Food structure - Effects on food functionality

Transcription

1 Food structure - Effects on food functionality Dr Bryony James Director, Research Centre for Surface and Materials Science (RCSMS) Department of Chemical and Materials Engineering University of Auckland Auckland New Zealand

2 Introduction Food engineering from the perspective of material properties Food structure affects food functionality as a result of texture. Food structure/food processing is also an important consideration as it protects (or otherwise) functionality.

3 Soft Matter approach Combination of physics, biology and chemistry. Essential to include aspects of materials science and engineering.

4 Properties! texture (mouthfeel)! taste/aroma! nutrition/functionality Structure! size of air spaces! granulometry! emulsion dispersion Processing! ripening! freezing! gelling

5 Properties Salivation/flavour release/swallowing Structure Mastication Kikunae Shintaro Ikeda Texture Kodama Akira Kuninaka All the mechanical, geometrical and surface attributes of a product Sea kelp bykatsuoshiitake perceptible means of mechanical, bushi tactile, visual and auditory receptors Glutamate 5 - inosinate 5 - guanylate Discovery of major 3 umami taste substances Acceptability Food choices

6 Structure Length scales in foods Molecular organisation Supramolecular organisation Food structure by processing Flavour compounds Emulsions Food products Water Carbohydrates Proteins Cassein micelles Food foams Food powders 1A 1nm 10nm 100nm 1µm 10µm 100µm 1mm 1cm Ubbink et al Soft Matter, 2008,

7 Structure Starch Ubbink et al Soft Matter, 2008, 4, James, TIFST, 2009, 20, Chocolate bloom Mayonnaise James, TIFST, 2009, 20,

8 Tools and Techniques Structural analysis Scanning Electron Microscopy (inc. cryo) Environmental SEM (wet samples!) In situ mechanical testing (sample in native state) Environmental STEM (high resolution imaging of emulsions) Confocal laser scanning microscopy Mechanical/rheological properties Sensory panels 50µm

9 Structure 50µm

10 Structure

11 Structure

12 Food Structure Platform Develop fundamental knowledge Explore link between solid food structure & sensory perception Manipulate solid food structures to enhance sensory appeal Develop new models for predicting the effects of food structure properties on the sensory qualities of foods Approach Design mono-attribute structures Quantify their properties Measure structure deformation and breakdown in the mouth Model the link between the two with Plant & Food Research Massey University

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14 Sensory and Engineering Correlations 1.0 Correlation with Eng. Panel PC Brittle Hard Stiff Brittle Chewy Crisp Crumbly Crunchy Firm Hard -1.0 Viscoelastic Tough Correlation with Eng. Panel PC1 Upcoming J. Text Stud paper

15 Sensory and Engineering Correlations 1.0 Correlation with Eng. Panel PC Coarse Mouthcoating Stringy Correlation with Eng. Panel PC1

16 Model food structure Ingredients Sensory hardness 1 st bite with incisors 1 st chew with molars during chew down)

17 Model food structure Food breakdown during oral processing Time intensity of textural attributes Real and synthetic bolus to investigate point of swallow Structure during mastication measured using instrumental techniques and related to sensory perception

18 Oral breakdown Start of mastication Just prior to swallowing

19 Instrumental tests 3-point bend Back extrusion 1 st bite with incisors 1 st chew with molars during chew down) Gujral, H.S. and N.S. Sodhi, Back extrusion properties of wheat porridge (Dalia). Journal of Food Engineering, (1): p

20 Collaborations Manipulating mastication by altering structure Altering nutritional outcomes by altering mastication Preserving functional ingredients by solid food structuring

21 The missing links Food science Functional foods Nutrition Food Engineering

22 The anti-inflammatory effects of Ω-3 PUFA have been associated with disease remission. However, there have been variable data in clinical trials variability in trial design has been suggested as a major factor, we suggest that variability in processing and presentation of the products may be equally or more important.

23 Preparation Source Formulation Production Shelf life eg. microencapsulation non-thermal processing manipulating mastication Structuring Mastication Ingestion Digestion

24 Collaborations Professor Mohammed Farid Novel processing routes Dr Bryony James Food structure/property linkages Dr Darrell Patterson Membrane separation Dr Emma Patterson Immobilised enzymes Dr Filipa Silva Microbial inactivation/nutraceuticals Dr Paul Stevenson Foam fractionation Associate Professor Brent Young Process control Dr Bronwen Smith Plant based foods, dietary fibre Dr Siew Young-Qwek Lipids, product development Professor Lynnette Ferguson Nutrition/Nutrigenomics

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