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26 February 2025, 13:30 - 17:00 hrs.
Latest insights about starch structure, phase transitions, modification and functionality
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Conducted by:
Assoc Prof Mario Martinez
Dept of Food Science
Aarhus University
Adjunct Assoc Prof
Whistler Center for Carbohydrate Research
(Purdue Universitry USA) |
Mario Martinez research program is on translational biopolymer science, approaching the structure and function of food biopolymers, their binding potential to plant secondary metabolites, the elucidation of their complex structural biochemistry, and their food structuring behaviour. Mario's team also works on understanding the fundamental aspects related to the structuring technologies of plant-based foods (e.g., using extrusion processing) as well as the establishment of green derivatization and compatibilization routes of polysaccharides into high-performing packaging materials. Mario is adjunct Associate Professor at the Whistler Center for Carbohydrate Research (Purdue University, IN, USA). All in all, Mario´s team relies on coherent and focused food system approaches to find common ground for health and environmental sustainability.
Topics covered
1. Main Features of Starch as a Polysaccharide and Hydrocolloid
The entire seminar will highlight four mains characteristics that makes starch the most used polysaccharide in the food industry:
1) it is an alpha-glucan,
2) abundant,
3) its molecules are “huge” and,
4) its nativity resembles a sponge behaviour.
2. Starch Biosynthesis
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Biosynthesis Pathway: Overview of the biochemical pathway of starch biosynthesis in plants, including the roles of enzymes such as ADP-glucose pyrophosphorylase, starch synthases, branching enzymes, and debranching enzymes.
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Formation of Granules: Description of how starch granules are formed within plant cells, with emphasis on the distinct structures in different plants.
3. Starch Structure and Composition
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Granular Structure: Microscopic and macroscopic structure of starch granules, including size, shape, and crystalline regions (A, B, and C-type).
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Amylose vs. Amylopectin: Detailed comparison of these two starch components, including their molecular structures, branching patterns, and functional implications.
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Molecular Architecture: Chain length distribution and molecular weight: introduction to analytical techniques and molecular structure-function relationships.
4. Starch Functionality
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State and phase transitions: Interplay between heat and moisture.
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Functional Properties: Key functional properties such as gelatinization, pasting (swelling) and retrogradation.
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Impact of Processing: How different processing methods (e.g., heating, cooling, shear) affect starch functionality in various applications.
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Practical example: Mesoscale structure of gluten-free bread with starch.
5. Starch Conversions and Modifications
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Physical Modifications: Acid-modified or thin-boiling starches, dextrins, pre-gelatinization, annealing, and heat-moisture treatment to alter starch properties.
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Chemical Modifications: Introduction to starch modifications including cross-linking, substitution (e.g., acetylation, hydroxypropylation), and oxidation, and their impacts on starch performance.
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Novel greener chemical methods for starch modifications: organocatalysts and deep eutectic solvents.
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Enzymatic Modifications: Use of enzymes like amylases, glucosidases, and pullulanases to modify starch structure for specific applications.
6. Starch Nutritional Metrics
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How is digestible starch digested and how can be measured in vitro?
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“A healthy label” vs “a positive metabolic response”
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Resistant Starch: Introduction to resistant starch types (RS1-RS5), their health benefits (e.g., gut health, blood sugar regulation), and sources.
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Dietary Fiber and Prebiotic Effects: Starch's role as a dietary fiber source and its prebiotic effects on the gut microbiome.
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Impact of Starch on Health: Discussion on the implications of starch consumption on weight management, metabolic health, and chronic diseases. |
