 3D MR Images of Bagel with Raisins Low S/NHigh S/NBagel with raisins13 raisins counted
28 3D MR Images of Extrudates Ununiform distribution of water and mobility– responsible for irregular shapes of baked products?
29 Slice 1Slice 2Raw0h1.5h3h6h9h12hLowHighMR images showing that moisture distribution in puffed rice kernels during temperingbecame more uniform with increasing tempering time.
30 Multi-component system Process modeling Ohmic heating of particulates-in-liquid system
31 Modeling of Ohmic Heating and MRI Verification Ohmic heating is efficient because it does not rely on heat transferSuitable for cooking/sterilization of solid particles in liquid (e.g., mixture of meats, carrots, potatoes and soup)Difficult to demonstrate actual sterilization value in multi-component systems such as particulates-in-liquidModeling provides insight into the heating behaviors of ohmic processInstrumental verification is important
34 Model Scheme Generated by FemLab based on Finite Element Method (FEM) 0.02-0.02m-0.020.02Cross-section at vessel centerMesh statistics:Number of nodes: 5643Number of edges: 6139Number of elements: 26599
35 Model Prediction vs. MRI Map (Case #1, 120 V) 10 Min40 Min50 Min
36 Model Prediction vs. MRI Map (Case #2, 240 V) 2.5 Min7.5 Min12.5 Min
37 Model Prediction vs. MRI Map: Hot and Cold Spot (Case #1, 120 V) 8090Model:potatoMRI:potatoModel:liquidMRI:liquid50010001500200025003000350010203040506070500100015002000250030003500102030405060708090Model:potatoMRI:potatoModel:liquidMRI:liquidHeating time (s)Temperature (C)MRI:liquidC)Model:liquidTemperature (MRI:potatoModel:potatoHeating time (s)
38 Model Prediction vs. MRI Map: Hot and Cold Spot (Case #2, 240 V) MRI: liquidModel: liquidMRI: potatoModel: potato
39 SummaryWe can understand the stability, properties, and processes of foods through the analysis of structure-function relationships.Future research should also look into structure-function relationships in biological activities and bioavailability of nutrients.There exist many opportunities for collaborative research with faculty in FScN and the food industry in this signature area.
40 Acknowledgements Thank You! Dr. Roger Ruan Dr. Ted Labuza Dr. Gary FulcherDr. Paul AddisDr. Eric BastienDr. Joe WarthesenDr. Zata VickersDr. Susan RaatzDr. Bernhard van LengerichDr. Victor HuangDr. Peter PesheckDr. Phil PerkinsDr. Kehua ChangDr. Lun YiMr. Zhenzhong LongMr. Li XuDr. Cheng ZouDr. Brock LundbergDr. Xiaofei YeDr. Myonsoo ChungDr. Hanwu LeiMr. Jun HanMr. Lide ChenMs. Qin LiuDr. Su NingDr. Jinning QiMs. Hong LiMr. Ray MillerMr. Fred RigelhofMs. Regina de BarrosMs. Michele FrenchMr. Shaobo DengMr. Fei YuMs. Yun LiThank You!
42 Cereal Chemistry & Technology: Bridging Health & Consumer Preferences throughFuture Research & Teachingin the Department of Food Science and NutritionUNIVERSITY OF MINNESOTA
43 President’s Initiative on Healthy Foods, Healthy Lives The four priority areas:To utilize and advance knowledge about the integration of agriculture, food science, nutrition, and medicine to promote healthy lives;To emphasize prevention of diet-related chronic diseases and obesity through diet, exercise, and human behavior;To enhance food safety at all stages, from farm to table; &To inform public policy.The University of Minnesota is uniquely positioned as a national leader for an initiative focusing on food and health promotion, being one of only two U.S. universities to integrate six key components on one campus: agriculture, human nutrition, medicine, public health, exercise science, and veterinary medicine.
44 My VisionDevelop nationally and internationally recognized cereal research and education programs at the University of MinnesotaDevelop specialized expertise in whole grains and phytochemicals from cerealsServe the local cereal industry by meeting their R&D needs and providing first class graduatesI understand that our food science student enrollment is low at moment. On the other hand, there is a great need for graduates trained in food science.But by working with all faculty members and the industry, through public education, A food scientist is not a highly trained chef!
45 Research Areas Cereals & Health Structure & Functions Process Dev & ModelResearch Areas
46 Half of the Grains Whole Grains New USDA Food PyramidHalf of the Grains Whole Grains
47 Offer healthy foods without sacrificing sensory quality Challenge:Offer healthy foods without sacrificing sensory quality
48 Whole Grain Issues & Opportunities Unaware of the health benefitsPoorly publicized definitionPoor sensory quality: “Nothing is better than good old white bread”Limited varieties and expensiveShort shelf stabilityProcess modification required
51 “Whole Grain Additives” Identification of ingredients and their health benefitsExtraction, purification, characterizationIncorporation into grain productsTesting/trialsRationaleAdd whole grain benefits to white flour products
52 Potential ProjectsExtraction and characterization of functional ingredients (“whole grain additives”) from cerealsGeneration and evaluation of resistant starch using extrusion cookingEvaluation of incorporation of whole grains and “whole grain additives” into cereal-based products in terms of sensory quality and health benefits preservationSafety issues in cereal foods (mycotoxin, acrylamide)In vivo study and modeling of fluid-mechanics and physiochemical properties of cereal foods in the digestive system in small animals using MRIProcess modeling and improvement
54 Publications Food and cereal science and chemistry, food Engineering Nutrition, biological and health scienceInterinstitutional co-authorships
55 Teaching Experience Food Technology SCAU, China, 1986-1990 Preservation & Processing of Fruits & Vegetables SCAU, China,Cereal Beverages AACC short course "Asian Food Technology," Baltimore, 1996Managing Water in Food and Biological Systems BAE 8703, UMN, presentBiological Processing Engineering BAE 4713, UMN, 2006
56 Teaching in FScNFSCN Grains: Introduction to Cereal Chemistry and TechnologyTeach other courses related to structure-function and preparation of functional ingredients and foodsNew course development
57 Extension and Outreach Public educationServe the industryProcess and product developmentProblem solvingSeminars/workshops
58 Collaborate as a “Whole” Future of Whole GrainsNutrition – discover new benefits, verify current claims, provide better definitionConsumer research – understand consumers’ expectation, hurdles to acceptanceProcess and product development – develop/modify processing technology, better quality and more varietiesAgronomy and breeding – screen existing grains, develop new grains with better quality through genomics
60 SummaryThe breadth and depth of my research experience and expertise allow me to establish strong research programs in the field of cereal chemistry and technologyMy research will promote the consumption of cereal products that offer health benefits with high sensory qualityI have the desire, capability and necessary interface to collaborate with researchers in different fieldsI am committed to enhance the teaching, extension and outreach programs in this departmentI have a good track record of research, grants, and publicationI work hard and will do my best to make a significant contribution to this great department.
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