Water relations in food-food carbohydrates

Aims

·   To provide a thorough understanding of the nature and properties of water in aqueous solutions in the presence of different solutes in order to understand the central role of water in biological matter and food systems. ·   To examine water-solute interactions at a molecular and macroscopic level. ·   To discuss the concept of ‘water activity’ in the context of food stability. ·   To introduce the concepts of ‘molecular mobility’, ‘glass transition’ and ‘state diagram’ and their relevance to product formulation, processing and shelf life of food items. ·   To provide an in depth understanding of molecular and supermolecular structures of food carbohydrates. ·   To offer an insight into the function of carbohydrates in foods and to explore the structure-functionality relations of these constituents. ·   To offer an insight into the analytical (qualitative and quantitative) aspects of carbohydrates. ·   To discuss the molecular and physical chemistry aspects of starch hydrocolloids.   

Prerequisites

Good Knowledge of General Chemistry and Organic Chemistry
 
  

Learning Outcomes

Students will acquire advanced knowledge related to the molecular and physical chemistry aspects of water relations in food as they apply to product quality changes and shelf life.   ·        Students will be exposed to equilibrium and kinetic aspects of physical and chemical processes occurring in food matrices.   ·      Students will be able to develop skills in product formulation with food carbohydrates for targeting specific functionalities.   ·        Students will be exposed to analytical methodology to isolate, characterize (molecular and physical state) and quantify food carbohydrates.   ·        Students will learn about the structure and functionality of starch polymers.      

Syllabus

The lectures will cover the following topics:   1.      Molecular structure and physical properties of water 2.      Water – solute interactions 3.      Water activity (aw) – food stability 4.      Water sorption phenomena 5.      The sorption isotherm and their use in prediction of packaging requirements and sorption characteristics of composite food matrices 6.      Physical states and transformations in food systems (temperature and water effects) 7.      Glass transition of amorphous food materials – State diagrams 8.      Concepts underlying the molecular mobility approach to food stability 9.      Technological aspects of molecular mobility: drying, freezing, freeze-drying 10.  Glass – transition  vs. aw  vs. water content 11.  Classification and functional properties of hydrocolloids 12.  Molecular structures and conformational aspects of carbohydrates – the role of solvent 13.  On the diversity of molecular structures of food polysaccharides 14.  Supermolecular assemblies – the functional state of polysaccharides 15.  Functions of carbohydrates in foods 16.  Fat replacers 17.  Isolation and characterization of food carbohydrates 18.  Physical, chemical and enzymic methods of analysis of carbohydrates 19.  Structural aspects of starch macromolecules 20.  State transformations of starch materials – role of water 21.  Technological aspects – applications: product formulation, stability  

Content Delivery

The course will combine basic knowledge of Physical Chemistry and Food Chemistry with applications on quality aspects and stability of food products.  After a thorough discussion on water relations in a food matrix, the usefulness of ‘‘water activity’’ and ‘‘glass transition – molecular mobility’’ as reliable indicators of food product stability will be fully explored. In the second part of the course, the molecular aspects and function of carbohydrates as ingredients in food products will be examined with an emphasis on structure-functionality relations. Analytical methodologies for isolation, characterization and quantification of carbohydrates will be also addressed. Moreover, the structure, physical state and properties of starch macromolecules will be discussed in the context of temperature- and water content-dependent state transformations of these constituents.        

Coursework And Assignment Details

will prepare (in groups) a short presentation at the last day of the course. A period of three days will be given for preparing this presentation. This assignment will carry up to 20% of the total grade of the course. Clarity and thoroughness of presentation will be the main criteria for this assignment. The rest 80% of the total grade will derive from the written exams that will take place after the end of the course. The exams will include both short essay and true or false questions with all answers to be justified.  All the material presented in the lectures will be included in the exam material. Auxiliary material will be provided for better understanding the lectures material.